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| author | Ritesh Harjani <riteshh@linux.ibm.com> | 2019-12-12 11:25:55 +0530 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-12-22 23:57:27 -0500 |
| commit | f629afe3369e9885fd6e9cc7a4f514b6a65cf9e9 (patch) | |
| tree | 7f7b3f170985b97099e2c7b9f149ebc0975e41eb /fs/ext4/file.c | |
| parent | 46cf053efec6a3a5f343fead837777efe8252a46 (diff) | |
| download | linux-f629afe3369e9885fd6e9cc7a4f514b6a65cf9e9.tar.gz | |
ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT
Apparently our current rwsem code doesn't like doing the trylock, then
lock for real scheme. So change our dax read/write methods to just do the
trylock for the RWF_NOWAIT case.
This seems to fix AIM7 regression in some scalable filesystems upto ~25%
in some cases. Claimed in commit 942491c9e6d6 ("xfs: fix AIM7 regression")
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20191212055557.11151-2-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/file.c')
| -rw-r--r-- | fs/ext4/file.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 6a7293a5cda2..977ac58dc718 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -88,9 +88,10 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; - if (!inode_trylock_shared(inode)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock_shared(inode)) return -EAGAIN; + } else { inode_lock_shared(inode); } /* @@ -487,9 +488,10 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) bool extend = false; struct inode *inode = file_inode(iocb->ki_filp); - if (!inode_trylock(inode)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) return -EAGAIN; + } else { inode_lock(inode); } |