From 11023d3f5fdf89bba5e1142127701ca6e6014587 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@suse.com>
Date: Mon, 5 Nov 2018 11:14:05 +0000
Subject: Btrfs: fix infinite loop on inode eviction after deduplication of eof
block
If we attempt to deduplicate the last block of a file A into the middle of
a file B, and file A's size is not a multiple of the block size, we end
rounding the deduplication length to 0 bytes, to avoid the data corruption
issue fixed by commit de02b9f6bb65 ("Btrfs: fix data corruption when
deduplicating between different files"). However a length of zero will
cause the insertion of an extent state with a start value greater (by 1)
then the end value, leading to a corrupt extent state that will trigger a
warning and cause chaos such as an infinite loop during inode eviction.
Example trace:
[96049.833585] ------------[ cut here ]------------
[96049.833714] WARNING: CPU: 0 PID: 24448 at fs/btrfs/extent_io.c:436 insert_state+0x101/0x120 [btrfs]
[96049.833767] CPU: 0 PID: 24448 Comm: xfs_io Not tainted 4.19.0-rc7-btrfs-next-39 #1
[96049.833768] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[96049.833780] RIP: 0010:insert_state+0x101/0x120 [btrfs]
[96049.833783] RSP: 0018:ffffafd2c3707af0 EFLAGS: 00010282
[96049.833785] RAX: 0000000000000000 RBX: 000000000004dfff RCX: 0000000000000006
[96049.833786] RDX: 0000000000000007 RSI: ffff99045c143230 RDI: ffff99047b2168a0
[96049.833787] RBP: ffff990457851cd0 R08: 0000000000000001 R09: 0000000000000000
[96049.833787] R10: ffffafd2c3707ab8 R11: 0000000000000000 R12: ffff9903b93b12c8
[96049.833788] R13: 000000000004e000 R14: ffffafd2c3707b80 R15: ffffafd2c3707b78
[96049.833790] FS: 00007f5c14e7d700(0000) GS:ffff99047b200000(0000) knlGS:0000000000000000
[96049.833791] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[96049.833792] CR2: 00007f5c146abff8 CR3: 0000000115f4c004 CR4: 00000000003606f0
[96049.833795] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[96049.833796] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[96049.833796] Call Trace:
[96049.833809] __set_extent_bit+0x46c/0x6a0 [btrfs]
[96049.833823] lock_extent_bits+0x6b/0x210 [btrfs]
[96049.833831] ? _raw_spin_unlock+0x24/0x30
[96049.833841] ? test_range_bit+0xdf/0x130 [btrfs]
[96049.833853] lock_extent_range+0x8e/0x150 [btrfs]
[96049.833864] btrfs_double_extent_lock+0x78/0xb0 [btrfs]
[96049.833875] btrfs_extent_same_range+0x14e/0x550 [btrfs]
[96049.833885] ? rcu_read_lock_sched_held+0x3f/0x70
[96049.833890] ? __kmalloc_node+0x2b0/0x2f0
[96049.833899] ? btrfs_dedupe_file_range+0x19a/0x280 [btrfs]
[96049.833909] btrfs_dedupe_file_range+0x270/0x280 [btrfs]
[96049.833916] vfs_dedupe_file_range_one+0xd9/0xe0
[96049.833919] vfs_dedupe_file_range+0x131/0x1b0
[96049.833924] do_vfs_ioctl+0x272/0x6e0
[96049.833927] ? __fget+0x113/0x200
[96049.833931] ksys_ioctl+0x70/0x80
[96049.833933] __x64_sys_ioctl+0x16/0x20
[96049.833937] do_syscall_64+0x60/0x1b0
[96049.833939] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[96049.833941] RIP: 0033:0x7f5c1478ddd7
[96049.833943] RSP: 002b:00007ffe15b196a8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[96049.833945] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5c1478ddd7
[96049.833946] RDX: 00005625ece322d0 RSI: 00000000c0189436 RDI: 0000000000000004
[96049.833947] RBP: 0000000000000000 R08: 00007f5c14a46f48 R09: 0000000000000040
[96049.833948] R10: 0000000000000541 R11: 0000000000000202 R12: 0000000000000000
[96049.833949] R13: 0000000000000000 R14: 0000000000000004 R15: 00005625ece322d0
[96049.833954] irq event stamp: 6196
[96049.833956] hardirqs last enabled at (6195): [<ffffffff91b00663>] console_unlock+0x503/0x640
[96049.833958] hardirqs last disabled at (6196): [<ffffffff91a037dd>] trace_hardirqs_off_thunk+0x1a/0x1c
[96049.833959] softirqs last enabled at (6114): [<ffffffff92600370>] __do_softirq+0x370/0x421
[96049.833964] softirqs last disabled at (6095): [<ffffffff91a8dd4d>] irq_exit+0xcd/0xe0
