linux/fs/nilfs2/the_nilfs.c
Ryusuke Konishi 1ab8425091 nilfs2: fix inode number range checks
Patch series "nilfs2: fix potential issues related to reserved inodes".

This series fixes one use-after-free issue reported by syzbot, caused by
nilfs2's internal inode being exposed in the namespace on a corrupted
filesystem, and a couple of flaws that cause problems if the starting
number of non-reserved inodes written in the on-disk super block is
intentionally (or corruptly) changed from its default value.  


This patch (of 3):

In the current implementation of nilfs2, "nilfs->ns_first_ino", which
gives the first non-reserved inode number, is read from the superblock,
but its lower limit is not checked.

As a result, if a number that overlaps with the inode number range of
reserved inodes such as the root directory or metadata files is set in the
super block parameter, the inode number test macros (NILFS_MDT_INODE and
NILFS_VALID_INODE) will not function properly.

In addition, these test macros use left bit-shift calculations using with
the inode number as the shift count via the BIT macro, but the result of a
shift calculation that exceeds the bit width of an integer is undefined in
the C specification, so if "ns_first_ino" is set to a large value other
than the default value NILFS_USER_INO (=11), the macros may potentially
malfunction depending on the environment.

Fix these issues by checking the lower bound of "nilfs->ns_first_ino" and
by preventing bit shifts equal to or greater than the NILFS_USER_INO
constant in the inode number test macros.

Also, change the type of "ns_first_ino" from signed integer to unsigned
integer to avoid the need for type casting in comparisons such as the
lower bound check introduced this time.

Link: https://lkml.kernel.org/r/20240623051135.4180-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240623051135.4180-2-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:15 -07:00

936 lines
24 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* the_nilfs shared structure.
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* Written by Ryusuke Konishi.
*
*/
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/random.h>
#include <linux/log2.h>
#include <linux/crc32.h>
#include "nilfs.h"
#include "segment.h"
#include "alloc.h"
#include "cpfile.h"
#include "sufile.h"
#include "dat.h"
#include "segbuf.h"
static int nilfs_valid_sb(struct nilfs_super_block *sbp);
void nilfs_set_last_segment(struct the_nilfs *nilfs,
sector_t start_blocknr, u64 seq, __u64 cno)
{
spin_lock(&nilfs->ns_last_segment_lock);
nilfs->ns_last_pseg = start_blocknr;
nilfs->ns_last_seq = seq;
nilfs->ns_last_cno = cno;
if (!nilfs_sb_dirty(nilfs)) {
if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
goto stay_cursor;
set_nilfs_sb_dirty(nilfs);
}
nilfs->ns_prev_seq = nilfs->ns_last_seq;
stay_cursor:
spin_unlock(&nilfs->ns_last_segment_lock);
}
/**
* alloc_nilfs - allocate a nilfs object
* @sb: super block instance
*
* Return Value: On success, pointer to the_nilfs is returned.
* On error, NULL is returned.
*/
struct the_nilfs *alloc_nilfs(struct super_block *sb)
{
struct the_nilfs *nilfs;
nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
if (!nilfs)
return NULL;
nilfs->ns_sb = sb;
nilfs->ns_bdev = sb->s_bdev;
atomic_set(&nilfs->ns_ndirtyblks, 0);
init_rwsem(&nilfs->ns_sem);
mutex_init(&nilfs->ns_snapshot_mount_mutex);
INIT_LIST_HEAD(&nilfs->ns_dirty_files);
INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
spin_lock_init(&nilfs->ns_inode_lock);
spin_lock_init(&nilfs->ns_next_gen_lock);
spin_lock_init(&nilfs->ns_last_segment_lock);
nilfs->ns_cptree = RB_ROOT;
spin_lock_init(&nilfs->ns_cptree_lock);
init_rwsem(&nilfs->ns_segctor_sem);
nilfs->ns_sb_update_freq = NILFS_SB_FREQ;
return nilfs;
}
/**
* destroy_nilfs - destroy nilfs object
* @nilfs: nilfs object to be released
*/
void destroy_nilfs(struct the_nilfs *nilfs)
{
might_sleep();
if (nilfs_init(nilfs)) {
brelse(nilfs->ns_sbh[0]);
brelse(nilfs->ns_sbh[1]);
}
kfree(nilfs);
}
static int nilfs_load_super_root(struct the_nilfs *nilfs,
struct super_block *sb, sector_t sr_block)
{
struct buffer_head *bh_sr;
struct nilfs_super_root *raw_sr;
