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linux/fs/xfs/xfs_mount.c

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/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would 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 License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_inum.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_inode.h"
#include "xfs_dir2.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_rtalloc.h"
#include "xfs_bmap.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_log.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_fsops.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_dinode.h"
#ifdef HAVE_PERCPU_SB
STATIC void xfs_icsb_balance_counter(xfs_mount_t *, xfs_sb_field_t,
int);
STATIC void xfs_icsb_balance_counter_locked(xfs_mount_t *, xfs_sb_field_t,
int);
STATIC void xfs_icsb_disable_counter(xfs_mount_t *, xfs_sb_field_t);
#else
#define xfs_icsb_balance_counter(mp, a, b) do { } while (0)
#define xfs_icsb_balance_counter_locked(mp, a, b) do { } while (0)
#endif
static DEFINE_MUTEX(xfs_uuid_table_mutex);
static int xfs_uuid_table_size;
static uuid_t *xfs_uuid_table;
/*
* See if the UUID is unique among mounted XFS filesystems.
* Mount fails if UUID is nil or a FS with the same UUID is already mounted.
*/
STATIC int
xfs_uuid_mount(
struct xfs_mount *mp)
{
uuid_t *uuid = &mp->m_sb.sb_uuid;
int hole, i;
if (mp->m_flags & XFS_MOUNT_NOUUID)
return 0;
if (uuid_is_nil(uuid)) {
xfs_warn(mp, "Filesystem has nil UUID - can't mount");
return XFS_ERROR(EINVAL);
}
mutex_lock(&xfs_uuid_table_mutex);
for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
if (uuid_is_nil(&xfs_uuid_table[i])) {
hole = i;
continue;
}
if (uuid_equal(uuid, &xfs_uuid_table[i]))
goto out_duplicate;
}
if (hole < 0) {
xfs_uuid_table = kmem_realloc(xfs_uuid_table,
(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
xfs_uuid_table_size * sizeof(*xfs_uuid_table),
KM_SLEEP);
hole = xfs_uuid_table_size++;
}
xfs_uuid_table[hole] = *uuid;
mutex_unlock(&xfs_uuid_table_mutex);
return 0;
out_duplicate:
mutex_unlock(&xfs_uuid_table_mutex);
xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
return XFS_ERROR(EINVAL);
}
STATIC void
xfs_uuid_unmount(
struct xfs_mount *mp)
{
uuid_t *uuid = &mp->m_sb.sb_uuid;
int i;
if (mp->m_flags & XFS_MOUNT_NOUUID)
return;
mutex_lock(&xfs_uuid_table_mutex);
for (i = 0; i < xfs_uuid_table_size; i++) {
if (uuid_is_nil(&xfs_uuid_table[i]))
continue;
if (!uuid_equal(uuid, &xfs_uuid_table[i]))
continue;
memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
break;
}
ASSERT(i < xfs_uuid_table_size);
mutex_unlock(&xfs_uuid_table_mutex);
}
STATIC void
__xfs_free_perag(
struct rcu_head *head)
{
struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
ASSERT(atomic_read(&pag->pag_ref) == 0);
kmem_free(pag);
}
/*
* Free up the per-ag resources associated with the mount structure.
*/
STATIC void
xfs_free_perag(
xfs_mount_t *mp)
{
xfs_agnumber_t agno;
struct xfs_perag *pag;
for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
spin_lock(&mp->m_perag_lock);
pag = radix_tree_delete(&mp->m_perag_tree, agno);
spin_unlock(&mp->m_perag_lock);
ASSERT(pag);
ASSERT(atomic_read(&pag->pag_ref) == 0);
call_rcu(&pag->rcu_head, __xfs_free_perag);
}
}
/*
* Check size of device based on the (data/realtime) block count.
* Note: this check is used by the growfs code as well as mount.
*/
int
xfs_sb_validate_fsb_count(
xfs_sb_t *sbp,
__uint64_t nblocks)
{
ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
ASSERT(sbp->sb_blocklog >= BBSHIFT);
#if XFS_BIG_BLKNOS /* Limited by ULONG_MAX of page cache index */
if (nblocks >> (PAGE_CACHE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
return EFBIG;
#else /* Limited by UINT_MAX of sectors */
if (nblocks << (sbp->sb_blocklog - BBSHIFT) > UINT_MAX)
return EFBIG;
#endif
return 0;
}
int
xfs_initialize_perag(
xfs_mount_t *mp,
xfs_agnumber_t agcount,
xfs_agnumber_t *maxagi)
{
xfs_agnumber_t index;
xfs_agnumber_t first_initialised = 0;
xfs_perag_t *pag;
xfs_agino_t agino;
xfs_ino_t ino;
xfs_sb_t *sbp = &mp->m_sb;
int error = -ENOMEM;
/*
* Walk the current per-ag tree so we don't try to initialise AGs
* that already exist (growfs case). Allocate and insert all the
* AGs we don't find ready for initialisation.
*/
for (index = 0; index < agcount; index++) {
pag = xfs_perag_get(mp, index);
if (pag) {
xfs_perag_put(pag);
continue;
}
if (!first_initialised)
first_initialised = index;
pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
if (!pag)
goto out_unwind;
pag->pag_agno = index;
pag->pag_mount = mp;
spin_lock_init(&pag->pag_ici_lock);
mutex_init(&pag->pag_ici_reclaim_lock);
INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
spin_lock_init(&pag->pag_buf_lock);
pag->pag_buf_tree = RB_ROOT;
if (radix_tree_preload(GFP_NOFS))
goto out_unwind;
spin_lock(&mp->m_perag_lock);
if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
BUG();
spin_unlock(&mp->m_perag_lock);
radix_tree_preload_end();
error = -EEXIST;
goto out_unwind;
}
spin_unlock(&mp->m_perag_lock);
radix_tree_preload_end();
}
/*
* If we mount with the inode64 option, or no inode overflows
* the legacy 32-bit address space clear the inode32 option.
*/
agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && ino > XFS_MAXINUMBER_32)
mp->m_flags |= XFS_MOUNT_32BITINODES;
else
mp->m_flags &= ~XFS_MOUNT_32BITINODES;
if (mp->m_flags & XFS_MOUNT_32BITINODES)
index = xfs_set_inode32(mp);
else
index = xfs_set_inode64(mp);
if (maxagi)
*maxagi = index;
return 0;
out_unwind:
kmem_free(pag);
for (; index > first_initialised; index--) {
pag = radix_tree_delete(&mp->m_perag_tree, index);
kmem_free(pag);
}
return error;
}
/*
* xfs_readsb
*
* Does the initial read of the superblock.
