linux/fs/btrfs
Josef Bacik f72ff01df9 btrfs: do not call synchronize_srcu() in inode_tree_del
Testing with the new fsstress uncovered a pretty nasty deadlock with
lookup and snapshot deletion.

Process A
unlink
 -> final iput
   -> inode_tree_del
     -> synchronize_srcu(subvol_srcu)

Process B
btrfs_lookup  <- srcu_read_lock() acquired here
  -> btrfs_iget
    -> find inode that has I_FREEING set
      -> __wait_on_freeing_inode()

We're holding the srcu_read_lock() while doing the iget in order to make
sure our fs root doesn't go away, and then we are waiting for the inode
to finish freeing.  However because the free'ing process is doing a
synchronize_srcu() we deadlock.

Fix this by dropping the synchronize_srcu() in inode_tree_del().  We
don't need people to stop accessing the fs root at this point, we're
only adding our empty root to the dead roots list.

A larger much more invasive fix is forthcoming to address how we deal
with fs roots, but this fixes the immediate problem.

Fixes: 76dda93c6a ("Btrfs: add snapshot/subvolume destroy ioctl")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13 14:09:08 +01:00
..
tests btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
acl.c btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
async-thread.c btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
async-thread.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
backref.c Btrfs: fix deadlock between fiemap and transaction commits 2019-07-30 18:25:12 +02:00
backref.h btrfs: fiemap: preallocate ulists for btrfs_check_shared 2019-07-01 13:34:53 +02:00
block-group.c btrfs: scrub: Don't check free space before marking a block group RO 2019-11-18 18:07:55 +01:00
block-group.h btrfs: scrub: Don't check free space before marking a block group RO 2019-11-18 18:07:55 +01:00
block-rsv.c btrfs: use btrfs_try_granting_tickets in update_global_rsv 2019-09-09 14:59:19 +02:00
block-rsv.h btrfs: migrate the global_block_rsv helpers to block-rsv.c 2019-07-02 12:30:55 +02:00
btrfs_inode.h Btrfs: remove unnecessary delalloc mutex for inodes 2019-11-18 17:51:46 +01:00
check-integrity.c btrfs: reduce stack usage for btrfsic_process_written_block 2019-09-09 14:58:58 +02:00
check-integrity.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
compression.c btrfs: drop bio_set_dev where not needed 2019-11-18 23:39:30 +01:00
compression.h btrfs: compression: remove ops pointer from workspace_manager 2019-11-18 12:46:59 +01:00
ctree.c btrfs: add blake2b to checksumming algorithms 2019-11-18 17:51:44 +01:00
ctree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
delalloc-space.c Btrfs: remove unnecessary delalloc mutex for inodes 2019-11-18 17:51:46 +01:00
delalloc-space.h btrfs: migrate the delalloc space stuff to it's own home 2019-07-04 17:26:17 +02:00
delayed-inode.c btrfs: use refcount_inc_not_zero in kill_all_nodes 2019-11-18 12:46:51 +01:00
delayed-inode.h Btrfs: delayed-inode: use rb_first_cached for ins_root and del_root 2018-10-15 17:23:33 +02:00
delayed-ref.c btrfs: rename btrfs_space_info_add_old_bytes 2019-09-09 14:59:18 +02:00
delayed-ref.h btrfs: migrate the delayed refs rsv code 2019-07-04 17:26:17 +02:00
dev-replace.c btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
dev-replace.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
dir-item.c btrfs: remove unused parameter fs_info from btrfs_extend_item 2019-04-29 19:02:50 +02:00
disk-io.c btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
disk-io.h btrfs: add __cold attribute to more functions 2019-11-18 12:46:52 +01:00
export.c btrfs: drop unused parameter is_new from btrfs_iget 2019-11-18 12:46:52 +01:00
export.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
extent_io.c btrfs: drop bdev argument from submit_extent_page 2019-11-18 23:43:58 +01:00
extent_io.h btrfs: opencode extent_buffer_get 2019-11-18 12:46:54 +01:00
extent_map.c btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
extent_map.h btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
extent-io-tree.h btrfs: move the failrec tree stuff into extent-io-tree.h 2019-11-18 12:46:47 +01:00
extent-tree.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
file-item.c btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
file.c Btrfs: fix cloning range with a hole when using the NO_HOLES feature 2019-12-13 13:29:22 +01:00
free-space-cache.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
free-space-cache.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
free-space-tree.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
