Received-SPF: pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Goldwyn Rodrigues <rgoldwyn@suse.de>
To:     linux-fsdevel@vger.kernel.org
Cc:     linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org,
        hch@infradead.org, andres@anarazel.de, david@fromorbit.com,
        riteshh@linux.ibm.com, linux-f2fs-devel@lists.sourceforge.net,
        Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 1/3] btrfs: fix inode rwsem regression
Date:   Wed, 11 Sep 2019 11:45:15 -0500
Message-Id: <20190911164517.16130-2-rgoldwyn@suse.de>
In-Reply-To: <20190911164517.16130-1-rgoldwyn@suse.de>
References: <20190911093926.pfkkx25mffzeuo32@alap3.anarazel.de>
 <20190911164517.16130-1-rgoldwyn@suse.de>
Sender: linux-ext4-owner@vger.kernel.org
Precedence: bulk

From: Goldwyn Rodrigues <rgoldwyn@suse.com>

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.  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>
---
 fs/btrfs/file.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 58a18ed11546..651b2b1f4219 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1893,9 +1893,10 @@ 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);
 	}
 
-- 
2.16.4