| Message ID | 20250109021320.429625-1-leo.lilong@huawei.com (mailing list archive) |
|---|---|
| State | Queued |
| Headers | show |
| Series | [v2] xfs: fix mount hang during primary superblock recovery failure | expand |
On Thu, Jan 09, 2025 at 10:13:20AM +0800, Long Li wrote: > 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. Can you post a regression test for us, pretty please? :) > 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); //write buffer 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 > Please add: Cc: <stable@vger.kernel.org> # v6.12 > Fixes: 6a18765b54e2 ("xfs: update the file system geometry after recoverying superblock buffers") > Signed-off-by: Long Li <leo.lilong@huawei.com> > --- > v1->v2: Add code comments and add the fixed stack description to the > commit message. > fs/xfs/xfs_buf_item_recover.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c > index 3d0c6402cb36..04122bbdd5f3 100644 > --- a/fs/xfs/xfs_buf_item_recover.c > +++ b/fs/xfs/xfs_buf_item_recover.c > @@ -1079,7 +1079,7 @@ 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) { > @@ -1096,6 +1096,15 @@ 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 do sb buffer recovery, log "...during sb buffer recovery..." and with those two things amended, Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> --D > + * 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. > -- > 2.39.2 > >
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
On Wed, Jan 08, 2025 at 08:41:42PM -0800, Darrick J. Wong wrote: > On Thu, Jan 09, 2025 at 10:13:20AM +0800, Long Li wrote: > > 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. > > Can you post a regression test for us, pretty please? :) > I performed regression testing by mounting specific images that can be obtained through fault injection on kernels without metadir feature support. I can provide it if anyone needs it.The image is big and inconvenient to send in the mail. The detailed steps are as follows: 1) Kernel Build - The latest realtime AG update bug [1] remains unfixed - Build kernel without CONFIG_XFS_RT 2) Mount XFS Image (superblock needs replay, incompatible with metadir and no realtime subvolume) 3) Mount Result Verification - Without the current patch: mount thread hangs indefinitely - With the current patch: mount thread does not hang, but XFS is shut down The xfstests already have the fault injection test, and this test requires mounting specific images on specifically-compiled kernels, making it impractical to incorporate into xfstests. > > 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); //write buffer 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 > > > > Please add: > Cc: <stable@vger.kernel.org> # v6.12 > > > Fixes: 6a18765b54e2 ("xfs: update the file system geometry after recoverying superblock buffers") > > Signed-off-by: Long Li <leo.lilong@huawei.com> > > --- > > v1->v2: Add code comments and add the fixed stack description to the > > commit message. > > fs/xfs/xfs_buf_item_recover.c | 11 ++++++++++- > > 1 file changed, 10 insertions(+), 1 deletion(-) > > > > diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c > > index 3d0c6402cb36..04122bbdd5f3 100644 > > --- a/fs/xfs/xfs_buf_item_recover.c > > +++ b/fs/xfs/xfs_buf_item_recover.c > > @@ -1079,7 +1079,7 @@ 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) { > > @@ -1096,6 +1096,15 @@ 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 do sb buffer recovery, log > > "...during sb buffer recovery..." > > and with those two things amended, > Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> > > --D Ok, thanks for your review. Long Li.
On Fri, Jan 10, 2025 at 09:40:16AM +0800, Long Li wrote: > On Wed, Jan 08, 2025 at 08:41:42PM -0800, Darrick J. Wong wrote: > > On Thu, Jan 09, 2025 at 10:13:20AM +0800, Long Li wrote: > > > 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. > > > > Can you post a regression test for us, pretty please? :) > > > > I performed regression testing by mounting specific images that can be > obtained through fault injection on kernels without metadir feature support. > I can provide it if anyone needs it.The image is big and inconvenient to send > in the mail. The detailed steps are as follows: > > 1) Kernel Build > - The latest realtime AG update bug [1] remains unfixed > - Build kernel without CONFIG_XFS_RT > > 2) Mount XFS Image (superblock needs replay, incompatible with metadir and > no realtime subvolume) > > 3) Mount Result Verification > - Without the current patch: mount thread hangs indefinitely > - With the current patch: mount thread does not hang, but XFS is shut down > > The xfstests already have the fault injection test, and this test requires > mounting specific images on specifically-compiled kernels, making it impractical > to incorporate into xfstests. > Sorry, forgot to add the fixed patch link: [1] https://patchwork.kernel.org/project/xfs/patch/20241217042737.1755365-1-hch@lst.de/
diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c index 3d0c6402cb36..04122bbdd5f3 100644 --- a/fs/xfs/xfs_buf_item_recover.c +++ b/fs/xfs/xfs_buf_item_recover.c @@ -1079,7 +1079,7 @@ 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) { @@ -1096,6 +1096,15 @@ 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 do 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.
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); //write buffer 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") Signed-off-by: Long Li <leo.lilong@huawei.com> --- v1->v2: Add code comments and add the fixed stack description to the commit message. fs/xfs/xfs_buf_item_recover.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)