[96049.833965] ---[ end trace db7b05f01b7fa10c ]---
[96049.935816] R13: 0000000000000000 R14: 00005562e5259240 R15: 00007ffff092b910
[96049.935822] irq event stamp: 6584
[96049.935823] hardirqs last enabled at (6583): [<ffffffff91b00663>] console_unlock+0x503/0x640
[96049.935825] hardirqs last disabled at (6584): [<ffffffff91a037dd>] trace_hardirqs_off_thunk+0x1a/0x1c
[96049.935827] softirqs last enabled at (6328): [<ffffffff92600370>] __do_softirq+0x370/0x421
[96049.935828] softirqs last disabled at (6313): [<ffffffff91a8dd4d>] irq_exit+0xcd/0xe0
[96049.935829] ---[ end trace db7b05f01b7fa123 ]---
[96049.935840] ------------[ cut here ]------------
[96049.936065] WARNING: CPU: 1 PID: 24463 at fs/btrfs/extent_io.c:436 insert_state+0x101/0x120 [btrfs]
[96049.936107] CPU: 1 PID: 24463 Comm: umount Tainted: G W 4.19.0-rc7-btrfs-next-39 #1
[96049.936108] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[96049.936117] RIP: 0010:insert_state+0x101/0x120 [btrfs]
[96049.936119] RSP: 0018:ffffafd2c3637bc0 EFLAGS: 00010282
[96049.936120] RAX: 0000000000000000 RBX: 000000000004dfff RCX: 0000000000000006
[96049.936121] RDX: 0000000000000007 RSI: ffff990445cf88e0 RDI: ffff99047b2968a0
[96049.936122] RBP: ffff990457851cd0 R08: 0000000000000001 R09: 0000000000000000
[96049.936123] R10: ffffafd2c3637b88 R11: 0000000000000000 R12: ffff9904574301e8
[96049.936124] R13: 000000000004e000 R14: ffffafd2c3637c50 R15: ffffafd2c3637c48
[96049.936125] FS: 00007fe4b87e72c0(0000) GS:ffff99047b280000(0000) knlGS:0000000000000000
[96049.936126] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[96049.936128] CR2: 00005562e52618d8 CR3: 00000001151c8005 CR4: 00000000003606e0
[96049.936129] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[96049.936131] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[96049.936131] Call Trace:
[96049.936141] __set_extent_bit+0x46c/0x6a0 [btrfs]
[96049.936154] lock_extent_bits+0x6b/0x210 [btrfs]
[96049.936167] btrfs_evict_inode+0x1e1/0x5a0 [btrfs]
[96049.936172] evict+0xbf/0x1c0
[96049.936174] dispose_list+0x51/0x80
[96049.936176] evict_inodes+0x193/0x1c0
[96049.936180] generic_shutdown_super+0x3f/0x110
[96049.936182] kill_anon_super+0xe/0x30
[96049.936189] btrfs_kill_super+0x13/0x100 [btrfs]
[96049.936191] deactivate_locked_super+0x3a/0x70
[96049.936193] cleanup_mnt+0x3b/0x80
[96049.936195] task_work_run+0x93/0xc0
[96049.936198] exit_to_usermode_loop+0xfa/0x100
[96049.936201] do_syscall_64+0x17f/0x1b0
[96049.936202] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[96049.936204] RIP: 0033:0x7fe4b80cfb37
[96049.936206] RSP: 002b:00007ffff092b688 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[96049.936207] RAX: 0000000000000000 RBX: 00005562e5259060 RCX: 00007fe4b80cfb37
[96049.936208] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00005562e525faa0
[96049.936209] RBP: 00005562e525faa0 R08: 00005562e525f770 R09: 0000000000000015
[96049.936210] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fe4b85d1e64
[96049.936211] R13: 0000000000000000 R14: 00005562e5259240 R15: 00007ffff092b910
[96049.936211] R13: 0000000000000000 R14: 00005562e5259240 R15: 00007ffff092b910
[96049.936216] irq event stamp: 6616
[96049.936219] hardirqs last enabled at (6615): [<ffffffff91b00663>] console_unlock+0x503/0x640
[96049.936219] hardirqs last disabled at (6616): [<ffffffff91a037dd>] trace_hardirqs_off_thunk+0x1a/0x1c
[96049.936222] softirqs last enabled at (6328): [<ffffffff92600370>] __do_softirq+0x370/0x421
[96049.936222] softirqs last disabled at (6313): [<ffffffff91a8dd4d>] irq_exit+0xcd/0xe0
[96049.936223] ---[ end trace db7b05f01b7fa124 ]---
The second stack trace, from inode eviction, is repeated forever due to
the infinite loop during eviction.
This is the same type of problem fixed way back in 2015 by commit
113e8283869b ("Btrfs: fix inode eviction infinite loop after extent_same
ioctl") and commit ccccf3d67294 ("Btrfs: fix inode eviction infinite loop
after cloning into it").
