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| author | Mike Snitzer <snitzer@redhat.com> | 2015-07-29 20:48:23 +0300 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-07-29 21:32:09 +0300 |
| commit | 795e633a2dc6cbbeac68bc7f6006082150d38bb7 (patch) | |
| tree | 1ebe7ece3ff3fd162494731e7e303f6207d893c0 /drivers/md | |
| parent | 3508e6590d4729ac07f01f7ae2256c2f9dc738b8 (diff) | |
| download | linux-795e633a2dc6cbbeac68bc7f6006082150d38bb7.tar.xz | |
dm cache: fix device destroy hang due to improper prealloc_used accounting
Commit 665022d72f9 ("dm cache: avoid calls to prealloc_free_structs() if
possible") introduced a regression that caused the removal of a DM cache
device to hang in cache_postsuspend()'s call to wait_for_migrations()
with the following stack trace:
[<ffffffff81651457>] schedule+0x37/0x80
[<ffffffffa041e21b>] cache_postsuspend+0xbb/0x470 [dm_cache]
[<ffffffff810ba970>] ? prepare_to_wait_event+0xf0/0xf0
[<ffffffffa0006f77>] dm_table_postsuspend_targets+0x47/0x60 [dm_mod]
[<ffffffffa0001eb5>] __dm_destroy+0x215/0x250 [dm_mod]
[<ffffffffa0004113>] dm_destroy+0x13/0x20 [dm_mod]
[<ffffffffa00098cd>] dev_remove+0x10d/0x170 [dm_mod]
[<ffffffffa00097c0>] ? dev_suspend+0x240/0x240 [dm_mod]
[<ffffffffa0009f85>] ctl_ioctl+0x255/0x4d0 [dm_mod]
[<ffffffff8127ac00>] ? SYSC_semtimedop+0x280/0xe10
[<ffffffffa000a213>] dm_ctl_ioctl+0x13/0x20 [dm_mod]
[<ffffffff811fd432>] do_vfs_ioctl+0x2d2/0x4b0
[<ffffffff81117d5f>] ? __audit_syscall_entry+0xaf/0x100
[<ffffffff81022636>] ? do_audit_syscall_entry+0x66/0x70
[<ffffffff811fd689>] SyS_ioctl+0x79/0x90
[<ffffffff81023e58>] ? syscall_trace_leave+0xb8/0x110
[<ffffffff81654f6e>] entry_SYSCALL_64_fastpath+0x12/0x71
Fix this by accounting for the call to prealloc_data_structs()
immediately _before_ the call as opposed to after. This is needed
because it is possible to break out of the control loop after the call
to prealloc_data_structs() but before prealloc_used was set to true.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-cache-target.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 64e96a2bed58..1fe93cfea7d3 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -1967,6 +1967,7 @@ static void process_deferred_bios(struct cache *cache) * this bio might require one, we pause until there are some * prepared mappings to process. */ + prealloc_used = true; if (prealloc_data_structs(cache, &structs)) { spin_lock_irqsave(&cache->lock, flags); bio_list_merge(&cache->deferred_bios, &bios); @@ -1982,7 +1983,6 @@ static void process_deferred_bios(struct cache *cache) process_discard_bio(cache, &structs, bio); else process_bio(cache, &structs, bio); - prealloc_used = true; } if (prealloc_used) @@ -2011,6 +2011,7 @@ static void process_deferred_cells(struct cache *cache) * this bio might require one, we pause until there are some * prepared mappings to process. */ + prealloc_used = true; if (prealloc_data_structs(cache, &structs)) { spin_lock_irqsave(&cache->lock, flags); list_splice(&cells, &cache->deferred_cells); @@ -2019,7 +2020,6 @@ static void process_deferred_cells(struct cache *cache) } process_cell(cache, &structs, cell); - prealloc_used = true; } if (prealloc_used) @@ -2081,6 +2081,7 @@ static void writeback_some_dirty_blocks(struct cache *cache) if (policy_writeback_work(cache->policy, &oblock, &cblock, busy)) break; /* no work to do */ + prealloc_used = true; if (prealloc_data_structs(cache, &structs) || get_cell(cache, oblock, &structs, &old_ocell)) { policy_set_dirty(cache->policy, oblock); @@ -2088,7 +2089,6 @@ static void writeback_some_dirty_blocks(struct cache *cache) } writeback(cache, &structs, oblock, cblock, old_ocell); - prealloc_used = true; } if (prealloc_used) |