blob: ef7f0218bccb45779157128139ab552e8b423832 [file] [log] [blame]
/*
* 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_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_inode.h"
#include "xfs_dinode.h"
#include "xfs_error.h"
#include "xfs_mru_cache.h"
#include "xfs_filestream.h"
#include "xfs_vnodeops.h"
#include "xfs_utils.h"
#include "xfs_buf_item.h"
#include "xfs_inode_item.h"
#include "xfs_rw.h"
#include "xfs_quota.h"
#include "xfs_trace.h"
#include <linux/kthread.h>
#include <linux/freezer.h>
STATIC xfs_inode_t *
xfs_inode_ag_lookup(
struct xfs_mount *mp,
struct xfs_perag *pag,
uint32_t *first_index,
int tag)
{
int nr_found;
struct xfs_inode *ip;
/*
* use a gang lookup to find the next inode in the tree
* as the tree is sparse and a gang lookup walks to find
* the number of objects requested.
*/
if (tag == XFS_ICI_NO_TAG) {
nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
(void **)&ip, *first_index, 1);
} else {
nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
(void **)&ip, *first_index, 1, tag);
}
if (!nr_found)
return NULL;
/*
* Update the index for the next lookup. Catch overflows
* into the next AG range which can occur if we have inodes
* in the last block of the AG and we are currently
* pointing to the last inode.
*/
*first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
if (*first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
return NULL;
return ip;
}
STATIC int
xfs_inode_ag_walk(
struct xfs_mount *mp,
struct xfs_perag *pag,
int (*execute)(struct xfs_inode *ip,
struct xfs_perag *pag, int flags),
int flags,
int tag,
int exclusive,
int *nr_to_scan)
{
uint32_t first_index;
int last_error = 0;
int skipped;
restart:
skipped = 0;
first_index = 0;
do {
int error = 0;
xfs_inode_t *ip;
if (exclusive)
write_lock(&pag->pag_ici_lock);
else
read_lock(&pag->pag_ici_lock);
ip = xfs_inode_ag_lookup(mp, pag, &first_index, tag);
if (!ip) {
if (exclusive)
write_unlock(&pag->pag_ici_lock);
else
read_unlock(&pag->pag_ici_lock);
break;
}
/* execute releases pag->pag_ici_lock */
error = execute(ip, pag, flags);
if (error == EAGAIN) {
skipped++;
continue;
}
if (error)
last_error = error;
/* bail out if the filesystem is corrupted. */
if (error == EFSCORRUPTED)
break;
} while ((*nr_to_scan)--);
if (skipped) {
delay(1);
goto restart;
}
return last_error;
}
int
xfs_inode_ag_iterator(
struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip,
struct xfs_perag *pag, int flags),
int flags,
int tag,
int exclusive,
int *nr_to_scan)
{
int error = 0;
int last_error = 0;
xfs_agnumber_t ag;
int nr;
nr = nr_to_scan ? *nr_to_scan : INT_MAX;
for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
struct xfs_perag *pag;
pag = xfs_perag_get(mp, ag);
error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
exclusive, &nr);
xfs_perag_put(pag);
if (error) {
last_error = error;
if (error == EFSCORRUPTED)
break;
}
if (nr <= 0)
break;
}
if (nr_to_scan)
*nr_to_scan = nr;
return XFS_ERROR(last_error);
}
/* must be called with pag_ici_lock held and releases it */
int
xfs_sync_inode_valid(
struct xfs_inode *ip,
struct xfs_perag *pag)
{
struct inode *inode = VFS_I(ip);
int error = EFSCORRUPTED;
/* nothing to sync during shutdown */
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
goto out_unlock;
/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
error = ENOENT;
if (xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
goto out_unlock;
/* If we can't grab the inode, it must on it's way to reclaim. */
if (!igrab(inode))
goto out_unlock;
if (is_bad_inode(inode)) {
IRELE(ip);
goto out_unlock;
}
/* inode is valid */
error = 0;
out_unlock:
read_unlock(&pag->pag_ici_lock);
return error;
}
STATIC int
xfs_sync_inode_data(
struct xfs_inode *ip,
struct xfs_perag *pag,
int flags)
{
struct inode *inode = VFS_I(ip);
struct address_space *mapping = inode->i_mapping;
int error = 0;
error = xfs_sync_inode_valid(ip, pag);
if (error)
return error;
if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
goto out_wait;
if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {
if (flags & SYNC_TRYLOCK)
goto out_wait;
xfs_ilock(ip, XFS_IOLOCK_SHARED);
}
error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ?