*/
int
xfs_readsb(
struct xfs_mount *mp,
int flags)
{
unsigned int sector_size;
struct xfs_buf *bp;
struct xfs_sb *sbp = &mp->m_sb;
int error;
int loud = !(flags & XFS_MFSI_QUIET);
const struct xfs_buf_ops *buf_ops;
ASSERT(mp->m_sb_bp == NULL);
ASSERT(mp->m_ddev_targp != NULL);
/*
* For the initial read, we must guess at the sector
* size based on the block device. It's enough to
* get the sb_sectsize out of the superblock and
* then reread with the proper length.
* We don't verify it yet, because it may not be complete.
*/
sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
buf_ops = NULL;
/*
* Allocate a (locked) buffer to hold the superblock.
* This will be kept around at all times to optimize
* access to the superblock.
*/
reread:
bp = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
BTOBB(sector_size), 0, buf_ops);
if (!bp) {
if (loud)
xfs_warn(mp, "SB buffer read failed");
return EIO;
}
if (bp->b_error) {
error = bp->b_error;
if (loud)
xfs_warn(mp, "SB validate failed with error %d.", error);
/* bad CRC means corrupted metadata */
if (error == EFSBADCRC)
error = EFSCORRUPTED;
goto release_buf;
}
/*
* Initialize the mount structure from the superblock.
*/
xfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
xfs_sb_quota_from_disk(sbp);
/*
* If we haven't validated the superblock, do so now before we try
* to check the sector size and reread the superblock appropriately.
*/
if (sbp->sb_magicnum != XFS_SB_MAGIC) {
if (loud)
xfs_warn(mp, "Invalid superblock magic number");
error = EINVAL;
goto release_buf;
}
/*
* We must be able to do sector-sized and sector-aligned IO.
*/
if (sector_size > sbp->sb_sectsize) {
if (loud)
xfs_warn(mp, "device supports %u byte sectors (not %u)",
sector_size, sbp->sb_sectsize);
error = ENOSYS;
goto release_buf;
}
if (buf_ops == NULL) {
/*
* Re-read the superblock so the buffer is correctly sized,
* and properly verified.
*/
xfs_buf_relse(bp);
sector_size = sbp->sb_sectsize;
buf_ops = loud ? &xfs_sb_buf_ops : &xfs_sb_quiet_buf_ops;
goto reread;
}
/* Initialize per-cpu counters */
xfs_icsb_reinit_counters(mp);
/* no need to be quiet anymore, so reset the buf ops */
bp->b_ops = &xfs_sb_buf_ops;
mp->m_sb_bp = bp;
xfs_buf_unlock(bp);
return 0;
release_buf:
xfs_buf_relse(bp);
return error;
}
/*
* Update alignment values based on mount options and sb values
*/
STATIC int
xfs_update_alignment(xfs_mount_t *mp)
{
xfs_sb_t *sbp = &(mp->m_sb);
if (mp->m_dalign) {
/*
* If stripe unit and stripe width are not multiples
* of the fs blocksize turn off alignment.
*/
if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
(BBTOB(mp->m_swidth) & mp->m_blockmask)) {
xfs_warn(mp,
"alignment check failed: sunit/swidth vs. blocksize(%d)",
sbp->sb_blocksize);
return XFS_ERROR(EINVAL);
} else {
/*
* Convert the stripe unit and width to FSBs.
*/
mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
xfs_warn(mp,
"alignment check failed: sunit/swidth vs. agsize(%d)",
sbp->sb_agblocks);
return XFS_ERROR(EINVAL);
} else if (mp->m_dalign) {
mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
} else {
xfs_warn(mp,
"alignment check failed: sunit(%d) less than bsize(%d)",
mp->m_dalign, sbp->sb_blocksize);
return XFS_ERROR(EINVAL);
}
}
/*
* Update superblock with new values
* and log changes
*/
if (xfs_sb_version_hasdalign(sbp)) {
if (sbp->sb_unit != mp->m_dalign) {
sbp->sb_unit = mp->m_dalign;
mp->m_update_flags |= XFS_SB_UNIT;
}
if (sbp->sb_width != mp->m_swidth) {
sbp->sb_width = mp->m_swidth;
mp->m_update_flags |= XFS_SB_WIDTH;
}
} else {
xfs_warn(mp,
"cannot change alignment: superblock does not support data alignment");
return XFS_ERROR(EINVAL);
}
} else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
xfs_sb_version_hasdalign(&mp->m_sb)) {
mp->m_dalign = sbp->sb_unit;
mp->m_swidth = sbp->sb_width;
}
return 0;
}
/*
* Set the maximum inode count for this filesystem
*/
STATIC void
xfs_set_maxicount(xfs_mount_t *mp)
{
xfs_sb_t *sbp = &(mp->m_sb);
__uint64_t icount;
if (sbp->sb_imax_pct) {
/*
* Make sure the maximum inode count is a multiple
* of the units we allocate inodes in.
*/
icount = sbp->sb_dblocks * sbp->sb_imax_pct;
do_div(icount, 100);
do_div(icount, mp->m_ialloc_blks);
mp->m_maxicount = (icount * mp->m_ialloc_blks) <<
sbp->sb_inopblog;
} else {
mp->m_maxicount = 0;
}
}
/*
* Set the default minimum read and write sizes unless
* already specified in a mount option.
* We use smaller I/O sizes when the file system
* is being used for NFS service (wsync mount option).
*/
STATIC void
xfs_set_rw_sizes(xfs_mount_t *mp)
{
xfs_sb_t *sbp = &(mp->m_sb);
int readio_log, writeio_log;
if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
if (mp->m_flags & XFS_MOUNT_WSYNC) {
readio_log = XFS_WSYNC_READIO_LOG;
writeio_log = XFS_WSYNC_WRITEIO_LOG;
} else {
readio_log = XFS_READIO_LOG_LARGE;
writeio_log = XFS_WRITEIO_LOG_LARGE;
}
} else {
readio_log = mp->m_readio_log;
writeio_log = mp->m_writeio_log;
}
if (sbp->sb_blocklog > readio_log) {
mp->m_readio_log = sbp->sb_blocklog;
} else {
mp->m_readio_log = readio_log;
}
mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
if (sbp->sb_blocklog > writeio_log) {
mp->m_writeio_log = sbp->sb_blocklog;
} else {
mp->m_writeio_log = writeio_log;
}
mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
}
/*
* precalculate the low space thresholds for dynamic speculative preallocation.
*/
void
xfs_set_low_space_thresholds(
struct xfs_mount *mp)
{
int i;
for (i = 0; i < XFS_LOWSP_MAX; i++) {
__uint64_t space = mp->m_sb.sb_dblocks;
do_div(space, 100);
mp->m_low_space[i] = space * (i + 1);
}
}
/*
* Set whether we're using inode alignment.
*/
STATIC void
xfs_set_inoalignment(xfs_mount_t *mp)
{
if (xfs_sb_version_hasalign(&mp->m_sb) &&
mp->m_sb.sb_inoalignmt >=
XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
else
mp->m_inoalign_mask = 0;
/*
* If we are using stripe alignment, check whether
* the stripe unit is a multiple of the inode alignment
*/
if (mp->m_dalign && mp->m_inoalign_mask &&
!(mp->m_dalign & mp->m_inoalign_mask))
mp->m_sinoalign = mp->m_dalign;
else
mp->m_sinoalign = 0;
}
/*
* Check that the data (and log if separate) is an ok size.
