#include <linux/kthread.h>
#include <linux/freezer.h>
+/*
+ * The inode lookup is done in batches to keep the amount of lock traffic and
+ * radix tree lookups to a minimum. The batch size is a trade off between
+ * lookup reduction and stack usage. This is in the reclaim path, so we can't
+ * be too greedy.
+ */
+#define XFS_LOOKUP_BATCH 32
-STATIC xfs_inode_t *
-xfs_inode_ag_lookup(
- struct xfs_mount *mp,
- struct xfs_perag *pag,
- uint32_t *first_index,
- int tag)
+STATIC int
+xfs_inode_ag_walk_grab(
+ struct xfs_inode *ip)
{
- int nr_found;
- struct xfs_inode *ip;
+ struct inode *inode = VFS_I(ip);
+
+ ASSERT(rcu_read_lock_held());
/*
- * 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.
+ * check for stale RCU freed inode
+ *
+ * If the inode has been reallocated, it doesn't matter if it's not in
+ * the AG we are walking - we are walking for writeback, so if it
+ * passes all the "valid inode" checks and is dirty, then we'll write
+ * it back anyway. If it has been reallocated and still being
+ * initialised, the XFS_INEW check below will catch it.
*/
- 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);
+ spin_lock(&ip->i_flags_lock);
+ if (!ip->i_ino)
+ goto out_unlock_noent;
+
+ /* avoid new or reclaimable inodes. Leave for reclaim code to flush */
+ if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
+ goto out_unlock_noent;
+ spin_unlock(&ip->i_flags_lock);
+
+ /* nothing to sync during shutdown */
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ return EFSCORRUPTED;
+
+ /* If we can't grab the inode, it must on it's way to reclaim. */
+ if (!igrab(inode))
+ return ENOENT;
+
+ if (is_bad_inode(inode)) {
+ IRELE(ip);
+ return ENOENT;
}
- 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;
+ /* inode is valid */
+ return 0;
+
+out_unlock_noent:
+ spin_unlock(&ip->i_flags_lock);
+ return ENOENT;
}
STATIC int
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)
+ int flags)
{
uint32_t first_index;
int last_error = 0;
int skipped;
+ int done;
+ int nr_found;
restart:
+ done = 0;
skipped = 0;
first_index = 0;
+ nr_found = 0;
do {
+ struct xfs_inode *batch[XFS_LOOKUP_BATCH];
int error = 0;
- xfs_inode_t *ip;
+ int i;
- 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);
+ rcu_read_lock();
+ nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
+ (void **)batch, first_index,
+ XFS_LOOKUP_BATCH);
+ if (!nr_found) {
+ rcu_read_unlock();
break;
}
- /* execute releases pag->pag_ici_lock */
- error = execute(ip, pag, flags);
- if (error == EAGAIN) {
- skipped++;
- continue;
+ /*
+ * Grab the inodes before we drop the lock. if we found
+ * nothing, nr == 0 and the loop will be skipped.
+ */
+ for (i = 0; i < nr_found; i++) {
+ struct xfs_inode *ip = batch[i];
+
+ if (done || xfs_inode_ag_walk_grab(ip))
+ batch[i] = 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.
+ *
+ * Because we may see inodes that are from the wrong AG
+ * due to RCU freeing and reallocation, only update the
+ * index if it lies in this AG. It was a race that lead
+ * us to see this inode, so another lookup from the
+ * same index will not find it again.
+ */
+ if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
+ continue;
+ first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
+ if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
+ done = 1;
+ }
+
+ /* unlock now we've grabbed the inodes. */
+ rcu_read_unlock();
+
+ for (i = 0; i < nr_found; i++) {
+ if (!batch[i])
+ continue;
+ error = execute(batch[i], pag, flags);
+ IRELE(batch[i]);
+ if (error == EAGAIN) {
+ skipped++;
+ continue;
+ }
+ if (error && last_error != EFSCORRUPTED)
+ last_error = error;
}
- if (error)
- last_error = error;
/* bail out if the filesystem is corrupted. */
if (error == EFSCORRUPTED)
break;
- } while ((*nr_to_scan)--);
+ } while (nr_found && !done);
if (skipped) {
delay(1);
return last_error;
}
-/*
- * Select the next per-ag structure to iterate during the walk. The reclaim
- * walk is optimised only to walk AGs with reclaimable inodes in them.
