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authorGoldwyn Rodrigues <rgoldwyn@suse.com>2019-09-11 11:45:15 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-01-17 19:48:32 +0100
commit3eb81bbf4e0b8eaf33c8315562f693128f683f02 (patch)
tree70be39f3a0e07ceecc22faaf30df1028eee1ca91 /fs
parent8aaefcaa5ee0900524a69983a014e57d57c4326c (diff)
btrfs: simplify inode locking for RWF_NOWAIT
commit 9cf35f673583ccc9f3e2507498b3079d56614ad3 upstream. This is similar to 942491c9e6d6 ("xfs: fix AIM7 regression"). Apparently our current rwsem code doesn't like doing the trylock, then lock for real scheme. This causes extra contention on the lock and can be measured eg. by AIM7 benchmark. So change our read/write methods to just do the trylock for the RWF_NOWAIT case. Fixes: edf064e7c6fe ("btrfs: nowait aio support") Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/file.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index eaafd00f93d4..5739b8fc7fff 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1903,9 +1903,10 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
(iocb->ki_flags & IOCB_NOWAIT))
return -EOPNOTSUPP;
- 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);
}