*/
STATIC int
xfs_check_sizes(xfs_mount_t *mp)
{
xfs_buf_t *bp;
xfs_daddr_t d;
d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
xfs_warn(mp, "filesystem size mismatch detected");
return XFS_ERROR(EFBIG);
}
bp = xfs_buf_read_uncached(mp->m_ddev_targp,
d - XFS_FSS_TO_BB(mp, 1),
XFS_FSS_TO_BB(mp, 1), 0, NULL);
if (!bp) {
xfs_warn(mp, "last sector read failed");
return EIO;
}
xfs_buf_relse(bp);
if (mp->m_logdev_targp != mp->m_ddev_targp) {
d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
xfs_warn(mp, "log size mismatch detected");
return XFS_ERROR(EFBIG);
}
bp = xfs_buf_read_uncached(mp->m_logdev_targp,
d - XFS_FSB_TO_BB(mp, 1),
XFS_FSB_TO_BB(mp, 1), 0, NULL);
if (!bp) {
xfs_warn(mp, "log device read failed");
return EIO;
}
xfs_buf_relse(bp);
}
return 0;
}
/*
* Clear the quotaflags in memory and in the superblock.
*/
int
xfs_mount_reset_sbqflags(
struct xfs_mount *mp)
{
int error;
struct xfs_trans *tp;
mp->m_qflags = 0;
/*
* It is OK to look at sb_qflags here in mount path,
* without m_sb_lock.
*/
if (mp->m_sb.sb_qflags == 0)
return 0;
spin_lock(&mp->m_sb_lock);
mp->m_sb.sb_qflags = 0;
spin_unlock(&mp->m_sb_lock);
/*
* If the fs is readonly, let the incore superblock run
* with quotas off but don't flush the update out to disk
*/
if (mp->m_flags & XFS_MOUNT_RDONLY)
return 0;
tp = xfs_trans_alloc(mp, XFS_TRANS_QM_SBCHANGE);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_qm_sbchange, 0, 0);
if (error) {
xfs_trans_cancel(tp, 0);
xfs_alert(mp, "%s: Superblock update failed!", __func__);
return error;
}
xfs_mod_sb(tp, XFS_SB_QFLAGS);
return xfs_trans_commit(tp, 0);
}
__uint64_t
xfs_default_resblks(xfs_mount_t *mp)
{
__uint64_t resblks;
/*
* We default to 5% or 8192 fsbs of space reserved, whichever is
* smaller. This is intended to cover concurrent allocation
* transactions when we initially hit enospc. These each require a 4
* block reservation. Hence by default we cover roughly 2000 concurrent
* allocation reservations.
*/
resblks = mp->m_sb.sb_dblocks;
do_div(resblks, 20);
resblks = min_t(__uint64_t, resblks, 8192);
return resblks;
}
/*
* This function does the following on an initial mount of a file system:
* - reads the superblock from disk and init the mount struct
* - if we're a 32-bit kernel, do a size check on the superblock
* so we don't mount terabyte filesystems
* - init mount struct realtime fields
* - allocate inode hash table for fs
* - init directory manager
* - perform recovery and init the log manager
*/
int
xfs_mountfs(
xfs_mount_t *mp)
{
xfs_sb_t *sbp = &(mp->m_sb);
xfs_inode_t *rip;
__uint64_t resblks;
uint quotamount = 0;
uint quotaflags = 0;
int error = 0;
xfs_sb_mount_common(mp, sbp);
/*
* Check for a mismatched features2 values. Older kernels
* read & wrote into the wrong sb offset for sb_features2
* on some platforms due to xfs_sb_t not being 64bit size aligned
* when sb_features2 was added, which made older superblock
* reading/writing routines swap it as a 64-bit value.
*
* For backwards compatibility, we make both slots equal.
*
* If we detect a mismatched field, we OR the set bits into the
* existing features2 field in case it has already been modified; we
* don't want to lose any features. We then update the bad location
* with the ORed value so that older kernels will see any features2
* flags, and mark the two fields as needing updates once the
* transaction subsystem is online.
*/
if (xfs_sb_has_mismatched_features2(sbp)) {
xfs_warn(mp, "correcting sb_features alignment problem");
sbp->sb_features2 |= sbp->sb_bad_features2;
sbp->sb_bad_features2 = sbp->sb_features2;
mp->m_update_flags |= XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2;
/*
* Re-check for ATTR2 in case it was found in bad_features2
* slot.
*/
if (xfs_sb_version_hasattr2(&mp->m_sb) &&
!(mp->m_flags & XFS_MOUNT_NOATTR2))
mp->m_flags |= XFS_MOUNT_ATTR2;
}
if (xfs_sb_version_hasattr2(&mp->m_sb) &&
(mp->m_flags & XFS_MOUNT_NOATTR2)) {
xfs_sb_version_removeattr2(&mp->m_sb);
mp->m_update_flags |= XFS_SB_FEATURES2;
/* update sb_versionnum for the clearing of the morebits */
if (!sbp->sb_features2)
mp->m_update_flags |= XFS_SB_VERSIONNUM;
}
/* always use v2 inodes by default now */
if (!(mp->m_sb.sb_versionnum & XFS_SB_VERSION_NLINKBIT)) {
mp->m_sb.sb_versionnum |= XFS_SB_VERSION_NLINKBIT;
mp->m_update_flags |= XFS_SB_VERSIONNUM;
}
/*
* Check if sb_agblocks is aligned at stripe boundary
* If sb_agblocks is NOT aligned turn off m_dalign since
* allocator alignment is within an ag, therefore ag has
* to be aligned at stripe boundary.
*/
error = xfs_update_alignment(mp);
if (error)
goto out;
xfs_alloc_compute_maxlevels(mp);
xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
xfs_ialloc_compute_maxlevels(mp);
xfs_set_maxicount(mp);
error = xfs_uuid_mount(mp);
if (error)
goto out;
/*
* Set the minimum read and write sizes
*/
xfs_set_rw_sizes(mp);
/* set the low space thresholds for dynamic preallocation */
xfs_set_low_space_thresholds(mp);
/*
* Set the inode cluster size.
* This may still be overridden by the file system
* block size if it is larger than the chosen cluster size.
*
* For v5 filesystems, scale the cluster size with the inode size to
* keep a constant ratio of inode per cluster buffer, but only if mkfs
* has set the inode alignment value appropriately for larger cluster
* sizes.
