From 4dd2cb4a28b7ab1f37163a4eba280926a13a8749 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 29 Nov 2011 12:06:14 -0600 Subject: xfs: force buffer writeback before blocking on the ilock in inode reclaim If we are doing synchronous inode reclaim we block the VM from making progress in memory reclaim. So if we encouter a flush locked inode promote it in the delwri list and wake up xfsbufd to write it out now. Without this we can get hangs of up to 30 seconds during workloads hitting synchronous inode reclaim. The scheme is copied from what we do for dquot reclaims. Reported-by: Simon Kirby Signed-off-by: Christoph Hellwig Tested-by: Simon Kirby Signed-off-by: Ben Myers --- fs/xfs/xfs_sync.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'fs/xfs/xfs_sync.c') diff --git a/fs/xfs/xfs_sync.c b/fs/xfs/xfs_sync.c index aa3dc1a4d53d..be5c51d8f757 100644 --- a/fs/xfs/xfs_sync.c +++ b/fs/xfs/xfs_sync.c @@ -770,6 +770,17 @@ restart: if (!xfs_iflock_nowait(ip)) { if (!(sync_mode & SYNC_WAIT)) goto out; + + /* + * If we only have a single dirty inode in a cluster there is + * a fair chance that the AIL push may have pushed it into + * the buffer, but xfsbufd won't touch it until 30 seconds + * from now, and thus we will lock up here. + * + * Promote the inode buffer to the front of the delwri list + * and wake up xfsbufd now. + */ + xfs_promote_inode(ip); xfs_iflock(ip); } -- cgit From 34625c661b01dab193c7e8a0151a63553e97cfdf Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 6 Dec 2011 21:58:12 +0000 Subject: xfs: remove xfs_qm_sync Now that we can't have any dirty dquots around that aren't in the AIL we can get rid of the explicit dquot syncing from xfssyncd and xfs_fs_sync_fs and instead rely on AIL pushing to write out any quota updates. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Signed-off-by: Ben Myers --- fs/xfs/xfs_qm.c | 94 ------------------------------------------------------ fs/xfs/xfs_qm.h | 6 ---- fs/xfs/xfs_quota.h | 5 --- fs/xfs/xfs_super.c | 11 ++----- fs/xfs/xfs_sync.c | 6 +--- 5 files changed, 3 insertions(+), 119 deletions(-) (limited to 'fs/xfs/xfs_sync.c') diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c index c704ea0115d5..9bf32558f5f4 100644 --- a/fs/xfs/xfs_qm.c +++ b/fs/xfs/xfs_qm.c @@ -879,100 +879,6 @@ xfs_qm_dqdetach( } } -int -xfs_qm_sync( - struct xfs_mount *mp, - int flags) -{ - struct xfs_quotainfo *q = mp->m_quotainfo; - int recl, restarts; - struct xfs_dquot *dqp; - int error; - - if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp)) - return 0; - - restarts = 0; - - again: - mutex_lock(&q->qi_dqlist_lock); - /* - * dqpurge_all() also takes the mplist lock and iterate thru all dquots - * in quotaoff. However, if the QUOTA_ACTIVE bits are not cleared - * when we have the mplist lock, we know that dquots will be consistent - * as long as we have it locked. - */ - if (!XFS_IS_QUOTA_ON(mp)) { - mutex_unlock(&q->qi_dqlist_lock); - return 0; - } - ASSERT(mutex_is_locked(&q->qi_dqlist_lock)); - list_for_each_entry(dqp, &q->qi_dqlist, q_mplist) { - /* - * If this is vfs_sync calling, then skip the dquots that - * don't 'seem' to be dirty. ie. don't acquire dqlock. - * This is very similar to what xfs_sync does with inodes. - */ - if (flags & SYNC_TRYLOCK) { - if (!XFS_DQ_IS_DIRTY(dqp)) - continue; - if (!xfs_qm_dqlock_nowait(dqp)) - continue; - } else { - xfs_dqlock(dqp); - } - - /* - * Now, find out for sure if this dquot is dirty or not. - */ - if (! XFS_DQ_IS_DIRTY(dqp)) { - xfs_dqunlock(dqp); - continue; - } - - /* XXX a sentinel would be better */ - recl = q->qi_dqreclaims; - if (!xfs_dqflock_nowait(dqp)) { - if (flags & SYNC_TRYLOCK) { - xfs_dqunlock(dqp); - continue; - } - /* - * If we can't grab the flush lock then if the caller - * really wanted us to give this our best shot, so - * see if we can give a push to the buffer before we wait - * on the flush lock. At this point, we know that - * even though the dquot is being flushed, - * it has (new) dirty data. - */ - xfs_qm_dqflock_pushbuf_wait(dqp); - } - /* - * Let