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bulkscore=0 phishscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607140013 Thanks a lot for your review. On 7/14/26 06:04, Darrick J. Wong wrote: > > On Mon, Jul 13, 2026 at 10:50:02PM +0800, Yun Zhou wrote: >> xfs_sync_sb_buf() holds sb/rtsb buffer locks across a synchronous >> xfs_trans_commit(), which flushes the CIL push workqueue internally. >> If shutdown occurs during the CIL push, xfs_buf_item_unpin() needs to >> lock these buffers to fail them, causing a deadlock: >> >> setlabel: holds buf lock -> flush_workqueue(xfs-cil) >> CIL push worker: xfs_buf_item_unpin -> xfs_buf_lock(same buf) >> >> Remove the xfs_trans_bhold() calls so that commit releases the buffer >> locks normally. After the sync commit, re-acquire the buffers via >> mp->m_sb_bp / mp->m_rtsb_bp for the on-disk writeback. > > Is there a risk of writing out the wrong superblock contents if > something else grabs the buffer lock(s) between the xfs_trans_commit and > the xfs_buf_lock calls? Can we walk off a garbage > xfs_mount::m_{rt,}sb_bp pointer if the filesystem is being torn down, or > does something prevent that? > There shouldn't be a risk of inconsistent contents. Each update to the sb buffer is a full overwrite of mp->m_sb via xfs_sb_to_disk(), performed under the buffer lock. So when we re-lock after commit, the buffer always contains a complete, consistent snapshot — we may see a newer version if someone else updated it in between, but never a partially written one. For the pointer lifetime: mp->m_sb_bp is allocated at mount and freed in xfs_unmountfs(). The caller holds mnt_want_write_file(), which prevents unmount from making progress, so the pointer should remain valid throughout xfs_sync_sb_buf(). BR, Yun