xfs: reinitialise per-AG structures if geometry changes during recovery (a798011c) · Commits · 戴 / test

If a crash occurs immediately after a filesystem grow operation, the updated superblock geometry is found only in the log. After we recover the log, the superblock is reread and re-initialised and so has the new geometry in memory. If the new geometry has more AGs than prior to the grow operation, then the new AGs will not have in-memory xfs_perag structurea associated with them. This will result in an oops when the first metadata buffer from a new AG is looked up in the buffer cache, as the block lies within the new geometry but then fails to find a perag structure on lookup. This is easily fixed by simply re-initialising the perag structure after re-reading the superblock at the conclusion of the first pahse of log recovery. This, however, does not fix the case of log recovery requiring access to metadata in the newly grown space. Fortunately for us, because the in-core superblock has not been updated, this will result in detection of access beyond the end of the filesystem and so recovery will fail at that point. If this proves to be a problem, then we can address it separately to the current reported issue. Reported-by:

Alex Lyakas <alex@zadarastorage.com> Tested-by:

Alex Lyakas <alex@zadarastorage.com> Signed-off-by:

Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_log_recover.c

+13 −9

Original line number	Diff line number	Diff line
		@@ -4891,6 +4891,7 @@ xlog_do_recover(
		xfs_daddr_t head_blk,
		xfs_daddr_t tail_blk)
		{
		struct xfs_mount *mp = log->l_mp;
		int error;
		xfs_buf_t *bp;
		xfs_sb_t *sbp;
		@@ -4905,7 +4906,7 @@ xlog_do_recover(
		/*
		* If IO errors happened during recovery, bail out.
		*/
		if (XFS_FORCED_SHUTDOWN(log->l_mp)) {
		if (XFS_FORCED_SHUTDOWN(mp)) {
		return -EIO;
		}

		@@ -4918,13 +4919,13 @@ xlog_do_recover(
		* or iunlinks they will have some entries in the AIL; so we look at
		* the AIL to determine how to set the tail_lsn.
		*/
		xlog_assign_tail_lsn(log->l_mp);
		xlog_assign_tail_lsn(mp);

		/*
		* Now that we've finished replaying all buffer and inode
		* updates, re-read in the superblock and reverify it.
		*/
		bp = xfs_getsb(log->l_mp, 0);
		bp = xfs_getsb(mp, 0);
		bp->b_flags &= ~(XBF_DONE \| XBF_ASYNC);
		ASSERT(!(bp->b_flags & XBF_WRITE));
		bp->b_flags \|= XBF_READ;
		@@ -4932,7 +4933,7 @@ xlog_do_recover(

		error = xfs_buf_submit_wait(bp);
		if (error) {
		if (!XFS_FORCED_SHUTDOWN(log->l_mp)) {
		if (!XFS_FORCED_SHUTDOWN(mp)) {
		xfs_buf_ioerror_alert(bp, __func__);
		ASSERT(0);
		}
		@@ -4941,14 +4942,17 @@ xlog_do_recover(
		}

		/* Convert superblock from on-disk format */
		sbp = &log->l_mp->m_sb;
		sbp = &mp->m_sb;
		xfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
		ASSERT(sbp->sb_magicnum == XFS_SB_MAGIC);
		ASSERT(xfs_sb_good_version(sbp));
		xfs_reinit_percpu_counters(log->l_mp);

		xfs_buf_relse(bp);

		/* re-initialise in-core superblock and geometry structures */
		xfs_reinit_percpu_counters(mp);
		error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
		if (error) {
		xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
		return error;
		}

		xlog_recover_check_summary(log);

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