Commit 9cf35f67 authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by David Sterba

btrfs: simplify inode locking for RWF_NOWAIT

This is similar to 942491c9 ("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: edf064e7 ("btrfs: nowait aio support")
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent af42d346
......@@ -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);
}
......
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