The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x efebe42d95fbba91dca6e3e32cb9e0612eb56de5 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025020458-showoff-enclosure-b449@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From efebe42d95fbba91dca6e3e32cb9e0612eb56de5 Mon Sep 17 00:00:00 2001 From: Long Li leo.lilong@huawei.com Date: Sat, 11 Jan 2025 15:05:44 +0800 Subject: [PATCH] xfs: fix mount hang during primary superblock recovery failure

When mounting an image containing a log with sb modifications that require log replay, the mount process hang all the time and stack as follows:

[root@localhost ~]# cat /proc/557/stack [<0>] xfs_buftarg_wait+0x31/0x70 [<0>] xfs_buftarg_drain+0x54/0x350 [<0>] xfs_mountfs+0x66e/0xe80 [<0>] xfs_fs_fill_super+0x7f1/0xec0 [<0>] get_tree_bdev_flags+0x186/0x280 [<0>] get_tree_bdev+0x18/0x30 [<0>] xfs_fs_get_tree+0x1d/0x30 [<0>] vfs_get_tree+0x2d/0x110 [<0>] path_mount+0xb59/0xfc0 [<0>] do_mount+0x92/0xc0 [<0>] __x64_sys_mount+0xc2/0x160 [<0>] x64_sys_call+0x2de4/0x45c0 [<0>] do_syscall_64+0xa7/0x240 [<0>] entry_SYSCALL_64_after_hwframe+0x76/0x7e

During log recovery, while updating the in-memory superblock from the primary SB buffer, if an error is encountered, such as superblock corruption occurs or some other reasons, we will proceed to out_release and release the xfs_buf. However, this is insufficient because the xfs_buf's log item has already been initialized and the xfs_buf is held by the buffer log item as follows, the xfs_buf will not be released, causing the mount thread to hang.

xlog_recover_do_primary_sb_buffer xlog_recover_do_reg_buffer xlog_recover_validate_buf_type xfs_buf_item_init(bp, mp)

The solution is straightforward, we simply need to allow it to be handled by the normal buffer write process. The filesystem will be shutdown before the submission of buffer_list in xlog_do_recovery_pass(), ensuring the correct release of the xfs_buf as follows:

xlog_do_recovery_pass error = xlog_recover_process xlog_recover_process_data xlog_recover_process_ophdr xlog_recovery_process_trans ... xlog_recover_buf_commit_pass2 error = xlog_recover_do_primary_sb_buffer //Encounter error and return if (error) goto out_writebuf ... out_writebuf: xfs_buf_delwri_queue(bp, buffer_list) //add bp to list return error ... if (!list_empty(&buffer_list)) if (error) xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR); //shutdown first xfs_buf_delwri_submit(&buffer_list); //submit buffers in list __xfs_buf_submit if (bp->b_mount->m_log && xlog_is_shutdown(bp->b_mount->m_log)) xfs_buf_ioend_fail(bp) //release bp correctly

Fixes: 6a18765b54e2 ("xfs: update the file system geometry after recoverying superblock buffers") Cc: stable@vger.kernel.org # v6.12 Signed-off-by: Long Li leo.lilong@huawei.com Reviewed-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Carlos Maiolino cem@kernel.org

diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c index b05d5b81f642..05a2f6927c12 100644 --- a/fs/xfs/xfs_buf_item_recover.c +++ b/fs/xfs/xfs_buf_item_recover.c @@ -1087,7 +1087,7 @@ xlog_recover_buf_commit_pass2( error = xlog_recover_do_primary_sb_buffer(mp, item, bp, buf_f, current_lsn); if (error) - goto out_release; + goto out_writebuf;

/* Update the rt superblock if we have one. */ if (xfs_has_rtsb(mp) && mp->m_rtsb_bp) { @@ -1104,6 +1104,15 @@ xlog_recover_buf_commit_pass2( xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn); }

+ /* + * Buffer held by buf log item during 'normal' buffer recovery must + * be committed through buffer I/O submission path to ensure proper + * release. When error occurs during sb buffer recovery, log shutdown + * will be done before submitting buffer list so that buffers can be + * released correctly through ioend failure path. + */ +out_writebuf: + /* * Perform delayed write on the buffer. Asynchronous writes will be * slower when taking into account all the buffers to be flushed.