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c3a326a657
linux/fs/ext4/mballoc.c
Aneesh Kumar K.V c3a326a657 ext4: cleanup mballoc header files 
Move some of the forward declaration of the static functions
to mballoc.c where they are used. This enables us to include
mballoc.h in other .c files. Also correct the buddy cache
documentation.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2008-11-25 15:11:52 -05:00

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/*
* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
* Written by Alex Tomas <alex@clusterfs.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public Licens
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
*/
/*
* mballoc.c contains the multiblocks allocation routines
*/
#include "mballoc.h"
/*
* MUSTDO:
* - test ext4_ext_search_left() and ext4_ext_search_right()
* - search for metadata in few groups
*
* TODO v4:
* - normalization should take into account whether file is still open
* - discard preallocations if no free space left (policy?)
* - don't normalize tails
* - quota
* - reservation for superuser
*
* TODO v3:
* - bitmap read-ahead (proposed by Oleg Drokin aka green)
* - track min/max extents in each group for better group selection
* - mb_mark_used() may allocate chunk right after splitting buddy
* - tree of groups sorted by number of free blocks
* - error handling
*/
/*
* The allocation request involve request for multiple number of blocks
* near to the goal(block) value specified.
*
* During initialization phase of the allocator we decide to use the group
* preallocation or inode preallocation depending on the size file. The
* size of the file could be the resulting file size we would have after
* allocation or the current file size which ever is larger. If the size is
* less that sbi->s_mb_stream_request we select the group
* preallocation. The default value of s_mb_stream_request is 16
* blocks. This can also be tuned via
* /proc/fs/ext4/<partition>/stream_req. The value is represented in terms
* of number of blocks.
*
* The main motivation for having small file use group preallocation is to
* ensure that we have small file closer in the disk.
*
* First stage the allocator looks at the inode prealloc list
* ext4_inode_info->i_prealloc_list contain list of prealloc spaces for
* this particular inode. The inode prealloc space is represented as:
*
* pa_lstart -> the logical start block for this prealloc space
* pa_pstart -> the physical start block for this prealloc space
* pa_len -> lenght for this prealloc space
* pa_free -> free space available in this prealloc space
*
* The inode preallocation space is used looking at the _logical_ start
* block. If only the logical file block falls within the range of prealloc
* space we will consume the particular prealloc space. This make sure that
* that the we have contiguous physical blocks representing the file blocks
*
* The important thing to be noted in case of inode prealloc space is that
* we don't modify the values associated to inode prealloc space except
* pa_free.
*
* If we are not able to find blocks in the inode prealloc space and if we
* have the group allocation flag set then we look at the locality group
* prealloc space. These are per CPU prealloc list repreasented as
*
* ext4_sb_info.s_locality_groups[smp_processor_id()]
*
* The reason for having a per cpu locality group is to reduce the contention
* between CPUs. It is possible to get scheduled at this point.
*
* The locality group prealloc space is used looking at whether we have
* enough free space (pa_free) withing the prealloc space.
*
* If we can't allocate blocks via inode prealloc or/and locality group
* prealloc then we look at the buddy cache. The buddy cache is represented
* by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
* mapped to the buddy and bitmap information regarding different
* groups. The buddy information is attached to buddy cache inode so that
* we can access them through the page cache. The information regarding
* each group is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are stored in the
* inode as:
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information. So for each group we
* take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE /
* blocksize) blocks. So it can have information regarding groups_per_page
* which is blocks_per_page/2
*
* The buddy cache inode is not stored on disk. The inode is thrown
* away when the filesystem is unmounted.
*
* We look for count number of blocks in the buddy cache. If we were able
* to locate that many free blocks we return with additional information
* regarding rest of the contiguous physical block available
*
* Before allocating blocks via buddy cache we normalize the request
* blocks. This ensure we ask for more blocks that we needed. The extra
* blocks that we get after allocation is added to the respective prealloc
* list. In case of inode preallocation we follow a list of heuristics
* based on file size. This can be found in ext4_mb_normalize_request. If
* we are doing a group prealloc we try to normalize the request to
* sbi->s_mb_group_prealloc. Default value of s_mb_group_prealloc is set to
* 512 blocks. This can be tuned via
* /proc/fs/ext4/<partition/group_prealloc. The value is represented in
* terms of number of blocks. If we have mounted the file system with -O
* stripe=<value> option the group prealloc request is normalized to the
* stripe value (sbi->s_stripe)
*
* The regular allocator(using the buddy cache) support few tunables.
*
* /proc/fs/ext4/<partition>/min_to_scan
* /proc/fs/ext4/<partition>/max_to_scan
* /proc/fs/ext4/<partition>/order2_req
*
* The regular allocator use buddy scan only if the request len is power of
* 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
* value of s_mb_order2_reqs can be tuned via
* /proc/fs/ext4/<partition>/order2_req. If the request len is equal to
* stripe size (sbi->s_stripe), we try to search for contigous block in
* stripe size. This should result in better allocation on RAID setup. If
* not we search in the specific group using bitmap for best extents. The
* tunable min_to_scan and max_to_scan controll the behaviour here.
* min_to_scan indicate how long the mballoc __must__ look for a best
* extent and max_to_scanindicate how long the mballoc __can__ look for a
* best extent in the found extents. Searching for the blocks starts with
* the group specified as the goal value in allocation context via
* ac_g_ex. Each group is first checked based on the criteria whether it
* can used for allocation. ext4_mb_good_group explains how the groups are
* checked.
*
* Both the prealloc space are getting populated as above. So for the first
* request we will hit the buddy cache which will result in this prealloc
* space getting filled. The prealloc space is then later used for the
* subsequent request.
*/
/*
* mballoc operates on the following data:
* - on-disk bitmap
* - in-core buddy (actually includes buddy and bitmap)
* - preallocation descriptors (PAs)
*
* there are two types of preallocations:
* - inode
* assiged to specific inode and can be used for this inode only.
* it describes part of inode's space preallocated to specific
* physical blocks. any block from that preallocated can be used
* independent. the descriptor just tracks number of blocks left
* unused. so, before taking some block from descriptor, one must
* make sure corresponded logical block isn't allocated yet. this
* also means that freeing any block within descriptor's range
* must discard all preallocated blocks.
* - locality group
* assigned to specific locality group which does not translate to
* permanent set of inodes: inode can join and leave group. space
* from this type of preallocation can be used for any inode. thus
* it's consumed from the beginning to the end.
*
* relation between them can be expressed as:
* in-core buddy = on-disk bitmap + preallocation descriptors
*
* this mean blocks mballoc considers used are:
* - allocated blocks (persistent)
* - preallocated blocks (non-persistent)
*
* consistency in mballoc world means that at any time a block is either
* free or used in ALL structures. notice: "any time" should not be read
* literally -- time is discrete and delimited by locks.
*
* to keep it simple, we don't use block numbers, instead we count number of
* blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
*
* all operations can be expressed as:
* - init buddy: buddy = on-disk + PAs
* - new PA: buddy += N; PA = N
* - use inode PA: on-disk += N; PA -= N
* - discard inode PA buddy -= on-disk - PA; PA = 0
* - use locality group PA on-disk += N; PA -= N
* - discard locality group PA buddy -= PA; PA = 0
* note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
* is used in real operation because we can't know actual used
* bits from PA, only from on-disk bitmap
*
* if we follow this strict logic, then all operations above should be atomic.
* given some of them can block, we'd have to use something like semaphores
* killing performance on high-end SMP hardware. let's try to relax it using
* the following knowledge:
* 1) if buddy is referenced, it's already initialized
* 2) while block is used in buddy and the buddy is referenced,
* nobody can re-allocate that block
* 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
* bit set and PA claims same block, it's OK. IOW, one can set bit in
* on-disk bitmap if buddy has same bit set or/and PA covers corresponded
* block
*
* so, now we're building a concurrency table:
* - init buddy vs.
* - new PA
* blocks for PA are allocated in the buddy, buddy must be referenced
* until PA is linked to allocation group to avoid concurrent buddy init
* - use inode PA
* we need to make sure that either on-disk bitmap or PA has uptodate data
* given (3) we care that PA-=N operation doesn't interfere with init
* - discard inode PA
* the simplest way would be to have buddy initialized by the discard
* - use locality group PA
* again PA-=N must be serialized with init
* - discard locality group PA
* the simplest way would be to have buddy initialized by the discard
* - new PA vs.
* - use inode PA
* i_data_sem serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* some mutex should serialize them
* - discard locality group PA
* discard process must wait until PA isn't used by another process
* - use inode PA
* - use inode PA
* i_data_sem or another mutex should serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* nothing wrong here -- they're different PAs covering different blocks
* - discard locality group PA
* discard process must wait until PA isn't used by another process
*
* now we're ready to make few consequences:
* - PA is referenced and while it is no discard is possible
* - PA is referenced until block isn't marked in on-disk bitmap
* - PA changes only after on-disk bitmap
* - discard must not compete with init. either init is done before
* any discard or they're serialized somehow
* - buddy init as sum of on-disk bitmap and PAs is done atomically
*
* a special case when we've used PA to emptiness. no need to modify buddy
* in this case, but we should care about concurrent init
*
*/
/*
* Logic in few words:
*
* - allocation:
* load group
* find blocks
* mark bits in on-disk bitmap
* release group
*
* - use preallocation:
* find proper PA (per-inode or group)
* load group
* mark bits in on-disk bitmap
* release group
* release PA
*
* - free:
* load group
* mark bits in on-disk bitmap
* release group
*
* - discard preallocations in group:
* mark PAs deleted
* move them onto local list
* load on-disk bitmap
* load group
* remove PA from object (inode or locality group)
* mark free blocks in-core
*
* - discard inode's preallocations:
*/
/*
* Locking rules
*
* Locks:
* - bitlock on a group (group)
* - object (inode/locality) (object)
* - per-pa lock (pa)
*
* Paths:
* - new pa
* object
* group
*
* - find and use pa:
* pa
*
* - release consumed pa:
* pa
* group
* object
*
* - generate in-core bitmap:
* group
* pa
*
* - discard all for given object (inode, locality group):
* object
* pa
* group
*
* - discard all for given group:
* group
* pa
* group
* object
*
*/
static struct kmem_cache *ext4_pspace_cachep;
static struct kmem_cache *ext4_ac_cachep;
static struct kmem_cache *ext4_free_ext_cachep;
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group);
static int ext4_mb_init_per_dev_proc(struct super_block *sb);
static int ext4_mb_destroy_per_dev_proc(struct super_block *sb);
static void release_blocks_on_commit(journal_t *journal, transaction_t *txn);
static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
{
#if BITS_PER_LONG == 64
*bit += ((unsigned long) addr & 7UL) << 3;
addr = (void *) ((unsigned long) addr & ~7UL);
#elif BITS_PER_LONG == 32
*bit += ((unsigned long) addr & 3UL) << 3;
addr = (void *) ((unsigned long) addr & ~3UL);
#else
#error "how many bits you are?!"