struct nilfs_super_block **sbp = nilfs->ns_sbp;
struct nilfs_inode *rawi;
unsigned int dat_entry_size, segment_usage_size, checkpoint_size;
unsigned int inode_size;
int err;
err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
if (unlikely(err))
return err;
down_read(&nilfs->ns_sem);
dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
up_read(&nilfs->ns_sem);
inode_size = nilfs->ns_inode_size;
rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
if (err)
goto failed;
rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
if (err)
goto failed_dat;
rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
err = nilfs_sufile_read(sb, segment_usage_size, rawi,
&nilfs->ns_sufile);
if (err)
goto failed_cpfile;
raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
failed:
brelse(bh_sr);
return err;
failed_cpfile:
iput(nilfs->ns_cpfile);
failed_dat:
iput(nilfs->ns_dat);
goto failed;
}
static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
{
memset(ri, 0, sizeof(*ri));
INIT_LIST_HEAD(&ri->ri_used_segments);
}
static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
{
nilfs_dispose_segment_list(&ri->ri_used_segments);
}
/**
* nilfs_store_log_cursor - load log cursor from a super block
* @nilfs: nilfs object
* @sbp: buffer storing super block to be read
*
* nilfs_store_log_cursor() reads the last position of the log
* containing a super root from a given super block, and initializes
* relevant information on the nilfs object preparatory for log
* scanning and recovery.
*/
static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
struct nilfs_super_block *sbp)
{
int ret = 0;
nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
nilfs->ns_prev_seq = nilfs->ns_last_seq;
nilfs->ns_seg_seq = nilfs->ns_last_seq;
nilfs->ns_segnum =
nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
nilfs->ns_cno = nilfs->ns_last_cno + 1;
if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
nilfs_err(nilfs->ns_sb,
"pointed segment number is out of range: segnum=%llu, nsegments=%lu",
(unsigned long long)nilfs->ns_segnum,
nilfs->ns_nsegments);
ret = -EINVAL;
}
return ret;
}
/**
* nilfs_get_blocksize - get block size from raw superblock data
* @sb: super block instance
* @sbp: superblock raw data buffer
* @blocksize: place to store block size
*
* nilfs_get_blocksize() calculates the block size from the block size
* exponent information written in @sbp and stores it in @blocksize,
* or aborts with an error message if it's too large.
*
* Return Value: On success, 0 is returned. If the block size is too
* large, -EINVAL is returned.
*/
static int nilfs_get_blocksize(struct super_block *sb,
struct nilfs_super_block *sbp, int *blocksize)
{
unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
if (unlikely(shift_bits >
ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)) {
nilfs_err(sb, "too large filesystem blocksize: 2 ^ %u KiB",
shift_bits);
return -EINVAL;
}
*blocksize = BLOCK_SIZE << shift_bits;
return 0;
}
/**
* load_nilfs - load and recover the nilfs
* @nilfs: the_nilfs structure to be released
* @sb: super block instance used to recover past segment
*
* load_nilfs() searches and load the latest super root,
* attaches the last segment, and does recovery if needed.
* The caller must call this exclusively for simultaneous mounts.
*/
int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
{
struct nilfs_recovery_info ri;
unsigned int s_flags = sb->s_flags;
int really_read_only = bdev_read_only(nilfs->ns_bdev);
int valid_fs = nilfs_valid_fs(nilfs);
int err;
if (!valid_fs) {
nilfs_warn(sb, "mounting unchecked fs");
if (s_flags & SB_RDONLY) {
nilfs_info(sb,
"recovery required for readonly filesystem");
nilfs_info(sb,
"write access will be enabled during recovery");
}
}
nilfs_init_recovery_info(&ri);
err = nilfs_search_super_root(nilfs, &ri);
if (unlikely(err)) {
struct nilfs_super_block **sbp = nilfs->ns_sbp;
int blocksize;
if (err != -EINVAL)
goto scan_error;
if (!nilfs_valid_sb(sbp[1])) {
nilfs_warn(sb,
"unable to fall back to spare super block");
goto scan_error;
}
nilfs_info(sb, "trying rollback from an earlier position");
/*
* restore super block with its spare and reconfigure
* relevant states of the nilfs object.
