From 51a60253a58514524b7a347c4e68553821a79d04 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Tue, 13 May 2014 22:01:02 +0100 Subject: 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:[] [] 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] [] ? read_extent_buffer+0xb9/0x120 [btrfs] [ 190.604020] [] fs_path_add_from_extent_buffer+0x45/0x60 [btrfs] [ 190.604020] [] get_first_ref+0x1f6/0x210 [btrfs] [ 190.604020] [] __get_cur_name_and_parent+0x174/0x3a0 [btrfs] [ 190.604020] [] ? kmem_cache_alloc_trace+0x11d/0x1e0 [ 190.604020] [] ? fs_path_alloc+0x24/0x60 [btrfs] [ 190.604020] [] 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 Signed-off-by: Chris Mason Reviewed-by: Liu Bo --- 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 eb6537a08c1b..fd38b5053479 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -1668,7 +1668,7 @@ 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); -- cgit v1.2.3