linux/fs/btrfs
Filipe Manana ccccf3d672 Btrfs: fix inode eviction infinite loop after cloning into it
If we attempt to clone a 0 length region into a file we can end up
inserting a range in the inode's extent_io tree with a start offset
that is greater then the end offset, which triggers immediately the
following warning:

[ 3914.619057] WARNING: CPU: 17 PID: 4199 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]()
[ 3914.620886] BTRFS: end < start 4095 4096
(...)
[ 3914.638093] Call Trace:
[ 3914.638636]  [<ffffffff81425fd9>] dump_stack+0x4c/0x65
[ 3914.639620]  [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb
[ 3914.640789]  [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs]
[ 3914.642041]  [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48
[ 3914.643236]  [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs]
[ 3914.644441]  [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs]
[ 3914.645711]  [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs]
[ 3914.646914]  [<ffffffff8142b2fb>] ? _raw_spin_unlock+0x28/0x33
[ 3914.648058]  [<ffffffffa03cbac4>] ? test_range_bit+0xcc/0xde [btrfs]
[ 3914.650105]  [<ffffffffa03cb3c3>] lock_extent+0x13/0x15 [btrfs]
[ 3914.651361]  [<ffffffffa03db39e>] lock_extent_range+0x3d/0xcd [btrfs]
[ 3914.652761]  [<ffffffffa03de1fe>] btrfs_ioctl_clone+0x278/0x388 [btrfs]
[ 3914.654128]  [<ffffffff811226dd>] ? might_fault+0x58/0xb5
[ 3914.655320]  [<ffffffffa03e0909>] btrfs_ioctl+0xb51/0x2195 [btrfs]
(...)
[ 3914.669271] ---[ end trace 14843d3e2e622fc1 ]---

This later makes the inode eviction handler enter an infinite loop that
keeps dumping the following warning over and over:

[ 3915.117629] WARNING: CPU: 22 PID: 4228 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]()
[ 3915.119913] BTRFS: end < start 4095 4096
(...)
[ 3915.137394] Call Trace:
[ 3915.137913]  [<ffffffff81425fd9>] dump_stack+0x4c/0x65
[ 3915.139154]  [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb
[ 3915.140316]  [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs]
[ 3915.141505]  [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48
[ 3915.142709]  [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs]
[ 3915.143849]  [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs]
[ 3915.145120]  [<ffffffffa038c1e3>] ? btrfs_kill_super+0x17/0x23 [btrfs]
[ 3915.146352]  [<ffffffff811548f6>] ? deactivate_locked_super+0x3b/0x50
[ 3915.147565]  [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs]
[ 3915.148785]  [<ffffffff8142b7e2>] ? _raw_write_unlock+0x28/0x33
[ 3915.149931]  [<ffffffffa03bc325>] btrfs_evict_inode+0x196/0x482 [btrfs]
[ 3915.151154]  [<ffffffff81168904>] evict+0xa0/0x148
[ 3915.152094]  [<ffffffff811689e5>] dispose_list+0x39/0x43
[ 3915.153081]  [<ffffffff81169564>] evict_inodes+0xdc/0xeb
[ 3915.154062]  [<ffffffff81154418>] generic_shutdown_super+0x49/0xef
[ 3915.155193]  [<ffffffff811546d1>] kill_anon_super+0x13/0x1e
[ 3915.156274]  [<ffffffffa038c1e3>] btrfs_kill_super+0x17/0x23 [btrfs]
(...)
[ 3915.167404] ---[ end trace 14843d3e2e622fc2 ]---

So just bail out of the clone ioctl if the length of the region to clone
is zero, without locking any extent range, in order to prevent this issue
(same behaviour as a pwrite with a 0 length for example).

This is trivial to reproduce. For example, the steps for the test I just
made for fstests:

  mkfs.btrfs -f SCRATCH_DEV
  mount SCRATCH_DEV $SCRATCH_MNT

  touch $SCRATCH_MNT/foo
  touch $SCRATCH_MNT/bar

  $CLONER_PROG -s 0 -d 4096 -l 0 $SCRATCH_MNT/foo $SCRATCH_MNT/bar
  umount $SCRATCH_MNT

A test case for fstests follows soon.