0 : XBF_ASYNC, FI_NONE);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
out_wait:
if (flags & SYNC_WAIT)
xfs_ioend_wait(ip);
IRELE(ip);
return error;
}
STATIC int
xfs_sync_inode_attr(
struct xfs_inode *ip,
struct xfs_perag *pag,
int flags)
{
int error = 0;
error = xfs_sync_inode_valid(ip, pag);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_SHARED);
if (xfs_inode_clean(ip))
goto out_unlock;
if (!xfs_iflock_nowait(ip)) {
if (!(flags & SYNC_WAIT))
goto out_unlock;
xfs_iflock(ip);
}
if (xfs_inode_clean(ip)) {
xfs_ifunlock(ip);
goto out_unlock;
}
error = xfs_iflush(ip, flags);
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_SHARED);
IRELE(ip);
return error;
}
/*
* Write out pagecache data for the whole filesystem.
*/
int
xfs_sync_data(
struct xfs_mount *mp,
int flags)
{
int error;
ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);
error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags,
XFS_ICI_NO_TAG, 0, NULL);
if (error)
return XFS_ERROR(error);
xfs_log_force(mp, (flags & SYNC_WAIT) ? XFS_LOG_SYNC : 0);
return 0;
}
/*
* Write out inode metadata (attributes) for the whole filesystem.
*/
int
xfs_sync_attr(
struct xfs_mount *mp,
int flags)
{
ASSERT((flags & ~SYNC_WAIT) == 0);
return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags,
XFS_ICI_NO_TAG, 0, NULL);
}
STATIC int
xfs_commit_dummy_trans(
struct xfs_mount *mp,
uint flags)
{
struct xfs_inode *ip = mp->m_rootip;
struct xfs_trans *tp;
int error;
/*
* Put a dummy transaction in the log to tell recovery
* that all others are OK.
*/
tp = xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0);
if (error) {
xfs_trans_cancel(tp, 0);
return error;
}
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_ihold(tp, ip);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
error = xfs_trans_commit(tp, 0);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
/* the log force ensures this transaction is pushed to disk */
xfs_log_force(mp, (flags & SYNC_WAIT) ? XFS_LOG_SYNC : 0);
return error;
}
STATIC int
xfs_sync_fsdata(
struct xfs_mount *mp)
{
struct xfs_buf *bp;
/*
* If the buffer is pinned then push on the log so we won't get stuck
* waiting in the write for someone, maybe ourselves, to flush the log.
*
* Even though we just pushed the log above, we did not have the
* superblock buffer locked at that point so it can become pinned in
* between there and here.
*/
bp = xfs_getsb(mp, 0);
if (XFS_BUF_ISPINNED(bp))
xfs_log_force(mp, 0);
return xfs_bwrite(mp, bp);
}
/*
* When remounting a filesystem read-only or freezing the filesystem, we have
* two phases to execute. This first phase is syncing the data before we
* quiesce the filesystem, and the second is flushing all the inodes out after
* we've waited for all the transactions created by the first phase to
* complete. The second phase ensures that the inodes are written to their
* location on disk rather than just existing in transactions in the log. This
* means after a quiesce there is no log replay required to write the inodes to
* disk (this is the main difference between a sync and a quiesce).
