linux-bl808/fs/btrfs
chandan 13a0db5a53 Btrfs: find_free_extent: Do not erroneously skip LOOP_CACHING_WAIT state
When executing generic/001 in a loop on a ppc64 machine (with both sectorsize
and nodesize set to 64k), the following call trace is observed,

WARNING: at /root/repos/linux/fs/btrfs/locking.c:253
Modules linked in:
CPU: 2 PID: 8353 Comm: umount Not tainted 4.3.0-rc5-13676-ga5e681d #54
task: c0000000f2b1f560 ti: c0000000f6008000 task.ti: c0000000f6008000
NIP: c000000000520c88 LR: c0000000004a3b34 CTR: 0000000000000000
REGS: c0000000f600a820 TRAP: 0700   Not tainted  (4.3.0-rc5-13676-ga5e681d)
MSR: 8000000102029032 <SF,VEC,EE,ME,IR,DR,RI>  CR: 24444884  XER: 00000000
CFAR: c0000000004a3b30 SOFTE: 1
GPR00: c0000000004a3b34 c0000000f600aaa0 c00000000108ac00 c0000000f5a808c0
GPR04: 0000000000000000 c0000000f600ae60 0000000000000000 0000000000000005
GPR08: 00000000000020a1 0000000000000001 c0000000f2b1f560 0000000000000030
GPR12: 0000000084842882 c00000000fdc0900 c0000000f600ae60 c0000000f070b800
GPR16: 0000000000000000 c0000000f3c8a000 0000000000000000 0000000000000049
GPR20: 0000000000000001 0000000000000001 c0000000f5aa01f8 0000000000000000
GPR24: 0f83e0f83e0f83e1 c0000000f5a808c0 c0000000f3c8d000 c000000000000000
GPR28: c0000000f600ae74 0000000000000001 c0000000f3c8d000 c0000000f5a808c0
NIP [c000000000520c88] .btrfs_tree_lock+0x48/0x2a0
LR [c0000000004a3b34] .btrfs_lock_root_node+0x44/0x80
Call Trace:
[c0000000f600aaa0] [c0000000f600ab80] 0xc0000000f600ab80 (unreliable)
[c0000000f600ab80] [c0000000004a3b34] .btrfs_lock_root_node+0x44/0x80
[c0000000f600ac00] [c0000000004a99dc] .btrfs_search_slot+0xa8c/0xc00
[c0000000f600ad40] [c0000000004ab878] .btrfs_insert_empty_items+0x98/0x120
[c0000000f600adf0] [c00000000050da44] .btrfs_finish_chunk_alloc+0x1d4/0x620
[c0000000f600af20] [c0000000004be854] .btrfs_create_pending_block_groups+0x1d4/0x2c0
[c0000000f600b020] [c0000000004bf188] .do_chunk_alloc+0x3c8/0x420
[c0000000f600b100] [c0000000004c27cc] .find_free_extent+0xbfc/0x1030
[c0000000f600b260] [c0000000004c2ce8] .btrfs_reserve_extent+0xe8/0x250
[c0000000f600b330] [c0000000004c2f90] .btrfs_alloc_tree_block+0x140/0x590
[c0000000f600b440] [c0000000004a47b4] .__btrfs_cow_block+0x124/0x780
[c0000000f600b530] [c0000000004a4fc0] .btrfs_cow_block+0xf0/0x250
[c0000000f600b5e0] [c0000000004a917c] .btrfs_search_slot+0x22c/0xc00
[c0000000f600b720] [c00000000050aa40] .btrfs_remove_chunk+0x1b0/0x9f0
[c0000000f600b850] [c0000000004c4e04] .btrfs_delete_unused_bgs+0x434/0x570
[c0000000f600b950] [c0000000004d3cb8] .close_ctree+0x2e8/0x3b0
[c0000000f600ba20] [c00000000049d178] .btrfs_put_super+0x18/0x30
[c0000000f600ba90] [c000000000243cd4] .generic_shutdown_super+0xa4/0x1a0
[c0000000f600bb10] [c0000000002441d8] .kill_anon_super+0x18/0x30
[c0000000f600bb90] [c00000000049c898] .btrfs_kill_super+0x18/0xc0
[c0000000f600bc10] [c0000000002444f8] .deactivate_locked_super+0x98/0xe0
[c0000000f600bc90] [c000000000269f94] .cleanup_mnt+0x54/0xa0
[c0000000f600bd10] [c0000000000bd744] .task_work_run+0xc4/0x100
[c0000000f600bdb0] [c000000000016334] .do_notify_resume+0x74/0x80
[c0000000f600be30] [c0000000000098b8] .ret_from_except_lite+0x64/0x68
Instruction dump:
fba1ffe8 fbc1fff0 fbe1fff8 7c791b78 f8010010 f821ff21 e94d0290 81030040
812a04e8 7d094a78 7d290034 5529d97e <0b090000> 3b400000 3be30050 3bc3004c

The above call trace is seen even on x86_64; albeit very rarely and that too
with nodesize set to 64k and with nospace_cache mount option being used.