*/
mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
if (xfs_sb_version_hascrc(&mp->m_sb)) {
int new_size = mp->m_inode_cluster_size;
new_size *= mp->m_sb.sb_inodesize / XFS_DINODE_MIN_SIZE;
if (mp->m_sb.sb_inoalignmt >= XFS_B_TO_FSBT(mp, new_size))
mp->m_inode_cluster_size = new_size;
}
/*
* Set inode alignment fields
*/
xfs_set_inoalignment(mp);
/*
* Check that the data (and log if separate) is an ok size.
*/
error = xfs_check_sizes(mp);
if (error)
goto out_remove_uuid;
/*
* Initialize realtime fields in the mount structure
*/
error = xfs_rtmount_init(mp);
if (error) {
xfs_warn(mp, "RT mount failed");
goto out_remove_uuid;
}
/*
* Copies the low order bits of the timestamp and the randomly
* set "sequence" number out of a UUID.
*/
uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
mp->m_dmevmask = 0; /* not persistent; set after each mount */
error = xfs_da_mount(mp);
if (error) {
xfs_warn(mp, "Failed dir/attr init: %d", error);
goto out_remove_uuid;
}
/*
* Initialize the precomputed transaction reservations values.
*/
xfs_trans_init(mp);
/*
* Allocate and initialize the per-ag data.
*/
spin_lock_init(&mp->m_perag_lock);
INIT_RADIX_TREE(&mp->m_perag_tree, GFP_ATOMIC);
error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
if (error) {
xfs_warn(mp, "Failed per-ag init: %d", error);
goto out_free_dir;
}
if (!sbp->sb_logblocks) {
xfs_warn(mp, "no log defined");
XFS_ERROR_REPORT("xfs_mountfs", XFS_ERRLEVEL_LOW, mp);
error = XFS_ERROR(EFSCORRUPTED);
goto out_free_perag;
}
/*
* log's mount-time initialization. Perform 1st part recovery if needed
*/
error = xfs_log_mount(mp, mp->m_logdev_targp,
XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
if (error) {
xfs_warn(mp, "log mount failed");
goto out_fail_wait;
}
/*
* Now the log is mounted, we know if it was an unclean shutdown or
* not. If it was, with the first phase of recovery has completed, we
* have consistent AG blocks on disk. We have not recovered EFIs yet,
* but they are recovered transactionally in the second recovery phase
* later.
*
* Hence we can safely re-initialise incore superblock counters from
* the per-ag data. These may not be correct if the filesystem was not
* cleanly unmounted, so we need to wait for recovery to finish before
* doing this.
*
* If the filesystem was cleanly unmounted, then we can trust the
* values in the superblock to be correct and we don't need to do
* anything here.
*
* If we are currently making the filesystem, the initialisation will
* fail as the perag data is in an undefined state.
*/
if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
!XFS_LAST_UNMOUNT_WAS_CLEAN(mp) &&
!mp->m_sb.sb_inprogress) {
error = xfs_initialize_perag_data(mp, sbp->sb_agcount);
if (error)
goto out_fail_wait;
}
/*
* Get and sanity-check the root inode.
* Save the pointer to it in the mount structure.
*/
error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip);
if (error) {
xfs_warn(mp, "failed to read root inode");
goto out_log_dealloc;
}
ASSERT(rip != NULL);
if (unlikely(!S_ISDIR(rip->i_d.di_mode))) {
xfs_warn(mp, "corrupted root inode %llu: not a directory",
(unsigned long long)rip->i_ino);
xfs_iunlock(rip, XFS_ILOCK_EXCL);
XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
mp);
error = XFS_ERROR(EFSCORRUPTED);
goto out_rele_rip;
}
mp->m_rootip = rip; /* save it */
xfs_iunlock(rip, XFS_ILOCK_EXCL);
/*
* Initialize realtime inode pointers in the mount structure
*/
error = xfs_rtmount_inodes(mp);
if (error) {
/*
* Free up the root inode.
*/
xfs_warn(mp, "failed to read RT inodes");
goto out_rele_rip;
}
/*
* If this is a read-only mount defer the superblock updates until
* the next remount into writeable mode. Otherwise we would never
* perform the update e.g. for the root filesystem.
*/
if (mp->m_update_flags && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
error = xfs_mount_log_sb(mp, mp->m_update_flags);
if (error) {
xfs_warn(mp, "failed to write sb changes");
goto out_rtunmount;
}
}
/*
* Initialise the XFS quota management subsystem for this mount
*/
if (XFS_IS_QUOTA_RUNNING(mp)) {
error = xfs_qm_newmount(mp, &quotamount, &quotaflags);
if (error)
goto out_rtunmount;
} else {
ASSERT(!XFS_IS_QUOTA_ON(mp));
/*
* If a file system had quotas running earlier, but decided to
* mount without -o uquota/pquota/gquota options, revoke the
* quotachecked license.
*/
if (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_ACCT) {
xfs_notice(mp, "resetting quota flags");
error = xfs_mount_reset_sbqflags(mp);
if (error)
return error;
}
}
/*
* Finish recovering the file system. This part needed to be
* delayed until after the root and real-time bitmap inodes
* were consistently read in.
*/
error = xfs_log_mount_finish(mp);
if (error) {
xfs_warn(mp, "log mount finish failed");
goto out_rtunmount;
}
/*
* Complete the quota initialisation, post-log-replay component.
*/
if (quotamount) {
ASSERT(mp->m_qflags == 0);
mp->m_qflags = quotaflags;
xfs_qm_mount_quotas(mp);
}
/*
* Now we are mounted, reserve a small amount of unused space for
* privileged transactions. This is needed so that transaction
* space required for critical operations can dip into this pool
* when at ENOSPC. This is needed for operations like create with
* attr, unwritten extent conversion at ENOSPC, etc. Data allocations
* are not allowed to use this reserved space.
*
* This may drive us straight to ENOSPC on mount, but that implies
* we were already there on the last unmount. Warn if this occurs.
*/
if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
resblks = xfs_default_resblks(mp);
error = xfs_reserve_blocks(mp, &resblks, NULL);
if (error)
xfs_warn(mp,
"Unable to allocate reserve blocks. Continuing without reserve pool.");
}
return 0;
out_rtunmount:
xfs_rtunmount_inodes(mp);
out_rele_rip:
IRELE(rip);
out_log_dealloc:
xfs_log_unmount(mp);
out_fail_wait:
if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
xfs_wait_buftarg(mp->m_logdev_targp);
xfs_wait_buftarg(mp->m_ddev_targp);
out_free_perag:
xfs_free_perag(mp);
out_free_dir:
xfs_da_unmount(mp);
out_remove_uuid:
xfs_uuid_unmount(mp);
out:
return error;
}
/*
* This flushes out the inodes,dquots and the superblock, unmounts the
* log and makes sure that incore structures are freed.
