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| author |   Mikulas Patocka <mpatocka@redhat.com> | 2014-10-16 14:45:20 -0400 |
|---|---|---|
| committer |   Mike Snitzer <snitzer@redhat.com> | 2014-10-17 01:40:23 -0400 |
| commit | 9d28eb12447ee08bb5d1e8bb3195cf20e1ecd1c0 (patch) | |
| tree | 24ece98c42840d5b51a1a1f5d520f6a41dd60c0c /drivers/md/dm-bufio.c | |
| parent | dm stripe: fix potential for leak in stripe_ctr error path (diff) | |
| download | linux-dev-9d28eb12447ee08bb5d1e8bb3195cf20e1ecd1c0.tar.xz linux-dev-9d28eb12447ee08bb5d1e8bb3195cf20e1ecd1c0.zip | |
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
Diffstat (limited to 'drivers/md/dm-bufio.c')
| -rw-r--r-- | drivers/md/dm-bufio.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 9ea5b6041eb2..0be200b6dbf2 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -1435,9 +1435,9 @@ static void drop_buffers(struct dm_bufio_client *c) /* * Test if the buffer is unused and too old, and commit it. - * At if noio is set, we must not do any I/O because we hold - * dm_bufio_clients_lock and we would risk deadlock if the I/O gets rerouted to - * different bufio client. + * And if GFP_NOFS is used, we must not do any I/O because we hold + * dm_bufio_clients_lock and we would risk deadlock if the I/O gets + * rerouted to different bufio client. */ static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp, unsigned long max_jiffies) @@ -1445,7 +1445,7 @@ static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp, if (jiffies - b->last_accessed < max_jiffies) return 0; - if (!(gfp & __GFP_IO)) { + if (!(gfp & __GFP_FS)) { if (test_bit(B_READING, &b->state) || test_bit(B_WRITING, &b->state) || test_bit(B_DIRTY, &b->state)) @@ -1487,7 +1487,7 @@ dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) unsigned long freed; c = container_of(shrink, struct dm_bufio_client, shrinker); - if (sc->gfp_mask & __GFP_IO) + if (sc->gfp_mask & __GFP_FS) dm_bufio_lock(c); else if (!dm_bufio_trylock(c)) return SHRINK_STOP; @@ -1504,7 +1504,7 @@ dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) unsigned long count; c = container_of(shrink, struct dm_bufio_client, shrinker); - if (sc->gfp_mask & __GFP_IO) + if (sc->gfp_mask & __GFP_FS) dm_bufio_lock(c); else if (!dm_bufio_trylock(c)) return 0; |