*/
/*
* First stage of freeze - no writers will make progress now we are here,
* so we flush delwri and delalloc buffers here, then wait for all I/O to
* complete. Data is frozen at that point. Metadata is not frozen,
* transactions can still occur here so don't bother flushing the buftarg
* because it'll just get dirty again.
*/
int
xfs_quiesce_data(
struct xfs_mount *mp)
{
int error, error2 = 0;
/* push non-blocking */
xfs_sync_data(mp, 0);
xfs_qm_sync(mp, SYNC_TRYLOCK);
/* push and block till complete */
xfs_sync_data(mp, SYNC_WAIT);
xfs_qm_sync(mp, SYNC_WAIT);
/* write superblock and hoover up shutdown errors */
error = xfs_sync_fsdata(mp);
/* make sure all delwri buffers are written out */
xfs_flush_buftarg(mp->m_ddev_targp, 1);
/* mark the log as covered if needed */
if (xfs_log_need_covered(mp))
error2 = xfs_commit_dummy_trans(mp, SYNC_WAIT);
/* flush data-only devices */
if (mp->m_rtdev_targp)
XFS_bflush(mp->m_rtdev_targp);
return error ? error : error2;
}
STATIC void
xfs_quiesce_fs(
struct xfs_mount *mp)
{
int count = 0, pincount;
xfs_reclaim_inodes(mp, 0);
xfs_flush_buftarg(mp->m_ddev_targp, 0);
/*
* This loop must run at least twice. The first instance of the loop
* will flush most meta data but that will generate more meta data
* (typically directory updates). Which then must be flushed and
* logged before we can write the unmount record. We also so sync
* reclaim of inodes to catch any that the above delwri flush skipped.
*/
do {
xfs_reclaim_inodes(mp, SYNC_WAIT);
xfs_sync_attr(mp, SYNC_WAIT);
pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1);
if (!pincount) {
delay(50);
count++;
}
} while (count < 2);
}
/*
* Second stage of a quiesce. The data is already synced, now we have to take
* care of the metadata. New transactions are already blocked, so we need to
* wait for any remaining transactions to drain out before proceding.
*/
void
xfs_quiesce_attr(
struct xfs_mount *mp)
{
int error = 0;
/* wait for all modifications to complete */
while (atomic_read(&mp->m_active_trans) > 0)
delay(100);
/* flush inodes and push all remaining buffers out to disk */
xfs_quiesce_fs(mp);
/*
* Just warn here till VFS can correctly support
* read-only remount without racing.
*/
WARN_ON(atomic_read(&mp->m_active_trans) != 0);
/* Push the superblock and write an unmount record */
error = xfs_log_sbcount(mp, 1);
if (error)
xfs_fs_cmn_err(CE_WARN, mp,
"xfs_attr_quiesce: failed to log sb changes. "
"Frozen image may not be consistent.");
xfs_log_unmount_write(mp);
xfs_unmountfs_writesb(mp);
}
/*
* Enqueue a work item to be picked up by the vfs xfssyncd thread.
* Doing this has two advantages:
* - It saves on stack space, which is tight in certain situations
* - It can be used (with care) as a mechanism to avoid deadlocks.
* Flushing while allocating in a full filesystem requires both.
*/
STATIC void
xfs_syncd_queue_work(
struct xfs_mount *mp,
void *data,
void (*syncer)(struct xfs_mount *, void *),
struct completion *completion)
{
struct xfs_sync_work *work;
work = kmem_alloc(sizeof(struct xfs_sync_work), KM_SLEEP);
INIT_LIST_HEAD(&work->w_list);
work->w_syncer = syncer;
work->w_data = data;
work->w_mount = mp;
work->w_completion = completion;
spin_lock(&mp->m_sync_lock);
list_add_tail(&work->w_list, &mp->m_sync_list);
spin_unlock(&mp->m_sync_lock);
wake_up_process(mp->m_sync_task);
}
/*
* Flush delayed allocate data, attempting to free up reserved space
* from existing allocations. At this point a new allocation attempt
* has failed with ENOSPC and we are in the process of scratching our
* heads, looking about for more room...