#endif
return addr;
}
static inline int mb_test_bit(int bit, void *addr)
{
/*
* ext4_test_bit on architecture like powerpc
* needs unsigned long aligned address
*/
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_bit(bit, addr);
}
static inline void mb_set_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_set_bit(bit, addr);
}
static inline void mb_set_bit_atomic(spinlock_t *lock, int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_set_bit_atomic(lock, bit, addr);
}
static inline void mb_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_clear_bit(bit, addr);
}
static inline void mb_clear_bit_atomic(spinlock_t *lock, int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_clear_bit_atomic(lock, bit, addr);
}
static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static inline int mb_find_next_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
{
char *bb;
BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b));
BUG_ON(max == NULL);
if (order > e4b->bd_blkbits + 1) {
*max = 0;
return NULL;
}
/* at order 0 we see each particular block */
*max = 1 << (e4b->bd_blkbits + 3);
if (order == 0)
return EXT4_MB_BITMAP(e4b);
bb = EXT4_MB_BUDDY(e4b) + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
return bb;
}
#ifdef DOUBLE_CHECK
static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int i;
struct super_block *sb = e4b->bd_sb;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group));
for (i = 0; i < count; i++) {
if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
ext4_fsblk_t blocknr;
blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
blocknr += first + i;
blocknr +=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
ext4_error(sb, __func__, "double-free of inode"
" %lu's block %llu(bit %u in group %u)",
inode ? inode->i_ino : 0, blocknr,
first + i, e4b->bd_group);
}
mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
{
int i;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
BUG_ON(!ext4_is_group_locked(e4b->bd_sb, e4b->bd_group));
for (i = 0; i < count; i++) {
BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
unsigned char *b1, *b2;
int i;
b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
b2 = (unsigned char *) bitmap;
for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
if (b1[i] != b2[i]) {
printk(KERN_ERR "corruption in group %u "
"at byte %u(%u): %x in copy != %x "
"on disk/prealloc\n",
e4b->bd_group, i, i * 8, b1[i], b2[i]);
BUG();
}
}
}
}
#else
static inline void mb_free_blocks_double(struct inode *inode,
struct ext4_buddy *e4b, int first, int count)
{
return;
}
static inline void mb_mark_used_double(struct ext4_buddy *e4b,
int first, int count)
{
return;
}
static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
return;
}
#endif
#ifdef AGGRESSIVE_CHECK
#define MB_CHECK_ASSERT(assert) \
do { \
if (!(assert)) { \
printk(KERN_EMERG \
"Assertion failure in %s() at %s:%d: \"%s\"\n", \
function, file, line, # assert); \
BUG(); \
} \
} while (0)
static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
const char *function, int line)
{
struct super_block *sb = e4b->bd_sb;
int order = e4b->bd_blkbits + 1;
int max;
int max2;
int i;
int j;
int k;
int count;
struct ext4_group_info *grp;
int fragments = 0;
int fstart;
struct list_head *cur;
void *buddy;
void *buddy2;
{
static int mb_check_counter;
if (mb_check_counter++ % 100 != 0)
return 0;
}
while (order > 1) {
buddy = mb_find_buddy(e4b, order, &max);
MB_CHECK_ASSERT(buddy);
buddy2 = mb_find_buddy(e4b, order - 1, &max2);
MB_CHECK_ASSERT(buddy2);
MB_CHECK_ASSERT(buddy != buddy2);
MB_CHECK_ASSERT(max * 2 == max2);
count = 0;
for (i = 0; i < max; i++) {
if (mb_test_bit(i, buddy)) {
/* only single bit in buddy2 may be 1 */
if (!mb_test_bit(i << 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit((i<<1)+1, buddy2));
} else if (!mb_test_bit((i << 1) + 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit(i << 1, buddy2));
}
continue;
}
/* both bits in buddy2 must be 0 */
MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
for (j = 0; j < (1 << order); j++) {
k = (i * (1 << order)) + j;
MB_CHECK_ASSERT(
!mb_test_bit(k, EXT4_MB_BITMAP(e4b)));
}
count++;
}
MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
order--;
}
fstart = -1;
buddy = mb_find_buddy(e4b, 0, &max);
for (i = 0; i < max; i++) {
if (!mb_test_bit(i, buddy)) {
MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
if (fstart == -1) {
fragments++;
fstart = i;
}
continue;
}
fstart = -1;
/* check used bits only */
for (j = 0; j < e4b->bd_blkbits + 1; j++) {
buddy2 = mb_find_buddy(e4b, j, &max2);
k = i >> j;
MB_CHECK_ASSERT(k < max2);
MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
}
}
MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
grp = ext4_get_group_info(sb, e4b->bd_group);
buddy = mb_find_buddy(e4b, 0, &max);
list_for_each(cur, &grp->bb_prealloc_list) {
ext4_group_t groupnr;
struct ext4_prealloc_space *pa;
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
MB_CHECK_ASSERT(groupnr == e4b->bd_group);
for (i = 0; i < pa->pa_len; i++)
MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
}
return 0;
}
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
__FILE__, __func__, __LINE__)
#else
#define mb_check_buddy(e4b)
#endif
/* FIXME!! need more doc */
static void ext4_mb_mark_free_simple(struct super_block *sb,
void *buddy, unsigned first, int len,
struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned short min;
unsigned short max;
unsigned short chunk;
unsigned short border;
BUG_ON(len > EXT4_BLOCKS_PER_GROUP(sb));
border = 2 << sb->s_blocksize_bits;
while (len > 0) {
/* find how many blocks can be covered since this position */
max = ffs(first | border) - 1;
/* find how many blocks of power 2 we need to mark */
min = fls(len) - 1;
if (max < min)
min = max;
chunk = 1 << min;
/* mark multiblock chunks only */
grp->bb_counters[min]++;
if (min > 0)
mb_clear_bit(first >> min,
buddy + sbi->s_mb_offsets[min]);
len -= chunk;
first += chunk;
}
}
static void ext4_mb_generate_buddy(struct super_block *sb,
void *buddy, void *bitmap, ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
unsigned short max = EXT4_BLOCKS_PER_GROUP(sb);
unsigned short i = 0;
unsigned short first;
unsigned short len;
unsigned free = 0;
unsigned fragments = 0;
unsigned long long period = get_cycles();
/* initialize buddy from bitmap which is aggregation
* of on-disk bitmap and preallocations */
i = mb_find_next_zero_bit(bitmap, max, 0);
grp->bb_first_free = i;
while (i < max) {
fragments++;
first = i;
i = mb_find_next_bit(bitmap, max, i);
len = i - first;
free += len;
if (len > 1)
ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
else
grp->bb_counters[0]++;
if (i < max)
i = mb_find_next_zero_bit(bitmap, max, i);
}
grp->bb_fragments = fragments;
if (free != grp->bb_free) {
ext4_error(sb, __func__,
"EXT4-fs: group %u: %u blocks in bitmap, %u in gd",
group, free, grp->bb_free);
/*
* If we intent to continue, we consider group descritor
* corrupt and update bb_free using bitmap value
*/
grp->bb_free = free;
}
clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
period = get_cycles() - period;
spin_lock(&EXT4_SB(sb)->s_bal_lock);
EXT4_SB(sb)->s_mb_buddies_generated++;
EXT4_SB(sb)->s_mb_generation_time += period;
spin_unlock(&EXT4_SB(sb)->s_bal_lock);
}
/* The buddy information is attached the buddy cache inode
* for convenience. The information regarding each group
* is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are
* stored in the inode as
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information.
* So for each group we take up 2 blocks. A page can
* contain blocks_per_page (PAGE_CACHE_SIZE / blocksize) blocks.
* So it can have information regarding groups_per_page which
* is blocks_per_page/2
*/
static int ext4_mb_init_cache(struct page *page, char *incore)
{
int blocksize;
int blocks_per_page;
int groups_per_page;
int err = 0;
int i;
ext4_group_t first_group;
int first_block;
struct super_block *sb;
struct buffer_head *bhs;
struct buffer_head **bh;
struct inode *inode;
char *data;
char *bitmap;
mb_debug("init page %lu\n", page->index);
inode = page->mapping->host;
sb = inode->i_sb;
blocksize = 1 << inode->i_blkbits;
blocks_per_page = PAGE_CACHE_SIZE / blocksize;
groups_per_page = blocks_per_page >> 1;
if (groups_per_page == 0)
groups_per_page = 1;
/* allocate buffer_heads to read bitmaps */
if (groups_per_page > 1) {
err = -ENOMEM;
i = sizeof(struct buffer_head *) * groups_per_page;
bh = kzalloc(i, GFP_NOFS);
if (bh == NULL)
goto out;
} else
bh = &bhs;
first_group = page->index * blocks_per_page / 2;
/* read all groups the page covers into the cache */
for (i = 0; i < groups_per_page; i++) {
struct ext4_group_desc *desc;
if (first_group + i >= EXT4_SB(sb)->s_groups_count)
break;
err = -EIO;
desc = ext4_get_group_desc(sb, first_group + i, NULL);
if (desc == NULL)
goto out;
err = -ENOMEM;
bh[i] = sb_getblk(sb, ext4_block_bitmap(sb, desc));
if (bh[i] == NULL)
goto out;
if (buffer_uptodate(bh[i]) &&
!(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))
continue;
lock_buffer(bh[i]);
spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
ext4_init_block_bitmap(sb, bh[i],
first_group + i, desc);
set_buffer_uptodate(bh[i]);
unlock_buffer(bh[i]);
spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
continue;
}
spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
get_bh(bh[i]);
bh[i]->b_end_io = end_buffer_read_sync;
submit_bh(READ, bh[i]);
mb_debug("read bitmap for group %u\n", first_group + i);
}
/* wait for I/O completion */
for (i = 0; i < groups_per_page && bh[i]; i++)
wait_on_buffer(bh[i]);
err = -EIO;
for (i = 0; i < groups_per_page && bh[i]; i++)
if (!buffer_uptodate(bh[i]))
goto out;
err = 0;
first_block = page->index * blocks_per_page;
for (i = 0; i < blocks_per_page; i++) {
int group;
struct ext4_group_info *grinfo;
group = (first_block + i) >> 1;
if (group >= EXT4_SB(sb)->s_groups_count)
break;
/*
* data carry information regarding this
* particular group in the format specified
* above
*
*/
data = page_address(page) + (i * blocksize);
bitmap = bh[group - first_group]->b_data;
/*
* We place the buddy block and bitmap block
* close together
*/
if ((first_block + i) & 1) {
/* this is block of buddy */
BUG_ON(incore == NULL);
mb_debug("put buddy for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
memset(data, 0xff, blocksize);
grinfo = ext4_get_group_info(sb, group);
grinfo->bb_fragments = 0;
memset(grinfo->bb_counters, 0,
sizeof(unsigned short)*(sb->s_blocksize_bits+2));
/*
* incore got set to the group block bitmap below
*/
ext4_mb_generate_buddy(sb, data, incore, group);
incore = NULL;
} else {
/* this is block of bitmap */
BUG_ON(incore != NULL);
mb_debug("put bitmap for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
/* see comments in ext4_mb_put_pa() */
ext4_lock_group(sb, group);
memcpy(data, bitmap, blocksize);
/* mark all preallocated blks used in in-core bitmap */
ext4_mb_generate_from_pa(sb, data, group);
ext4_unlock_group(sb, group);
/* set incore so that the buddy information can be
* generated using this
*/
incore = data;
}
}
SetPageUptodate(page);
out:
if (bh) {
for (i = 0; i < groups_per_page && bh[i]; i++)
brelse(bh[i]);
if (bh != &bhs)
kfree(bh);
}
return err;
}
static noinline_for_stack int
ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
struct ext4_buddy *e4b)
{
int blocks_per_page;
int block;
int pnum;
int poff;
struct page *page;
int ret;
struct ext4_group_info *grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
mb_debug("load group %u\n", group);
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
grp = ext4_get_group_info(sb, group);
e4b->bd_blkbits = sb->s_blocksize_bits;
e4b->bd_info = ext4_get_group_info(sb, group);
e4b->bd_sb = sb;
e4b->bd_group = group;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
e4b->alloc_semp = &grp->alloc_sem;
/* Take the read lock on the group alloc
* sem. This would make sure a parallel
* ext4_mb_init_group happening on other
* groups mapped by the page is blocked
* till we are done with allocation
*/
down_read(e4b->alloc_semp);
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
/* we could use find_or_create_page(), but it locks page
* what we'd like to avoid in fast path ... */
page = find_get_page(inode->i_mapping, pnum);
if (page == NULL || !PageUptodate(page)) {
if (page)
/*
* drop the page reference and try
* to get the page with lock. If we
* are not uptodate that implies
* somebody just created the page but
* is yet to initialize the same. So
* wait for it to initialize.
*/
page_cache_release(page);
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, NULL);
if (ret) {
unlock_page(page);
goto err;
}
mb_cmp_bitmaps(e4b, page_address(page) +
(poff * sb->s_blocksize));
}
unlock_page(page);
}
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
e4b->bd_bitmap_page = page;
e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
mark_page_accessed(page);
block++;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_get_page(inode->i_mapping, pnum);
if (page == NULL || !PageUptodate(page)) {
if (page)
page_cache_release(page);
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
if (ret) {
unlock_page(page);
goto err;
}
}
unlock_page(page);
}
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
e4b->bd_buddy_page = page;
e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
mark_page_accessed(page);
BUG_ON(e4b->bd_bitmap_page == NULL);
BUG_ON(e4b->bd_buddy_page == NULL);
return 0;
err:
if (e4b->bd_bitmap_page)
page_cache_release(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
page_cache_release(e4b->bd_buddy_page);
e4b->bd_buddy = NULL;
e4b->bd_bitmap = NULL;
/* Done with the buddy cache */
up_read(e4b->alloc_semp);
return ret;
}
static void ext4_mb_release_desc(struct ext4_buddy *e4b)
{
if (e4b->bd_bitmap_page)
page_cache_release(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
page_cache_release(e4b->bd_buddy_page);
/* Done with the buddy cache */
up_read(e4b->alloc_semp);
}
static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
{
int order = 1;
void *bb;
BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b));
BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
bb = EXT4_MB_BUDDY(e4b);
while (order <= e4b->bd_blkbits + 1) {
block = block >> 1;
if (!mb_test_bit(block, bb)) {
/* this block is part of buddy of order 'order' */
return order;
}
bb += 1 << (e4b->bd_blkbits - order);
order++;
}
return 0;
}
static void mb_clear_bits(spinlock_t *lock, void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: clear whole word at once */
addr = bm + (cur >> 3);
*addr = 0;
cur += 32;
continue;
}
mb_clear_bit_atomic(lock, cur, bm);
cur++;
}
}
static void mb_set_bits(spinlock_t *lock, void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: set whole word at once */
addr = bm + (cur >> 3);
*addr = 0xffffffff;
cur += 32;
continue;
}
mb_set_bit_atomic(lock, cur, bm);
cur++;
}
}
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
__releases(bitlock)
__acquires(bitlock)
{
int block = 0;
int max = 0;
int order;
void *buddy;
void *buddy2;
struct super_block *sb = e4b->bd_sb;
BUG_ON(first + count > (sb->s_blocksize << 3));
BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group));
mb_check_buddy(e4b);
mb_free_blocks_double(inode, e4b, first, count);
e4b->bd_info->bb_free += count;
if (first < e4b->bd_info->bb_first_free)
e4b->bd_info->bb_first_free = first;
/* let's maintain fragments counter */
if (first != 0)
block = !mb_test_bit(first - 1, EXT4_MB_BITMAP(e4b));
if (first + count < EXT4_SB(sb)->s_mb_maxs[0])
max = !mb_test_bit(first + count, EXT4_MB_BITMAP(e4b));
if (block && max)
e4b->bd_info->bb_fragments--;
else if (!block && !max)
e4b->bd_info->bb_fragments++;
/* let's maintain buddy itself */
while (count-- > 0) {
block = first++;
order = 0;
if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) {
ext4_fsblk_t blocknr;
blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
blocknr += block;
blocknr +=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
ext4_unlock_group(sb, e4b->bd_group);
ext4_error(sb, __func__, "double-free of inode"
" %lu's block %llu(bit %u in group %u)",
inode ? inode->i_ino : 0, blocknr, block,
e4b->bd_group);
ext4_lock_group(sb, e4b->bd_group);
}
mb_clear_bit(block, EXT4_MB_BITMAP(e4b));
e4b->bd_info->bb_counters[order]++;
/* start of the buddy */
buddy = mb_find_buddy(e4b, order, &max);
do {
block &= ~1UL;
if (mb_test_bit(block, buddy) ||
mb_test_bit(block + 1, buddy))
break;
/* both the buddies are free, try to coalesce them */
buddy2 = mb_find_buddy(e4b, order + 1, &max);
if (!buddy2)
break;
if (order > 0) {
/* for special purposes, we don't set
* free bits in bitmap */
mb_set_bit(block, buddy);
mb_set_bit(block + 1, buddy);
}
e4b->bd_info->bb_counters[order]--;
e4b->bd_info->bb_counters[order]--;
block = block >> 1;
order++;
e4b->bd_info->bb_counters[order]++;
mb_clear_bit(block, buddy2);
buddy = buddy2;
} while (1);
}
mb_check_buddy(e4b);
}
static int mb_find_extent(struct ext4_buddy *e4b, int order, int block,
int needed, struct ext4_free_extent *ex)
{
int next = block;
int max;
int ord;
void *buddy;
BUG_ON(!ext4_is_group_locked(e4b->bd_sb, e4b->bd_group));
BUG_ON(ex == NULL);
buddy = mb_find_buddy(e4b, order, &max);
BUG_ON(buddy == NULL);
BUG_ON(block >= max);
if (mb_test_bit(block, buddy)) {
ex->fe_len = 0;
ex->fe_start = 0;
ex->fe_group = 0;
return 0;
}
/* FIXME dorp order completely ? */
if (likely(order == 0)) {
/* find actual order */
order = mb_find_order_for_block(e4b, block);
block = block >> order;
}
ex->fe_len = 1 << order;
ex->fe_start = block << order;
ex->fe_group = e4b->bd_group;
/* calc difference from given start */
next = next - ex->fe_start;
ex->fe_len -= next;
ex->fe_start += next;
while (needed > ex->fe_len &&
(buddy = mb_find_buddy(e4b, order, &max))) {
if (block + 1 >= max)
break;
next = (block + 1) * (1 << order);
if (mb_test_bit(next, EXT4_MB_BITMAP(e4b)))
break;
ord = mb_find_order_for_block(e4b, next);
order = ord;
block = next >> order;
ex->fe_len += 1 << order;
}
BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3)));
return ex->fe_len;
}
static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
{
int ord;
int mlen = 0;
int max = 0;
int cur;
int start = ex->fe_start;
int len = ex->fe_len;
unsigned ret = 0;
int len0 = len;
void *buddy;
BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
BUG_ON(e4b->bd_group != ex->fe_group);
BUG_ON(!ext4_is_group_locked(e4b->bd_sb, e4b->bd_group));
mb_check_buddy(e4b);
mb_mark_used_double(e4b, start, len);
e4b->bd_info->bb_free -= len;
if (e4b->bd_info->bb_first_free == start)
e4b->bd_info->bb_first_free += len;
/* let's maintain fragments counter */
if (start != 0)
mlen = !mb_test_bit(start - 1, EXT4_MB_BITMAP(e4b));
if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
max = !mb_test_bit(start + len, EXT4_MB_BITMAP(e4b));
if (mlen && max)
e4b->bd_info->bb_fragments++;
else if (!mlen && !max)
e4b->bd_info->bb_fragments--;
/* let's maintain buddy itself */
while (len) {
ord = mb_find_order_for_block(e4b, start);
if (((start >> ord) << ord) == start && len >= (1 << ord)) {
/* the whole chunk may be allocated at once! */
mlen = 1 << ord;
buddy = mb_find_buddy(e4b, ord, &max);
BUG_ON((start >> ord) >= max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
start += mlen;
len -= mlen;
BUG_ON(len < 0);
continue;
}
/* store for history */
if (ret == 0)
ret = len | (ord << 16);
/* we have to split large buddy */
BUG_ON(ord <= 0);
buddy = mb_find_buddy(e4b, ord, &max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
ord--;
cur = (start >> ord) & ~1U;
buddy = mb_find_buddy(e4b, ord, &max);
mb_clear_bit(cur, buddy);
mb_clear_bit(cur + 1, buddy);
e4b->bd_info->bb_counters[ord]++;
e4b->bd_info->bb_counters[ord]++;
}
mb_set_bits(sb_bgl_lock(EXT4_SB(e4b->bd_sb), ex->fe_group),
EXT4_MB_BITMAP(e4b), ex->fe_start, len0);
mb_check_buddy(e4b);
return ret;
}
/*
* Must be called under group lock!