go of the mplist lock. We don't want to hold it - * across a disk write - */ - mutex_unlock(&q->qi_dqlist_lock); - error = xfs_qm_dqflush(dqp, flags); - xfs_dqunlock(dqp); - if (error && XFS_FORCED_SHUTDOWN(mp)) - return 0; /* Need to prevent umount failure */ - else if (error) - return error; - - mutex_lock(&q->qi_dqlist_lock); - if (recl != q->qi_dqreclaims) { - if (++restarts >= XFS_QM_SYNC_MAX_RESTARTS) - break; - - mutex_unlock(&q->qi_dqlist_lock); - goto again; - } - } - - mutex_unlock(&q->qi_dqlist_lock); - return 0; -} - /* * The hash chains and the mplist use the same xfs_dqhash structure as * their list head, but we can take the mplist qh_lock and one of the diff --git a/fs/xfs/xfs_qm.h b/fs/xfs/xfs_qm.h index 43b9abe1052c..9b4f3adefbc5 100644 --- a/fs/xfs/xfs_qm.h +++ b/fs/xfs/xfs_qm.h @@ -32,12 +32,6 @@ extern struct xfs_qm *xfs_Gqm; extern kmem_zone_t *qm_dqzone; extern kmem_zone_t *qm_dqtrxzone; -/* - * Used in xfs_qm_sync called by xfs_sync to count the max times that it can - * iterate over the mountpt's dquot list in one call. - */ -#define XFS_QM_SYNC_MAX_RESTARTS 7 - /* * Ditto, for xfs_qm_dqreclaim_one. */ diff --git a/fs/xfs/xfs_quota.h b/fs/xfs/xfs_quota.h index a595f29567fe..707ba33e3196 100644 --- a/fs/xfs/xfs_quota.h +++ b/fs/xfs/xfs_quota.h @@ -326,7 +326,6 @@ extern int xfs_qm_dqattach_locked(struct xfs_inode *, uint); extern void xfs_qm_dqdetach(struct xfs_inode *); extern void xfs_qm_dqrele(struct xfs_dquot *); extern void xfs_qm_statvfs(struct xfs_inode *, struct kstatfs *); -extern int xfs_qm_sync(struct xfs_mount *, int); extern int xfs_qm_newmount(struct xfs_mount *, uint *, uint *); extern void xfs_qm_mount_quotas(struct xfs_mount *); extern void xfs_qm_unmount(struct xfs_mount *); @@ -366,10 +365,6 @@ static inline int xfs_trans_reserve_quota_bydquots(struct xfs_trans *tp, #define xfs_qm_dqdetach(ip) #define xfs_qm_dqrele(d) #define xfs_qm_statvfs(ip, s) -static inline int xfs_qm_sync(struct xfs_mount *mp, int flags) -{ - return 0; -} #define xfs_qm_newmount(mp, a, b) (0) #define xfs_qm_mount_quotas(mp) #define xfs_qm_unmount(mp) diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 0e76348d958a..88cd0c893163 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1025,17 +1025,10 @@ xfs_fs_sync_fs( int error; /* - * Not much we can do for the first async pass. Writing out the - * superblock would be counter-productive as we are going to redirty - * when writing out other data and metadata (and writing out a single - * block is quite fast anyway). - * - * Try to asynchronously kick off quota syncing at least. + * Doing anything during the async pass would be counterproductive. */ - if (!wait) { - xfs_qm_sync(mp, SYNC_TRYLOCK); + if (!wait) return 0; - } error = xfs_quiesce_data(mp); if (error) diff --git a/fs/xfs/xfs_sync.c b/fs/xfs/xfs_sync.c index be5c51d8f757..5b9ec37a3e07 100644 --- a/fs/xfs/xfs_sync.c +++ b/fs/xfs/xfs_sync.c @@ -359,10 +359,7 @@ xfs_quiesce_data( { int error, error2 = 0; - xfs_qm_sync(mp, SYNC_TRYLOCK); - xfs_qm_sync(mp, SYNC_WAIT); - - /* force out the newly dirtied log buffers */ + /* force out the log */ xfs_log_force(mp, XFS_LOG_SYNC); /* write superblock and hoover up shutdown errors */ @@ -470,7 +467,6 @@ xfs_sync_worker( error = xfs_fs_log_dummy(mp); else xfs_log_force(mp, 0); - error = xfs_qm_sync(mp, SYNC_TRYLOCK); /* start pushing all the metadata that is currently dirty */ xfs_ail_push_all(mp->m_ail); -- cgit From be4f1ac828776bbc7868a68b465cd8eedb733cfd Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 20 Dec 2011 20:08:41 +0000 Subject: xfs: log all dirty inodes in xfs_fs_sync_fs Since Linux 2.6.36 the writeback code has introduces various measures for live lock prevention during sync(). Unfortunately some of these are actively harmful for the XFS model, where the inode gets marked dirty for metadata from the data I/O handler. The older_than_this checks that are now more strictly enforced since writeback: avoid livelocking WB_SYNC_ALL writeback by only calling into __writeback_inodes_sb and thus