*/
STATIC void
xfs_flush_inodes_work(
struct xfs_mount *mp,
void *arg)
{
struct inode *inode = arg;
xfs_sync_data(mp, SYNC_TRYLOCK);
xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);
iput(inode);
}
void
xfs_flush_inodes(
xfs_inode_t *ip)
{
struct inode *inode = VFS_I(ip);
DECLARE_COMPLETION_ONSTACK(completion);
igrab(inode);
xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inodes_work, &completion);
wait_for_completion(&completion);
xfs_log_force(ip->i_mount, XFS_LOG_SYNC);
}
/*
* Every sync period we need to unpin all items, reclaim inodes and sync
* disk quotas. We might need to cover the log to indicate that the
* filesystem is idle.
*/
STATIC void
xfs_sync_worker(
struct xfs_mount *mp,
void *unused)
{
int error;
if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
xfs_log_force(mp, 0);
xfs_reclaim_inodes(mp, 0);
/* dgc: errors ignored here */
error = xfs_qm_sync(mp, SYNC_TRYLOCK);
if (xfs_log_need_covered(mp))
error = xfs_commit_dummy_trans(mp, 0);
}
mp->m_sync_seq++;
wake_up(&mp->m_wait_single_sync_task);
}
STATIC int
xfssyncd(
void *arg)
{
struct xfs_mount *mp = arg;
long timeleft;
xfs_sync_work_t *work, *n;
LIST_HEAD (tmp);
set_freezable();
timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
for (;;) {
if (list_empty(&mp->m_sync_list))
timeleft = schedule_timeout_interruptible(timeleft);
/* swsusp */
try_to_freeze();
if (kthread_should_stop() && list_empty(&mp->m_sync_list))
break;
spin_lock(&mp->m_sync_lock);
/*
* We can get woken by laptop mode, to do a sync -
* that's the (only!) case where the list would be
* empty with time remaining.
*/
if (!timeleft || list_empty(&mp->m_sync_list)) {
if (!timeleft)
timeleft = xfs_syncd_centisecs *
msecs_to_jiffies(10);
INIT_LIST_HEAD(&mp->m_sync_work.w_list);
list_add_tail(&mp->m_sync_work.w_list,
&mp->m_sync_list);
}
list_splice_init(&mp->m_sync_list, &tmp);
spin_unlock(&mp->m_sync_lock);
list_for_each_entry_safe(work, n, &tmp, w_list) {
(*work->w_syncer)(mp, work->w_data);
list_del(&work->w_list);
if (work == &mp->m_sync_work)
continue;
if (work->w_completion)
complete(work->w_completion);
kmem_free(work);
}
}
return 0;
}
int
xfs_syncd_init(
struct xfs_mount *mp)
{
mp->m_sync_work.w_syncer = xfs_sync_worker;
mp->m_sync_work.w_mount = mp;
mp->m_sync_work.w_completion = NULL;
mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd/%s", mp->m_fsname);
if (IS_ERR(mp->m_sync_task))
return -PTR_ERR(mp->m_sync_task);
return 0;
}
void
xfs_syncd_stop(
struct xfs_mount *mp)
{
kthread_stop(mp->m_sync_task);
}
void
__xfs_inode_set_reclaim_tag(
struct xfs_perag *pag,
struct xfs_inode *ip)
{
radix_tree_tag_set(&pag->pag_ici_root,
XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
XFS_ICI_RECLAIM_TAG);
pag->pag_ici_reclaimable++;
}
/*
* We set the inode flag atomically with the radix tree tag.
* Once we get tag lookups on the radix tree, this inode flag
* can go away.
