[XFS] Always reset btree cursor after an insert (ddea2d52) · Commits · 戴 / test

fs/xfs/xfs_bmap.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -1746,11 +1746,18 @@ xfs_bmap_add_extent_unwritten_real(
		if ((error = xfs_bmbt_insert(cur, &i)))
		goto done;
		XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		if ((error = xfs_bmbt_increment(cur, 0, &i)))
		/*
		* Reset the cursor to the position of the new extent
		* we are about to insert as we can't trust it after
		* the previous insert.
		*/
		if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
		new->br_startblock, new->br_blockcount,
		&i)))
		goto done;
		XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		XFS_WANT_CORRUPTED_GOTO(i == 0, done);
		/* new middle extent - newext */
		cur->bc_rec.b = *new;
		cur->bc_rec.b.br_state = new->br_state;
		if ((error = xfs_bmbt_insert(cur, &i)))
		goto done;
		XFS_WANT_CORRUPTED_GOTO(i == 1, done);

fs/xfs/xfs_bmap_btree.c

+4 −34

Original line number	Diff line number	Diff line
		@@ -2029,22 +2029,8 @@ xfs_bmbt_increment(
		* Insert the current record at the point referenced by cur.
		*
		* A multi-level split of the tree on insert will invalidate the original
		* cursor. It appears, however, that some callers assume that the cursor is
		* always valid. Hence if we do a multi-level split we need to revalidate the
		* cursor.
		*
		* When a split occurs, we will see a new cursor returned. Use that as a
		* trigger to determine if we need to revalidate the original cursor. If we get
		* a split, then use the original irec to lookup up the path of the record we
		* just inserted.
		*
		* Note that the fact that the btree root is in the inode means that we can
		* have the level of the tree change without a "split" occurring at the root
		* level. What happens is that the root is migrated to an allocated block and
		* the inode root is pointed to it. This means a single split can change the
		* level of the tree (level 2 -> level 3) and invalidate the old cursor. Hence
		* the level change should be accounted as a split so as to correctly trigger a
		* revalidation of the old cursor.
		* cursor. All callers of this function should assume that the cursor is
		* no longer valid and revalidate it.
		*/
		int /* error */
		xfs_bmbt_insert(
		@@ -2057,14 +2043,11 @@ xfs_bmbt_insert(
		xfs_fsblock_t nbno;
		xfs_btree_cur_t *ncur;
		xfs_bmbt_rec_t nrec;
		xfs_bmbt_irec_t oirec; /* original irec */
		xfs_btree_cur_t *pcur;
		int splits = 0;

		XFS_BMBT_TRACE_CURSOR(cur, ENTRY);
		level = 0;
		nbno = NULLFSBLOCK;
		oirec = cur->bc_rec.b;
		xfs_bmbt_disk_set_all(&nrec, &cur->bc_rec.b);
		ncur = NULL;
		pcur = cur;
		@@ -2073,13 +2056,11 @@ xfs_bmbt_insert(
		&i))) {
		if (pcur != cur)
		xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
		goto error0;
		XFS_BMBT_TRACE_CURSOR(cur, ERROR);
		return error;
		}
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		if (pcur != cur && (ncur \|\| nbno == NULLFSBLOCK)) {
		/* allocating a new root is effectively a split */
		if (cur->bc_nlevels != pcur->bc_nlevels)
		splits++;
		cur->bc_nlevels = pcur->bc_nlevels;
		cur->bc_private.b.allocated +=
		pcur->bc_private.b.allocated;
		@@ -2093,21 +2074,10 @@ xfs_bmbt_insert(
		xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
		}
		if (ncur) {
		splits++;
		pcur = ncur;
		ncur = NULL;
		}
		} while (nbno != NULLFSBLOCK);

		if (splits > 1) {
		/* revalidate the old cursor as we had a multi-level split */
		error = xfs_bmbt_lookup_eq(cur, oirec.br_startoff,
		oirec.br_startblock, oirec.br_blockcount, &i);
		if (error)
		goto error0;
		ASSERT(i == 1);
		}

		XFS_BMBT_TRACE_CURSOR(cur, EXIT);
		*stat = i;
		return 0;

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