*/
static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int ret;
BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
ret = mb_mark_used(e4b, &ac->ac_b_ex);
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_tail = ret & 0xffff;
ac->ac_buddy = ret >> 16;
/*
* take the page reference. We want the page to be pinned
* so that we don't get a ext4_mb_init_cache_call for this
* group until we update the bitmap. That would mean we
* double allocate blocks. The reference is dropped
* in ext4_mb_release_context
*/
ac->ac_bitmap_page = e4b->bd_bitmap_page;
get_page(ac->ac_bitmap_page);
ac->ac_buddy_page = e4b->bd_buddy_page;
get_page(ac->ac_buddy_page);
/* store last allocated for subsequent stream allocation */
if ((ac->ac_flags & EXT4_MB_HINT_DATA)) {
spin_lock(&sbi->s_md_lock);
sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
spin_unlock(&sbi->s_md_lock);
}
}
/*
* regular allocator, for general purposes allocation
*/
static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b,
int finish_group)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
struct ext4_free_extent ex;
int max;
if (ac->ac_status == AC_STATUS_FOUND)
return;
/*
* We don't want to scan for a whole year
*/
if (ac->ac_found > sbi->s_mb_max_to_scan &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
ac->ac_status = AC_STATUS_BREAK;
return;
}
/*
* Haven't found good chunk so far, let's continue
*/
if (bex->fe_len < gex->fe_len)
return;
if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
&& bex->fe_group == e4b->bd_group) {
/* recheck chunk's availability - we don't know
* when it was found (within this lock-unlock
* period or not) */
max = mb_find_extent(e4b, 0, bex->fe_start, gex->fe_len, &ex);
if (max >= gex->fe_len) {
ext4_mb_use_best_found(ac, e4b);
return;
}
}
}
/*
* The routine checks whether found extent is good enough. If it is,
* then the extent gets marked used and flag is set to the context
* to stop scanning. Otherwise, the extent is compared with the
* previous found extent and if new one is better, then it's stored
* in the context. Later, the best found extent will be used, if
* mballoc can't find good enough extent.
*
* FIXME: real allocation policy is to be designed yet!
*/
static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
struct ext4_free_extent *ex,
struct ext4_buddy *e4b)
{
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
BUG_ON(ex->fe_len <= 0);
BUG_ON(ex->fe_len >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
BUG_ON(ex->fe_start >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
ac->ac_found++;
/*
* The special case - take what you catch first
*/
if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* Let's check whether the chuck is good enough
*/
if (ex->fe_len == gex->fe_len) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* If this is first found extent, just store it in the context
*/
if (bex->fe_len == 0) {
*bex = *ex;
return;
}
/*
* If new found extent is better, store it in the context
*/
if (bex->fe_len < gex->fe_len) {
/* if the request isn't satisfied, any found extent
* larger than previous best one is better */
if (ex->fe_len > bex->fe_len)
*bex = *ex;
} else if (ex->fe_len > gex->fe_len) {
/* if the request is satisfied, then we try to find
* an extent that still satisfy the request, but is
* smaller than previous one */
if (ex->fe_len < bex->fe_len)
*bex = *ex;
}
ext4_mb_check_limits(ac, e4b, 0);
}
static int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_free_extent ex = ac->ac_b_ex;
ext4_group_t group = ex.fe_group;
int max;
int err;
BUG_ON(ex.fe_len <= 0);
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return err;
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, 0, ex.fe_start, ex.fe_len, &ex);
if (max > 0) {
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_release_desc(e4b);
return 0;
}
static int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
ext4_group_t group = ac->ac_g_ex.fe_group;
int max;
int err;
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_super_block *es = sbi->s_es;
struct ext4_free_extent ex;
if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
return 0;
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return err;
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, 0, ac->ac_g_ex.fe_start,
ac->ac_g_ex.fe_len, &ex);
if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
ext4_fsblk_t start;
start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) +
ex.fe_start + le32_to_cpu(es->s_first_data_block);
/* use do_div to get remainder (would be 64-bit modulo) */
if (do_div(start, sbi->s_stripe) == 0) {
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
} else if (max >= ac->ac_g_ex.fe_len) {
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
} else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
/* Sometimes, caller may want to merge even small
* number of blocks to an existing extent */
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_release_desc(e4b);
return 0;
}
/*
* The routine scans buddy structures (not bitmap!) from given order
* to max order and tries to find big enough chunk to satisfy the req
*/
static void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_group_info *grp = e4b->bd_info;
void *buddy;
int i;
int k;
int max;
BUG_ON(ac->ac_2order <= 0);
for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
if (grp->bb_counters[i] == 0)
continue;
buddy = mb_find_buddy(e4b, i, &max);
BUG_ON(buddy == NULL);
k = mb_find_next_zero_bit(buddy, max, 0);
BUG_ON(k >= max);
ac->ac_found++;
ac->ac_b_ex.fe_len = 1 << i;
ac->ac_b_ex.fe_start = k << i;
ac->ac_b_ex.fe_group = e4b->bd_group;
ext4_mb_use_best_found(ac, e4b);
BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len);
if (EXT4_SB(sb)->s_mb_stats)
atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
break;
}
}
/*
* The routine scans the group and measures all found extents.
* In order to optimize scanning, caller must pass number of
* free blocks in the group, so the routine can know upper limit.
*/
static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
void *bitmap = EXT4_MB_BITMAP(e4b);
struct ext4_free_extent ex;
int i;
int free;
free = e4b->bd_info->bb_free;
BUG_ON(free <= 0);
i = e4b->bd_info->bb_first_free;
while (free && ac->ac_status == AC_STATUS_CONTINUE) {
i = mb_find_next_zero_bit(bitmap,
EXT4_BLOCKS_PER_GROUP(sb), i);
if (i >= EXT4_BLOCKS_PER_GROUP(sb)) {
/*
* IF we have corrupt bitmap, we won't find any
* free blocks even though group info says we
* we have free blocks
*/
ext4_error(sb, __func__, "%d free blocks as per "
"group info. But bitmap says 0",
free);
break;
}
mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex);
BUG_ON(ex.fe_len <= 0);
if (free < ex.fe_len) {
ext4_error(sb, __func__, "%d free blocks as per "
"group info. But got %d blocks",
free, ex.fe_len);
/*
* The number of free blocks differs. This mostly
* indicate that the bitmap is corrupt. So exit
* without claiming the space.
*/
break;
}
ext4_mb_measure_extent(ac, &ex, e4b);
i += ex.fe_len;
free -= ex.fe_len;
}
ext4_mb_check_limits(ac, e4b, 1);
}
/*
* This is a special case for storages like raid5
* we try to find stripe-aligned chunks for stripe-size requests
* XXX should do so at least for multiples of stripe size as well
*/
static void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
void *bitmap = EXT4_MB_BITMAP(e4b);
struct ext4_free_extent ex;
ext4_fsblk_t first_group_block;
ext4_fsblk_t a;
ext4_grpblk_t i;
int max;
BUG_ON(sbi->s_stripe == 0);
/* find first stripe-aligned block in group */
first_group_block = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
+ le32_to_cpu(sbi->s_es->s_first_data_block);
a = first_group_block + sbi->s_stripe - 1;
do_div(a, sbi->s_stripe);
i = (a * sbi->s_stripe) - first_group_block;
while (i < EXT4_BLOCKS_PER_GROUP(sb)) {
if (!mb_test_bit(i, bitmap)) {
max = mb_find_extent(e4b, 0, i, sbi->s_stripe, &ex);
if (max >= sbi->s_stripe) {
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
break;
}
}
i += sbi->s_stripe;
}
}
static int ext4_mb_good_group(struct ext4_allocation_context *ac,
ext4_group_t group, int cr)
{
unsigned free, fragments;
unsigned i, bits;
struct ext4_group_desc *desc;
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
BUG_ON(cr < 0 || cr >= 4);
BUG_ON(EXT4_MB_GRP_NEED_INIT(grp));
free = grp->bb_free;
fragments = grp->bb_fragments;
if (free == 0)
return 0;
if (fragments == 0)
return 0;
switch (cr) {
case 0:
BUG_ON(ac->ac_2order == 0);
/* If this group is uninitialized, skip it initially */
desc = ext4_get_group_desc(ac->ac_sb, group, NULL);
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))
return 0;
bits = ac->ac_sb->s_blocksize_bits + 1;
for (i = ac->ac_2order; i <= bits; i++)
if (grp->bb_counters[i] > 0)
return 1;
break;
case 1:
if ((free / fragments) >= ac->ac_g_ex.fe_len)
return 1;
break;
case 2:
if (free >= ac->ac_g_ex.fe_len)
return 1;
break;
case 3:
return 1;
default:
BUG();
}
return 0;
}
/*
* lock the group_info alloc_sem of all the groups
* belonging to the same buddy cache page. This
* make sure other parallel operation on the buddy
* cache doesn't happen whild holding the buddy cache
* lock
*/
int ext4_mb_get_buddy_cache_lock(struct super_block *sb, ext4_group_t group)
{
int i;
int block, pnum;
int blocks_per_page;
int groups_per_page;
ext4_group_t first_group;
struct ext4_group_info *grp;
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
first_group = pnum * blocks_per_page / 2;
groups_per_page = blocks_per_page >> 1;
if (groups_per_page == 0)
groups_per_page = 1;
/* read all groups the page covers into the cache */
for (i = 0; i < groups_per_page; i++) {
if ((first_group + i) >= EXT4_SB(sb)->s_groups_count)
break;
grp = ext4_get_group_info(sb, first_group + i);
/* take all groups write allocation
* semaphore. This make sure there is
* no block allocation going on in any
* of that groups
*/
down_write(&grp->alloc_sem);
}
return i;
}
void ext4_mb_put_buddy_cache_lock(struct super_block *sb,
ext4_group_t group, int locked_group)
{
int i;
int block, pnum;
int blocks_per_page;
ext4_group_t first_group;
struct ext4_group_info *grp;
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
first_group = pnum * blocks_per_page / 2;
/* release locks on all the groups */
for (i = 0; i < locked_group; i++) {
grp = ext4_get_group_info(sb, first_group + i);
/* take all groups write allocation
* semaphore. This make sure there is
* no block allocation going on in any
* of that groups
*/
up_write(&grp->alloc_sem);
}
}
static int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
{
int ret;
void *bitmap;
int blocks_per_page;
int block, pnum, poff;
int num_grp_locked = 0;
struct ext4_group_info *this_grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
struct page *page = NULL, *bitmap_page = NULL;
mb_debug("init group %lu\n", group);
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
this_grp = ext4_get_group_info(sb, group);
/*
* This ensures we don't add group
* to this buddy cache via resize
*/
num_grp_locked = ext4_mb_get_buddy_cache_lock(sb, group);
if (!EXT4_MB_GRP_NEED_INIT(this_grp)) {
/*
* somebody initialized the group
* return without doing anything
*/
ret = 0;
goto err;
}
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
ret = ext4_mb_init_cache(page, NULL);
if (ret) {
unlock_page(page);
goto err;
}
unlock_page(page);
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
mark_page_accessed(page);
bitmap_page = page;
bitmap = page_address(page) + (poff * sb->s_blocksize);
/* init buddy cache */
block++;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page == bitmap_page) {
/*
* If both the bitmap and buddy are in
* the same page we don't need to force
* init the buddy
*/
unlock_page(page);
} else if (page) {
BUG_ON(page->mapping != inode->i_mapping);
ret = ext4_mb_init_cache(page, bitmap);
if (ret) {
unlock_page(page);
goto err;
}
unlock_page(page);
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
mark_page_accessed(page);
err:
ext4_mb_put_buddy_cache_lock(sb, group, num_grp_locked);
if (bitmap_page)
page_cache_release(bitmap_page);
if (page)
page_cache_release(page);
return ret;
}
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
ext4_group_t group;
ext4_group_t i;
int cr;
int err = 0;
int bsbits;
struct ext4_sb_info *sbi;
struct super_block *sb;
struct ext4_buddy e4b;
loff_t size, isize;
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
/* first, try the goal */
err = ext4_mb_find_by_goal(ac, &e4b);
if (err || ac->ac_status == AC_STATUS_FOUND)
goto out;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
goto out;
/*
* ac->ac2_order is set only if the fe_len is a power of 2
* if ac2_order is set we also set criteria to 0 so that we
* try exact allocation using buddy.