*/
void
xfs_inode_set_reclaim_tag(
xfs_inode_t *ip)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
write_lock(&pag->pag_ici_lock);
spin_lock(&ip->i_flags_lock);
__xfs_inode_set_reclaim_tag(pag, ip);
__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
spin_unlock(&ip->i_flags_lock);
write_unlock(&pag->pag_ici_lock);
xfs_perag_put(pag);
}
void
__xfs_inode_clear_reclaim_tag(
xfs_mount_t *mp,
xfs_perag_t *pag,
xfs_inode_t *ip)
{
radix_tree_tag_clear(&pag->pag_ici_root,
XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
pag->pag_ici_reclaimable--;
}
/*
* Inodes in different states need to be treated differently, and the return
* value of xfs_iflush is not sufficient to get this right. The following table
* lists the inode states and the reclaim actions necessary for non-blocking
* reclaim:
*
*
* inode state iflush ret required action
* --------------- ---------- ---------------
* bad - reclaim
* shutdown EIO unpin and reclaim
* clean, unpinned 0 reclaim
* stale, unpinned 0 reclaim
* clean, pinned(*) 0 requeue
* stale, pinned EAGAIN requeue
* dirty, delwri ok 0 requeue
* dirty, delwri blocked EAGAIN requeue
* dirty, sync flush 0 reclaim
*
* (*) dgc: I don't think the clean, pinned state is possible but it gets
* handled anyway given the order of checks implemented.
*
* As can be seen from the table, the return value of xfs_iflush() is not
* sufficient to correctly decide the reclaim action here. The checks in
* xfs_iflush() might look like duplicates, but they are not.
*
* Also, because we get the flush lock first, we know that any inode that has
* been flushed delwri has had the flush completed by the time we check that
* the inode is clean. The clean inode check needs to be done before flushing
* the inode delwri otherwise we would loop forever requeuing clean inodes as
* we cannot tell apart a successful delwri flush and a clean inode from the
* return value of xfs_iflush().
*
* Note that because the inode is flushed delayed write by background
* writeback, the flush lock may already be held here and waiting on it can
* result in very long latencies. Hence for sync reclaims, where we wait on the
* flush lock, the caller should push out delayed write inodes first before
* trying to reclaim them to minimise the amount of time spent waiting. For
* background relaim, we just requeue the inode for the next pass.
*
* Hence the order of actions after gaining the locks should be:
* bad => reclaim
* shutdown => unpin and reclaim
* pinned, delwri => requeue
* pinned, sync => unpin
* stale => reclaim
* clean => reclaim
* dirty, delwri => flush and requeue
* dirty, sync => flush, wait and reclaim
*/
STATIC int
xfs_reclaim_inode(
struct xfs_inode *ip,
struct xfs_perag *pag,
int sync_mode)
{
int error = 0;
/*
* The radix tree lock here protects a thread in xfs_iget from racing
* with us starting reclaim on the inode. Once we have the
* XFS_IRECLAIM flag set it will not touch us.
*/
spin_lock(&ip->i_flags_lock);
ASSERT_ALWAYS(__xfs_iflags_test(ip, XFS_IRECLAIMABLE));
if (__xfs_iflags_test(ip, XFS_IRECLAIM)) {
/* ignore as it is already under reclaim */
spin_unlock(&ip->i_flags_lock);
write_unlock(&pag->pag_ici_lock);
return 0;
}
__xfs_iflags_set(ip, XFS_IRECLAIM);
spin_unlock(&ip->i_flags_lock);
write_unlock(&pag->pag_ici_lock);
xfs_ilock(ip, XFS_ILOCK_EXCL);
if (!xfs_iflock_nowait(ip)) {
if (!(sync_mode & SYNC_WAIT))
goto out;
xfs_iflock(ip);
}
if (is_bad_inode(VFS_I(ip)))
goto reclaim;
if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
xfs_iunpin_wait(ip);
goto reclaim;
}
if (xfs_ipincount(ip)) {
if (!(sync_mode & SYNC_WAIT)) {
xfs_ifunlock(ip);
goto out;
}
xfs_iunpin_wait(ip);
}
if (xfs_iflags_test(ip, XFS_ISTALE))
goto reclaim;
if (xfs_inode_clean(ip))
goto reclaim;
/* Now we have an inode that needs flushing */
error = xfs_iflush(ip, sync_mode);
if (sync_mode & SYNC_WAIT) {
xfs_iflock(ip);
goto reclaim;
}
/*
* When we have to flush an inode but don't have SYNC_WAIT set, we
* flush the inode out using a delwri buffer and wait for the next
* call into reclaim to find it in a clean state instead of waiting for
* it now. We also don't return errors here - if the error is transient
* then the next reclaim pass will flush the inode, and if the error
* is permanent then the next sync reclaim will reclaim the inode and
* pass on the error.
