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efebe42d95
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: 6a18765b54 ("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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.