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authorNeilBrown <neilb@suse.de>2007-01-26 09:57:11 +0100
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-26 22:51:00 +0100
commit2a2275d630b982e5f90206f9bc497f6695a3ec5d (patch)
tree88cddee709b2107b74e5424810d4ffb6e3772382 /drivers/md/raid1.c
parent[PATCH] knfsd: Fix type mismatch with filldir_t used by nfsd (diff)
downloadlinux-2a2275d630b982e5f90206f9bc497f6695a3ec5d.tar.xz
linux-2a2275d630b982e5f90206f9bc497f6695a3ec5d.zip
[PATCH] md: fix potential memalloc deadlock in md
If a GFP_KERNEL allocation is attempted in md while the mddev_lock is held, it is possible for a deadlock to eventuate. This happens if the array was marked 'clean', and the memalloc triggers a write-out to the md device. For the writeout to succeed, the array must be marked 'dirty', and that requires getting the mddev_lock. So, before attempting a GFP_KERNEL allocation while holding the lock, make sure the array is marked 'dirty' (unless it is currently read-only). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/md/raid1.c')
-rw-r--r--drivers/md/raid1.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index ab74d40cac98..97ee870b265d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2104,6 +2104,8 @@ static int raid1_reshape(mddev_t *mddev)
return -EINVAL;
}
+ md_allow_write(mddev);
+
raid_disks = mddev->raid_disks + mddev->delta_disks;
if (raid_disks < conf->raid_disks) {