*/
if (error && error != EAGAIN && !XFS_FORCED_SHUTDOWN(ip->i_mount)) {
xfs_fs_cmn_err(CE_WARN, ip->i_mount,
"inode 0x%llx background reclaim flush failed with %d",
(long long)ip->i_ino, error);
}
out:
xfs_iflags_clear(ip, XFS_IRECLAIM);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
/*
* We could return EAGAIN here to make reclaim rescan the inode tree in
* a short while. However, this just burns CPU time scanning the tree
* waiting for IO to complete and xfssyncd never goes back to the idle
* state. Instead, return 0 to let the next scheduled background reclaim
* attempt to reclaim the inode again.
*/
return 0;
reclaim:
xfs_ifunlock(ip);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_ireclaim(ip);
return error;
}
int
xfs_reclaim_inodes(
xfs_mount_t *mp,
int mode)
{
return xfs_inode_ag_iterator(mp, xfs_reclaim_inode, mode,
XFS_ICI_RECLAIM_TAG, 1, NULL);
}
/*
* Shrinker infrastructure.
*
* This is all far more complex than it needs to be. It adds a global list of
* mounts because the shrinkers can only call a global context. We need to make
* the shrinkers pass a context to avoid the need for global state.
*/
static LIST_HEAD(xfs_mount_list);
static struct rw_semaphore xfs_mount_list_lock;
static int
xfs_reclaim_inode_shrink(
int nr_to_scan,
gfp_t gfp_mask)
{
struct xfs_mount *mp;
struct xfs_perag *pag;
xfs_agnumber_t ag;
int reclaimable = 0;
if (nr_to_scan) {
if (!(gfp_mask & __GFP_FS))
return -1;
down_read(&xfs_mount_list_lock);
list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0,
XFS_ICI_RECLAIM_TAG, 1, &nr_to_scan);
if (nr_to_scan <= 0)
break;
}
up_read(&xfs_mount_list_lock);
}
down_read(&xfs_mount_list_lock);
list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
pag = xfs_perag_get(mp, ag);
reclaimable += pag->pag_ici_reclaimable;
xfs_perag_put(pag);
}
}
up_read(&xfs_mount_list_lock);
return reclaimable;
}
static struct shrinker xfs_inode_shrinker = {
.shrink = xfs_reclaim_inode_shrink,
.seeks = DEFAULT_SEEKS,
};
void __init
xfs_inode_shrinker_init(void)
{
init_rwsem(&xfs_mount_list_lock);
register_shrinker(&xfs_inode_shrinker);
}
void
xfs_inode_shrinker_destroy(void)
{
ASSERT(list_empty(&xfs_mount_list));
unregister_shrinker(&xfs_inode_shrinker);
}
void
xfs_inode_shrinker_register(
struct xfs_mount *mp)
{
down_write(&xfs_mount_list_lock);
list_add_tail(&mp->m_mplist, &xfs_mount_list);
up_write(&xfs_mount_list_lock);
}
void
xfs_inode_shrinker_unregister(
struct xfs_mount *mp)
{
down_write(&xfs_mount_list_lock);
list_del(&mp->m_mplist);
up_write(&xfs_mount_list_lock);
}