[PATCH 17/22] xfs: scrub directory freespace

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Check the free space information in a directory.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/scrub/dir.c |  337 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 337 insertions(+)


diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
index 1d6b5329..661aec3 100644
--- a/fs/xfs/scrub/dir.c
+++ b/fs/xfs/scrub/dir.c
@@ -232,6 +232,338 @@ xfs_scrub_dir_rec(
 #undef XFS_SCRUB_DIRENT_GOTO
 #undef XFS_SCRUB_DIRENT_CHECK
 
+#define XFS_SCRUB_DIR_BLOCK_CHECK(fs_ok) \
+	XFS_SCRUB_DATA_CHECK(sc, XFS_DATA_FORK, \
+		lblk << mp->m_sb.sb_blocklog, "dir", fs_ok)
+#define XFS_SCRUB_DIR_BLOCK_GOTO(fs_ok, label) \
+	XFS_SCRUB_DATA_GOTO(sc, XFS_DATA_FORK, \
+		lblk << mp->m_sb.sb_blocklog, "dir", fs_ok, label)
+#define XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO(label) \
+	XFS_SCRUB_FILE_OP_ERROR_GOTO(sc, XFS_DATA_FORK, \
+		lblk << mp->m_sb.sb_blocklog, "dir", &error, label)
+/* Is this free entry either in the bestfree or smaller than all of them? */
+static inline bool
+xfs_scrub_directory_check_free_entry(
+	struct xfs_dir2_data_free	*bf,
+	struct xfs_dir2_data_unused	*dup)
+{
+	struct xfs_dir2_data_free	*dfp;
+	unsigned int			smallest;
+
+	smallest = -1U;
+	for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
+		if (dfp->offset &&
+		    be16_to_cpu(dfp->length) == be16_to_cpu(dup->length))
+			return true;
+		if (smallest < be16_to_cpu(dfp->length))
+			smallest = be16_to_cpu(dfp->length);
+	}
+
+	return be16_to_cpu(dup->length) <= smallest;
+}
+
+/* Check free space info in a directory data block. */
+STATIC int
+xfs_scrub_directory_data_bestfree(
+	struct xfs_scrub_context	*sc,
+	xfs_dablk_t			lblk,
+	bool				is_block)
+{
+	struct xfs_dir2_data_unused	*dup;
+	struct xfs_dir2_data_free	*dfp;
+	struct xfs_buf			*bp;
+	struct xfs_dir2_data_free	*bf;
+	struct xfs_mount		*mp = sc->mp;
+	char				*ptr;
+	char				*endptr;
+	u16				tag;
+	int				newlen;
+	int				offset;
+	int				error;
+
+	if (is_block) {
+		/* dir block format */
+		XFS_SCRUB_DIR_BLOCK_CHECK(lblk ==
+				XFS_B_TO_FSBT(mp, XFS_DIR2_DATA_OFFSET));
+		error = xfs_dir3_block_read(sc->tp, sc->ip, &bp);
+	} else {
+		/* dir data format */
+		error = xfs_dir3_data_read(sc->tp, sc->ip, lblk, -1, &bp);
+	}
+	XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO(out);
+
+	/* Do the bestfrees correspond to actual free space? */
+	bf = sc->ip->d_ops->data_bestfree_p(bp->b_addr);
+	for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
+		offset = be16_to_cpu(dfp->offset);
+		XFS_SCRUB_DIR_BLOCK_GOTO(offset < BBTOB(bp->b_length), nextloop);
+		if (!offset)
+			continue;
+		dup = (struct xfs_dir2_data_unused *)(bp->b_addr + offset);
+		tag = be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup));
+
+		XFS_SCRUB_DIR_BLOCK_CHECK(dup->freetag ==
+				cpu_to_be16(XFS_DIR2_DATA_FREE_TAG));
+		XFS_SCRUB_DIR_BLOCK_CHECK(be16_to_cpu(dup->length) ==
+				be16_to_cpu(dfp->length));
+		XFS_SCRUB_DIR_BLOCK_CHECK(tag ==
+				((char *)dup - (char *)bp->b_addr));
+nextloop:;
+	}
+
+	/* Make sure the bestfrees are actually the best free spaces. */
+	ptr = (char *)sc->ip->d_ops->data_entry_p(bp->b_addr);
+	if (is_block) {
+		struct xfs_dir2_block_tail	*btp;
+
+		btp = xfs_dir2_block_tail_p(sc->mp->m_dir_geo, bp->b_addr);
+		endptr = (char *)xfs_dir2_block_leaf_p(btp);
+	} else
+		endptr = (char *)bp->b_addr + BBTOB(bp->b_length);
+	while (ptr < endptr) {
+		dup = (struct xfs_dir2_data_unused *)ptr;
+		/* Skip real entries */
+		if (dup->freetag != cpu_to_be16(XFS_DIR2_DATA_FREE_TAG)) {
+			struct xfs_dir2_data_entry	*dep;
+
+			dep = (struct xfs_dir2_data_entry *)ptr;
+			newlen = sc->ip->d_ops->data_entsize(dep->namelen);
+			XFS_SCRUB_DIR_BLOCK_GOTO(newlen > 0, out_buf);
+			ptr += newlen;
+			XFS_SCRUB_DIR_BLOCK_CHECK(ptr <= endptr);
+			continue;
+		}
+
+		/* Spot check this free entry */
+		tag = be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup));
+		XFS_SCRUB_DIR_BLOCK_CHECK(tag ==
+				((char *)dup - (char *)bp->b_addr));
+
+		/*
+		 * Either this entry is a bestfree or it's smaller than
+		 * any of the bestfrees.