*/
void
xfs_unmountfs(
struct xfs_mount *mp)
{
__uint64_t resblks;
int error;
cancel_delayed_work_sync(&mp->m_eofblocks_work);
xfs_qm_unmount_quotas(mp);
xfs_rtunmount_inodes(mp);
IRELE(mp->m_rootip);
/*
* We can potentially deadlock here if we have an inode cluster
* that has been freed has its buffer still pinned in memory because
* the transaction is still sitting in a iclog. The stale inodes
* on that buffer will have their flush locks held until the
* transaction hits the disk and the callbacks run. the inode
* flush takes the flush lock unconditionally and with nothing to
* push out the iclog we will never get that unlocked. hence we
* need to force the log first.
*/
xfs_log_force(mp, XFS_LOG_SYNC);
/*
* Flush all pending changes from the AIL.
*/
xfs_ail_push_all_sync(mp->m_ail);
/*
* And reclaim all inodes. At this point there should be no dirty
* inodes and none should be pinned or locked, but use synchronous
* reclaim just to be sure. We can stop background inode reclaim
* here as well if it is still running.
*/
cancel_delayed_work_sync(&mp->m_reclaim_work);
xfs_reclaim_inodes(mp, SYNC_WAIT);
xfs_qm_unmount(mp);
/*
* Unreserve any blocks we have so that when we unmount we don't account
* the reserved free space as used. This is really only necessary for
* lazy superblock counting because it trusts the incore superblock
* counters to be absolutely correct on clean unmount.
*
* We don't bother correcting this elsewhere for lazy superblock
* counting because on mount of an unclean filesystem we reconstruct the
* correct counter value and this is irrelevant.
*
* For non-lazy counter filesystems, this doesn't matter at all because
* we only every apply deltas to the superblock and hence the incore
* value does not matter....
*/
resblks = 0;
error = xfs_reserve_blocks(mp, &resblks, NULL);
if (error)
xfs_warn(mp, "Unable to free reserved block pool. "
"Freespace may not be correct on next mount.");
error = xfs_log_sbcount(mp);
if (error)
xfs_warn(mp, "Unable to update superblock counters. "
"Freespace may not be correct on next mount.");
xfs_log_unmount(mp);
xfs_da_unmount(mp);
xfs_uuid_unmount(mp);
#if defined(DEBUG)
xfs_errortag_clearall(mp, 0);
#endif
xfs_free_perag(mp);
}
int
xfs_fs_writable(xfs_mount_t *mp)
{
return !(mp->m_super->s_writers.frozen || XFS_FORCED_SHUTDOWN(mp) ||
(mp->m_flags & XFS_MOUNT_RDONLY));
}
/*
* xfs_log_sbcount
*
* Sync the superblock counters to disk.
*
* Note this code can be called during the process of freezing, so
* we may need to use the transaction allocator which does not
* block when the transaction subsystem is in its frozen state.
*/
int
xfs_log_sbcount(xfs_mount_t *mp)
{
xfs_trans_t *tp;
int error;
if (!xfs_fs_writable(mp))
return 0;
xfs_icsb_sync_counters(mp, 0);
/*
* we don't need to do this if we are updating the superblock
* counters on every modification.
*/
if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
return 0;
tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_COUNT, KM_SLEEP);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_sb, 0, 0);
if (error) {
xfs_trans_cancel(tp, 0);
return error;
}
xfs_mod_sb(tp, XFS_SB_IFREE | XFS_SB_ICOUNT | XFS_SB_FDBLOCKS);
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp, 0);
return error;
}
/*
* xfs_mod_incore_sb_unlocked() is a utility routine commonly used to apply
* a delta to a specified field in the in-core superblock. Simply
* switch on the field indicated and apply the delta to that field.
* Fields are not allowed to dip below zero, so if the delta would
* do this do not apply it and return EINVAL.
*
* The m_sb_lock must be held when this routine is called.
*/
STATIC int
xfs_mod_incore_sb_unlocked(
xfs_mount_t *mp,
xfs_sb_field_t field,
int64_t delta,
int rsvd)
{
int scounter; /* short counter for 32 bit fields */
long long lcounter; /* long counter for 64 bit fields */
long long res_used, rem;
/*
* With the in-core superblock spin lock held, switch
* on the indicated field. Apply the delta to the
* proper field. If the fields value would dip below
* 0, then do not apply the delta and return EINVAL.
*/
switch (field) {
case XFS_SBS_ICOUNT:
lcounter = (long long)mp->m_sb.sb_icount;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_icount = lcounter;
return 0;
case XFS_SBS_IFREE:
lcounter = (long long)mp->m_sb.sb_ifree;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_ifree = lcounter;
return 0;
case XFS_SBS_FDBLOCKS:
lcounter = (long long)
mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
if (delta > 0) { /* Putting blocks back */
if (res_used > delta) {
mp->m_resblks_avail += delta;
} else {
rem = delta - res_used;
mp->m_resblks_avail = mp->m_resblks;
lcounter += rem;
}
} else { /* Taking blocks away */
lcounter += delta;
if (lcounter >= 0) {
mp->m_sb.sb_fdblocks = lcounter +
XFS_ALLOC_SET_ASIDE(mp);
return 0;
}
/*
* We are out of blocks, use any available reserved
* blocks if were allowed to.
*/
if (!rsvd)
return XFS_ERROR(ENOSPC);
lcounter = (long long)mp->m_resblks_avail + delta;
if (lcounter >= 0) {
mp->m_resblks_avail = lcounter;
return 0;
}
printk_once(KERN_WARNING
"Filesystem \"%s\": reserve blocks depleted! "
"Consider increasing reserve pool size.",
mp->m_fsname);
return XFS_ERROR(ENOSPC);
}
mp->m_sb.sb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
return 0;
case XFS_SBS_FREXTENTS:
lcounter = (long long)mp->m_sb.sb_frextents;
lcounter += delta;
if (lcounter < 0) {
return XFS_ERROR(ENOSPC);
}
mp->m_sb.sb_frextents = lcounter;
return 0;
case XFS_SBS_DBLOCKS:
lcounter = (long long)mp->m_sb.sb_dblocks;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_dblocks = lcounter;
return 0;
case XFS_SBS_AGCOUNT:
scounter = mp->m_sb.sb_agcount;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_agcount = scounter;
return 0;
case XFS_SBS_IMAX_PCT:
scounter = mp->m_sb.sb_imax_pct;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_imax_pct = scounter;
return 0;
case XFS_SBS_REXTSIZE:
scounter = mp->m_sb.sb_rextsize;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rextsize = scounter;
return 0;
case XFS_SBS_RBMBLOCKS:
scounter = mp->m_sb.sb_rbmblocks;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rbmblocks = scounter;
return 0;
case XFS_SBS_RBLOCKS:
lcounter = (long long)mp->m_sb.sb_rblocks;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rblocks = lcounter;
return 0;
case XFS_SBS_REXTENTS:
lcounter = (long long)mp->m_sb.sb_rextents;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rextents = lcounter;
return 0;
case XFS_SBS_REXTSLOG:
scounter = mp->m_sb.sb_rextslog;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rextslog = scounter;
return 0;
default:
ASSERT(0);
return XFS_ERROR(EINVAL);
}
}
/*
* xfs_mod_incore_sb() is used to change a field in the in-core
* superblock structure by the specified delta. This modification
* is protected by the m_sb_lock. Just use the xfs_mod_incore_sb_unlocked()
* routine to do the work.
