Hi! We are using external SAS storage via LSI MegaRAID SAS 9280-8e controller. When storage suddenly goes offline (cable unplug or expander glitch) the kernel (Fedora 3.3.5-2 64bit) outputs to log lots of kernel: [111163.509223] sd 4:2:2:0: rejecting I/O to offline device but later crashes with ------------[ cut here ]------------ WARNING: at fs/btrfs/extent-tree.c:4927 __btrfs_free_extent+0x628/0x6d0 [btrfs]() Hardware name: S5500WBV Modules linked in: binfmt_misc mpt2sas scsi_transport_sas raid_class mptctl mptbase ip6t_REJECT nf_conntrack_ipv4 nf_conntrack_ipv6 nf_defrag_ipv6 nf_defrag_ipv4 xt_state nf_conntrack ip6table_filter ip6_tables btrfs zlib_deflate libcrc32c iTCO_wdt i7core_edac igb edac_core i2c_i801 iTCO_vendor_support ioatdma dca joydev i2c_core ses enclosure megaraid_sas [last unloaded: scsi_wait_scan] Pid: 1749, comm: btrfs-transacti Not tainted 3.3.5-2.fc16.x86_64 #1 Call Trace: [<ffffffff81057abf>] warn_slowpath_common+0x7f/0xc0 [<ffffffff81057b1a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa00e1328>] __btrfs_free_extent+0x628/0x6d0 [btrfs] [<ffffffffa00e53a4>] run_clustered_refs+0x424/0x8f0 [btrfs] [<ffffffff810902e1>] ? update_curr+0x141/0x1f0 [<ffffffffa013372b>] ? find_ref_head+0xab/0xe0 [btrfs] [<ffffffffa00e59ee>] btrfs_run_delayed_refs+0x17e/0x4a0 [btrfs] [<ffffffffa0110590>] ? btrfs_run_ordered_operations+0x1c0/0x1e0 [btrfs] [<ffffffffa00f63f4>] btrfs_commit_transaction+0x94/0x820 [btrfs] [<ffffffff8107a7d0>] ? remove_wait_queue+0x50/0x50 [<ffffffffa00f05ad>] transaction_kthread+0x23d/0x2a0 [btrfs] sd 4:2:2:0: rejecting I/O to offline device sd 4:2:2:0: rejecting I/O to offline device [<ffffffffa00f0370>] ? write_dev_supers+0x270/0x270 [btrfs] [<ffffffff81079d83>] kthread+0x93/0xa0 [<ffffffff815fd6a4>] kernel_thread_helper+0x4/0x10 [<ffffffff81079cf0>] ? kthread_freezable_should_stop+0x70/0x70 [<ffffffff815fd6a0>] ? gs_change+0x13/0x13 ---[ end trace 4fd999c522cb517f ]--- btrfs unable to find ref byte nr 1241473052672 parent 0 root 7 owner 0 offset 0 BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffffa01173e2>] map_private_extent_buffer+0x12/0x150 [btrfs] PGD 0 Oops: 0000 [#1] SMP CPU 12 Modules linked in: binfmt_misc mpt2sas scsi_transport_sas raid_class mptctl mptbase ip6t_REJECT nf_conntrack_ipv4 nf_conntrack_ipv6 nf_defrag_ipv6 nf_defrag_ipv4 xt_state nf_conntrack ip6table_filter ip6_tables btrfs zlib_deflate libcrc32c iTCO_wdt i7core_edac igb edac_core i2c_i801 iTCO_vendor_support ioatdma dca joydev i2c_core ses enclosure megaraid_sas [last unloaded: scsi_wait_scan] Pid: 1749, comm: btrfs-transacti Tainted: G W 3.3.5-2.fc16.x86_64 #1 Intel Corporation S5500WBV/S5500WB RIP: 0010:[<ffffffffa01173e2>] [<ffffffffa01173e2>] map_private_extent_buffer+0x12/0x150 [btrfs] RSP: 0018:ffff88024cf4daa0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000065 RCX: ffff88024cf4dad0 RDX: 0000000000000004 RSI: 000000000000007a RDI: 0000000000000000 RBP: ffff88024cf4dac0 R08: ffff88024cf4dad8 R09: ffff88024cf4dae0 R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000007a R13: 0000000000000000 R14: 00000000fffffffb R15: 0000000000001000 FS: 0000000000000000(0000) GS:ffff880267cc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 0000000001c05000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process btrfs-transacti (pid: 1749, threadinfo ffff88024cf4c000, task ffff8802588e5cc0) Stack: 00000000fffffffb 0000000000000065 000000000000007a 0000000000000000 ffff88024cf4db10 ffffffffa010caac ffff88024cf4db20 ffff88024cf4dae0 0000000000000007 000001210d8f7000 0000000000000000 ffff88044f00fab0 Call Trace: [<ffffffffa010caac>] btrfs_item_size+0x3c/0x90 [btrfs] [<ffffffffa00e0f32>] __btrfs_free_extent+0x232/0x6d0 [btrfs] [<ffffffffa00e53a4>] run_clustered_refs+0x424/0x8f0 [btrfs] [<ffffffff810902e1>] ? update_curr+0x141/0x1f0 [<ffffffffa013372b>] ? find_ref_head+0xab/0xe0 [btrfs] [<ffffffffa00e59ee>] btrfs_run_delayed_refs+0x17e/0x4a0 [btrfs] [<ffffffffa00f63f4>] btrfs_commit_transaction+0x94/0x820 [btrfs] [<ffffffff8107a7d0>] ? remove_wait_queue+0x50/0x50 [<ffffffffa00f05ad>] transaction_kthread+0x23d/0x2a0 [btrfs] [<ffffffffa00f0370>] ? write_dev_supers+0x270/0x270 [btrfs] [<ffffffff81079d83>] kthread+0x93/0xa0 [<ffffffff815fd6a4>] kernel_thread_helper+0x4/0x10 sd 4:2:2:0: rejecting I/O to offline device [<ffffffff81079cf0>] ? kthread_freezable_should_stop+0x70/0x70 [<ffffffff815fd6a0>] ? gs_change+0x13/0x13 Code: 83 c0 01 48 89 85 78 ff ff ff e9 c0 fc ff ff 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 55 41 54 53 48 83 ec 08 66 66 66 66 90 <4c> 8b 27 4d 89 cd 48 89 cb 41 81 e4 ff 0f 00 00 4a 8d 04 26 4c RIP [<ffffffffa01173e2>] map_private_extent_buffer+0x12/0x150 [btrfs] RSP <ffff88024cf4daa0> CR2: 0000000000000000 ---[ end trace 4fd999c522cb5180 ]--- I hope this will be useful. Regards, -- Tomash Brechko -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html