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authorChristoph Hellwig <hch@infradead.org>2011-12-20 20:08:41 +0000
committerBen Myers <bpm@sgi.com>2011-12-23 16:41:47 -0600
commitbe4f1ac828776bbc7868a68b465cd8eedb733cfd (patch)
treee1200a933beeb93702ce0c571a4ca3304f3cab72
parent0b8fd3033c308e4088760aa1d38ce77197b4e074 (diff)
downloadlinux-linaro-be4f1ac828776bbc7868a68b465cd8eedb733cfd.tar.gz
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 <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Tested-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
-rw-r--r--fs/xfs/xfs_super.c28
-rw-r--r--fs/xfs/xfs_sync.c36
-rw-r--r--fs/xfs/xfs_sync.h2
3 files changed, 42 insertions, 24 deletions
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 1add17ca335..8a899496fd5 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -869,27 +869,6 @@ xfs_fs_dirty_inode(
}
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,
struct writeback_control *wbc)
@@ -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 be5c51d8f75..f0994aedcd1 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 941202e7ac6..fa965479d78 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);