*/
int
xfs_mod_incore_sb(
struct xfs_mount *mp,
xfs_sb_field_t field,
int64_t delta,
int rsvd)
{
int status;
#ifdef HAVE_PERCPU_SB
ASSERT(field < XFS_SBS_ICOUNT || field > XFS_SBS_FDBLOCKS);
#endif
spin_lock(&mp->m_sb_lock);
status = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
spin_unlock(&mp->m_sb_lock);
return status;
}
/*
* Change more than one field in the in-core superblock structure at a time.
*
* The fields and changes to those fields are specified in the array of
* xfs_mod_sb structures passed in. Either all of the specified deltas
* will be applied or none of them will. If any modified field dips below 0,
* then all modifications will be backed out and EINVAL will be returned.
*
* Note that this function may not be used for the superblock values that
* are tracked with the in-memory per-cpu counters - a direct call to
* xfs_icsb_modify_counters is required for these.
*/
int
xfs_mod_incore_sb_batch(
struct xfs_mount *mp,
xfs_mod_sb_t *msb,
uint nmsb,
int rsvd)
{
xfs_mod_sb_t *msbp;
int error = 0;
/*
* Loop through the array of mod structures and apply each individually.
* If any fail, then back out all those which have already been applied.
* Do all of this within the scope of the m_sb_lock so that all of the
* changes will be atomic.
*/
spin_lock(&mp->m_sb_lock);
for (msbp = msb; msbp < (msb + nmsb); msbp++) {
ASSERT(msbp->msb_field < XFS_SBS_ICOUNT ||
msbp->msb_field > XFS_SBS_FDBLOCKS);
error = xfs_mod_incore_sb_unlocked(mp, msbp->msb_field,
msbp->msb_delta, rsvd);
if (error)
goto unwind;
}
spin_unlock(&mp->m_sb_lock);
return 0;
unwind:
while (--msbp >= msb) {
error = xfs_mod_incore_sb_unlocked(mp, msbp->msb_field,
-msbp->msb_delta, rsvd);
ASSERT(error == 0);
}
spin_unlock(&mp->m_sb_lock);
return error;
}
/*
* xfs_getsb() is called to obtain the buffer for the superblock.
* The buffer is returned locked and read in from disk.
* The buffer should be released with a call to xfs_brelse().
*
* If the flags parameter is BUF_TRYLOCK, then we'll only return
* the superblock buffer if it can be locked without sleeping.
* If it can't then we'll return NULL.
*/
struct xfs_buf *
xfs_getsb(
struct xfs_mount *mp,
int flags)
{
struct xfs_buf *bp = mp->m_sb_bp;
if (!xfs_buf_trylock(bp)) {
if (flags & XBF_TRYLOCK)
return NULL;
xfs_buf_lock(bp);
}
xfs_buf_hold(bp);
ASSERT(XFS_BUF_ISDONE(bp));
return bp;
}
/*
* Used to free the superblock along various error paths.
*/
void
xfs_freesb(
struct xfs_mount *mp)
{
struct xfs_buf *bp = mp->m_sb_bp;
xfs_buf_lock(bp);
mp->m_sb_bp = NULL;
xfs_buf_relse(bp);
}
/*
* Used to log changes to the superblock unit and width fields which could
* be altered by the mount options, as well as any potential sb_features2
* fixup. Only the first superblock is updated.
*/
int
xfs_mount_log_sb(
xfs_mount_t *mp,
__int64_t fields)
{
xfs_trans_t *tp;
int error;
ASSERT(fields & (XFS_SB_UNIT | XFS_SB_WIDTH | XFS_SB_UUID |
XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2 |
XFS_SB_VERSIONNUM));
tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_sb, 0, 0);
if (error) {
xfs_trans_cancel(tp, 0);
return error;
}
xfs_mod_sb(tp, fields);
error = xfs_trans_commit(tp, 0);
return error;
}
/*
* If the underlying (data/log/rt) device is readonly, there are some
* operations that cannot proceed.
*/
int
xfs_dev_is_read_only(
struct xfs_mount *mp,
char *message)
{
if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
xfs_readonly_buftarg(mp->m_logdev_targp) ||
(mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
xfs_notice(mp, "%s required on read-only device.", message);
xfs_notice(mp, "write access unavailable, cannot proceed.");
return EROFS;
}
return 0;
}
#ifdef HAVE_PERCPU_SB
/*
* Per-cpu incore superblock counters
*
* Simple concept, difficult implementation
*
* Basically, replace the incore superblock counters with a distributed per cpu
* counter for contended fields (e.g. free block count).
*
* Difficulties arise in that the incore sb is used for ENOSPC checking, and
* hence needs to be accurately read when we are running low on space. Hence
* there is a method to enable and disable the per-cpu counters based on how
* much "stuff" is available in them.
*
* Basically, a counter is enabled if there is enough free resource to justify
* running a per-cpu fast-path. If the per-cpu counter runs out (i.e. a local
* ENOSPC), then we disable the counters to synchronise all callers and
* re-distribute the available resources.
*
* If, once we redistributed the available resources, we still get a failure,
* we disable the per-cpu counter and go through the slow path.
*
* The slow path is the current xfs_mod_incore_sb() function. This means that
* when we disable a per-cpu counter, we need to drain its resources back to
* the global superblock. We do this after disabling the counter to prevent
* more threads from queueing up on the counter.
*
* Essentially, this means that we still need a lock in the fast path to enable
* synchronisation between the global counters and the per-cpu counters. This
* is not a problem because the lock will be local to a CPU almost all the time
* and have little contention except when we get to ENOSPC conditions.
*
* Basically, this lock becomes a barrier that enables us to lock out the fast
* path while we do things like enabling and disabling counters and
* synchronising the counters.
*
* Locking rules:
*
* 1. m_sb_lock before picking up per-cpu locks
* 2. per-cpu locks always picked up via for_each_online_cpu() order
* 3. accurate counter sync requires m_sb_lock + per cpu locks
* 4. modifying per-cpu counters requires holding per-cpu lock
* 5. modifying global counters requires holding m_sb_lock
* 6. enabling or disabling a counter requires holding the m_sb_lock
* and _none_ of the per-cpu locks.
*
* Disabled counters are only ever re-enabled by a balance operation
* that results in more free resources per CPU than a given threshold.
* To ensure counters don't remain disabled, they are rebalanced when
* the global resource goes above a higher threshold (i.e. some hysteresis
* is present to prevent thrashing).
*/
#ifdef CONFIG_HOTPLUG_CPU
/*
* hot-plug CPU notifier support.