*/
memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
/* verify consistency between two super blocks */
err = nilfs_get_blocksize(sb, sbp[0], &blocksize);
if (err)
goto scan_error;
if (blocksize != nilfs->ns_blocksize) {
nilfs_warn(sb,
"blocksize differs between two super blocks (%d != %d)",
blocksize, nilfs->ns_blocksize);
err = -EINVAL;
goto scan_error;
}
err = nilfs_store_log_cursor(nilfs, sbp[0]);
if (err)
goto scan_error;
/* drop clean flag to allow roll-forward and recovery */
nilfs->ns_mount_state &= ~NILFS_VALID_FS;
valid_fs = 0;
err = nilfs_search_super_root(nilfs, &ri);
if (err)
goto scan_error;
}
err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
if (unlikely(err)) {
nilfs_err(sb, "error %d while loading super root", err);
goto failed;
}
err = nilfs_sysfs_create_device_group(sb);
if (unlikely(err))
goto sysfs_error;
if (valid_fs)
goto skip_recovery;
if (s_flags & SB_RDONLY) {
__u64 features;
if (nilfs_test_opt(nilfs, NORECOVERY)) {
nilfs_info(sb,
"norecovery option specified, skipping roll-forward recovery");
goto skip_recovery;
}
features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
~NILFS_FEATURE_COMPAT_RO_SUPP;
if (features) {
nilfs_err(sb,
"couldn't proceed with recovery because of unsupported optional features (%llx)",
(unsigned long long)features);
err = -EROFS;
goto failed_unload;
}
if (really_read_only) {
nilfs_err(sb,
"write access unavailable, cannot proceed");
err = -EROFS;
goto failed_unload;
}
sb->s_flags &= ~SB_RDONLY;
} else if (nilfs_test_opt(nilfs, NORECOVERY)) {
nilfs_err(sb,
"recovery cancelled because norecovery option was specified for a read/write mount");
err = -EINVAL;
goto failed_unload;
}
err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
if (err)
goto failed_unload;
down_write(&nilfs->ns_sem);
nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
err = nilfs_cleanup_super(sb);
up_write(&nilfs->ns_sem);
if (err) {
nilfs_err(sb,
"error %d updating super block. recovery unfinished.",
err);
goto failed_unload;
}
nilfs_info(sb, "recovery complete");
skip_recovery:
nilfs_clear_recovery_info(&ri);
sb->s_flags = s_flags;
return 0;
scan_error:
nilfs_err(sb, "error %d while searching super root", err);
goto failed;
failed_unload:
nilfs_sysfs_delete_device_group(nilfs);
sysfs_error:
iput(nilfs->ns_cpfile);
iput(nilfs->ns_sufile);
iput(nilfs->ns_dat);
failed:
nilfs_clear_recovery_info(&ri);
sb->s_flags = s_flags;
return err;
}
static unsigned long long nilfs_max_size(unsigned int blkbits)
{
unsigned int max_bits;
unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
if (max_bits < 64)
res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
return res;
}
/**
* nilfs_nrsvsegs - calculate the number of reserved segments
* @nilfs: nilfs object
* @nsegs: total number of segments
*/
unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
{
return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
100));
}
/**
* nilfs_max_segment_count - calculate the maximum number of segments
* @nilfs: nilfs object
*/
static u64 nilfs_max_segment_count(struct the_nilfs *nilfs)
{
u64 max_count = U64_MAX;
max_count = div64_ul(max_count, nilfs->ns_blocks_per_segment);
return min_t(u64, max_count, ULONG_MAX);
}
void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
{
nilfs->ns_nsegments = nsegs;
nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
}
static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
struct nilfs_super_block *sbp)
{
u64 nsegments, nblocks;
if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
nilfs_err(nilfs->ns_sb,
"unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).",
le32_to_cpu(sbp->s_rev_level),
le16_to_cpu(sbp->s_minor_rev_level),
NILFS_CURRENT_REV, NILFS_MINOR_REV);
return -EINVAL;
}
nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
if (nilfs->ns_sbsize > BLOCK_SIZE)
return -EINVAL;
nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
if (nilfs->ns_inode_size > nilfs->ns_blocksize) {
nilfs_err(nilfs->ns_sb, "too large inode size: %d bytes",
nilfs->ns_inode_size);
return -EINVAL;
} else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) {
nilfs_err(nilfs->ns_sb, "too small inode size: %d bytes",
nilfs->ns_inode_size);
return -EINVAL;
}
nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
if (nilfs->ns_first_ino < NILFS_USER_INO) {
nilfs_err(nilfs->ns_sb,
"too small lower limit for non-reserved inode numbers: %u",
nilfs->ns_first_ino);
return -EINVAL;
}
nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