*/
i = fls(ac->ac_g_ex.fe_len);
ac->ac_2order = 0;
/*
* We search using buddy data only if the order of the request
* is greater than equal to the sbi_s_mb_order2_reqs
* You can tune it via /proc/fs/ext4/<partition>/order2_req
*/
if (i >= sbi->s_mb_order2_reqs) {
/*
* This should tell if fe_len is exactly power of 2
*/
if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
ac->ac_2order = i - 1;
}
bsbits = ac->ac_sb->s_blocksize_bits;
/* if stream allocation is enabled, use global goal */
size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
isize = i_size_read(ac->ac_inode) >> bsbits;
if (size < isize)
size = isize;
if (size < sbi->s_mb_stream_request &&
(ac->ac_flags & EXT4_MB_HINT_DATA)) {
/* TBD: may be hot point */
spin_lock(&sbi->s_md_lock);
ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
spin_unlock(&sbi->s_md_lock);
}
/* Let's just scan groups to find more-less suitable blocks */
cr = ac->ac_2order ? 0 : 1;
/*
* cr == 0 try to get exact allocation,
* cr == 3 try to get anything
*/
repeat:
for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
ac->ac_criteria = cr;
/*
* searching for the right group start
* from the goal value specified
*/
group = ac->ac_g_ex.fe_group;
for (i = 0; i < EXT4_SB(sb)->s_groups_count; group++, i++) {
struct ext4_group_info *grp;
struct ext4_group_desc *desc;
if (group == EXT4_SB(sb)->s_groups_count)
group = 0;
/* quick check to skip empty groups */
grp = ext4_get_group_info(sb, group);
if (grp->bb_free == 0)
continue;
/*
* if the group is already init we check whether it is
* a good group and if not we don't load the buddy
*/
if (EXT4_MB_GRP_NEED_INIT(grp)) {
/*
* we need full data about the group
* to make a good selection
*/
err = ext4_mb_init_group(sb, group);
if (err)
goto out;
}
/*
* If the particular group doesn't satisfy our
* criteria we continue with the next group
*/
if (!ext4_mb_good_group(ac, group, cr))
continue;
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err)
goto out;
ext4_lock_group(sb, group);
if (!ext4_mb_good_group(ac, group, cr)) {
/* someone did allocation from this group */
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
continue;
}
ac->ac_groups_scanned++;
desc = ext4_get_group_desc(sb, group, NULL);
if (cr == 0 || (desc->bg_flags &
cpu_to_le16(EXT4_BG_BLOCK_UNINIT) &&
ac->ac_2order != 0))
ext4_mb_simple_scan_group(ac, &e4b);
else if (cr == 1 &&
ac->ac_g_ex.fe_len == sbi->s_stripe)
ext4_mb_scan_aligned(ac, &e4b);
else
ext4_mb_complex_scan_group(ac, &e4b);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
if (ac->ac_status != AC_STATUS_CONTINUE)
break;
}
}
if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
/*
* We've been searching too long. Let's try to allocate
* the best chunk we've found so far
*/
ext4_mb_try_best_found(ac, &e4b);
if (ac->ac_status != AC_STATUS_FOUND) {
/*
* Someone more lucky has already allocated it.
* The only thing we can do is just take first
* found block(s)
printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
*/
ac->ac_b_ex.fe_group = 0;
ac->ac_b_ex.fe_start = 0;
ac->ac_b_ex.fe_len = 0;
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_flags |= EXT4_MB_HINT_FIRST;
cr = 3;
atomic_inc(&sbi->s_mb_lost_chunks);
goto repeat;
}
}
out:
return err;
}
#ifdef EXT4_MB_HISTORY
struct ext4_mb_proc_session {
struct ext4_mb_history *history;
struct super_block *sb;
int start;
int max;
};
static void *ext4_mb_history_skip_empty(struct ext4_mb_proc_session *s,
struct ext4_mb_history *hs,
int first)
{
if (hs == s->history + s->max)
hs = s->history;
if (!first && hs == s->history + s->start)
return NULL;
while (hs->orig.fe_len == 0) {
hs++;
if (hs == s->history + s->max)
hs = s->history;
if (hs == s->history + s->start)
return NULL;
}
return hs;
}
static void *ext4_mb_seq_history_start(struct seq_file *seq, loff_t *pos)
{
struct ext4_mb_proc_session *s = seq->private;
struct ext4_mb_history *hs;
int l = *pos;
if (l == 0)
return SEQ_START_TOKEN;
hs = ext4_mb_history_skip_empty(s, s->history + s->start, 1);
if (!hs)
return NULL;
while (--l && (hs = ext4_mb_history_skip_empty(s, ++hs, 0)) != NULL);
return hs;
}
static void *ext4_mb_seq_history_next(struct seq_file *seq, void *v,
loff_t *pos)
{
struct ext4_mb_proc_session *s = seq->private;
struct ext4_mb_history *hs = v;
++*pos;
if (v == SEQ_START_TOKEN)
return ext4_mb_history_skip_empty(s, s->history + s->start, 1);
else
return ext4_mb_history_skip_empty(s, ++hs, 0);
}
static int ext4_mb_seq_history_show(struct seq_file *seq, void *v)
{
char buf[25], buf2[25], buf3[25], *fmt;
struct ext4_mb_history *hs = v;
if (v == SEQ_START_TOKEN) {
seq_printf(seq, "%-5s %-8s %-23s %-23s %-23s %-5s "
"%-5s %-2s %-5s %-5s %-5s %-6s\n",
"pid", "inode", "original", "goal", "result", "found",
"grps", "cr", "flags", "merge", "tail", "broken");
return 0;
}
if (hs->op == EXT4_MB_HISTORY_ALLOC) {
fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u "
"%-5u %-5s %-5u %-6u\n";
sprintf(buf2, "%u/%d/%u@%u", hs->result.fe_group,
hs->result.fe_start, hs->result.fe_len,
hs->result.fe_logical);
sprintf(buf, "%u/%d/%u@%u", hs->orig.fe_group,
hs->orig.fe_start, hs->orig.fe_len,
hs->orig.fe_logical);
sprintf(buf3, "%u/%d/%u@%u", hs->goal.fe_group,
hs->goal.fe_start, hs->goal.fe_len,
hs->goal.fe_logical);
seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2,
hs->found, hs->groups, hs->cr, hs->flags,
hs->merged ? "M" : "", hs->tail,
hs->buddy ? 1 << hs->buddy : 0);
} else if (hs->op == EXT4_MB_HISTORY_PREALLOC) {
fmt = "%-5u %-8u %-23s %-23s %-23s\n";
sprintf(buf2, "%u/%d/%u@%u", hs->result.fe_group,
hs->result.fe_start, hs->result.fe_len,
hs->result.fe_logical);
sprintf(buf, "%u/%d/%u@%u", hs->orig.fe_group,
hs->orig.fe_start, hs->orig.fe_len,
hs->orig.fe_logical);
seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2);
} else if (hs->op == EXT4_MB_HISTORY_DISCARD) {
sprintf(buf2, "%u/%d/%u", hs->result.fe_group,
hs->result.fe_start, hs->result.fe_len);
seq_printf(seq, "%-5u %-8u %-23s discard\n",
hs->pid, hs->ino, buf2);
} else if (hs->op == EXT4_MB_HISTORY_FREE) {
sprintf(buf2, "%u/%d/%u", hs->result.fe_group,
hs->result.fe_start, hs->result.fe_len);
seq_printf(seq, "%-5u %-8u %-23s free\n",
hs->pid, hs->ino, buf2);
}
return 0;
}
static void ext4_mb_seq_history_stop(struct seq_file *seq, void *v)
{
}
static struct seq_operations ext4_mb_seq_history_ops = {
.start = ext4_mb_seq_history_start,
.next = ext4_mb_seq_history_next,
.stop = ext4_mb_seq_history_stop,
.show = ext4_mb_seq_history_show,
};
static int ext4_mb_seq_history_open(struct inode *inode, struct file *file)
{
struct super_block *sb = PDE(inode)->data;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_mb_proc_session *s;
int rc;
int size;
if (unlikely(sbi->s_mb_history == NULL))
return -ENOMEM;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (s == NULL)
return -ENOMEM;
s->sb = sb;
size = sizeof(struct ext4_mb_history) * sbi->s_mb_history_max;
s->history = kmalloc(size, GFP_KERNEL);
if (s->history == NULL) {
kfree(s);
return -ENOMEM;
}
spin_lock(&sbi->s_mb_history_lock);
memcpy(s->history, sbi->s_mb_history, size);
s->max = sbi->s_mb_history_max;
s->start = sbi->s_mb_history_cur % s->max;
spin_unlock(&sbi->s_mb_history_lock);
rc = seq_open(file, &ext4_mb_seq_history_ops);
if (rc == 0) {
struct seq_file *m = (struct seq_file *)file->private_data;
m->private = s;
} else {
kfree(s->history);
kfree(s);
}
return rc;
}
static int ext4_mb_seq_history_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = (struct seq_file *)file->private_data;
struct ext4_mb_proc_session *s = seq->private;
kfree(s->history);
kfree(s);
return seq_release(inode, file);
}
static ssize_t ext4_mb_seq_history_write(struct file *file,
const char __user *buffer,
size_t count, loff_t *ppos)
{
struct seq_file *seq = (struct seq_file *)file->private_data;
struct ext4_mb_proc_session *s = seq->private;
struct super_block *sb = s->sb;
char str[32];
int value;
if (count >= sizeof(str)) {
printk(KERN_ERR "EXT4-fs: %s string too long, max %u bytes\n",
"mb_history", (int)sizeof(str));
return -EOVERFLOW;
}
if (copy_from_user(str, buffer, count))
return -EFAULT;
value = simple_strtol(str, NULL, 0);
if (value < 0)
return -ERANGE;
EXT4_SB(sb)->s_mb_history_filter = value;
return count;
}
static struct file_operations ext4_mb_seq_history_fops = {
.owner = THIS_MODULE,
.open = ext4_mb_seq_history_open,
.read = seq_read,
.write = ext4_mb_seq_history_write,
.llseek = seq_lseek,
.release = ext4_mb_seq_history_release,
};
static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
{
struct super_block *sb = seq->private;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t group;
if (*pos < 0 || *pos >= sbi->s_groups_count)
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct super_block *sb = seq->private;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t group;
++*pos;
if (*pos < 0 || *pos >= sbi->s_groups_count)
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
struct super_block *sb = seq->private;
ext4_group_t group = (ext4_group_t) ((unsigned long) v);
int i;
int err;
struct ext4_buddy e4b;
struct sg {
struct ext4_group_info info;
unsigned short counters[16];
} sg;
group--;
if (group == 0)
seq_printf(seq, "#%-5s: %-5s %-5s %-5s "
"[ %-5s %-5s %-5s %-5s %-5s %-5s %-5s "
"%-5s %-5s %-5s %-5s %-5s %-5s %-5s ]\n",
"group", "free", "frags", "first",
"2^0", "2^1", "2^2", "2^3", "2^4", "2^5", "2^6",
"2^7", "2^8", "2^9", "2^10", "2^11", "2^12", "2^13");
i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
sizeof(struct ext4_group_info);
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
seq_printf(seq, "#%-5u: I/O error\n", group);
return 0;
}
ext4_lock_group(sb, group);
memcpy(&sg, ext4_get_group_info(sb, group), i);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
sg.info.bb_fragments, sg.info.bb_first_free);
for (i = 0; i <= 13; i++)
seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ?
sg.info.bb_counters[i] : 0);
seq_printf(seq, " ]\n");
return 0;
}
static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
{
}
static struct seq_operations ext4_mb_seq_groups_ops = {
.start = ext4_mb_seq_groups_start,
.next = ext4_mb_seq_groups_next,
.stop = ext4_mb_seq_groups_stop,
.show = ext4_mb_seq_groups_show,
};
static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file)
{
struct super_block *sb = PDE(inode)->data;
int rc;
rc = seq_open(file, &ext4_mb_seq_groups_ops);
if (rc == 0) {
struct seq_file *m = (struct seq_file *)file->private_data;
m->private = sb;
}
return rc;
}
static struct file_operations ext4_mb_seq_groups_fops = {
.owner = THIS_MODULE,
.open = ext4_mb_seq_groups_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static void ext4_mb_history_release(struct super_block *sb)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (sbi->s_proc != NULL) {
remove_proc_entry("mb_groups", sbi->s_proc);
remove_proc_entry("mb_history", sbi->s_proc);
}
kfree(sbi->s_mb_history);
}
static void ext4_mb_history_init(struct super_block *sb)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
int i;
if (sbi->s_proc != NULL) {
proc_create_data("mb_history", S_IRUGO, sbi->s_proc,
&ext4_mb_seq_history_fops, sb);
proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
&ext4_mb_seq_groups_fops, sb);
}
sbi->s_mb_history_max = 1000;
sbi->s_mb_history_cur = 0;
spin_lock_init(&sbi->s_mb_history_lock);
i = sbi->s_mb_history_max * sizeof(struct ext4_mb_history);
sbi->s_mb_history = kzalloc(i, GFP_KERNEL);
/* if we can't allocate history, then we simple won't use it */
}
static noinline_for_stack void
ext4_mb_store_history(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_mb_history h;
if (unlikely(sbi->s_mb_history == NULL))
return;
if (!(ac->ac_op & sbi->s_mb_history_filter))
return;
h.op = ac->ac_op;
h.pid = current->pid;
h.ino = ac->ac_inode ? ac->ac_inode->i_ino : 0;
h.orig = ac->ac_o_ex;
h.result = ac->ac_b_ex;
h.flags = ac->ac_flags;
h.found = ac->ac_found;
h.groups = ac->ac_groups_scanned;
h.cr = ac->ac_criteria;
h.tail = ac->ac_tail;
h.buddy = ac->ac_buddy;
h.merged = 0;
if (ac->ac_op == EXT4_MB_HISTORY_ALLOC) {
if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
h.merged = 1;
h.goal = ac->ac_g_ex;
h.result = ac->ac_f_ex;
}
spin_lock(&sbi->s_mb_history_lock);
memcpy(sbi->s_mb_history + sbi->s_mb_history_cur, &h, sizeof(h));
if (++sbi->s_mb_history_cur >= sbi->s_mb_history_max)
sbi->s_mb_history_cur = 0;
spin_unlock(&sbi->s_mb_history_lock);
}
#else
#define ext4_mb_history_release(sb)
#define ext4_mb_history_init(sb)
#endif
/* Create and initialize ext4_group_info data for the given group. */
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *desc)
{
int i, len;
int metalen = 0;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_group_info **meta_group_info;
/*
* First check if this group is the first of a reserved block.