*
* We need a notifier per filesystem as we need to be able to identify
* the filesystem to balance the counters out. This is achieved by
* having a notifier block embedded in the xfs_mount_t and doing pointer
* magic to get the mount pointer from the notifier block address.
*/
STATIC int
xfs_icsb_cpu_notify(
struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
xfs_icsb_cnts_t *cntp;
xfs_mount_t *mp;
mp = (xfs_mount_t *)container_of(nfb, xfs_mount_t, m_icsb_notifier);
cntp = (xfs_icsb_cnts_t *)
per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
/* Easy Case - initialize the area and locks, and
* then rebalance when online does everything else for us. */
memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
break;
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
xfs_icsb_lock(mp);
xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
xfs_icsb_unlock(mp);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
/* Disable all the counters, then fold the dead cpu's
* count into the total on the global superblock and
* re-enable the counters. */
xfs_icsb_lock(mp);
spin_lock(&mp->m_sb_lock);
xfs_icsb_disable_counter(mp, XFS_SBS_ICOUNT);
xfs_icsb_disable_counter(mp, XFS_SBS_IFREE);
xfs_icsb_disable_counter(mp, XFS_SBS_FDBLOCKS);
mp->m_sb.sb_icount += cntp->icsb_icount;
mp->m_sb.sb_ifree += cntp->icsb_ifree;
mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks;
memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
xfs_icsb_balance_counter_locked(mp, XFS_SBS_ICOUNT, 0);
xfs_icsb_balance_counter_locked(mp, XFS_SBS_IFREE, 0);
xfs_icsb_balance_counter_locked(mp, XFS_SBS_FDBLOCKS, 0);
spin_unlock(&mp->m_sb_lock);
xfs_icsb_unlock(mp);
break;
}
return NOTIFY_OK;
}
#endif /* CONFIG_HOTPLUG_CPU */
int
xfs_icsb_init_counters(
xfs_mount_t *mp)
{
xfs_icsb_cnts_t *cntp;
int i;
mp->m_sb_cnts = alloc_percpu(xfs_icsb_cnts_t);
if (mp->m_sb_cnts == NULL)
return -ENOMEM;
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
}
mutex_init(&mp->m_icsb_mutex);
/*
* start with all counters disabled so that the
* initial balance kicks us off correctly
*/
mp->m_icsb_counters = -1;
#ifdef CONFIG_HOTPLUG_CPU
mp->m_icsb_notifier.notifier_call = xfs_icsb_cpu_notify;
mp->m_icsb_notifier.priority = 0;
register_hotcpu_notifier(&mp->m_icsb_notifier);
#endif /* CONFIG_HOTPLUG_CPU */
return 0;
}
void
xfs_icsb_reinit_counters(
xfs_mount_t *mp)
{
xfs_icsb_lock(mp);
/*
* start with all counters disabled so that the
* initial balance kicks us off correctly
*/
mp->m_icsb_counters = -1;
xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
xfs_icsb_unlock(mp);
}
void
xfs_icsb_destroy_counters(
xfs_mount_t *mp)
{
if (mp->m_sb_cnts) {
unregister_hotcpu_notifier(&mp->m_icsb_notifier);
free_percpu(mp->m_sb_cnts);
}
mutex_destroy(&mp->m_icsb_mutex);
}
STATIC void
xfs_icsb_lock_cntr(
xfs_icsb_cnts_t *icsbp)
{
while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) {
ndelay(1000);
}
}
STATIC void
xfs_icsb_unlock_cntr(
xfs_icsb_cnts_t *icsbp)
{
clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags);
}
STATIC void
xfs_icsb_lock_all_counters(
xfs_mount_t *mp)
{
xfs_icsb_cnts_t *cntp;
int i;
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
xfs_icsb_lock_cntr(cntp);
}
}
STATIC void
xfs_icsb_unlock_all_counters(
xfs_mount_t *mp)
{
xfs_icsb_cnts_t *cntp;
int i;
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
xfs_icsb_unlock_cntr(cntp);
}
}
STATIC void
xfs_icsb_count(
xfs_mount_t *mp,
xfs_icsb_cnts_t *cnt,
int flags)
{
xfs_icsb_cnts_t *cntp;
int i;
memset(cnt, 0, sizeof(xfs_icsb_cnts_t));
if (!(flags & XFS_ICSB_LAZY_COUNT))
xfs_icsb_lock_all_counters(mp);
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
cnt->icsb_icount += cntp->icsb_icount;
cnt->icsb_ifree += cntp->icsb_ifree;
cnt->icsb_fdblocks += cntp->icsb_fdblocks;
}
if (!(flags & XFS_ICSB_LAZY_COUNT))
xfs_icsb_unlock_all_counters(mp);
}
STATIC int
xfs_icsb_counter_disabled(
xfs_mount_t *mp,
xfs_sb_field_t field)
{
ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
return test_bit(field, &mp->m_icsb_counters);
}
STATIC void
xfs_icsb_disable_counter(
xfs_mount_t *mp,
xfs_sb_field_t field)
{
xfs_icsb_cnts_t cnt;
ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
/*
* If we are already disabled, then there is nothing to do
* here. We check before locking all the counters to avoid
* the expensive lock operation when being called in the
* slow path and the counter is already disabled. This is
* safe because the only time we set or clear this state is under
* the m_icsb_mutex.
*/
if (xfs_icsb_counter_disabled(mp, field))
return;
xfs_icsb_lock_all_counters(mp);
if (!test_and_set_bit(field, &mp->m_icsb_counters)) {
/* drain back to superblock */
xfs_icsb_count(mp, &cnt, XFS_ICSB_LAZY_COUNT);
switch(field) {
case XFS_SBS_ICOUNT:
mp->m_sb.sb_icount = cnt.icsb_icount;
break;
case XFS_SBS_IFREE:
mp->m_sb.sb_ifree = cnt.icsb_ifree;
break;
case XFS_SBS_FDBLOCKS:
mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
break;
default:
BUG();
}
}
xfs_icsb_unlock_all_counters(mp);
}
STATIC void
xfs_icsb_enable_counter(
xfs_mount_t *mp,
xfs_sb_field_t field,
uint64_t count,
uint64_t resid)
{
xfs_icsb_cnts_t *cntp;
int i;
ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
xfs_icsb_lock_all_counters(mp);
for_each_online_cpu(i) {
cntp = per_cpu_ptr(mp->m_sb_cnts, i);
switch (field) {
case XFS_SBS_ICOUNT:
cntp->icsb_icount = count + resid;
break;
case XFS_SBS_IFREE:
cntp->icsb_ifree = count + resid;
break;
case XFS_SBS_FDBLOCKS:
cntp->icsb_fdblocks = count + resid;
break;
default:
BUG();
break;
}
resid = 0;
}
clear_bit(field, &mp->m_icsb_counters);
xfs_icsb_unlock_all_counters(mp);
}
void
xfs_icsb_sync_counters_locked(
xfs_mount_t *mp,
int flags)
{
xfs_icsb_cnts_t cnt;
xfs_icsb_count(mp, &cnt, flags);
if (!xfs_icsb_counter_disabled(mp, XFS_SBS_ICOUNT))
mp->m_sb.sb_icount = cnt.icsb_icount;
if (!xfs_icsb_counter_disabled(mp, XFS_SBS_IFREE))
mp->m_sb.sb_ifree = cnt.icsb_ifree;
if (!xfs_icsb_counter_disabled(mp, XFS_SBS_FDBLOCKS))
mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
}
/*
* Accurate update of per-cpu counters to incore superblock
*/
void
xfs_icsb_sync_counters(
xfs_mount_t *mp,
int flags)
{
spin_lock(&mp->m_sb_lock);
xfs_icsb_sync_counters_locked(mp, flags);
spin_unlock(&mp->m_sb_lock);
}
/*
* Balance and enable/disable counters as necessary.