+		 */
+		XFS_SCRUB_DIR_BLOCK_CHECK(
+				xfs_scrub_directory_check_free_entry(bf, dup));
+
+		/* Move on. */
+		newlen = be16_to_cpu(dup->length);
+		XFS_SCRUB_DIR_BLOCK_GOTO(newlen > 0, out_buf);
+		ptr += newlen;
+		XFS_SCRUB_DIR_BLOCK_CHECK(ptr <= endptr);
+	}
+out_buf:
+	xfs_trans_brelse(sc->tp, bp);
+out:
+	return error;
+}
+
+/* Is this the longest free entry in the block? */
+static inline bool
+xfs_scrub_directory_check_freesp(
+	struct xfs_inode		*dp,
+	struct xfs_buf			*dbp,
+	unsigned int			len)
+{
+	struct xfs_dir2_data_free	*bf;
+	struct xfs_dir2_data_free	*dfp;
+	unsigned int			longest = 0;
+	int				offset;
+
+	bf = dp->d_ops->data_bestfree_p(dbp->b_addr);
+	for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
+		offset = be16_to_cpu(dfp->offset);
+		if (!offset)
+			continue;
+		if (longest < be16_to_cpu(dfp->length))
+			longest = be16_to_cpu(dfp->length);
+	}
+
+	return longest == len;
+}
+
+/* Check free space info in a directory leaf1 block. */
+STATIC int
+xfs_scrub_directory_leaf1_bestfree(
+	struct xfs_scrub_context	*sc,
+	struct xfs_da_args		*args,
+	xfs_dablk_t			lblk)
+{
+	struct xfs_dir2_leaf_tail	*ltp;
+	struct xfs_buf			*dbp;
+	struct xfs_buf			*bp;
+	struct xfs_mount		*mp = sc->mp;
+	__be16				*bestp;
+	__u16				best;
+	int				i;
+	int				error;
+
+	/* Read the free space block */
+	error = xfs_dir3_leaf_read(sc->tp, sc->ip, lblk, -1, &bp);
+	XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO(out);
+
+	/* Check all the entries. */
+	ltp = xfs_dir2_leaf_tail_p(mp->m_dir_geo, bp->b_addr);
+	bestp = xfs_dir2_leaf_bests_p(ltp);
+	for (i = 0; i < be32_to_cpu(ltp->bestcount); i++, bestp++) {
+		best = be16_to_cpu(*bestp);
+		if (best == NULLDATAOFF)
+			continue;
+		error = xfs_dir3_data_read(sc->tp, sc->ip,
+				i * args->geo->fsbcount, -1, &dbp);
+		XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO(skip_buf);
+		XFS_SCRUB_DIR_BLOCK_CHECK(
+				xfs_scrub_directory_check_freesp(sc->ip, dbp,
+					best));
+		xfs_trans_brelse(sc->tp, dbp);
+skip_buf:
+		;
+	}
+out:
+	return error;
+}
+
+/* Check free space info in a directory freespace block. */
+STATIC int
+xfs_scrub_directory_free_bestfree(
+	struct xfs_scrub_context	*sc,
+	struct xfs_da_args		*args,
+	xfs_dablk_t			lblk)
+{
+	struct xfs_dir3_icfree_hdr	freehdr;
+	struct xfs_buf			*dbp;
+	struct xfs_buf			*bp;
+	struct xfs_mount		*mp = sc->mp;
+	__be16				*bestp;
+	__be16				best;
+	int				i;
+	int				error;
+
+	/* Read the free space block */
+	error = xfs_dir2_free_read(sc->tp, sc->ip, lblk, &bp);
+	XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO(out);
+
+	/* Check all the entries. */
+	sc->ip->d_ops->free_hdr_from_disk(&freehdr, bp->b_addr);
+	bestp = sc->ip->d_ops->free_bests_p(bp->b_addr);
+	for (i = 0; i < freehdr.nvalid; i++, bestp++) {
+		best = be16_to_cpu(*bestp);
+		if (best == NULLDATAOFF)
+			continue;
+		error = xfs_dir3_data_read(sc->tp, sc->ip,
+				(freehdr.firstdb + i) * args->geo->fsbcount,
+				-1, &dbp);
+		XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO(skip_buf);
+		XFS_SCRUB_DIR_BLOCK_CHECK(
+				xfs_scrub_directory_check_freesp(sc->ip, dbp,
+					best));
+		xfs_trans_brelse(sc->tp, dbp);
+skip_buf:
+		;
+	}
+out:
+	return error;
+}
+
+#define for_each_extent_dablk(lblk, args, got) \
