This is a note to let you know that I've just added the patch titled Revert "ext4: remove block_device_ejected" to the 4.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: revert-ext4-remove-block_device_ejected.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From bdfe0cbd746aa9b2509c2f6d6be17193cf7facd7 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o <tytso@xxxxxxx> Date: Sun, 16 Aug 2015 10:03:57 -0400 Subject: Revert "ext4: remove block_device_ejected" From: Theodore Ts'o <tytso@xxxxxxx> commit bdfe0cbd746aa9b2509c2f6d6be17193cf7facd7 upstream. This reverts commit 08439fec266c3cc5702953b4f54bdf5649357de0. Unfortunately we still need to test for bdi->dev to avoid a crash when a USB stick is yanked out while a file system is mounted: usb 2-2: USB disconnect, device number 2 Buffer I/O error on dev sdb1, logical block 15237120, lost sync page write JBD2: Error -5 detected when updating journal superblock for sdb1-8. BUG: unable to handle kernel paging request at 34beb000 IP: [<c136ce88>] __percpu_counter_add+0x18/0xc0 *pdpt = 0000000023db9001 *pde = 0000000000000000 Oops: 0000 [#1] SMP CPU: 0 PID: 4083 Comm: umount Tainted: G U OE 4.1.1-040101-generic #201507011435 Hardware name: LENOVO 7675CTO/7675CTO, BIOS 7NETC2WW (2.22 ) 03/22/2011 task: ebf06b50 ti: ebebc000 task.ti: ebebc000 EIP: 0060:[<c136ce88>] EFLAGS: 00010082 CPU: 0 EIP is at __percpu_counter_add+0x18/0xc0 EAX: f21c8e88 EBX: f21c8e88 ECX: 00000000 EDX: 00000001 ESI: 00000001 EDI: 00000000 EBP: ebebde60 ESP: ebebde40 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 34beb000 CR3: 33354200 CR4: 000007f0 Stack: c1abe100 edcb0098 edcb00ec ffffffff f21c8e68 ffffffff f21c8e68 f286d160 ebebde84 c1160454 00000010 00000282 f72a77f8 00000984 f72a77f8 f286d160 f286d170 ebebdea0 c11e613f 00000000 00000282 f72a77f8 edd7f4d0 00000000 Call Trace: [<c1160454>] account_page_dirtied+0x74/0x110 [<c11e613f>] __set_page_dirty+0x3f/0xb0 [<c11e6203>] mark_buffer_dirty+0x53/0xc0 [<c124a0cb>] ext4_commit_super+0x17b/0x250 [<c124ac71>] ext4_put_super+0xc1/0x320 [<c11f04ba>] ? fsnotify_unmount_inodes+0x1aa/0x1c0 [<c11cfeda>] ? evict_inodes+0xca/0xe0 [<c11b925a>] generic_shutdown_super+0x6a/0xe0 [<c10a1df0>] ? prepare_to_wait_event+0xd0/0xd0 [<c1165a50>] ? unregister_shrinker+0x40/0x50 [<c11b92f6>] kill_block_super+0x26/0x70 [<c11b94f5>] deactivate_locked_super+0x45/0x80 [<c11ba007>] deactivate_super+0x47/0x60 [<c11d2b39>] cleanup_mnt+0x39/0x80 [<c11d2bc0>] __cleanup_mnt+0x10/0x20 [<c1080b51>] task_work_run+0x91/0xd0 [<c1011e3c>] do_notify_resume+0x7c/0x90 [<c1720da5>] work_notify Code: 8b 55 e8 e9 f4 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 55 89 e5 83 ec 20 89 5d f4 89 c3 89 75 f8 89 d6 89 7d fc 89 cf 8b 48 14 <64> 8b 01 89 45 ec 89 c2 8b 45 08 c1 fa 1f 01 75 ec 89 55 f0 89 EIP: [<c136ce88>] __percpu_counter_add+0x18/0xc0 SS:ESP 0068:ebebde40 CR2: 0000000034beb000 ---[ end trace dd564a7bea834ecd ]--- Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=101011 Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ext4/super.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -325,6 +325,22 @@ static void save_error_info(struct super ext4_commit_super(sb, 1); } +/* + * The del_gendisk() function uninitializes the disk-specific data + * structures, including the bdi structure, without telling anyone + * else. Once this happens, any attempt to call mark_buffer_dirty() + * (for example, by ext4_commit_super), will cause a kernel OOPS. + * This is a kludge to prevent these oops until we can put in a proper + * hook in del_gendisk() to inform the VFS and file system layers. + */ +static int block_device_ejected(struct super_block *sb) +{ + struct inode *bd_inode = sb->s_bdev->bd_inode; + struct backing_dev_info *bdi = inode_to_bdi(bd_inode); + + return bdi->dev == NULL; +} + static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn) { struct super_block *sb = journal->j_private; @@ -4617,7 +4633,7 @@ static int ext4_commit_super(struct supe struct buffer_head *sbh = EXT4_SB(sb)->s_sbh; int error = 0; - if (!sbh) + if (!sbh || block_device_ejected(sb)) return error; if (buffer_write_io_error(sbh)) { /* Patches currently in stable-queue which might be from tytso@xxxxxxx are queue-4.2/ext4-don-t-manipulate-recovery-flag-when-freezing-no-journal-fs.patch queue-4.2/revert-ext4-remove-block_device_ejected.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html