dm bufio: change __GFP_IO to __GFP_FS in shrinker callbacks
authorMikulas Patocka <mpatocka@redhat.com>
Thu, 16 Oct 2014 18:45:20 +0000 (14:45 -0400)
committerMike Snitzer <snitzer@redhat.com>
Fri, 17 Oct 2014 05:40:23 +0000 (01:40 -0400)
commit9d28eb12447ee08bb5d1e8bb3195cf20e1ecd1c0
tree24ece98c42840d5b51a1a1f5d520f6a41dd60c0c
parenta3f2af2547884e02f7e43f995a6c442a4e54f1ea
dm bufio: change __GFP_IO to __GFP_FS in shrinker callbacks

The shrinker uses gfp flags to indicate what kind of operation can the
driver wait for. If __GFP_IO flag is present, the driver can wait for
block I/O operations, if __GFP_FS flag is present, the driver can wait on
operations involving the filesystem.

dm-bufio tested for __GFP_IO. However, dm-bufio can run on a loop block
device that makes calls into the filesystem. If __GFP_IO is present and
__GFP_FS isn't, dm-bufio could still block on filesystem operations if it
runs on a loop block device.

The change from __GFP_IO to __GFP_FS supposedly fixes one observed (though
unreproducible) deadlock involving dm-bufio and loop device.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
drivers/md/dm-bufio.c