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authorBrian Behlendorf <[email protected]>2011-07-19 09:31:23 -0700
committerBrian Behlendorf <[email protected]>2011-07-19 11:55:42 -0700
commitabd39a8289c3bc2766f281933689d5140445aa85 (patch)
tree890301d67ad752ece9e890745e67b37fef912b31 /module
parenta140dc5469399eaf2347ee7db503275f38f5dc12 (diff)
Fix zio_execute() deadlock
To avoid deadlocking the system it is crucial that all memory allocations performed in the zio_execute() call path are marked KM_PUSHPAGE (GFP_NOFS). This ensures that while a z_wr_iss thread is processing the syncing transaction group it does not re-enter the filesystem code and deadlock on itself. Call Trace: [<ffffffffa02580e8>] cv_wait_common+0x78/0xe0 [spl] [<ffffffffa0347bab>] txg_wait_open+0x7b/0xa0 [zfs] [<ffffffffa030e73d>] dmu_tx_wait+0xed/0xf0 [zfs] [<ffffffffa0376a49>] zfs_putpage+0x219/0x360 [zfs] [<ffffffffa038d75e>] zpl_putpage+0x1e/0x60 [zfs] [<ffffffffa038d7b2>] zpl_writepage+0x12/0x20 [zfs] [<ffffffff8115f907>] writeout+0xa7/0xd0 [<ffffffff8115fa6b>] move_to_new_page+0x13b/0x170 [<ffffffff8115fed4>] migrate_pages+0x434/0x4c0 [<ffffffff811559ab>] compact_zone+0x4fb/0x780 [<ffffffff81155ed1>] compact_zone_order+0xa1/0xe0 [<ffffffff8115602c>] try_to_compact_pages+0x11c/0x190 [<ffffffff811200bb>] __alloc_pages_nodemask+0x5eb/0x8b0 [<ffffffff81159932>] kmem_getpages+0x62/0x170 [<ffffffff8115a54a>] fallback_alloc+0x1ba/0x270 [<ffffffff8115a2c9>] ____cache_alloc_node+0x99/0x160 [<ffffffff8115b059>] __kmalloc+0x189/0x220 [<ffffffffa02539fb>] kmem_alloc_debug+0xeb/0x130 [spl] [<ffffffffa031454a>] dnode_hold_impl+0x46a/0x550 [zfs] [<ffffffffa0314649>] dnode_hold+0x19/0x20 [zfs] [<ffffffffa03042e3>] dmu_read+0x33/0x180 [zfs] [<ffffffffa034729d>] space_map_load+0xfd/0x320 [zfs] [<ffffffffa03300bc>] metaslab_activate+0x10c/0x170 [zfs] [<ffffffffa0330ad9>] metaslab_alloc+0x469/0x800 [zfs] [<ffffffffa038963c>] zio_dva_allocate+0x6c/0x2f0 [zfs] [<ffffffffa038a249>] zio_execute+0x99/0xf0 [zfs] [<ffffffffa0254b1c>] taskq_thread+0x1cc/0x330 [spl] [<ffffffff8108ddf6>] kthread+0x96/0xa0 Signed-off-by: Brian Behlendorf <[email protected]> Issue #291
Diffstat (limited to 'module')
-rw-r--r--module/zfs/dnode.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c
index d341b58ee..9889c3c36 100644
--- a/module/zfs/dnode.c
+++ b/module/zfs/dnode.c
@@ -1074,7 +1074,8 @@ dnode_hold_impl(objset_t *os, uint64_t object, int flag,
int i;
dnode_children_t *winner;
children_dnodes = kmem_alloc(sizeof (dnode_children_t) +
- (epb - 1) * sizeof (dnode_handle_t), KM_SLEEP | KM_NODEBUG);
+ (epb - 1) * sizeof (dnode_handle_t),
+ KM_PUSHPAGE | KM_NODEBUG);
children_dnodes->dnc_count = epb;
dnh = &children_dnodes->dnc_children[0];
for (i = 0; i < epb; i++) {