only sampling the current cut off time once. But on a slow enough devices the previous asynchronous sync pass might not have fully completed yet, and thus XFS might mark metadata dirty only after that sampling of the cut off time for the blocking pass already happened. I have not myself reproduced this myself on a real system, but by introducing artificial delay into the XFS I/O completion workqueues it can be reproduced easily. Fix this by iterating over all XFS inodes in ->sync_fs and log all that are dirty. This might log inode that only got redirtied after the previous pass, but given how cheap delayed logging of inodes is it isn't a major concern for performance. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Tested-by: Mark Tinguely Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_super.c | 28 ++++------------------------ fs/xfs/xfs_sync.c | 36 ++++++++++++++++++++++++++++++++++++ fs/xfs/xfs_sync.h | 2 ++ 3 files changed, 42 insertions(+), 24 deletions(-) (limited to 'fs/xfs/xfs_sync.c') diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 1add17ca3350..8a899496fd5f 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -868,27 +868,6 @@ xfs_fs_dirty_inode( XFS_I(inode)->i_update_core = 1; } -STATIC int -xfs_log_inode( - struct xfs_inode *ip) -{ - struct xfs_mount *mp = ip->i_mount; - struct xfs_trans *tp; - int error; - - tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS); - error = xfs_trans_reserve(tp, 0, XFS_FSYNC_TS_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_log_inode(tp, ip, XFS_ILOG_CORE); - return xfs_trans_commit(tp, 0); -} - STATIC int xfs_fs_write_inode( struct inode *inode, @@ -902,8 +881,6 @@ xfs_fs_write_inode( if (XFS_FORCED_SHUTDOWN(mp)) return -XFS_ERROR(EIO); - if (!ip->i_update_core) - return 0; if (wbc->sync_mode == WB_SYNC_ALL || wbc->for_kupdate) { /* @@ -913,11 +890,14 @@ xfs_fs_write_inode( * ->sync_fs call do that for thus, which reduces the number * of synchronous log forces dramatically. */ - error = xfs_log_inode(ip); + error = xfs_log_dirty_inode(ip, NULL, 0); if (error) goto out; return 0; } else { + if (!ip->i_update_core) + return 0; + /* * We make this non-blocking if the inode is contended, return * EAGAIN to indicate to the caller that they did not succeed. diff --git a/fs/xfs/xfs_sync.c b/fs/xfs/xfs_sync.c index be5c51d8f757..f0994aedcd15 100644 --- a/fs/xfs/xfs_sync.c +++ b/fs/xfs/xfs_sync.c @@ -336,6 +336,32 @@ xfs_sync_fsdata( return error; } +int +xfs_log_dirty_inode( + struct xfs_inode *ip, + struct xfs_perag *pag, + int flags) +{ + struct xfs_mount *mp = ip->i_mount; + struct xfs_trans *tp; + int error; + + if (!ip->i_update_core) + return 0; + + tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS); + error = xfs_trans_reserve(tp, 0, XFS_FSYNC_TS_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_log_inode(tp, ip, XFS_ILOG_CORE); + return xfs_trans_commit(tp, 0); +} + /* * 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 @@ -359,6 +385,16 @@ xfs_quiesce_data( { int error, error2 = 0; + /* + * Log all pending size and timestamp updates. The vfs writeback + * code is supposed to do this, but due to its overagressive + * livelock detection it will skip inodes where appending writes + * were written out in the first non-blocking sync phase if their + * completion took long enough that it happened after taking the + * timestamp for the cut-off in the blocking phase. + */ + xfs_inode_ag_iterator(mp, xfs_log_dirty_inode, 0); + xfs_qm_sync(mp, SYNC_TRYLOCK); xfs_qm_sync(mp, SYNC_WAIT); diff --git a/fs/xfs/xfs_sync.h b/fs/xfs/xfs_sync.h index 941202e7ac6e..fa965479d788 100644 --- a/fs/xfs/xfs_sync.h +++ b/fs/xfs/xfs_sync.h @@ -34,6 +34,8 @@ void xfs_quiesce_attr(struct xfs_mount *mp); void xfs_flush_inodes(struct xfs_inode *ip); +int xfs_log_dirty_inode(struct xfs_inode *ip, struct xfs_perag *pag, int flags); + int xfs_reclaim_inodes(struct xfs_mount *mp, int mode); int xfs_reclaim_inodes_count(struct xfs_mount *mp); void xfs_reclaim_inodes_nr(struct xfs_mount *mp, int nr_to_scan); -- cgit