nilfs_err(nilfs->ns_sb, "too short segment: %lu blocks",
nilfs->ns_blocks_per_segment);
return -EINVAL;
}
nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
nilfs->ns_r_segments_percentage =
le32_to_cpu(sbp->s_r_segments_percentage);
if (nilfs->ns_r_segments_percentage < 1 ||
nilfs->ns_r_segments_percentage > 99) {
nilfs_err(nilfs->ns_sb,
"invalid reserved segments percentage: %lu",
nilfs->ns_r_segments_percentage);
return -EINVAL;
}
nsegments = le64_to_cpu(sbp->s_nsegments);
if (nsegments > nilfs_max_segment_count(nilfs)) {
nilfs_err(nilfs->ns_sb,
"segment count %llu exceeds upper limit (%llu segments)",
(unsigned long long)nsegments,
(unsigned long long)nilfs_max_segment_count(nilfs));
return -EINVAL;
}
nblocks = sb_bdev_nr_blocks(nilfs->ns_sb);
if (nblocks) {
u64 min_block_count = nsegments * nilfs->ns_blocks_per_segment;
/*
* To avoid failing to mount early device images without a
* second superblock, exclude that block count from the
* "min_block_count" calculation.
*/
if (nblocks < min_block_count) {
nilfs_err(nilfs->ns_sb,
"total number of segment blocks %llu exceeds device size (%llu blocks)",
(unsigned long long)min_block_count,
(unsigned long long)nblocks);
return -EINVAL;
}
}
nilfs_set_nsegments(nilfs, nsegments);
nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
return 0;
}
static int nilfs_valid_sb(struct nilfs_super_block *sbp)
{
static unsigned char sum[4];
const int sumoff = offsetof(struct nilfs_super_block, s_sum);
size_t bytes;
u32 crc;
if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
return 0;
bytes = le16_to_cpu(sbp->s_bytes);
if (bytes < sumoff + 4 || bytes > BLOCK_SIZE)
return 0;
crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
sumoff);
crc = crc32_le(crc, sum, 4);
crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
bytes - sumoff - 4);
return crc == le32_to_cpu(sbp->s_sum);
}
/**
* nilfs_sb2_bad_offset - check the location of the second superblock
* @sbp: superblock raw data buffer
* @offset: byte offset of second superblock calculated from device size
*
* nilfs_sb2_bad_offset() checks if the position on the second
* superblock is valid or not based on the filesystem parameters
* stored in @sbp. If @offset points to a location within the segment
* area, or if the parameters themselves are not normal, it is
* determined to be invalid.
*
* Return Value: true if invalid, false if valid.
*/
static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
{
unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
u32 blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
u64 nsegments = le64_to_cpu(sbp->s_nsegments);
u64 index;
if (blocks_per_segment < NILFS_SEG_MIN_BLOCKS ||
shift_bits > ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)
return true;
index = offset >> (shift_bits + BLOCK_SIZE_BITS);
do_div(index, blocks_per_segment);
return index < nsegments;
}
static void nilfs_release_super_block(struct the_nilfs *nilfs)
{
int i;
for (i = 0; i < 2; i++) {
if (nilfs->ns_sbp[i]) {
brelse(nilfs->ns_sbh[i]);
nilfs->ns_sbh[i] = NULL;
nilfs->ns_sbp[i] = NULL;
}
}
}
void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
{
brelse(nilfs->ns_sbh[0]);
nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
nilfs->ns_sbh[1] = NULL;
nilfs->ns_sbp[1] = NULL;
}
void nilfs_swap_super_block(struct the_nilfs *nilfs)
{
struct buffer_head *tsbh = nilfs->ns_sbh[0];
struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
nilfs->ns_sbh[1] = tsbh;
nilfs->ns_sbp[1] = tsbp;
}
static int nilfs_load_super_block(struct the_nilfs *nilfs,
struct super_block *sb, int blocksize,
struct nilfs_super_block **sbpp)
{
struct nilfs_super_block **sbp = nilfs->ns_sbp;
struct buffer_head **sbh = nilfs->ns_sbh;
u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev);
int valid[2], swp = 0, older;
if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) {
nilfs_err(sb, "device size too small");
return -EINVAL;
}
sb2off = NILFS_SB2_OFFSET_BYTES(devsize);
sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
&sbh[0]);
sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
if (!sbp[0]) {
if (!sbp[1]) {
nilfs_err(sb, "unable to read superblock");
return -EIO;
}
nilfs_warn(sb,
"unable to read primary superblock (blocksize = %d)",
blocksize);
} else if (!sbp[1]) {
nilfs_warn(sb,
"unable to read secondary superblock (blocksize = %d)",
blocksize);
}
/*
* Compare two super blocks and set 1 in swp if the secondary
* super block is valid and newer. Otherwise, set 0 in swp.