*
* Thresholds for re-enabling counters are somewhat magic. inode counts are
* chosen to be the same number as single on disk allocation chunk per CPU, and
* free blocks is something far enough zero that we aren't going thrash when we
* get near ENOSPC. We also need to supply a minimum we require per cpu to
* prevent looping endlessly when xfs_alloc_space asks for more than will
* be distributed to a single CPU but each CPU has enough blocks to be
* reenabled.
*
* Note that we can be called when counters are already disabled.
* xfs_icsb_disable_counter() optimises the counter locking in this case to
* prevent locking every per-cpu counter needlessly.
*/
#define XFS_ICSB_INO_CNTR_REENABLE (uint64_t)64
#define XFS_ICSB_FDBLK_CNTR_REENABLE(mp) \
(uint64_t)(512 + XFS_ALLOC_SET_ASIDE(mp))
STATIC void
xfs_icsb_balance_counter_locked(
xfs_mount_t *mp,
xfs_sb_field_t field,
int min_per_cpu)
{
uint64_t count, resid;
int weight = num_online_cpus();
uint64_t min = (uint64_t)min_per_cpu;
/* disable counter and sync counter */
xfs_icsb_disable_counter(mp, field);
/* update counters - first CPU gets residual*/
switch (field) {
case XFS_SBS_ICOUNT:
count = mp->m_sb.sb_icount;
resid = do_div(count, weight);
if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
return;
break;
case XFS_SBS_IFREE:
count = mp->m_sb.sb_ifree;
resid = do_div(count, weight);
if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
return;
break;
case XFS_SBS_FDBLOCKS:
count = mp->m_sb.sb_fdblocks;
resid = do_div(count, weight);
if (count < max(min, XFS_ICSB_FDBLK_CNTR_REENABLE(mp)))
return;
break;
default:
BUG();
count = resid = 0; /* quiet, gcc */
break;
}
xfs_icsb_enable_counter(mp, field, count, resid);
}
STATIC void
xfs_icsb_balance_counter(
xfs_mount_t *mp,
xfs_sb_field_t fields,
int min_per_cpu)
{
spin_lock(&mp->m_sb_lock);
xfs_icsb_balance_counter_locked(mp, fields, min_per_cpu);
spin_unlock(&mp->m_sb_lock);
}
int
xfs_icsb_modify_counters(
xfs_mount_t *mp,
xfs_sb_field_t field,
int64_t delta,
int rsvd)
{
xfs_icsb_cnts_t *icsbp;
long long lcounter; /* long counter for 64 bit fields */
int ret = 0;
might_sleep();
again:
preempt_disable();
icsbp = this_cpu_ptr(mp->m_sb_cnts);
/*
* if the counter is disabled, go to slow path
*/
if (unlikely(xfs_icsb_counter_disabled(mp, field)))
goto slow_path;
xfs_icsb_lock_cntr(icsbp);
if (unlikely(xfs_icsb_counter_disabled(mp, field))) {
xfs_icsb_unlock_cntr(icsbp);
goto slow_path;
}
switch (field) {
case XFS_SBS_ICOUNT:
lcounter = icsbp->icsb_icount;
lcounter += delta;
if (unlikely(lcounter < 0))
goto balance_counter;
icsbp->icsb_icount = lcounter;
break;
case XFS_SBS_IFREE:
lcounter = icsbp->icsb_ifree;
lcounter += delta;
if (unlikely(lcounter < 0))
goto balance_counter;
icsbp->icsb_ifree = lcounter;
break;
case XFS_SBS_FDBLOCKS:
BUG_ON((mp->m_resblks - mp->m_resblks_avail) != 0);
lcounter = icsbp->icsb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
lcounter += delta;
if (unlikely(lcounter < 0))
goto balance_counter;
icsbp->icsb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
break;
default:
BUG();
break;
}
xfs_icsb_unlock_cntr(icsbp);
preempt_enable();
return 0;
slow_path:
preempt_enable();
/*
* serialise with a mutex so we don't burn lots of cpu on
* the superblock lock. We still need to hold the superblock
* lock, however, when we modify the global structures.
*/
xfs_icsb_lock(mp);
/*
* Now running atomically.
*
* If the counter is enabled, someone has beaten us to rebalancing.
* Drop the lock and try again in the fast path....
*/
if (!(xfs_icsb_counter_disabled(mp, field))) {
xfs_icsb_unlock(mp);
goto again;
}
/*
* The counter is currently disabled. Because we are
* running atomically here, we know a rebalance cannot
* be in progress. Hence we can go straight to operating
* on the global superblock. We do not call xfs_mod_incore_sb()
* here even though we need to get the m_sb_lock. Doing so
* will cause us to re-enter this function and deadlock.
* Hence we get the m_sb_lock ourselves and then call
* xfs_mod_incore_sb_unlocked() as the unlocked path operates
* directly on the global counters.
*/
spin_lock(&mp->m_sb_lock);
ret = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
spin_unlock(&mp->m_sb_lock);
/*
* Now that we've modified the global superblock, we
* may be able to re-enable the distributed counters
* (e.g. lots of space just got freed). After that
* we are done.
*/
if (ret != ENOSPC)
xfs_icsb_balance_counter(mp, field, 0);
xfs_icsb_unlock(mp);
return ret;
balance_counter:
xfs_icsb_unlock_cntr(icsbp);
preempt_enable();
/*
* We may have multiple threads here if multiple per-cpu
* counters run dry at the same time. This will mean we can
* do more balances than strictly necessary but it is not
* the common slowpath case.
*/
xfs_icsb_lock(mp);
/*
* running atomically.
*
* This will leave the counter in the correct state for future
* accesses. After the rebalance, we simply try again and our retry
* will either succeed through the fast path or slow path without
* another balance operation being required.
*/
xfs_icsb_balance_counter(mp, field, delta);
xfs_icsb_unlock(mp);
goto again;
}
#endif
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