* If it's true, we have to allocate a new table of pointers
* to ext4_group_info structures
*/
if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
metalen = sizeof(*meta_group_info) <<
EXT4_DESC_PER_BLOCK_BITS(sb);
meta_group_info = kmalloc(metalen, GFP_KERNEL);
if (meta_group_info == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate mem for a "
"buddy group\n");
goto exit_meta_group_info;
}
sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
meta_group_info;
}
/*
* calculate needed size. if change bb_counters size,
* don't forget about ext4_mb_generate_buddy()
*/
len = offsetof(typeof(**meta_group_info),
bb_counters[sb->s_blocksize_bits + 2]);
meta_group_info =
sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
meta_group_info[i] = kzalloc(len, GFP_KERNEL);
if (meta_group_info[i] == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
goto exit_group_info;
}
set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
&(meta_group_info[i]->bb_state));
/*
* initialize bb_free to be able to skip
* empty groups without initialization
*/
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
meta_group_info[i]->bb_free =
ext4_free_blocks_after_init(sb, group, desc);
} else {
meta_group_info[i]->bb_free =
le16_to_cpu(desc->bg_free_blocks_count);
}
INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
init_rwsem(&meta_group_info[i]->alloc_sem);
meta_group_info[i]->bb_free_root.rb_node = NULL;;
#ifdef DOUBLE_CHECK
{
struct buffer_head *bh;
meta_group_info[i]->bb_bitmap =
kmalloc(sb->s_blocksize, GFP_KERNEL);
BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
bh = ext4_read_block_bitmap(sb, group);
BUG_ON(bh == NULL);
memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
sb->s_blocksize);
put_bh(bh);
}
#endif
return 0;
exit_group_info:
/* If a meta_group_info table has been allocated, release it now */
if (group % EXT4_DESC_PER_BLOCK(sb) == 0)
kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
exit_meta_group_info:
return -ENOMEM;
} /* ext4_mb_add_groupinfo */
/*
* Update an existing group.
* This function is used for online resize
*/
void ext4_mb_update_group_info(struct ext4_group_info *grp, ext4_grpblk_t add)
{
grp->bb_free += add;
}
static int ext4_mb_init_backend(struct super_block *sb)
{
ext4_group_t i;
int metalen;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
int num_meta_group_infos;
int num_meta_group_infos_max;
int array_size;
struct ext4_group_info **meta_group_info;
struct ext4_group_desc *desc;
/* This is the number of blocks used by GDT */
num_meta_group_infos = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) -
1) >> EXT4_DESC_PER_BLOCK_BITS(sb);
/*
* This is the total number of blocks used by GDT including
* the number of reserved blocks for GDT.
* The s_group_info array is allocated with this value
* to allow a clean online resize without a complex
* manipulation of pointer.
* The drawback is the unused memory when no resize
* occurs but it's very low in terms of pages
* (see comments below)
* Need to handle this properly when META_BG resizing is allowed
*/
num_meta_group_infos_max = num_meta_group_infos +
le16_to_cpu(es->s_reserved_gdt_blocks);
/*
* array_size is the size of s_group_info array. We round it
* to the next power of two because this approximation is done
* internally by kmalloc so we can have some more memory
* for free here (e.g. may be used for META_BG resize).
*/
array_size = 1;
while (array_size < sizeof(*sbi->s_group_info) *
num_meta_group_infos_max)
array_size = array_size << 1;
/* An 8TB filesystem with 64-bit pointers requires a 4096 byte
* kmalloc. A 128kb malloc should suffice for a 256TB filesystem.
* So a two level scheme suffices for now. */
sbi->s_group_info = kmalloc(array_size, GFP_KERNEL);
if (sbi->s_group_info == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate buddy meta group\n");
return -ENOMEM;
}
sbi->s_buddy_cache = new_inode(sb);
if (sbi->s_buddy_cache == NULL) {
printk(KERN_ERR "EXT4-fs: can't get new inode\n");
goto err_freesgi;
}
EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
metalen = sizeof(*meta_group_info) << EXT4_DESC_PER_BLOCK_BITS(sb);
for (i = 0; i < num_meta_group_infos; i++) {
if ((i + 1) == num_meta_group_infos)
metalen = sizeof(*meta_group_info) *
(sbi->s_groups_count -
(i << EXT4_DESC_PER_BLOCK_BITS(sb)));
meta_group_info = kmalloc(metalen, GFP_KERNEL);
if (meta_group_info == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate mem for a "
"buddy group\n");
goto err_freemeta;
}
sbi->s_group_info[i] = meta_group_info;
}
for (i = 0; i < sbi->s_groups_count; i++) {
desc = ext4_get_group_desc(sb, i, NULL);
if (desc == NULL) {
printk(KERN_ERR
"EXT4-fs: can't read descriptor %u\n", i);
goto err_freebuddy;
}
if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
goto err_freebuddy;
}
return 0;
err_freebuddy:
while (i-- > 0)
kfree(ext4_get_group_info(sb, i));
i = num_meta_group_infos;
err_freemeta:
while (i-- > 0)
kfree(sbi->s_group_info[i]);
iput(sbi->s_buddy_cache);
err_freesgi:
kfree(sbi->s_group_info);
return -ENOMEM;
}
int ext4_mb_init(struct super_block *sb, int needs_recovery)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned i, j;
unsigned offset;
unsigned max;
int ret;
i = (sb->s_blocksize_bits + 2) * sizeof(unsigned short);
sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_offsets == NULL) {
return -ENOMEM;
}
i = (sb->s_blocksize_bits + 2) * sizeof(unsigned int);
sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_maxs == NULL) {
kfree(sbi->s_mb_maxs);
return -ENOMEM;
}
/* order 0 is regular bitmap */
sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
sbi->s_mb_offsets[0] = 0;
i = 1;
offset = 0;
max = sb->s_blocksize << 2;
do {
sbi->s_mb_offsets[i] = offset;
sbi->s_mb_maxs[i] = max;
offset += 1 << (sb->s_blocksize_bits - i);
max = max >> 1;
i++;
} while (i <= sb->s_blocksize_bits + 1);
/* init file for buddy data */
ret = ext4_mb_init_backend(sb);
if (ret != 0) {
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
return ret;
}
spin_lock_init(&sbi->s_md_lock);
spin_lock_init(&sbi->s_bal_lock);
sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
sbi->s_mb_stats = MB_DEFAULT_STATS;
sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
sbi->s_mb_history_filter = EXT4_MB_HISTORY_DEFAULT;
sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC;
sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
if (sbi->s_locality_groups == NULL) {
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
return -ENOMEM;
}
for_each_possible_cpu(i) {
struct ext4_locality_group *lg;
lg = per_cpu_ptr(sbi->s_locality_groups, i);
mutex_init(&lg->lg_mutex);
for (j = 0; j < PREALLOC_TB_SIZE; j++)
INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
spin_lock_init(&lg->lg_prealloc_lock);
}
ext4_mb_init_per_dev_proc(sb);
ext4_mb_history_init(sb);
if (sbi->s_journal)
sbi->s_journal->j_commit_callback = release_blocks_on_commit;
printk(KERN_INFO "EXT4-fs: mballoc enabled\n");
return 0;
}
/* need to called with ext4 group lock (ext4_lock_group) */
static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
{
struct ext4_prealloc_space *pa;
struct list_head *cur, *tmp;
int count = 0;
list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
list_del(&pa->pa_group_list);
count++;
kmem_cache_free(ext4_pspace_cachep, pa);
}
if (count)
mb_debug("mballoc: %u PAs left\n", count);
}
int ext4_mb_release(struct super_block *sb)
{
ext4_group_t i;
int num_meta_group_infos;
struct ext4_group_info *grinfo;
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (sbi->s_group_info) {
for (i = 0; i < sbi->s_groups_count; i++) {
grinfo = ext4_get_group_info(sb, i);
#ifdef DOUBLE_CHECK
kfree(grinfo->bb_bitmap);
#endif
ext4_lock_group(sb, i);
ext4_mb_cleanup_pa(grinfo);
ext4_unlock_group(sb, i);
kfree(grinfo);
}
num_meta_group_infos = (sbi->s_groups_count +
EXT4_DESC_PER_BLOCK(sb) - 1) >>
EXT4_DESC_PER_BLOCK_BITS(sb);
for (i = 0; i < num_meta_group_infos; i++)
kfree(sbi->s_group_info[i]);
kfree(sbi->s_group_info);
}
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
if (sbi->s_buddy_cache)
iput(sbi->s_buddy_cache);
if (sbi->s_mb_stats) {
printk(KERN_INFO
"EXT4-fs: mballoc: %u blocks %u reqs (%u success)\n",
atomic_read(&sbi->s_bal_allocated),
atomic_read(&sbi->s_bal_reqs),
atomic_read(&sbi->s_bal_success));
printk(KERN_INFO
"EXT4-fs: mballoc: %u extents scanned, %u goal hits, "
"%u 2^N hits, %u breaks, %u lost\n",
atomic_read(&sbi->s_bal_ex_scanned),
atomic_read(&sbi->s_bal_goals),
atomic_read(&sbi->s_bal_2orders),
atomic_read(&sbi->s_bal_breaks),
atomic_read(&sbi->s_mb_lost_chunks));
printk(KERN_INFO
"EXT4-fs: mballoc: %lu generated and it took %Lu\n",
sbi->s_mb_buddies_generated++,
sbi->s_mb_generation_time);
printk(KERN_INFO
"EXT4-fs: mballoc: %u preallocated, %u discarded\n",
atomic_read(&sbi->s_mb_preallocated),
atomic_read(&sbi->s_mb_discarded));
}
free_percpu(sbi->s_locality_groups);
ext4_mb_history_release(sb);
ext4_mb_destroy_per_dev_proc(sb);
return 0;
}
/*
* This function is called by the jbd2 layer once the commit has finished,
* so we know we can free the blocks that were released with that commit.
*/
static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
{
struct super_block *sb = journal->j_private;
struct ext4_buddy e4b;
struct ext4_group_info *db;
int err, count = 0, count2 = 0;
struct ext4_free_data *entry;
ext4_fsblk_t discard_block;
struct list_head *l, *ltmp;
list_for_each_safe(l, ltmp, &txn->t_private_list) {
entry = list_entry(l, struct ext4_free_data, list);
mb_debug("gonna free %u blocks in group %u (0x%p):",
entry->count, entry->group, entry);
err = ext4_mb_load_buddy(sb, entry->group, &e4b);
/* we expect to find existing buddy because it's pinned */
BUG_ON(err != 0);
db = e4b.bd_info;
/* there are blocks to put in buddy to make them really free */
count += entry->count;
count2++;
ext4_lock_group(sb, entry->group);
/* Take it out of per group rb tree */
rb_erase(&entry->node, &(db->bb_free_root));
mb_free_blocks(NULL, &e4b, entry->start_blk, entry->count);
if (!db->bb_free_root.rb_node) {
/* No more items in the per group rb tree
* balance refcounts from ext4_mb_free_metadata()
*/
page_cache_release(e4b.bd_buddy_page);
page_cache_release(e4b.bd_bitmap_page);
}
ext4_unlock_group(sb, entry->group);
discard_block = (ext4_fsblk_t) entry->group * EXT4_BLOCKS_PER_GROUP(sb)
+ entry->start_blk
+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
trace_mark(ext4_discard_blocks, "dev %s blk %llu count %u", sb->s_id,
(unsigned long long) discard_block, entry->count);
sb_issue_discard(sb, discard_block, entry->count);
kmem_cache_free(ext4_free_ext_cachep, entry);
ext4_mb_release_desc(&e4b);
}
mb_debug("freed %u blocks in %u structures\n", count, count2);
}
#define EXT4_MB_STATS_NAME "stats"
#define EXT4_MB_MAX_TO_SCAN_NAME "max_to_scan"
#define EXT4_MB_MIN_TO_SCAN_NAME "min_to_scan"
#define EXT4_MB_ORDER2_REQ "order2_req"
#define EXT4_MB_STREAM_REQ "stream_req"
#define EXT4_MB_GROUP_PREALLOC "group_prealloc"
static int ext4_mb_init_per_dev_proc(struct super_block *sb)
{
#ifdef CONFIG_PROC_FS
mode_t mode = S_IFREG | S_IRUGO | S_IWUSR;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct proc_dir_entry *proc;
if (sbi->s_proc == NULL)
return -EINVAL;
EXT4_PROC_HANDLER(EXT4_MB_STATS_NAME, mb_stats);
EXT4_PROC_HANDLER(EXT4_MB_MAX_TO_SCAN_NAME, mb_max_to_scan);
EXT4_PROC_HANDLER(EXT4_MB_MIN_TO_SCAN_NAME, mb_min_to_scan);
EXT4_PROC_HANDLER(EXT4_MB_ORDER2_REQ, mb_order2_reqs);
EXT4_PROC_HANDLER(EXT4_MB_STREAM_REQ, mb_stream_request);
EXT4_PROC_HANDLER(EXT4_MB_GROUP_PREALLOC, mb_group_prealloc);
return 0;
err_out:
remove_proc_entry(EXT4_MB_GROUP_PREALLOC, sbi->s_proc);
remove_proc_entry(EXT4_MB_STREAM_REQ, sbi->s_proc);
remove_proc_entry(EXT4_MB_ORDER2_REQ, sbi->s_proc);
remove_proc_entry(EXT4_MB_MIN_TO_SCAN_NAME, sbi->s_proc);
remove_proc_entry(EXT4_MB_MAX_TO_SCAN_NAME, sbi->s_proc);
remove_proc_entry(EXT4_MB_STATS_NAME, sbi->s_proc);
return -ENOMEM;
#else
return 0;
#endif
}
static int ext4_mb_destroy_per_dev_proc(struct super_block *sb)
{
#ifdef CONFIG_PROC_FS
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (sbi->s_proc == NULL)
return -EINVAL;
remove_proc_entry(EXT4_MB_GROUP_PREALLOC, sbi->s_proc);
remove_proc_entry(EXT4_MB_STREAM_REQ, sbi->s_proc);
remove_proc_entry(EXT4_MB_ORDER2_REQ, sbi->s_proc);
remove_proc_entry(EXT4_MB_MIN_TO_SCAN_NAME, sbi->s_proc);
remove_proc_entry(EXT4_MB_MAX_TO_SCAN_NAME, sbi->s_proc);
remove_proc_entry(EXT4_MB_STATS_NAME, sbi->s_proc);
#endif
return 0;
}
int __init init_ext4_mballoc(void)
{
ext4_pspace_cachep =
kmem_cache_create("ext4_prealloc_space",
sizeof(struct ext4_prealloc_space),
0, SLAB_RECLAIM_ACCOUNT, NULL);
if (ext4_pspace_cachep == NULL)
return -ENOMEM;
ext4_ac_cachep =
kmem_cache_create("ext4_alloc_context",
sizeof(struct ext4_allocation_context),
0, SLAB_RECLAIM_ACCOUNT, NULL);
if (ext4_ac_cachep == NULL) {
kmem_cache_destroy(ext4_pspace_cachep);
return -ENOMEM;
}
ext4_free_ext_cachep =
kmem_cache_create("ext4_free_block_extents",
sizeof(struct ext4_free_data),
0, SLAB_RECLAIM_ACCOUNT, NULL);
if (ext4_free_ext_cachep == NULL) {
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
return -ENOMEM;
}
return 0;
}
void exit_ext4_mballoc(void)
{
/* XXX: synchronize_rcu(); */
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
kmem_cache_destroy(ext4_free_ext_cachep);
}
/*
* Check quota and mark choosed space (ac->ac_b_ex) non-free in bitmaps
* Returns 0 if success or error code
*/
static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
handle_t *handle, unsigned int reserv_blks)
{
struct buffer_head *bitmap_bh = NULL;
struct ext4_super_block *es;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block;
int err, len;
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(ac->ac_b_ex.fe_len <= 0);
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
es = sbi->s_es;
err = -EIO;
bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
if (!bitmap_bh)
goto out_err;
err = ext4_journal_get_write_access(handle, bitmap_bh);
if (err)
goto out_err;
err = -EIO;
gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
if (!gdp)
goto out_err;
ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
gdp->bg_free_blocks_count);
err = ext4_journal_get_write_access(handle, gdp_bh);
if (err)
goto out_err;
block = ac->ac_b_ex.fe_group * EXT4_BLOCKS_PER_GROUP(sb)
+ ac->ac_b_ex.fe_start
+ le32_to_cpu(es->s_first_data_block);
len = ac->ac_b_ex.fe_len;
if (in_range(ext4_block_bitmap(sb, gdp), block, len) ||
in_range(ext4_inode_bitmap(sb, gdp), block, len) ||
in_range(block, ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group) ||
in_range(block + len - 1, ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group)) {
ext4_error(sb, __func__,
"Allocating block in system zone - block = %llu",
block);
/* File system mounted not to panic on error
* Fix the bitmap and repeat the block allocation
* We leak some of the blocks here.