The reason for the above call trace is,
btrfs_remove_chunk
  check_system_chunk
    Allocate chunk if required
  For each physical stripe on underlying device,
    btrfs_free_dev_extent
      ...
      Take lock on Device tree's root node
      btrfs_cow_block("dev tree's root node");
        btrfs_reserve_extent
          find_free_extent
	    index = BTRFS_RAID_DUP;
	    have_caching_bg = false;

            When in LOOP_CACHING_NOWAIT state, Assume we find a block group
	    which is being cached; Hence have_caching_bg is set to true

            When repeating the search for the next RAID index, we set
	    have_caching_bg to false.

Hence right after completing the LOOP_CACHING_NOWAIT state, we incorrectly
skip LOOP_CACHING_WAIT state and move to LOOP_ALLOC_CHUNK state where we
allocate a chunk and try to add entries corresponding to the chunk's physical
stripe into the device tree. When doing so the task deadlocks itself waiting
for the blocking lock on the root node of the device tree.

This commit fixes the issue by introducing a new local variable to help
indicate as to whether a block group of any RAID type is being cached.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-03 07:44:20 -08:00
..
tests Btrfs: add fragment=* debug mount option 2015-10-21 18:51:43 -07:00
acl.c btrfs: remove useless ACL check 2014-06-09 17:20:42 -07:00
async-thread.c btrfs: async_thread: Fix workqueue 'max_active' value when initializing 2015-08-31 11:46:40 -07:00
async-thread.h btrfs: async_thread: Fix workqueue 'max_active' value when initializing 2015-08-31 11:46:40 -07:00
backref.c btrfs: fix use after free iterating extrefs 2015-10-26 19:38:28 -07:00
backref.h btrfs: cleanup, remove inode_item_info helper 2015-01-14 19:23:47 +01:00
btrfs_inode.h Btrfs: Direct I/O: Fix space accounting 2015-09-21 13:47:55 -07:00
check-integrity.c Merge branch 'cleanups/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4 2015-10-21 18:21:40 -07:00
check-integrity.h
compression.c Merge branch 'cleanups/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4 2015-10-21 18:21:40 -07:00
compression.h btrfs: constify structs with op functions or static definitions 2015-02-16 18:48:44 +01:00
ctree.c Merge branch 'cleanups/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4 2015-10-21 18:21:40 -07:00
ctree.h btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans 2015-10-26 19:44:39 -07:00
delayed-inode.c btrfs: comment the rest of implicit barriers before waitqueue_active 2015-10-10 18:42:00 +02:00
delayed-inode.h Btrfs: introduce the delayed inode ref deletion for the single link inode 2014-01-28 13:20:09 -08:00
delayed-ref.c btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans 2015-10-26 19:44:39 -07:00
delayed-ref.h btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans 2015-10-26 19:44:39 -07:00
dev-replace.c Merge branch 'fix/waitqueue-barriers' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4 2015-10-12 16:24:40 -07:00
dev-replace.h
dir-item.c Btrfs: make xattr replace operations atomic 2014-11-20 17:20:07 -08:00
disk-io.c btrfs: clear PF_NOFREEZE in cleaner_kthread() 2015-10-26 19:42:30 -07:00
disk-io.h Btrfs: add btrfs_read_dev_one_super() to read one specific SB 2015-10-01 17:29:38 +02:00
export.c BTRFS: support NFSv2 export 2015-10-06 06:55:23 -07:00
export.h
extent-tree.c Btrfs: find_free_extent: Do not erroneously skip LOOP_CACHING_WAIT state 2015-11-03 07:44:20 -08:00
extent-tree.h btrfs: qgroup: Add new qgroup calculation function 2015-06-10 09:25:49 -07:00
extent_io.c btrfs: extent_io: Introduce new function clear_record_extent_bits() 2015-10-21 18:37:44 -07:00
extent_io.h btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function 2015-10-21 18:37:45 -07:00
extent_map.c Btrfs: do not move em to modified list when unpinning 2014-11-21 11:59:54 -08:00
extent_map.h Btrfs: fix NULL pointer crash when running balance and scrub concurrently 2014-06-19 14:20:55 -07:00
file-item.c Merge branch 'cleanups-post-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.1 2015-03-25 10:52:48 -07:00
file.c btrfs: Fix a data space underflow warning 2015-11-03 07:44:20 -08:00