*/
valid[0] = nilfs_valid_sb(sbp[0]);
valid[1] = nilfs_valid_sb(sbp[1]);
swp = valid[1] && (!valid[0] ||
le64_to_cpu(sbp[1]->s_last_cno) >
le64_to_cpu(sbp[0]->s_last_cno));
if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
brelse(sbh[1]);
sbh[1] = NULL;
sbp[1] = NULL;
valid[1] = 0;
swp = 0;
}
if (!valid[swp]) {
nilfs_release_super_block(nilfs);
nilfs_err(sb, "couldn't find nilfs on the device");
return -EINVAL;
}
if (!valid[!swp])
nilfs_warn(sb,
"broken superblock, retrying with spare superblock (blocksize = %d)",
blocksize);
if (swp)
nilfs_swap_super_block(nilfs);
/*
* Calculate the array index of the older superblock data.
* If one has been dropped, set index 0 pointing to the remaining one,
* otherwise set index 1 pointing to the old one (including if both
* are the same).
*
* Divided case valid[0] valid[1] swp -> older
* -------------------------------------------------------------
* Both SBs are invalid 0 0 N/A (Error)
* SB1 is invalid 0 1 1 0
* SB2 is invalid 1 0 0 0
* SB2 is newer 1 1 1 0
* SB2 is older or the same 1 1 0 1
*/
older = valid[1] ^ swp;
nilfs->ns_sbwcount = 0;
nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
nilfs->ns_prot_seq = le64_to_cpu(sbp[older]->s_last_seq);
*sbpp = sbp[0];
return 0;
}
/**
* init_nilfs - initialize a NILFS instance.
* @nilfs: the_nilfs structure
* @sb: super block
*
* init_nilfs() performs common initialization per block device (e.g.
* reading the super block, getting disk layout information, initializing
* shared fields in the_nilfs).
*
* Return Value: On success, 0 is returned. On error, a negative error
* code is returned.
*/
int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
{
struct nilfs_super_block *sbp;
int blocksize;
int err;
down_write(&nilfs->ns_sem);
blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
if (!blocksize) {
nilfs_err(sb, "unable to set blocksize");
err = -EINVAL;
goto out;
}
err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
if (err)
goto out;
err = nilfs_store_magic(sb, sbp);
if (err)
goto failed_sbh;
err = nilfs_check_feature_compatibility(sb, sbp);
if (err)
goto failed_sbh;
err = nilfs_get_blocksize(sb, sbp, &blocksize);
if (err)
goto failed_sbh;
if (blocksize < NILFS_MIN_BLOCK_SIZE) {
nilfs_err(sb,
"couldn't mount because of unsupported filesystem blocksize %d",
blocksize);
err = -EINVAL;
goto failed_sbh;
}
if (sb->s_blocksize != blocksize) {
int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
if (blocksize < hw_blocksize) {
nilfs_err(sb,
"blocksize %d too small for device (sector-size = %d)",
blocksize, hw_blocksize);
err = -EINVAL;
goto failed_sbh;
}
nilfs_release_super_block(nilfs);
if (!sb_set_blocksize(sb, blocksize)) {
nilfs_err(sb, "bad blocksize %d", blocksize);
err = -EINVAL;
goto out;
}
err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
if (err)
goto out;
/*
* Not to failed_sbh; sbh is released automatically
* when reloading fails.