*/
mb_set_bits(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group),
bitmap_bh->b_data, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len);
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (!err)
err = -EAGAIN;
goto out_err;
}
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
bitmap_bh->b_data));
}
}
#endif
mb_set_bits(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group), bitmap_bh->b_data,
ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len);
spin_lock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
gdp->bg_free_blocks_count =
cpu_to_le16(ext4_free_blocks_after_init(sb,
ac->ac_b_ex.fe_group,
gdp));
}
le16_add_cpu(&gdp->bg_free_blocks_count, -ac->ac_b_ex.fe_len);
gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
/*
* Now reduce the dirty block count also. Should not go negative
*/
if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
/* release all the reserved blocks if non delalloc */
percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks);
else
percpu_counter_sub(&sbi->s_dirtyblocks_counter,
ac->ac_b_ex.fe_len);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi,
ac->ac_b_ex.fe_group);
spin_lock(sb_bgl_lock(sbi, flex_group));
sbi->s_flex_groups[flex_group].free_blocks -= ac->ac_b_ex.fe_len;
spin_unlock(sb_bgl_lock(sbi, flex_group));
}
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (err)
goto out_err;
err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
out_err:
sb->s_dirt = 1;
brelse(bitmap_bh);
return err;
}
/*
* here we normalize request for locality group
* Group request are normalized to s_strip size if we set the same via mount
* option. If not we set it to s_mb_group_prealloc which can be configured via
* /proc/fs/ext4/<partition>/group_prealloc
*
* XXX: should we try to preallocate more than the group has now?
*/
static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
BUG_ON(lg == NULL);
if (EXT4_SB(sb)->s_stripe)
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe;
else
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
mb_debug("#%u: goal %u blocks for locality group\n",
current->pid, ac->ac_g_ex.fe_len);
}
/*
* Normalization means making request better in terms of
* size and alignment
*/
static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
int bsbits, max;
ext4_lblk_t end;
loff_t size, orig_size, start_off;
ext4_lblk_t start, orig_start;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_prealloc_space *pa;
/* do normalize only data requests, metadata requests
do not need preallocation */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
/* sometime caller may want exact blocks */
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
/* caller may indicate that preallocation isn't
* required (it's a tail, for example) */
if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
return;
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
ext4_mb_normalize_group_request(ac);
return ;
}
bsbits = ac->ac_sb->s_blocksize_bits;
/* first, let's learn actual file size
* given current request is allocated */
size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
size = size << bsbits;
if (size < i_size_read(ac->ac_inode))
size = i_size_read(ac->ac_inode);
/* max size of free chunks */
max = 2 << bsbits;
#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
(req <= (size) || max <= (chunk_size))
/* first, try to predict filesize */
/* XXX: should this table be tunable? */
start_off = 0;
if (size <= 16 * 1024) {
size = 16 * 1024;
} else if (size <= 32 * 1024) {
size = 32 * 1024;
} else if (size <= 64 * 1024) {
size = 64 * 1024;
} else if (size <= 128 * 1024) {
size = 128 * 1024;
} else if (size <= 256 * 1024) {
size = 256 * 1024;
} else if (size <= 512 * 1024) {
size = 512 * 1024;
} else if (size <= 1024 * 1024) {
size = 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(21 - bsbits)) << 21;
size = 2 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(22 - bsbits)) << 22;
size = 4 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
(8<<20)>>bsbits, max, 8 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(23 - bsbits)) << 23;
size = 8 * 1024 * 1024;
} else {
start_off = (loff_t)ac->ac_o_ex.fe_logical << bsbits;
size = ac->ac_o_ex.fe_len << bsbits;
}
orig_size = size = size >> bsbits;
orig_start = start = start_off >> bsbits;
/* don't cover already allocated blocks in selected range */
if (ar->pleft && start <= ar->lleft) {
size -= ar->lleft + 1 - start;
start = ar->lleft + 1;
}
if (ar->pright && start + size - 1 >= ar->lright)
size -= start + size - ar->lright;
end = start + size;
/* check we don't cross already preallocated blocks */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
ext4_lblk_t pa_end;
if (pa->pa_deleted)
continue;
spin_lock(&pa->pa_lock);
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
pa_end = pa->pa_lstart + pa->pa_len;
/* PA must not overlap original request */
BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
ac->ac_o_ex.fe_logical < pa->pa_lstart));
/* skip PA normalized request doesn't overlap with */
if (pa->pa_lstart >= end) {
spin_unlock(&pa->pa_lock);
continue;
}
if (pa_end <= start) {
spin_unlock(&pa->pa_lock);
continue;
}
BUG_ON(pa->pa_lstart <= start && pa_end >= end);
if (pa_end <= ac->ac_o_ex.fe_logical) {
BUG_ON(pa_end < start);
start = pa_end;
}
if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
BUG_ON(pa->pa_lstart > end);
end = pa->pa_lstart;
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
size = end - start;
/* XXX: extra loop to check we really don't overlap preallocations */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
ext4_lblk_t pa_end;
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0) {
pa_end = pa->pa_lstart + pa->pa_len;
BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
if (start + size <= ac->ac_o_ex.fe_logical &&
start > ac->ac_o_ex.fe_logical) {
printk(KERN_ERR "start %lu, size %lu, fe_logical %lu\n",
(unsigned long) start, (unsigned long) size,
(unsigned long) ac->ac_o_ex.fe_logical);
}
BUG_ON(start + size <= ac->ac_o_ex.fe_logical &&
start > ac->ac_o_ex.fe_logical);
BUG_ON(size <= 0 || size >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
/* now prepare goal request */
/* XXX: is it better to align blocks WRT to logical
* placement or satisfy big request as is */
ac->ac_g_ex.fe_logical = start;
ac->ac_g_ex.fe_len = size;
/* define goal start in order to merge */
if (ar->pright && (ar->lright == (start + size))) {
/* merge to the right */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
&ac->ac_f_ex.fe_group,
&ac->ac_f_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
if (ar->pleft && (ar->lleft + 1 == start)) {
/* merge to the left */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
&ac->ac_f_ex.fe_group,
&ac->ac_f_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
mb_debug("goal: %u(was %u) blocks at %u\n", (unsigned) size,
(unsigned) orig_size, (unsigned) start);
}
static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
atomic_inc(&sbi->s_bal_reqs);
atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
if (ac->ac_o_ex.fe_len >= ac->ac_g_ex.fe_len)
atomic_inc(&sbi->s_bal_success);
atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
atomic_inc(&sbi->s_bal_goals);
if (ac->ac_found > sbi->s_mb_max_to_scan)
atomic_inc(&sbi->s_bal_breaks);
}
ext4_mb_store_history(ac);
}
/*
* use blocks preallocated to inode
*/
static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
ext4_fsblk_t start;
ext4_fsblk_t end;
int len;
/* found preallocated blocks, use them */
start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
len = end - start;
ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
BUG_ON(start < pa->pa_pstart);
BUG_ON(start + len > pa->pa_pstart + pa->pa_len);
BUG_ON(pa->pa_free < len);
pa->pa_free -= len;
mb_debug("use %llu/%u from inode pa %p\n", start, len, pa);
}
/*
* use blocks preallocated to locality group
*/
static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
unsigned int len = ac->ac_o_ex.fe_len;
ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
&ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
/* we don't correct pa_pstart or pa_plen here to avoid
* possible race when the group is being loaded concurrently
* instead we correct pa later, after blocks are marked
* in on-disk bitmap -- see ext4_mb_release_context()
* Other CPUs are prevented from allocating from this pa by lg_mutex
*/
mb_debug("use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
}
/*
* Return the prealloc space that have minimal distance
* from the goal block. @cpa is the prealloc
* space that is having currently known minimal distance
* from the goal block.
*/
static struct ext4_prealloc_space *
ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
struct ext4_prealloc_space *pa,
struct ext4_prealloc_space *cpa)
{
ext4_fsblk_t cur_distance, new_distance;
if (cpa == NULL) {
atomic_inc(&pa->pa_count);
return pa;
}
cur_distance = abs(goal_block - cpa->pa_pstart);
new_distance = abs(goal_block - pa->pa_pstart);
if (cur_distance < new_distance)
return cpa;
/* drop the previous reference */
atomic_dec(&cpa->pa_count);
atomic_inc(&pa->pa_count);
return pa;
}
/*
* search goal blocks in preallocated space
*/
static noinline_for_stack int
ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
{
int order, i;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa, *cpa = NULL;
ext4_fsblk_t goal_block;
/* only data can be preallocated */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return 0;
/* first, try per-file preallocation */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
/* all fields in this condition don't change,
* so we can skip locking for them */
if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len)
continue;
/* found preallocated blocks, use them */
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 && pa->pa_free) {
atomic_inc(&pa->pa_count);
ext4_mb_use_inode_pa(ac, pa);
spin_unlock(&pa->pa_lock);
ac->ac_criteria = 10;
rcu_read_unlock();
return 1;
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
/* can we use group allocation? */
if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
return 0;
/* inode may have no locality group for some reason */
lg = ac->ac_lg;
if (lg == NULL)
return 0;
order = fls(ac->ac_o_ex.fe_len) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
goal_block = ac->ac_g_ex.fe_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
ac->ac_g_ex.fe_start +
le32_to_cpu(EXT4_SB(ac->ac_sb)->s_es->s_first_data_block);
/*
* search for the prealloc space that is having
* minimal distance from the goal block.
*/
for (i = order; i < PREALLOC_TB_SIZE; i++) {
rcu_read_lock();
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
pa_inode_list) {
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 &&
pa->pa_free >= ac->ac_o_ex.fe_len) {
cpa = ext4_mb_check_group_pa(goal_block,
pa, cpa);
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
}
if (cpa) {
ext4_mb_use_group_pa(ac, cpa);
ac->ac_criteria = 20;
return 1;
}
return 0;
}
/*
* the function goes through all preallocation in this group and marks them
* used in in-core bitmap. buddy must be generated from this bitmap
* Need to be called with ext4 group lock (ext4_lock_group)
*/
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct ext4_prealloc_space *pa;
struct list_head *cur;
ext4_group_t groupnr;
ext4_grpblk_t start;
int preallocated = 0;
int count = 0;
int len;
/* all form of preallocation discards first load group,
* so the only competing code is preallocation use.
* we don't need any locking here
* notice we do NOT ignore preallocations with pa_deleted
* otherwise we could leave used blocks available for
* allocation in buddy when concurrent ext4_mb_put_pa()
* is dropping preallocation
*/
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
&groupnr, &start);
len = pa->pa_len;
spin_unlock(&pa->pa_lock);
if (unlikely(len == 0))
continue;
BUG_ON(groupnr != group);
mb_set_bits(sb_bgl_lock(EXT4_SB(sb), group),
bitmap, start, len);
preallocated += len;
count++;
}
mb_debug("prellocated %u for group %u\n", preallocated, group);
}
static void ext4_mb_pa_callback(struct rcu_head *head)
{
struct ext4_prealloc_space *pa;
pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
kmem_cache_free(ext4_pspace_cachep, pa);
}
/*
* drops a reference to preallocated space descriptor
* if this was the last reference and the space is consumed
*/
static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
struct super_block *sb, struct ext4_prealloc_space *pa)
{
ext4_group_t grp;
if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0)
return;
/* in this short window concurrent discard can set pa_deleted */
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 1) {
spin_unlock(&pa->pa_lock);
return;
}
pa->pa_deleted = 1;
spin_unlock(&pa->pa_lock);
/* -1 is to protect from crossing allocation group */
ext4_get_group_no_and_offset(sb, pa->pa_pstart - 1, &grp, NULL);
/*
* possible race:
*
* P1 (buddy init) P2 (regular allocation)
* find block B in PA
* copy on-disk bitmap to buddy
* mark B in on-disk bitmap
* drop PA from group
* mark all PAs in buddy
*
* thus, P1 initializes buddy with B available. to prevent this
* we make "copy" and "mark all PAs" atomic and serialize "drop PA"
* against that pair
*/
ext4_lock_group(sb, grp);
list_del(&pa->pa_group_list);
ext4_unlock_group(sb, grp);
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
/*
* creates new preallocated space for given inode
*/
static noinline_for_stack int
ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
struct ext4_inode_info *ei;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
if (pa == NULL)
return -ENOMEM;
if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
int winl;
int wins;
int win;
int offs;
/* we can't allocate as much as normalizer wants.