CC: <stable@vger.kernel.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-04-13 07:03:28 -07:00
..
tests Btrfs: add sanity test for outstanding_extents accounting 2015-03-17 16:36:31 -04:00
acl.c btrfs: remove useless ACL check 2014-06-09 17:20:42 -07:00
async-thread.c btrfs: use correct type for workqueue flags 2015-02-16 18:48:47 +01:00
async-thread.h btrfs: use correct type for workqueue flags 2015-02-16 18:48:47 +01:00
backref.c btrfs: use explicit initializer for seq_elem 2015-03-03 17:23:59 +01:00
backref.h btrfs: cleanup, remove inode_item_info helper 2015-01-14 19:23:47 +01:00
btrfs_inode.h Btrfs: fix metadata inconsistencies after directory fsync 2015-03-26 17:56:23 -07:00
check-integrity.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
check-integrity.h block: submit_bio_wait() conversions 2013-11-24 16:33:41 -07:00
compression.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
compression.h btrfs: constify structs with op functions or static definitions 2015-02-16 18:48:44 +01:00
ctree.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
ctree.h Btrfs: fix use after free when close_ctree frees the orphan_rsv 2015-04-10 14:07:29 -07:00
delayed-inode.c Btrfs: delayed-inode: replace root args iff only fs_info used 2015-02-16 18:48:43 +01:00
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: account for crcs in delayed ref processing 2015-04-10 14:04:47 -07:00
delayed-ref.h Btrfs: account for crcs in delayed ref processing 2015-04-10 14:04:47 -07:00
dev-replace.c btrfs: cleanup 64bit/32bit divs, compile time constants 2015-03-03 17:23:57 +01:00
dev-replace.h
dir-item.c Btrfs: make xattr replace operations atomic 2014-11-20 17:20:07 -08:00
disk-io.c Btrfs: fix use after free when close_ctree frees the orphan_rsv 2015-04-10 14:07:29 -07:00
disk-io.h Btrfs: disk-io: replace root args iff only fs_info used 2015-02-16 18:48:43 +01:00
export.c btrfs: kill the key type accessor helpers 2014-09-17 13:37:12 -07:00
export.h
extent_io.c btrfs: incorrect handling for fiemap_fill_next_extent return 2015-03-26 18:10:24 -07:00
extent_io.h btrfs: constify structs with op functions or static definitions 2015-02-16 18:48:44 +01:00
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
extent-tree.c Btrfs: fix use after free when close_ctree frees the orphan_rsv 2015-04-10 14:07:29 -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 metadata inconsistencies after directory fsync 2015-03-26 17:56:23 -07:00
free-space-cache.c Btrfs: allow block group cache writeout outside critical section in commit 2015-04-10 14:07:22 -07:00
free-space-cache.h Btrfs: allow block group cache writeout outside critical section in commit 2015-04-10 14:07:22 -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: fix fsync log replay for inodes with a mix of regular refs and extrefs 2015-01-21 18:02:05 -08:00
inode-map.c Btrfs: allow block group cache writeout outside critical section in commit 2015-04-10 14:07:22 -07:00
inode-map.h
inode.c Btrfs: don't steal from the global reserve if we don't have the space 2015-04-10 14:06:59 -07:00
ioctl.c Btrfs: fix inode eviction infinite loop after cloning into it 2015-04-13 07:03:28 -07:00
Kconfig rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
locking.c btrfs: fix lockups from btrfs_clear_path_blocking 2014-11-19 10:34:35 -08:00
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: fix fsync race leading to ordered extent memory leaks 2015-03-02 14:04:44 -08:00
ordered-data.h Btrfs: collect only the necessary ordered extents on ranged fsync 2014-11-21 11:59:56 -08:00
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 btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
props.c btrfs: constify structs with op functions or static definitions 2015-02-16 18:48:44 +01:00
props.h Btrfs: add support for inode properties 2014-01-28 13:20:24 -08:00
qgroup.c Btrfs: change the insertion criteria for the qgroup operations rbtree 2015-03-26 17:55:52 -07:00
qgroup.h btrfs: qgroup: account shared subtrees during snapshot delete 2014-08-15 07:43:14 -07:00
raid56.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
raid56.h Btrfs: Make raid_map array be inlined in btrfs_bio structure 2015-01-21 18:06:47 -08:00
rcu-string.h
reada.c Btrfs: add ref_count and free function for btrfs_bio 2015-01-21 18:06:48 -08:00
relocation.c Btrfs: allow block group cache writeout outside critical section in commit 2015-04-10 14:07:22 -07:00
root-tree.c Btrfs: use bitfield instead of integer data type for the some variants in btrfs_root 2014-06-09 17:20:40 -07:00
scrub.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
send.c Btrfs: incremental send, remove dead code 2015-03-26 17:55:52 -07:00
send.h btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
struct-funcs.c
super.c btrfs: cleanup orphans while looking up default subvolume 2015-03-26 18:10:25 -07:00
sysfs.c btrfs: constify structs with op functions or static definitions 2015-02-16 18:48:44 +01:00
sysfs.h btrfs: switch helper macros to static inlines in sysfs.h 2015-03-03 17:24:02 +01:00
transaction.c Btrfs: allow block group cache writeout outside critical section in commit 2015-04-10 14:07:22 -07:00
transaction.h Btrfs: allow block group cache writeout outside critical section in commit 2015-04-10 14:07:22 -07:00
tree-defrag.c Btrfs: use bitfield instead of integer data type for the some variants in btrfs_root 2014-06-09 17:20:40 -07:00
tree-log.c btrfs: actively run the delayed refs while deleting large files 2015-04-10 14:00:14 -07:00
tree-log.h Btrfs: fix metadata inconsistencies after directory fsync 2015-03-26 17:56:23 -07:00
ulist.c Btrfs: do not export ulist functions 2014-01-29 07:06:27 -08:00
ulist.h Btrfs: Fix memory corruption by ulist_add_merge() on 32bit arch 2014-08-15 07:43:19 -07:00
uuid-tree.c Btrfs: make btrfs_search_forward return with nodes unlocked 2014-09-17 13:38:02 -07:00
volumes.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
volumes.h btrfs: remove unused fs_info arg from btrfs_close_extra_devices() 2015-02-16 18:48:45 +01:00
xattr.c btrfs: don't accept bare namespace as a valid xattr 2015-03-26 18:10:24 -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