- */
-static struct xfs_perag *
-xfs_inode_ag_iter_next_pag(
- struct xfs_mount *mp,
- xfs_agnumber_t *first,
- int tag)
-{
- struct xfs_perag *pag = NULL;
-
- if (tag == XFS_ICI_RECLAIM_TAG) {
- int found;
- int ref;
-
- spin_lock(&mp->m_perag_lock);
- found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
- (void **)&pag, *first, 1, tag);
- if (found <= 0) {
- spin_unlock(&mp->m_perag_lock);
- return NULL;
- }
- *first = pag->pag_agno + 1;
- /* open coded pag reference increment */
- ref = atomic_inc_return(&pag->pag_ref);
- spin_unlock(&mp->m_perag_lock);
- trace_xfs_perag_get_reclaim(mp, pag->pag_agno, ref, _RET_IP_);
- } else {
- pag = xfs_perag_get(mp, *first);
- (*first)++;
- }
- return pag;
-}
-
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 flags)
{
struct xfs_perag *pag;
int error = 0;
int last_error = 0;
xfs_agnumber_t ag;
- int nr;
- nr = nr_to_scan ? *nr_to_scan : INT_MAX;
ag = 0;
- while ((pag = xfs_inode_ag_iter_next_pag(mp, &ag, tag))) {
- error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
- exclusive, &nr);
+ while ((pag = xfs_perag_get(mp, ag))) {
+ ag = pag->pag_agno + 1;
+ error = xfs_inode_ag_walk(mp, pag, execute, flags);
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 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;
out_wait:
if (flags & SYNC_WAIT)
xfs_ioend_wait(ip);
- IRELE(ip);
return error;
}
{
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;
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_SHARED);
- IRELE(ip);
return 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);
+ error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags);
if (error)
return XFS_ERROR(error);
{
ASSERT((flags & ~SYNC_WAIT) == 0);
- return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags,
- XFS_ICI_NO_TAG, 0, NULL);
+ return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags);
}
STATIC int
/* mark the log as covered if needed */
if (xfs_log_need_covered(mp))
- error2 = xfs_fs_log_dummy(mp, SYNC_WAIT);
+ error2 = xfs_fs_log_dummy(mp);
/* flush data-only devices */
if (mp->m_rtdev_targp)
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 (mp->m_super->s_frozen == SB_UNFROZEN &&
xfs_log_need_covered(mp))
- error = xfs_fs_log_dummy(mp, 0);
+ error = xfs_fs_log_dummy(mp);
+ else
+ xfs_log_force(mp, 0);
+ xfs_reclaim_inodes(mp, 0);
+ error = xfs_qm_sync(mp, SYNC_TRYLOCK);
}
mp->m_sync_seq++;
wake_up(&mp->m_wait_single_sync_task);
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(&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);
+ spin_unlock(&pag->pag_ici_lock);
xfs_perag_put(pag);
}
__xfs_inode_clear_reclaim(pag, ip);
}
+/*
+ * Grab the inode for reclaim exclusively.
+ * Return 0 if we grabbed it, non-zero otherwise.
+ */
+STATIC int
+xfs_reclaim_inode_grab(
+ struct xfs_inode *ip,
+ int flags)
+{
+ ASSERT(rcu_read_lock_held());
+
+ /* quick check for stale RCU freed inode */
+ if (!ip->i_ino)
+ return 1;
+
+ /*
+ * do some unlocked checks first to avoid unnecessary lock traffic.
+ * The first is a flush lock check, the second is a already in reclaim
+ * check. Only do these checks if we are not going to block on locks.
+ */
+ if ((flags & SYNC_TRYLOCK) &&
+ (!ip->i_flush.done || __xfs_iflags_test(ip, XFS_IRECLAIM))) {
+ return 1;
+ }
+
+ /*
+ * 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.
+ *
+ * Due to RCU lookup, we may find inodes that have been freed and only
+ * have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
+ * aren't candidates for reclaim at all, so we must check the
+ * XFS_IRECLAIMABLE is set first before proceeding to reclaim.
+ */
+ spin_lock(&ip->i_flags_lock);
+ if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
+ __xfs_iflags_test(ip, XFS_IRECLAIM)) {
+ /* not a reclaim candidate. */
+ spin_unlock(&ip->i_flags_lock);
+ return 1;
+ }
+ __xfs_iflags_set(ip, XFS_IRECLAIM);
+ spin_unlock(&ip->i_flags_lock);
+ return 0;
+}
+
/*
* 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
{
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))
* added to the tree assert that it's been there before to catch
* problems with the inode life time early on.
*/
- write_lock(&pag->pag_ici_lock);
+ spin_lock(&pag->pag_ici_lock);
if (!radix_tree_delete(&pag->pag_ici_root,
XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino)))
ASSERT(0);
__xfs_inode_clear_reclaim(pag, ip);
- write_unlock(&pag->pag_ici_lock);
+ spin_unlock(&pag->pag_ici_lock);
/*
* Here we do an (almost) spurious inode lock in order to coordinate
}
+/*
+ * Walk the AGs and reclaim the inodes in them. Even if the filesystem is
+ * corrupted, we still want to try to reclaim all the inodes. If we don't,
+ * then a shut down during filesystem unmount reclaim walk leak all the
+ * unreclaimed inodes.