So fix this by returning immediately if the deduplication range length
gets rounded down to 0 bytes, as there is nothing that needs to be done in
such case.
Example reproducer:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ xfs_io -f -c "pwrite -S 0xe6 0 100" /mnt/foo
$ xfs_io -f -c "pwrite -S 0xe6 0 1M" /mnt/bar
# Unmount the filesystem and mount it again so that we start without any
# extent state records when we ask for the deduplication.
$ umount /mnt
$ mount /dev/sdb /mnt
$ xfs_io -c "dedupe /mnt/foo 0 500K 100" /mnt/bar
# This unmount triggers the infinite loop.
$ umount /mnt
A test case for fstests will follow soon.
Fixes: de02b9f6bb65 ("Btrfs: fix data corruption when deduplicating between different files")
CC: <stable@vger.kernel.org> # 4.19+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/ioctl.c | 2 ++
1 file changed, 2 insertions(+)
(limited to 'fs/btrfs/ioctl.c')
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a990a9045139..ed3ba55f65ac 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3488,6 +3488,8 @@ static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 olen,
const u64 sz = BTRFS_I(src)->root->fs_info->sectorsize;
len = round_down(i_size_read(src), sz) - loff;
+ if (len == 0)
+ return 0;
olen = len;
}
}
--
cgit
From ac765f83f1397646c11092a032d4f62c3d478b81 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@suse.com>
Date: Mon, 5 Nov 2018 11:14:17 +0000
Subject: Btrfs: fix data corruption due to cloning of eof block
We currently allow cloning a range from a file which includes the last
block of the file even if the file's size is not aligned to the block
size. This is fine and useful when the destination file has the same size,
but when it does not and the range ends somewhere in the middle of the
destination file, it leads to corruption because the bytes between the EOF
and the end of the block have undefined data (when there is support for
discard/trimming they have a value of 0x00).
Example:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ export foo_size=$((256 * 1024 + 100))
$ xfs_io -f -c "pwrite -S 0x3c 0 $foo_size" /mnt/foo
$ xfs_io -f -c "pwrite -S 0xb5 0 1M" /mnt/bar
$ xfs_io -c "reflink /mnt/foo 0 512K $foo_size" /mnt/bar
$ od -A d -t x1 /mnt/bar
0000000 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5
*
0524288 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c
*
0786528 3c 3c 3c 3c 00 00 00 00 00 00 00 00 00 00 00 00
0786544 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0790528 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5
*
1048576
The bytes in the range from 786532 (512Kb + 256Kb + 100 bytes) to 790527
(512Kb + 256Kb + 4Kb - 1) got corrupted, having now a value of 0x00 instead
of 0xb5.
This is similar to the problem we had for deduplication that got recently
fixed by commit de02b9f6bb65 ("Btrfs: fix data corruption when
deduplicating between different files").
Fix this by not allowing such operations to be performed and return the
errno -EINVAL to user space. This is what XFS is doing as well at the VFS
level. This change however now makes us return -EINVAL instead of
-EOPNOTSUPP for cases where the source range maps to an inline extent and
the destination range's end is smaller then the destination file's size,
since the detection of inline extents is done during the actual process of
dropping file extent items (at __btrfs_drop_extents()). Returning the
-EINVAL error is done early on and solely based on the input parameters
(offsets and length) and destination file's size. This makes us consistent
with XFS and anyone else supporting cloning since this case is now checked
at a higher level in the VFS and is where the -EINVAL will be returned
from starting with kernel 4.20 (the VFS changed was introduced in 4.20-rc1
by commit 07d19dc9fbe9 ("vfs: avoid problematic remapping requests into
partial EOF block"). So this change is more geared towards stable kernels,
as it's unlikely the new VFS checks get removed intentionally.
A test case for fstests follows soon, as well as an update to filter
existing tests that expect -EOPNOTSUPP to accept -EINVAL as well.
CC: <stable@vger.kernel.org> # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/ioctl.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
(limited to 'fs/btrfs/ioctl.c')
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ed3ba55f65ac..95f9625dccc4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4279,9 +4279,17 @@ static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
goto out_unlock;
if (len == 0)
olen = len = src->i_size - off;
- /* if we extend to eof, continue to block boundary */
- if (off + len == src->i_size)
+ /*
+ * If we extend to eof, continue to block boundary if and only if the
+ * destination end offset matches the destination file's size, otherwise
+ * we would be corrupting data by placing the eof block into the middle
+ * of a file.
+ */
+ if (off + len == src->i_size) {
+ if (!IS_ALIGNED(len, bs) && destoff + len < inode->i_size)
+ goto out_unlock;
len = ALIGN(src->i_size, bs) - off;
+ }
if (len == 0) {
ret = 0;
--
cgit