I just noticed that there's a bugreport from opensuse user tripping over the same BUG() during log replay (and his problem was solved by btrfs-zero-log), probably after some crash. The kernel version was 3.1 ie. without the corruption fixes, so while it happened during normal use (and not via a crafted fs image), I'm not sure if this is still the case with recent kernels.
Turning the BUG in __btrfs_map_block to return needs checking the value in not-so-few callers and from various callpaths, it's not straightforward to do eg. a quick return during mount, as in your case. Good that Jeff Mahoney's error handling series reduce the number of callers to update. david ------------[ cut here ]------------ WARNING: at /home/abuild/rpmbuild/BUILD/kernel-desktop-3.1.0/linux-3.1/fs/btrfs/tree-log.c:1729 walk_down_log_tree+0x 15a/0x3e0 [btrfs]() Pid: 8978, comm: mount Not tainted 3.1.0-1.2-desktop #1 Call Trace: [<ffffffff810043fa>] dump_trace+0xaa/0x2b0 [<ffffffff81582a4a>] dump_stack+0x69/0x6f [<ffffffff8105386b>] warn_slowpath_common+0x7b/0xc0 [<ffffffffa0573cba>] walk_down_log_tree+0x15a/0x3e0 [btrfs] [<ffffffffa0574267>] walk_log_tree+0xc7/0x1f0 [btrfs] [<ffffffffa057803c>] btrfs_recover_log_trees+0x1ec/0x2d0 [btrfs] [<ffffffffa0544303>] open_ctree+0x13c3/0x1740 [btrfs] [<ffffffffa0522733>] btrfs_fill_super.isra.36+0x73/0x150 [btrfs] [<ffffffffa0523b29>] btrfs_mount+0x359/0x3e0 [btrfs] [<ffffffff81156465>] mount_fs+0x45/0x1d0 [<ffffffff8116fdb6>] vfs_kern_mount+0x66/0xd0 [<ffffffff81171383>] do_kern_mount+0x53/0x120 [<ffffffff81172e35>] do_mount+0x1a5/0x260 [<ffffffff811732da>] sys_mount+0x9a/0xf0 [<ffffffff815a3292>] system_call_fastpath+0x16/0x1b [<00007fc524137daa>] 0x7fc524137da9 ---[ end trace 2bf4520d35da960f ]--- unable to find logical 5493736079360 len 4096 ------------[ cut here ]------------ 1728 if (btrfs_header_level(cur) != *level) 1729 WARN_ON(1); kernel BUG at /home/abuild/rpmbuild/BUILD/kernel-desktop-3.1.0/linux-3.1/fs/btrfs/volumes.c:2891! invalid opcode: 0000 [#1] PREEMPT SMP CPU 1 Pid: 8978, comm: mount Tainted: G W 3.1.0-1.2-desktop #1 RIP: 0010:[<ffffffffa0568e28>] [<ffffffffa0568e28>] __btrfs_map_block+0x7c8/0x890 [btrfs] RSP: 0018:ffff8801b7507798 EFLAGS: 00010296 RAX: 0000000000000043 RBX: 000004ff1c300000 RCX: 0000000000002a82 RDX: 000000000000723a RSI: 0000000000000046 RDI: 0000000000000202 RBP: ffff8801b7507860 R08: 000000000000000a R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff8801dcd10cc0 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001 FS: 00007fc524c587e0(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007faea5cb8000 CR3: 00000001b74f4000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process mount (pid: 8978, threadinfo ffff8801b7506000, task ffff8801b0d9c740) Call Trace: [<ffffffffa056baa7>] btrfs_map_bio+0x57/0x210 [btrfs] [<ffffffffa05600d4>] submit_one_bio+0x64/0xa0 [btrfs] [<ffffffffa05653c7>] read_extent_buffer_pages+0x367/0x4a0 [btrfs] [<ffffffffa053fd10>] btree_read_extent_buffer_pages.isra.63+0x80/0xc0 [btrfs] [<ffffffffa0542b3a>] btrfs_read_buffer+0x2a/0x40 [btrfs] [<ffffffffa0576d56>] replay_one_buffer+0x46/0x360 [btrfs] [<ffffffffa0573d6d>] walk_down_log_tree+0x20d/0x3e0 [btrfs] [<ffffffffa0574267>] walk_log_tree+0xc7/0x1f0 [btrfs] [<ffffffffa057803c>] btrfs_recover_log_trees+0x1ec/0x2d0 [btrfs] [<ffffffffa0544303>] open_ctree+0x13c3/0x1740 [btrfs] [<ffffffffa0522733>] btrfs_fill_super.isra.36+0x73/0x150 [btrfs] [<ffffffffa0523b29>] btrfs_mount+0x359/0x3e0 [btrfs] [<ffffffff81156465>] mount_fs+0x45/0x1d0 [<ffffffff8116fdb6>] vfs_kern_mount+0x66/0xd0 [<ffffffff81171383>] do_kern_mount+0x53/0x120 [<ffffffff81172e35>] do_mount+0x1a5/0x260 [<ffffffff811732da>] sys_mount+0x9a/0xf0 [<ffffffff815a3292>] system_call_fastpath+0x16/0x1b [<00007fc524137daa>] 0x7fc524137da9 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