+ */
+int
+xfs_reclaim_inodes_ag(
+ struct xfs_mount *mp,
+ int flags,
+ int *nr_to_scan)
+{
+ struct xfs_perag *pag;
+ int error = 0;
+ int last_error = 0;
+ xfs_agnumber_t ag;
+ int trylock = flags & SYNC_TRYLOCK;
+ int skipped;
+
+restart:
+ ag = 0;
+ skipped = 0;
+ while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
+ unsigned long first_index = 0;
+ int done = 0;
+ int nr_found = 0;
+
+ ag = pag->pag_agno + 1;
+
+ if (trylock) {
+ if (!mutex_trylock(&pag->pag_ici_reclaim_lock)) {
+ skipped++;
+ xfs_perag_put(pag);
+ continue;
+ }
+ first_index = pag->pag_ici_reclaim_cursor;
+ } else
+ mutex_lock(&pag->pag_ici_reclaim_lock);
+
+ do {
+ struct xfs_inode *batch[XFS_LOOKUP_BATCH];
+ int i;
+
+ rcu_read_lock();
+ nr_found = radix_tree_gang_lookup_tag(
+ &pag->pag_ici_root,
+ (void **)batch, first_index,
+ XFS_LOOKUP_BATCH,
+ XFS_ICI_RECLAIM_TAG);
+ if (!nr_found) {
+ rcu_read_unlock();
+ break;
+ }
+
+ /*
+ * Grab the inodes before we drop the lock. if we found
+ * nothing, nr == 0 and the loop will be skipped.
+ */
+ for (i = 0; i < nr_found; i++) {
+ struct xfs_inode *ip = batch[i];
+
+ if (done || xfs_reclaim_inode_grab(ip, flags))
+ batch[i] = 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.
+ *
+ * Because we may see inodes that are from the
+ * wrong AG due to RCU freeing and
+ * reallocation, only update the index if it
+ * lies in this AG. It was a race that lead us
+ * to see this inode, so another lookup from
+ * the same index will not find it again.
+ */
+ if (XFS_INO_TO_AGNO(mp, ip->i_ino) !=
+ pag->pag_agno)
+ continue;
+ first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
+ if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
+ done = 1;
+ }
+
+ /* unlock now we've grabbed the inodes. */
+ rcu_read_unlock();
+
+ for (i = 0; i < nr_found; i++) {
+ if (!batch[i])
+ continue;
+ error = xfs_reclaim_inode(batch[i], pag, flags);
+ if (error && last_error != EFSCORRUPTED)
+ last_error = error;
+ }
+
+ *nr_to_scan -= XFS_LOOKUP_BATCH;
+
+ } while (nr_found && !done && *nr_to_scan > 0);
+
+ if (trylock && !done)
+ pag->pag_ici_reclaim_cursor = first_index;
+ else
+ pag->pag_ici_reclaim_cursor = 0;
+ mutex_unlock(&pag->pag_ici_reclaim_lock);
+ xfs_perag_put(pag);
+ }
+
+ /*
+ * if we skipped any AG, and we still have scan count remaining, do
+ * another pass this time using blocking reclaim semantics (i.e
+ * waiting on the reclaim locks and ignoring the reclaim cursors). This
+ * ensure that when we get more reclaimers than AGs we block rather
+ * than spin trying to execute reclaim.
+ */
+ if (trylock && skipped && *nr_to_scan > 0) {
+ trylock = 0;
+ goto restart;
+ }
+ return XFS_ERROR(last_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);
+ int nr_to_scan = INT_MAX;
+
+ return xfs_reclaim_inodes_ag(mp, mode, &nr_to_scan);
}
/*
if (!(gfp_mask & __GFP_FS))
return -1;
- xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0,
- XFS_ICI_RECLAIM_TAG, 1, &nr_to_scan);
- /* if we don't exhaust the scan, don't bother coming back */
+ xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK, &nr_to_scan);
+ /* terminate if we don't exhaust the scan */
if (nr_to_scan > 0)
return -1;
}
reclaimable = 0;
ag = 0;
- while ((pag = xfs_inode_ag_iter_next_pag(mp, &ag,
- XFS_ICI_RECLAIM_TAG))) {
+ while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
+ ag = pag->pag_agno + 1;
reclaimable += pag->pag_ici_reclaimable;
xfs_perag_put(pag);
}
projects / mv-sheeva.git / blobdiff