+		for ((lblk) = roundup((xfs_dablk_t)(got)->br_startoff, (args)->geo->fsbcount); \
+		     (lblk) < (got)->br_startoff + (got)->br_blockcount; \
+		     (lblk) += (args)->geo->fsbcount)
+/* Check free space information in directories. */
+STATIC int
+xfs_scrub_directory_blocks(
+	struct xfs_scrub_context	*sc)
+{
+	struct xfs_bmbt_irec		got;
+	struct xfs_da_args		args;
+	struct xfs_ifork		*ifp;
+	struct xfs_mount		*mp = sc->mp;
+	xfs_fileoff_t			leaf_lblk;
+	xfs_fileoff_t			free_lblk;
+	xfs_fileoff_t			lblk;
+	xfs_extnum_t			idx;
+	bool				found;
+	int				is_block = 0;
+	int				error;
+
+	/* Ignore local format directories. */
+	if (sc->ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS &&
+	    sc->ip->i_d.di_format != XFS_DINODE_FMT_BTREE)
+		return 0;
+
+	ifp = XFS_IFORK_PTR(sc->ip, XFS_DATA_FORK);
+	lblk = XFS_B_TO_FSB(mp, XFS_DIR2_DATA_OFFSET);
+	leaf_lblk = XFS_B_TO_FSB(mp, XFS_DIR2_LEAF_OFFSET);
+	free_lblk = XFS_B_TO_FSB(mp, XFS_DIR2_FREE_OFFSET);
+
+	/* Is this a block dir? */
+	args.dp = sc->ip;
+	args.geo = mp->m_dir_geo;
+	args.trans = sc->tp;
+	error = xfs_dir2_isblock(&args, &is_block);
+	XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO(out);
+
+	/* Iterate all the data extents in the directory... */
+	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &idx, &got);
+	while (found) {
+		/* No more data blocks... */
+		if (got.br_startoff >= leaf_lblk)
+			break;
+
+		/* Check each data block's bestfree data */
+		for_each_extent_dablk(lblk, &args, &got) {
+			error = xfs_scrub_directory_data_bestfree(sc, lblk,
+					is_block);
+			if (error)
+				goto out;
+		}
+
+		found = xfs_iext_get_extent(ifp, ++idx, &got);
+	}
+
+	/* Look for a leaf1 block, which has free info. */
+	if (xfs_iext_lookup_extent(sc->ip, ifp, leaf_lblk, &idx, &got) &&
+	    got.br_startoff == leaf_lblk &&
+	    got.br_blockcount == args.geo->fsbcount &&
+	    !xfs_iext_get_extent(ifp, ++idx, &got)) {
+		XFS_SCRUB_DIR_BLOCK_GOTO(!is_block, not_leaf1);
+		error = xfs_scrub_directory_leaf1_bestfree(sc, &args,
+				leaf_lblk);
+		if (error)
+			goto out;
+	}
+not_leaf1:
+
+	/* Scan for free blocks */
+	lblk = free_lblk;
+	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &idx, &got);
+	while (found) {
+		/*
+		 * Dirs can't have blocks mapped above 2^32.
+		 * Single-block dirs shouldn't even be here.
+		 */
+		lblk = got.br_startoff;
+		XFS_SCRUB_DIR_BLOCK_GOTO(!(lblk & ~((1ULL << 32) - 1ULL)), out);
+		XFS_SCRUB_DIR_BLOCK_GOTO(!is_block, nextfree);
+
+		/* Check each dir free block's bestfree data */
+		for_each_extent_dablk(lblk, &args, &got) {
+			error = xfs_scrub_directory_free_bestfree(sc, &args,
+					lblk);
+			if (error)
+				goto out;
+		}
+
+nextfree:
+		found = xfs_iext_get_extent(ifp, ++idx, &got);
+	}
+out:
+	return error;
+}
+#undef for_each_extent_dablk
+#undef XFS_SCRUB_DIR_BLOCK_OP_ERROR_GOTO
+#undef XFS_SCRUB_DIR_BLOCK_CHECK
+
 /* Scrub a whole directory. */
 int
 xfs_scrub_directory(
@@ -258,6 +590,11 @@ xfs_scrub_directory(
 	if (error)
 		return error;
 
+	/* Check the freespace. */
+	error = xfs_scrub_directory_blocks(sc);
+	if (error)
+		return error;
+
 	/* Check that every dirent we see can also be looked up by hash. */
 	bufsize = (size_t)min_t(loff_t, 32768, sc->ip->i_d.di_size);
 	sdc.sc = sc;