*/
}
nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
nilfs->ns_blocksize = blocksize;
get_random_bytes(&nilfs->ns_next_generation,
sizeof(nilfs->ns_next_generation));
err = nilfs_store_disk_layout(nilfs, sbp);
if (err)
goto failed_sbh;
sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
err = nilfs_store_log_cursor(nilfs, sbp);
if (err)
goto failed_sbh;
set_nilfs_init(nilfs);
err = 0;
out:
up_write(&nilfs->ns_sem);
return err;
failed_sbh:
nilfs_release_super_block(nilfs);
goto out;
}
int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
size_t nsegs)
{
sector_t seg_start, seg_end;
sector_t start = 0, nblocks = 0;
unsigned int sects_per_block;
__u64 *sn;
int ret = 0;
sects_per_block = (1 << nilfs->ns_blocksize_bits) /
bdev_logical_block_size(nilfs->ns_bdev);
for (sn = segnump; sn < segnump + nsegs; sn++) {
nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
if (!nblocks) {
start = seg_start;
nblocks = seg_end - seg_start + 1;
} else if (start + nblocks == seg_start) {
nblocks += seg_end - seg_start + 1;
} else {
ret = blkdev_issue_discard(nilfs->ns_bdev,
start * sects_per_block,
nblocks * sects_per_block,
GFP_NOFS);
if (ret < 0)
return ret;
nblocks = 0;
}
}
if (nblocks)
ret = blkdev_issue_discard(nilfs->ns_bdev,
start * sects_per_block,
nblocks * sects_per_block,
GFP_NOFS);
return ret;
}
int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
{
unsigned long ncleansegs;
ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
*nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
return 0;
}
int nilfs_near_disk_full(struct the_nilfs *nilfs)
{
unsigned long ncleansegs, nincsegs;
ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
nilfs->ns_blocks_per_segment + 1;
return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
}
struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
{
struct rb_node *n;
struct nilfs_root *root;
spin_lock(&nilfs->ns_cptree_lock);
n = nilfs->ns_cptree.rb_node;
while (n) {
root = rb_entry(n, struct nilfs_root, rb_node);
if (cno < root->cno) {
n = n->rb_left;
} else if (cno > root->cno) {
n = n->rb_right;
} else {
refcount_inc(&root->count);
spin_unlock(&nilfs->ns_cptree_lock);
return root;
}
}
spin_unlock(&nilfs->ns_cptree_lock);
return NULL;
}
struct nilfs_root *
nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
{
struct rb_node **p, *parent;
struct nilfs_root *root, *new;
int err;
root = nilfs_lookup_root(nilfs, cno);
if (root)
return root;
new = kzalloc(sizeof(*root), GFP_KERNEL);
if (!new)
return NULL;
spin_lock(&nilfs->ns_cptree_lock);
p = &nilfs->ns_cptree.rb_node;
parent = NULL;
while (*p) {
parent = *p;
root = rb_entry(parent, struct nilfs_root, rb_node);
if (cno < root->cno) {
p = &(*p)->rb_left;
} else if (cno > root->cno) {
p = &(*p)->rb_right;
} else {
refcount_inc(&root->count);
spin_unlock(&nilfs->ns_cptree_lock);
kfree(new);
return root;
}
}
new->cno = cno;
new->ifile = NULL;
new->nilfs = nilfs;
refcount_set(&new->count, 1);
atomic64_set(&new->inodes_count, 0);
atomic64_set(&new->blocks_count, 0);
rb_link_node(&new->rb_node, parent, p);
rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
spin_unlock(&nilfs->ns_cptree_lock);
err = nilfs_sysfs_create_snapshot_group(new);
if (err) {
kfree(new);
new = NULL;
}
return new;
}
void nilfs_put_root(struct nilfs_root *root)
{
struct the_nilfs *nilfs = root->nilfs;
if (refcount_dec_and_lock(&root->count, &nilfs->ns_cptree_lock)) {
rb_erase(&root->rb_node, &nilfs->ns_cptree);
spin_unlock(&nilfs->ns_cptree_lock);
nilfs_sysfs_delete_snapshot_group(root);
iput(root->ifile);
kfree(root);
}
}