Re: [PATCH] xfs: fix incorrect log_flushed on fsync
From: Christoph Hellwig <hch@lst.de>
Date: 2017-08-31 13:47:22
Also in:
linux-fsdevel, stable
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
I think something like the following patch (totally untested, just an idea) should fix the issue, right?
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index c4893e226fd8..555fcae9a18f 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c@@ -135,7 +135,7 @@ xfs_file_fsync( struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; int error = 0; - int log_flushed = 0; + unsigned int flushseq; xfs_lsn_t lsn = 0; trace_xfs_file_fsync(ip);
@@ -143,6 +143,7 @@ xfs_file_fsync( error = file_write_and_wait_range(file, start, end); if (error) return error; + flushseq = READ_ONCE(mp->m_flushseq); if (XFS_FORCED_SHUTDOWN(mp)) return -EIO;
@@ -181,7 +182,7 @@ xfs_file_fsync( } if (lsn) { - error = _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed); + error = _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL); ip->i_itemp->ili_fsync_fields = 0; } xfs_iunlock(ip, XFS_ILOCK_SHARED);
@@ -193,8 +194,9 @@ xfs_file_fsync( * an already allocated file and thus do not have any metadata to * commit. */ - if (!log_flushed && !XFS_IS_REALTIME_INODE(ip) && - mp->m_logdev_targp == mp->m_ddev_targp) + if (!XFS_IS_REALTIME_INODE(ip) && + mp->m_logdev_targp == mp->m_ddev_targp && + flushseq == READ_ONCE(mp->m_flushseq)) xfs_blkdev_issue_flush(mp->m_ddev_targp); return error;
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index bcb2f860e508..3c0cbb98581e 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c@@ -2922,6 +2922,8 @@ xlog_state_done_syncing( iclog->ic_state = XLOG_STATE_DONE_SYNC; } + log->l_mp->m_flushseq++; + /* * Someone could be sleeping prior to writing out the next * iclog buffer, we wake them all, one will get to do the
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e0792d036be2..556e01a0175e 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h@@ -79,6 +79,7 @@ typedef struct xfs_mount { struct percpu_counter m_icount; /* allocated inodes counter */ struct percpu_counter m_ifree; /* free inodes counter */ struct percpu_counter m_fdblocks; /* free block counter */ + unsigned int m_flushseq; struct xfs_buf *m_sb_bp; /* buffer for superblock */ char *m_fsname; /* filesystem name */