* so, found space must get proper lstart
* to cover original request */
BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
/* we're limited by original request in that
* logical block must be covered any way
* winl is window we can move our chunk within */
winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
/* also, we should cover whole original request */
wins = ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len;
/* the smallest one defines real window */
win = min(winl, wins);
offs = ac->ac_o_ex.fe_logical % ac->ac_b_ex.fe_len;
if (offs && offs < win)
win = offs;
ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical - win;
BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
}
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
pa->pa_lstart = ac->ac_b_ex.fe_logical;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
atomic_set(&pa->pa_count, 1);
spin_lock_init(&pa->pa_lock);
pa->pa_deleted = 0;
pa->pa_linear = 0;
mb_debug("new inode pa %p: %llu/%u for %u\n", pa,
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
ext4_mb_use_inode_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
ei = EXT4_I(ac->ac_inode);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
pa->pa_obj_lock = &ei->i_prealloc_lock;
pa->pa_inode = ac->ac_inode;
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
spin_lock(pa->pa_obj_lock);
list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
spin_unlock(pa->pa_obj_lock);
return 0;
}
/*
* creates new preallocated space for locality group inodes belongs to
*/
static noinline_for_stack int
ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
BUG_ON(ext4_pspace_cachep == NULL);
pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
if (pa == NULL)
return -ENOMEM;
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_lstart = pa->pa_pstart;
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
atomic_set(&pa->pa_count, 1);
spin_lock_init(&pa->pa_lock);
INIT_LIST_HEAD(&pa->pa_inode_list);
pa->pa_deleted = 0;
pa->pa_linear = 1;
mb_debug("new group pa %p: %llu/%u for %u\n", pa,
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
ext4_mb_use_group_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
lg = ac->ac_lg;
BUG_ON(lg == NULL);
pa->pa_obj_lock = &lg->lg_prealloc_lock;
pa->pa_inode = NULL;
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
/*
* We will later add the new pa to the right bucket
* after updating the pa_free in ext4_mb_release_context
*/
return 0;
}
static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
{
int err;
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
err = ext4_mb_new_group_pa(ac);
else
err = ext4_mb_new_inode_pa(ac);
return err;
}
/*
* finds all unused blocks in on-disk bitmap, frees them in
* in-core bitmap and buddy.
* @pa must be unlinked from inode and group lists, so that
* nobody else can find/use it.
* the caller MUST hold group/inode locks.
* TODO: optimize the case when there are no in-core structures yet
*/
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
struct ext4_prealloc_space *pa,
struct ext4_allocation_context *ac)
{
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned int end;
unsigned int next;
ext4_group_t group;
ext4_grpblk_t bit;
sector_t start;
int err = 0;
int free = 0;
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
end = bit + pa->pa_len;
if (ac) {
ac->ac_sb = sb;
ac->ac_inode = pa->pa_inode;
ac->ac_op = EXT4_MB_HISTORY_DISCARD;
}
while (bit < end) {
bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
if (bit >= end)
break;
next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +
le32_to_cpu(sbi->s_es->s_first_data_block);
mb_debug(" free preallocated %u/%u in group %u\n",
(unsigned) start, (unsigned) next - bit,
(unsigned) group);
free += next - bit;
if (ac) {
ac->ac_b_ex.fe_group = group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = next - bit;
ac->ac_b_ex.fe_logical = 0;
ext4_mb_store_history(ac);
}
mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
bit = next + 1;
}
if (free != pa->pa_free) {
printk(KERN_CRIT "pa %p: logic %lu, phys. %lu, len %lu\n",
pa, (unsigned long) pa->pa_lstart,
(unsigned long) pa->pa_pstart,
(unsigned long) pa->pa_len);
ext4_error(sb, __func__, "free %u, pa_free %u",
free, pa->pa_free);
/*
* pa is already deleted so we use the value obtained
* from the bitmap and continue.
*/
}
atomic_add(free, &sbi->s_mb_discarded);
return err;
}
static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
struct ext4_prealloc_space *pa,
struct ext4_allocation_context *ac)
{
struct super_block *sb = e4b->bd_sb;
ext4_group_t group;
ext4_grpblk_t bit;
if (ac)
ac->ac_op = EXT4_MB_HISTORY_DISCARD;
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
if (ac) {
ac->ac_sb = sb;
ac->ac_inode = NULL;
ac->ac_b_ex.fe_group = group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = pa->pa_len;
ac->ac_b_ex.fe_logical = 0;
ext4_mb_store_history(ac);
}
return 0;
}
/*
* releases all preallocations in given group
*
* first, we need to decide discard policy:
* - when do we discard
* 1) ENOSPC
* - how many do we discard
* 1) how many requested
*/
static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block *sb,
ext4_group_t group, int needed)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
struct list_head list;
struct ext4_buddy e4b;
int err;
int busy = 0;
int free = 0;
mb_debug("discard preallocation for group %u\n", group);
if (list_empty(&grp->bb_prealloc_list))
return 0;
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (bitmap_bh == NULL) {
ext4_error(sb, __func__, "Error in reading block "
"bitmap for %u", group);
return 0;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
ext4_error(sb, __func__, "Error in loading buddy "
"information for %u", group);
put_bh(bitmap_bh);
return 0;
}
if (needed == 0)
needed = EXT4_BLOCKS_PER_GROUP(sb) + 1;
INIT_LIST_HEAD(&list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
repeat:
ext4_lock_group(sb, group);
list_for_each_entry_safe(pa, tmp,
&grp->bb_prealloc_list, pa_group_list) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
spin_unlock(&pa->pa_lock);
busy = 1;
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* seems this one can be freed ... */
pa->pa_deleted = 1;
/* we can trust pa_free ... */
free += pa->pa_free;
spin_unlock(&pa->pa_lock);
list_del(&pa->pa_group_list);
list_add(&pa->u.pa_tmp_list, &list);
}
/* if we still need more blocks and some PAs were used, try again */
if (free < needed && busy) {
busy = 0;
ext4_unlock_group(sb, group);
/*
* Yield the CPU here so that we don't get soft lockup
* in non preempt case.
*/
yield();
goto repeat;
}
/* found anything to free? */
if (list_empty(&list)) {
BUG_ON(free != 0);
goto out;
}
/* now free all selected PAs */
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
/* remove from object (inode or locality group) */
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
if (pa->pa_linear)
ext4_mb_release_group_pa(&e4b, pa, ac);
else
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
out:
ext4_unlock_group(sb, group);
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
ext4_mb_release_desc(&e4b);
put_bh(bitmap_bh);
return free;
}
/*
* releases all non-used preallocated blocks for given inode
*
* It's important to discard preallocations under i_data_sem
* We don't want another block to be served from the prealloc
* space when we are discarding the inode prealloc space.
*
* FIXME!! Make sure it is valid at all the call sites
*/
void ext4_discard_preallocations(struct inode *inode)
{
struct ext4_inode_info *ei = EXT4_I(inode);
struct super_block *sb = inode->i_sb;
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
ext4_group_t group = 0;
struct list_head list;
struct ext4_buddy e4b;
int err;
if (!S_ISREG(inode->i_mode)) {
/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
return;
}
mb_debug("discard preallocation for inode %lu\n", inode->i_ino);
INIT_LIST_HEAD(&list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
repeat:
/* first, collect all pa's in the inode */
spin_lock(&ei->i_prealloc_lock);
while (!list_empty(&ei->i_prealloc_list)) {
pa = list_entry(ei->i_prealloc_list.next,
struct ext4_prealloc_space, pa_inode_list);
BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/* this shouldn't happen often - nobody should
* use preallocation while we're discarding it */
spin_unlock(&pa->pa_lock);
spin_unlock(&ei->i_prealloc_lock);
printk(KERN_ERR "uh-oh! used pa while discarding\n");
WARN_ON(1);
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
if (pa->pa_deleted == 0) {
pa->pa_deleted = 1;
spin_unlock(&pa->pa_lock);
list_del_rcu(&pa->pa_inode_list);
list_add(&pa->u.pa_tmp_list, &list);
continue;
}
/* someone is deleting pa right now */
spin_unlock(&pa->pa_lock);
spin_unlock(&ei->i_prealloc_lock);
/* we have to wait here because pa_deleted
* doesn't mean pa is already unlinked from
* the list. as we might be called from
* ->clear_inode() the inode will get freed
* and concurrent thread which is unlinking
* pa from inode's list may access already
* freed memory, bad-bad-bad */
/* XXX: if this happens too often, we can
* add a flag to force wait only in case
* of ->clear_inode(), but not in case of
* regular truncate */
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
spin_unlock(&ei->i_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
BUG_ON(pa->pa_linear != 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
ext4_error(sb, __func__, "Error in loading buddy "
"information for %u", group);
continue;
}
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (bitmap_bh == NULL) {
ext4_error(sb, __func__, "Error in reading block "
"bitmap for %u", group);
ext4_mb_release_desc(&e4b);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
put_bh(bitmap_bh);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
}
/*
* finds all preallocated spaces and return blocks being freed to them
* if preallocated space becomes full (no block is used from the space)
* then the function frees space in buddy
* XXX: at the moment, truncate (which is the only way to free blocks)
* discards all preallocations
*/
static void ext4_mb_return_to_preallocation(struct inode *inode,
struct ext4_buddy *e4b,
sector_t block, int count)
{
BUG_ON(!list_empty(&EXT4_I(inode)->i_prealloc_list));
}
#ifdef MB_DEBUG
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
ext4_group_t i;
printk(KERN_ERR "EXT4-fs: Can't allocate:"
" Allocation context details:\n");
printk(KERN_ERR "EXT4-fs: status %d flags %d\n",
ac->ac_status, ac->ac_flags);
printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
"best %lu/%lu/%lu@%lu cr %d\n",
(unsigned long)ac->ac_o_ex.fe_group,
(unsigned long)ac->ac_o_ex.fe_start,
(unsigned long)ac->ac_o_ex.fe_len,
(unsigned long)ac->ac_o_ex.fe_logical,
(unsigned long)ac->ac_g_ex.fe_group,
(unsigned long)ac->ac_g_ex.fe_start,
(unsigned long)ac->ac_g_ex.fe_len,
(unsigned long)ac->ac_g_ex.fe_logical,
(unsigned long)ac->ac_b_ex.fe_group,
(unsigned long)ac->ac_b_ex.fe_start,
(unsigned long)ac->ac_b_ex.fe_len,
(unsigned long)ac->ac_b_ex.fe_logical,
(int)ac->ac_criteria);
printk(KERN_ERR "EXT4-fs: %lu scanned, %d found\n", ac->ac_ex_scanned,
ac->ac_found);
printk(KERN_ERR "EXT4-fs: groups: \n");
for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
struct ext4_group_info *grp = ext4_get_group_info(sb, i);
struct ext4_prealloc_space *pa;
ext4_grpblk_t start;
struct list_head *cur;
ext4_lock_group(sb, i);
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space,
pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
NULL, &start);
spin_unlock(&pa->pa_lock);
printk(KERN_ERR "PA:%lu:%d:%u \n", i,
start, pa->pa_len);
}
ext4_unlock_group(sb, i);
if (grp->bb_free == 0)
continue;
printk(KERN_ERR "%lu: %d/%d \n",
i, grp->bb_free, grp->bb_fragments);
}
printk(KERN_ERR "\n");
}
#else
static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
return;
}
#endif
/*
* We use locality group preallocation for small size file. The size of the
* file is determined by the current size or the resulting size after
* allocation which ever is larger
*
* One can tune this size via /proc/fs/ext4/<partition>/stream_req
*/
static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int bsbits = ac->ac_sb->s_blocksize_bits;
loff_t size, isize;
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
isize = i_size_read(ac->ac_inode) >> bsbits;
size = max(size, isize);
/* don't use group allocation for large files */
if (size >= sbi->s_mb_stream_request)
return;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
BUG_ON(ac->ac_lg != NULL);
/*
* locality group prealloc space are per cpu. The reason for having
* per cpu locality group is to reduce the contention between block
* request from multiple CPUs.