free-space-tree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
inode-item.c btrfs: Make btrfs_find_name_in_ext_backref return struct btrfs_inode_extref 2019-09-09 14:59:16 +02:00
inode-map.c btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents() 2019-10-15 18:50:07 +02:00
inode-map.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
inode.c btrfs: do not call synchronize_srcu() in inode_tree_del 2019-12-13 14:09:08 +01:00
ioctl.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
Kconfig btrfs: add sha256 to checksumming algorithm 2019-11-18 17:51:43 +01:00
locking.c btrfs: document extent buffer locking 2019-11-18 17:51:50 +01:00
locking.h btrfs: move btrfs_unlock_up_safe to other locking functions 2019-11-18 12:46:49 +01:00
lzo.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
Makefile btrfs: migrate the block group lookup code 2019-09-09 14:59:04 +02:00
misc.h btrfs: add 64bit safe helper for power of two checks 2019-11-18 12:46:50 +01:00
ordered-data.c Btrfs: fix block group remaining RO forever after error during device replace 2019-11-18 18:07:55 +01:00
ordered-data.h Btrfs: fix block group remaining RO forever after error during device replace 2019-11-18 18:07:55 +01:00
orphan.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
print-tree.c btrfs: rename extent buffer block group item accessors 2019-11-18 17:51:45 +01:00
print-tree.h btrfs: print-tree: debugging output enhancement 2018-04-20 19:18:16 +02:00
props.c btrfs: props: remove unnecessary hash_init() 2019-11-18 12:46:55 +01:00
props.h btrfs: delete unused function btrfs_set_prop_trans 2019-04-29 19:02:54 +02:00
qgroup.c btrfs: Fix error messages in qgroup_rescan_init 2019-12-13 13:29:12 +01:00
qgroup.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
raid56.c btrfs: remove pointless local variable in lock_stripe_add() 2019-11-18 12:47:00 +01:00
raid56.h btrfs: constify map parameter for nr_parity_stripes and nr_data_stripes 2019-07-01 13:34:58 +02:00
rcu-string.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
reada.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
ref-verify.c btrfs: fix uninitialized ret in ref-verify 2019-10-03 15:00:56 +02:00
ref-verify.h btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod() 2019-04-29 19:02:49 +02:00
relocation.c btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
root-tree.c btrfs: rename the btrfs_calc_*_metadata_size helpers 2019-09-09 14:59:13 +02:00
scrub.c Btrfs: fix block group remaining RO forever after error during device replace 2019-11-18 18:07:55 +01:00
send.c Btrfs: send, skip backreference walking for extents with many references 2019-11-18 17:51:48 +01:00
send.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
space-info.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
space-info.h Btrfs: remove wait queue from space_info structure 2019-11-18 17:51:46 +01:00
struct-funcs.c btrfs: tie extent buffer and it's token together 2019-09-09 14:59:16 +02:00
super.c btrfs: add support for 4-copy replication (raid1c4) 2019-11-18 17:51:49 +01:00
sysfs.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
sysfs.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
transaction.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
transaction.h btrfs: Rename btrfs_join_transaction_nolock 2019-11-18 12:46:54 +01:00
tree-checker.c btrfs: tree-checker: Check item size before reading file extent type 2019-11-18 17:51:48 +01:00
tree-checker.h btrfs: get fs_info from eb in btrfs_check_chunk_valid 2019-04-29 19:02:39 +02:00
tree-defrag.c btrfs: open code now trivial btrfs_set_lock_blocking 2019-02-25 14:13:27 +01:00
tree-log.c btrfs: opencode extent_buffer_get 2019-11-18 12:46:54 +01:00
tree-log.h btrfs: get fs_info from trans in btrfs_set_log_full_commit 2019-04-29 19:02:41 +02:00
ulist.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
ulist.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
uuid-tree.c btrfs: remove unused parameter fs_info from btrfs_extend_item 2019-04-29 19:02:50 +02:00
volumes.c btrfs: change btrfs_fs_devices::rotating to bool 2019-11-18 17:51:51 +01:00
volumes.h btrfs: change btrfs_fs_devices::rotating to bool 2019-11-18 17:51:51 +01:00
xattr.c Btrfs: fix failure to persist compression property xattr deletion on fsync 2019-06-17 16:37:17 +02:00
xattr.h btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
zlib.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
zstd.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00