Filipe David Borba Manana
2014-May-13 21:01 UTC
[PATCH] Btrfs: send, fix incorrect ref access when using extrefs
When running send, if an inode only has extended reference items
associated to it and no regular references, send.c:get_first_ref()
was incorrectly assuming the reference it found was of type
BTRFS_INODE_REF_KEY due to use of the wrong key variable.
This caused weird behaviour when using the found item has a regular
reference, such as weird path string, and occasionally (when lucky)
a crash:
[ 190.600652] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 190.600994] Modules linked in: btrfs xor raid6_pq binfmt_misc nfsd
auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc psmouse serio_raw
evbug pcspkr i2c_piix4 e1000 floppy
[ 190.602565] CPU: 2 PID: 14520 Comm: btrfs Not tainted
3.13.0-fdm-btrfs-next-26+ #1
[ 190.602728] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 190.602868] task: ffff8800d447c920 ti: ffff8801fa79e000 task.ti:
ffff8801fa79e000
[ 190.603030] RIP: 0010:[<ffffffff813266b4>] [<ffffffff813266b4>]
memcpy+0x54/0x110
[ 190.603262] RSP: 0018:ffff8801fa79f880 EFLAGS: 00010202
[ 190.603395] RAX: ffff8800d4326e3f RBX: 000000000000036a RCX: ffff880000000000
[ 190.603553] RDX: 000000000000032a RSI: ffe708844042936a RDI: ffff8800d43271a9
[ 190.603710] RBP: ffff8801fa79f8c8 R08: 00000000003a4ef0 R09: 0000000000000000
[ 190.603867] R10: 793a4ef09f000000 R11: 9f0000000053726f R12: ffff8800d43271a9
[ 190.604020] R13: 0000160000000000 R14: ffff8802110134f0 R15: 000000000000036a
[ 190.604020] FS: 00007fb423d09b80(0000) GS:ffff880216200000(0000)
knlGS:0000000000000000
[ 190.604020] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 190.604020] CR2: 00007fb4229d4b78 CR3: 00000001f5d76000 CR4: 00000000000006e0
[ 190.604020] Stack:
[ 190.604020] ffffffffa01f4d49 ffff8801fa79f8f0 00000000000009f9
ffff8801fa79f8c8
[ 190.604020] 00000000000009f9 ffff880211013260 000000000000f971
ffff88021147dba8
[ 190.604020] 00000000000009f9 ffff8801fa79f918 ffffffffa02367f5
ffff8801fa79f928
[ 190.604020] Call Trace:
[ 190.604020] [<ffffffffa01f4d49>] ? read_extent_buffer+0xb9/0x120
[btrfs]
[ 190.604020] [<ffffffffa02367f5>]
fs_path_add_from_extent_buffer+0x45/0x60 [btrfs]
[ 190.604020] [<ffffffffa0238806>] get_first_ref+0x1f6/0x210 [btrfs]
[ 190.604020] [<ffffffffa0238994>] __get_cur_name_and_parent+0x174/0x3a0
[btrfs]
[ 190.604020] [<ffffffff8118df3d>] ? kmem_cache_alloc_trace+0x11d/0x1e0
[ 190.604020] [<ffffffffa0236674>] ? fs_path_alloc+0x24/0x60 [btrfs]
[ 190.604020] [<ffffffffa0238c91>] get_cur_path+0xd1/0x240 [btrfs]
(...)
Steps to reproduce (either crash or some weirdness like an odd path string):
mkfs.btrfs -f -O extref /dev/sdd
mount /dev/sdd /mnt
mkdir /mnt/testdir
touch /mnt/testdir/foobar
for i in `seq 1 2550`; do
ln /mnt/testdir/foobar /mnt/testdir/foobar_link_`printf "%04d"
$i`
done
ln /mnt/testdir/foobar /mnt/testdir/final_foobar_name
rm -f /mnt/testdir/foobar
for i in `seq 1 2550`; do
rm -f /mnt/testdir/foobar_link_`printf "%04d" $i`
done
btrfs subvolume snapshot -r /mnt /mnt/mysnap
btrfs send /mnt/mysnap -f /tmp/mysnap.send
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
fs/btrfs/send.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 40f353f..0035bdd 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -1688,7 +1688,7 @@ static int get_first_ref(struct btrfs_root *root, u64 ino,
goto out;
}
- if (key.type == BTRFS_INODE_REF_KEY) {
+ if (found_key.type == BTRFS_INODE_REF_KEY) {
struct btrfs_inode_ref *iref;
iref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
--
1.9.1
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