*/
ac->ac_lg = per_cpu_ptr(sbi->s_locality_groups, raw_smp_processor_id());
/* we're going to use group allocation */
ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
/* serialize all allocations in the group */
mutex_lock(&ac->ac_lg->lg_mutex);
}
static noinline_for_stack int
ext4_mb_initialize_context(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
struct super_block *sb = ar->inode->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
ext4_group_t group;
unsigned int len;
ext4_fsblk_t goal;
ext4_grpblk_t block;
/* we can't allocate > group size */
len = ar->len;
/* just a dirty hack to filter too big requests */
if (len >= EXT4_BLOCKS_PER_GROUP(sb) - 10)
len = EXT4_BLOCKS_PER_GROUP(sb) - 10;
/* start searching from the goal */
goal = ar->goal;
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= ext4_blocks_count(es))
goal = le32_to_cpu(es->s_first_data_block);
ext4_get_group_no_and_offset(sb, goal, &group, &block);
/* set up allocation goals */
ac->ac_b_ex.fe_logical = ar->logical;
ac->ac_b_ex.fe_group = 0;
ac->ac_b_ex.fe_start = 0;
ac->ac_b_ex.fe_len = 0;
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_groups_scanned = 0;
ac->ac_ex_scanned = 0;
ac->ac_found = 0;
ac->ac_sb = sb;
ac->ac_inode = ar->inode;
ac->ac_o_ex.fe_logical = ar->logical;
ac->ac_o_ex.fe_group = group;
ac->ac_o_ex.fe_start = block;
ac->ac_o_ex.fe_len = len;
ac->ac_g_ex.fe_logical = ar->logical;
ac->ac_g_ex.fe_group = group;
ac->ac_g_ex.fe_start = block;
ac->ac_g_ex.fe_len = len;
ac->ac_f_ex.fe_len = 0;
ac->ac_flags = ar->flags;
ac->ac_2order = 0;
ac->ac_criteria = 0;
ac->ac_pa = NULL;
ac->ac_bitmap_page = NULL;
ac->ac_buddy_page = NULL;
ac->ac_lg = NULL;
/* we have to define context: we'll we work with a file or
* locality group. this is a policy, actually */
ext4_mb_group_or_file(ac);
mb_debug("init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
"left: %u/%u, right %u/%u to %swritable\n",
(unsigned) ar->len, (unsigned) ar->logical,
(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
(unsigned) ar->lleft, (unsigned) ar->pleft,
(unsigned) ar->lright, (unsigned) ar->pright,
atomic_read(&ar->inode->i_writecount) ? "" : "non-");
return 0;
}
static noinline_for_stack void
ext4_mb_discard_lg_preallocations(struct super_block *sb,
struct ext4_locality_group *lg,
int order, int total_entries)
{
ext4_group_t group = 0;
struct ext4_buddy e4b;
struct list_head discard_list;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
mb_debug("discard locality group preallocation\n");
INIT_LIST_HEAD(&discard_list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
pa_inode_list) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/*
* This is the pa that we just used
* for block allocation. So don't
* free that
*/
spin_unlock(&pa->pa_lock);
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* only lg prealloc space */
BUG_ON(!pa->pa_linear);
/* seems this one can be freed ... */
pa->pa_deleted = 1;
spin_unlock(&pa->pa_lock);
list_del_rcu(&pa->pa_inode_list);
list_add(&pa->u.pa_tmp_list, &discard_list);
total_entries--;
if (total_entries <= 5) {
/*
* we want to keep only 5 entries
* allowing it to grow to 8. This
* mak sure we don't call discard
* soon for this list.
*/
break;
}
}
spin_unlock(&lg->lg_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
if (ext4_mb_load_buddy(sb, group, &e4b)) {
ext4_error(sb, __func__, "Error in loading buddy "
"information for %u", group);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_group_pa(&e4b, pa, ac);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
}
/*
* We have incremented pa_count. So it cannot be freed at this
* point. Also we hold lg_mutex. So no parallel allocation is
* possible from this lg. That means pa_free cannot be updated.
*
* A parallel ext4_mb_discard_group_preallocations is possible.
* which can cause the lg_prealloc_list to be updated.
*/
static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
{
int order, added = 0, lg_prealloc_count = 1;
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
order = fls(pa->pa_free) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
/* Add the prealloc space to lg */
rcu_read_lock();
list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
pa_inode_list) {
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
if (!added && pa->pa_free < tmp_pa->pa_free) {
/* Add to the tail of the previous entry */
list_add_tail_rcu(&pa->pa_inode_list,
&tmp_pa->pa_inode_list);
added = 1;
/*
* we want to count the total
* number of entries in the list
*/
}
spin_unlock(&tmp_pa->pa_lock);
lg_prealloc_count++;
}
if (!added)
list_add_tail_rcu(&pa->pa_inode_list,
&lg->lg_prealloc_list[order]);
rcu_read_unlock();
/* Now trim the list to be not more than 8 elements */
if (lg_prealloc_count > 8) {
ext4_mb_discard_lg_preallocations(sb, lg,
order, lg_prealloc_count);
return;
}
return ;
}
/*
* release all resource we used in allocation
*/
static int ext4_mb_release_context(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa = ac->ac_pa;
if (pa) {
if (pa->pa_linear) {
/* see comment in ext4_mb_use_group_pa() */
spin_lock(&pa->pa_lock);
pa->pa_pstart += ac->ac_b_ex.fe_len;
pa->pa_lstart += ac->ac_b_ex.fe_len;
pa->pa_free -= ac->ac_b_ex.fe_len;
pa->pa_len -= ac->ac_b_ex.fe_len;
spin_unlock(&pa->pa_lock);
/*
* We want to add the pa to the right bucket.
* Remove it from the list and while adding
* make sure the list to which we are adding
* doesn't grow big.
*/
if (likely(pa->pa_free)) {
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
ext4_mb_add_n_trim(ac);
}
}
ext4_mb_put_pa(ac, ac->ac_sb, pa);
}
if (ac->ac_bitmap_page)
page_cache_release(ac->ac_bitmap_page);
if (ac->ac_buddy_page)
page_cache_release(ac->ac_buddy_page);
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
mutex_unlock(&ac->ac_lg->lg_mutex);
ext4_mb_collect_stats(ac);
return 0;
}
static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
{
ext4_group_t i;
int ret;
int freed = 0;
for (i = 0; i < EXT4_SB(sb)->s_groups_count && needed > 0; i++) {
ret = ext4_mb_discard_group_preallocations(sb, i, needed);
freed += ret;
needed -= ret;
}
return freed;
}
/*
* Main entry point into mballoc to allocate blocks
* it tries to use preallocation first, then falls back
* to usual allocation
*/
ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
struct ext4_allocation_request *ar, int *errp)
{
int freed;
struct ext4_allocation_context *ac = NULL;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block = 0;
unsigned int inquota;
unsigned int reserv_blks = 0;
sb = ar->inode->i_sb;
sbi = EXT4_SB(sb);
if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag) {
/*
* With delalloc we already reserved the blocks
*/
while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
/* let others to free the space */
yield();
ar->len = ar->len >> 1;
}
if (!ar->len) {
*errp = -ENOSPC;
return 0;
}
reserv_blks = ar->len;
}
while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) {
ar->flags |= EXT4_MB_HINT_NOPREALLOC;
ar->len--;
}
if (ar->len == 0) {
*errp = -EDQUOT;
return 0;
}
inquota = ar->len;
if (EXT4_I(ar->inode)->i_delalloc_reserved_flag)
ar->flags |= EXT4_MB_DELALLOC_RESERVED;
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (!ac) {
ar->len = 0;
*errp = -ENOMEM;
goto out1;
}
*errp = ext4_mb_initialize_context(ac, ar);
if (*errp) {
ar->len = 0;
goto out2;
}
ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
if (!ext4_mb_use_preallocated(ac)) {
ac->ac_op = EXT4_MB_HISTORY_ALLOC;
ext4_mb_normalize_request(ac, ar);
repeat:
/* allocate space in core */
ext4_mb_regular_allocator(ac);
/* as we've just preallocated more space than
* user requested orinally, we store allocated
* space in a special descriptor */
if (ac->ac_status == AC_STATUS_FOUND &&
ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
ext4_mb_new_preallocation(ac);
}
if (likely(ac->ac_status == AC_STATUS_FOUND)) {
*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_blks);
if (*errp == -EAGAIN) {
ac->ac_b_ex.fe_group = 0;
ac->ac_b_ex.fe_start = 0;
ac->ac_b_ex.fe_len = 0;
ac->ac_status = AC_STATUS_CONTINUE;
goto repeat;
} else if (*errp) {
ac->ac_b_ex.fe_len = 0;
ar->len = 0;
ext4_mb_show_ac(ac);
} else {
block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
ar->len = ac->ac_b_ex.fe_len;
}
} else {
freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
if (freed)
goto repeat;
*errp = -ENOSPC;
ac->ac_b_ex.fe_len = 0;
ar->len = 0;
ext4_mb_show_ac(ac);
}
ext4_mb_release_context(ac);
out2:
kmem_cache_free(ext4_ac_cachep, ac);
out1:
if (ar->len < inquota)
DQUOT_FREE_BLOCK(ar->inode, inquota - ar->len);
return block;
}
/*
* We can merge two free data extents only if the physical blocks
* are contiguous, AND the extents were freed by the same transaction,
* AND the blocks are associated with the same group.
*/
static int can_merge(struct ext4_free_data *entry1,
struct ext4_free_data *entry2)
{
if ((entry1->t_tid == entry2->t_tid) &&
(entry1->group == entry2->group) &&
((entry1->start_blk + entry1->count) == entry2->start_blk))
return 1;
return 0;
}
static noinline_for_stack int
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
ext4_group_t group, ext4_grpblk_t block, int count)
{
struct ext4_group_info *db = e4b->bd_info;
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_free_data *entry, *new_entry;
struct rb_node **n = &db->bb_free_root.rb_node, *node;
struct rb_node *parent = NULL, *new_node;
BUG_ON(!ext4_handle_valid(handle));
BUG_ON(e4b->bd_bitmap_page == NULL);
BUG_ON(e4b->bd_buddy_page == NULL);
new_entry = kmem_cache_alloc(ext4_free_ext_cachep, GFP_NOFS);
new_entry->start_blk = block;
new_entry->group = group;
new_entry->count = count;
new_entry->t_tid = handle->h_transaction->t_tid;
new_node = &new_entry->node;
ext4_lock_group(sb, group);
if (!*n) {
/* first free block exent. We need to
protect buddy cache from being freed,
* otherwise we'll refresh it from
* on-disk bitmap and lose not-yet-available
* blocks */
page_cache_get(e4b->bd_buddy_page);
page_cache_get(e4b->bd_bitmap_page);
}
while (*n) {
parent = *n;
entry = rb_entry(parent, struct ext4_free_data, node);
if (block < entry->start_blk)
n = &(*n)->rb_left;
else if (block >= (entry->start_blk + entry->count))
n = &(*n)->rb_right;
else {
ext4_unlock_group(sb, group);
ext4_error(sb, __func__,
"Double free of blocks %d (%d %d)",
block, entry->start_blk, entry->count);
return 0;
}
}
rb_link_node(new_node, parent, n);
rb_insert_color(new_node, &db->bb_free_root);
/* Now try to see the extent can be merged to left and right */
node = rb_prev(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, node);
if (can_merge(entry, new_entry)) {
new_entry->start_blk = entry->start_blk;
new_entry->count += entry->count;
rb_erase(node, &(db->bb_free_root));
spin_lock(&sbi->s_md_lock);
list_del(&entry->list);
spin_unlock(&sbi->s_md_lock);
kmem_cache_free(ext4_free_ext_cachep, entry);
}
}
node = rb_next(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, node);
if (can_merge(new_entry, entry)) {
new_entry->count += entry->count;
rb_erase(node, &(db->bb_free_root));
spin_lock(&sbi->s_md_lock);
list_del(&entry->list);
spin_unlock(&sbi->s_md_lock);
kmem_cache_free(ext4_free_ext_cachep, entry);
}
}
/* Add the extent to transaction's private list */
spin_lock(&sbi->s_md_lock);
list_add(&new_entry->list, &handle->h_transaction->t_private_list);
spin_unlock(&sbi->s_md_lock);
ext4_unlock_group(sb, group);
return 0;
}
/*
* Main entry point into mballoc to free blocks
*/
void ext4_mb_free_blocks(handle_t *handle, struct inode *inode,
unsigned long block, unsigned long count,
int metadata, unsigned long *freed)
{
struct buffer_head *bitmap_bh = NULL;
struct super_block *sb = inode->i_sb;
struct ext4_allocation_context *ac = NULL;
struct ext4_group_desc *gdp;
struct ext4_super_block *es;
unsigned int overflow;
ext4_grpblk_t bit;
struct buffer_head *gd_bh;
ext4_group_t block_group;
struct ext4_sb_info *sbi;
struct ext4_buddy e4b;
int err = 0;
int ret;
*freed = 0;
sbi = EXT4_SB(sb);
es = EXT4_SB(sb)->s_es;
if (block < le32_to_cpu(es->s_first_data_block) ||
block + count < block ||
block + count > ext4_blocks_count(es)) {
ext4_error(sb, __func__,
"Freeing blocks not in datazone - "
"block = %lu, count = %lu", block, count);
goto error_return;
}
ext4_debug("freeing block %lu\n", block);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac) {
ac->ac_op = EXT4_MB_HISTORY_FREE;
ac->ac_inode = inode;
ac->ac_sb = sb;
}
do_more:
overflow = 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb);
count -= overflow;
}
bitmap_bh = ext4_read_block_bitmap(sb, block_group);
if (!bitmap_bh) {
err = -EIO;
goto error_return;
}
gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
if (!gdp) {
err = -EIO;
goto error_return;
}
if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
in_range(block, ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group) ||
in_range(block + count - 1, ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group)) {
ext4_error(sb, __func__,
"Freeing blocks in system zone - "
"Block = %lu, count = %lu", block, count);
/* err = 0. ext4_std_error should be a no op */
goto error_return;
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, bitmap_bh);
if (err)
goto error_return;
/*
* We are about to modify some metadata. Call the journal APIs
* to unshare ->b_data if a currently-committing transaction is
* using it
*/
BUFFER_TRACE(gd_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gd_bh);
if (err)
goto error_return;
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < count; i++)
BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
}
#endif
mb_clear_bits(sb_bgl_lock(sbi, block_group), bitmap_bh->b_data,
bit, count);
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (err)
goto error_return;
if (ac) {
ac->ac_b_ex.fe_group = block_group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = count;
ext4_mb_store_history(ac);
}
err = ext4_mb_load_buddy(sb, block_group, &e4b);
if (err)
goto error_return;
if (metadata && ext4_handle_valid(handle)) {
/* blocks being freed are metadata. these blocks shouldn't
* be used until this transaction is committed */
ext4_mb_free_metadata(handle, &e4b, block_group, bit, count);
} else {
ext4_lock_group(sb, block_group);
mb_free_blocks(inode, &e4b, bit, count);
ext4_mb_return_to_preallocation(inode, &e4b, block, count);
ext4_unlock_group(sb, block_group);
}
spin_lock(sb_bgl_lock(sbi, block_group));
le16_add_cpu(&gdp->bg_free_blocks_count, count);
gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
spin_unlock(sb_bgl_lock(sbi, block_group));
percpu_counter_add(&sbi->s_freeblocks_counter, count);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
spin_lock(sb_bgl_lock(sbi, flex_group));
sbi->s_flex_groups[flex_group].free_blocks += count;
spin_unlock(sb_bgl_lock(sbi, flex_group));
}
ext4_mb_release_desc(&e4b);
*freed += count;
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
if (!err)
err = ret;
if (overflow && !err) {
block += count;
count = overflow;
put_bh(bitmap_bh);
goto do_more;
}
sb->s_dirt = 1;
error_return:
brelse(bitmap_bh);
ext4_std_error(sb, err);
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
return;
}
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