free-space-cache.c Btrfs: don't do extra bitmap search in one bit case 2015-10-21 18:55:41 -07:00
free-space-cache.h Btrfs: keep track of largest extent in bitmaps 2015-10-21 18:55:40 -07:00
hash.c btrfs: LLVMLinux: Remove VLAIS 2014-10-14 10:51:22 +02:00
hash.h Btrfs: fix btrfs boot when compiled as built-in 2014-01-28 13:20:31 -08:00
inode-item.c Btrfs: consolidate btrfs_error() to btrfs_std_error() 2015-09-29 16:30:00 +02:00
inode-map.c btrfs: qgroup: Cleanup old inaccurate facilities 2015-10-21 18:41:06 -07:00
inode-map.h
inode.c btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans 2015-10-26 19:44:39 -07:00
ioctl.c btrfs: check unsupported filters in balance arguments 2015-10-26 19:38:26 -07:00
Kconfig rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
locking.c btrfs: comment the rest of implicit barriers before waitqueue_active 2015-10-10 18:42:00 +02:00
locking.h btrfs: fix lockups from btrfs_clear_path_blocking 2014-11-19 10:34:35 -08:00
lzo.c btrfs: constify structs with op functions or static definitions 2015-02-16 18:48:44 +01:00
Makefile Btrfs: add sanity tests for new qgroup accounting code 2014-06-09 17:20:49 -07:00
math.h btrfs: cleanup 64bit/32bit divs, compile time constants 2015-03-03 17:23:57 +01:00
ordered-data.c Btrfs: change how we wait for pending ordered extents 2015-10-21 18:51:40 -07:00
ordered-data.h Btrfs: change how we wait for pending ordered extents 2015-10-21 18:51:40 -07:00
orphan.c btrfs: kill the key type accessor helpers 2014-09-17 13:37:12 -07:00
print-tree.c btrfs: remove parameter blocksize from read_tree_block 2014-10-02 17:14:50 +02:00
print-tree.h
props.c btrfs: cleanup iterating over prop_handlers array 2015-10-21 18:28:48 +02:00
props.h Btrfs: add support for inode properties 2014-01-28 13:20:24 -08:00
qgroup.c btrfs: qgroup: Fix a rebase bug which will cause qgroup double free 2015-10-26 19:44:39 -07:00
qgroup.h btrfs: qgroup: Check if qgroup reserved space leaked 2015-10-21 18:41:10 -07:00
raid56.c btrfs: comment waitqueue_active implied by locks 2015-10-10 18:35:10 +02:00
raid56.h Btrfs: add RAID 5/6 BTRFS_RBIO_REBUILD_MISSING operation 2015-08-09 07:34:26 -07:00
rcu-string.h
reada.c btrfs: reada: Fix returned errno code 2015-10-21 18:29:50 +02:00
relocation.c Btrfs: fix regression running delayed references when using qgroups 2015-10-25 19:53:26 +00:00
root-tree.c Merge branch 'cleanups/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4 2015-10-21 18:21:40 -07:00
scrub.c btrfs: switch message printers to ratelimited variants 2015-10-08 13:04:06 +02:00
send.c btrfs: fix resending received snapshot with parent 2015-10-13 20:04:10 +01:00
send.h
struct-funcs.c
super.c Btrfs: add fragment=* debug mount option 2015-10-21 18:51:43 -07:00
sysfs.c Btrfs: rename super_kobj to fsid_kobj 2015-09-29 16:29:59 +02:00
sysfs.h Btrfs: rename btrfs_kobj_rm_device to btrfs_sysfs_rm_device_link 2015-09-29 16:29:59 +02:00
transaction.c Merge branch 'allocator-fixes' into for-linus-4.4 2015-10-21 19:00:38 -07:00
transaction.h Merge branch 'allocator-fixes' into for-linus-4.4 2015-10-21 19:00:38 -07:00
tree-defrag.c Btrfs: cleanup: remove unnecessary check before btrfs_free_path is called 2015-08-31 11:46:41 -07:00
tree-log.c Btrfs: fix regression running delayed references when using qgroups 2015-10-25 19:53:26 +00:00
tree-log.h Btrfs: fix metadata inconsistencies after directory fsync 2015-03-26 17:56:23 -07:00
ulist.c btrfs: ulist: Add ulist_del() function. 2015-06-10 09:26:17 -07:00
ulist.h btrfs: ulist: Add ulist_del() function. 2015-06-10 09:26:17 -07:00
uuid-tree.c Btrfs: make btrfs_search_forward return with nodes unlocked 2014-09-17 13:38:02 -07:00
volumes.c btrfs: extend balance filter usage to take minimum and maximum 2015-10-26 19:38:30 -07:00
volumes.h btrfs: add balance filters limits, stripes and usage to supported mask 2015-10-26 19:38:30 -07:00
xattr.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
xattr.h btrfs: use generic posix ACL infrastructure 2014-01-25 23:58:18 -05:00
zlib.c btrfs: constify structs with op functions or static definitions 2015-02-16 18:48:44 +01:00