xfs: add CRC checks to block format directory blocks

Now that directory buffers are made from a single struct xfs_buf, we
can add CRC calculation and checking callbacks. While there, add all
the fields to the on disk structures for future functionality such
as d_type support, uuids, block numbers, owner inode, etc.

To distinguish between the different on disk formats, change the
magic numbers for the new format directory blocks.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_dir2_block.c

 /*
  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2013 Red Hat, Inc.
  * All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or
@@ -28,11 +29,13 @@
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_inode_item.h"
+#include "xfs_buf_item.h"
 #include "xfs_dir2.h"
 #include "xfs_dir2_format.h"
 #include "xfs_dir2_priv.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
+#include "xfs_cksum.h"
 
 /*
  * Local function prototypes.
@@ -56,44 +59,74 @@ xfs_dir_startup(void)
 	xfs_dir_hash_dotdot = xfs_da_hashname((unsigned char *)"..", 2);
 }
 
-static void
-xfs_dir2_block_verify(
+static bool
+xfs_dir3_block_verify(
 	struct xfs_buf		*bp)
 {
 	struct xfs_mount	*mp = bp->b_target->bt_mount;
-	struct xfs_dir2_data_hdr *hdr = bp->b_addr;
-	int			block_ok = 0;
-
-	block_ok = hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
-	block_ok = block_ok && __xfs_dir2_data_check(NULL, bp) == 0;
-
-	if (!block_ok) {
-		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, hdr);
-		xfs_buf_ioerror(bp, EFSCORRUPTED);
+	struct xfs_dir3_blk_hdr	*hdr3 = bp->b_addr;
+
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		if (hdr3->magic != cpu_to_be32(XFS_DIR3_BLOCK_MAGIC))
+			return false;
+		if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_uuid))
+			return false;
+		if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
+			return false;
+	} else {
+		if (hdr3->magic != cpu_to_be32(XFS_DIR2_BLOCK_MAGIC))
+			return false;
 	}
+	if (__xfs_dir2_data_check(NULL, bp))
+		return false;
+	return true;
 }
 
 static void
-xfs_dir2_block_read_verify(
+xfs_dir3_block_read_verify(
 	struct xfs_buf	*bp)
 {
-	xfs_dir2_block_verify(bp);
+	struct xfs_mount	*mp = bp->b_target->bt_mount;
+
+	if ((xfs_sb_version_hascrc(&mp->m_sb) &&
+	     !xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
+					  XFS_DIR3_DATA_CRC_OFF)) ||
+	    !xfs_dir3_block_verify(bp)) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+		xfs_buf_ioerror(bp, EFSCORRUPTED);
+	}
 }
 
 static void
-xfs_dir2_block_write_verify(
+xfs_dir3_block_write_verify(
 	struct xfs_buf	*bp)
 {
-	xfs_dir2_block_verify(bp);
+	struct xfs_mount	*mp = bp->b_target->bt_mount;
+	struct xfs_buf_log_item	*bip = bp->b_fspriv;
+	struct xfs_dir3_blk_hdr	*hdr3 = bp->b_addr;
+
+	if (!xfs_dir3_block_verify(bp)) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+		xfs_buf_ioerror(bp, EFSCORRUPTED);
+		return;
+	}
+
+	if (!xfs_sb_version_hascrc(&mp->m_sb))
+		return;
+
+	if (bip)
+		hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);
+
+	xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), XFS_DIR3_DATA_CRC_OFF);
 }
 
-const struct xfs_buf_ops xfs_dir2_block_buf_ops = {
-	.verify_read = xfs_dir2_block_read_verify,
-	.verify_write = xfs_dir2_block_write_verify,
+const struct xfs_buf_ops xfs_dir3_block_buf_ops = {
+	.verify_read = xfs_dir3_block_read_verify,
+	.verify_write = xfs_dir3_block_write_verify,
 };
 
 static int
-xfs_dir2_block_read(
+xfs_dir3_block_read(
 	struct xfs_trans	*tp,
 	struct xfs_inode	*dp,
 	struct xfs_buf		**bpp)
@@ -101,7 +134,29 @@ xfs_dir2_block_read(
 	struct xfs_mount	*mp = dp->i_mount;
 
 	return xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, bpp,
-				XFS_DATA_FORK, &xfs_dir2_block_buf_ops);
+				XFS_DATA_FORK, &xfs_dir3_block_buf_ops);
+}
+
+static void
+xfs_dir3_block_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct xfs_inode	*dp)
+{
+	struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
+
+	bp->b_ops = &xfs_dir3_block_buf_ops;
+
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		memset(hdr3, 0, sizeof(*hdr3));
+		hdr3->magic = cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
+		hdr3->blkno = cpu_to_be64(bp->b_bn);
+		hdr3->owner = cpu_to_be64(dp->i_ino);
+		uuid_copy(&hdr3->uuid, &mp->m_sb.sb_uuid);
+		return;
+
+	}
+	hdr3->magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
 }
 
 static void
@@ -121,7 +176,7 @@ xfs_dir2_block_need_space(
 	struct xfs_dir2_data_unused	*enddup = NULL;
 
 	*compact = 0;
-	bf = hdr->bestfree;
+	bf = xfs_dir3_data_bestfree_p(hdr);
 
 	/*
 	 * If there are stale entries we'll use one for the leaf.
@@ -303,7 +358,7 @@ xfs_dir2_block_addname(
 	mp = dp->i_mount;
 
 	/* Read the (one and only) directory block into bp. */
-	error = xfs_dir2_block_read(tp, dp, &bp);
+	error = xfs_dir3_block_read(tp, dp, &bp);
 	if (error)
 		return error;
 
@@ -531,7 +586,7 @@ xfs_dir2_block_getdents(
 	if (xfs_dir2_dataptr_to_db(mp, *offset) > mp->m_dirdatablk)
 		return 0;
 
-	error = xfs_dir2_block_read(NULL, dp, &bp);
+	error = xfs_dir3_block_read(NULL, dp, &bp);
 	if (error)
 		return error;
 
@@ -546,7 +601,7 @@ xfs_dir2_block_getdents(
 	 * Set up values for the loop.
 	 */
 	btp = xfs_dir2_block_tail_p(mp, hdr);
-	ptr = (char *)(hdr + 1);
+	ptr = (char *)xfs_dir3_data_entry_p(hdr);
 	endptr = (char *)xfs_dir2_block_leaf_p(btp);
 
 	/*
@@ -711,7 +766,7 @@ xfs_dir2_block_lookup_int(
 	tp = args->trans;
 	mp = dp->i_mount;
 
-	error = xfs_dir2_block_read(tp, dp, &bp);
+	error = xfs_dir3_block_read(tp, dp, &bp);
 	if (error)
 		return error;
 
@@ -974,9 +1029,12 @@ xfs_dir2_leaf_to_block(
 	 * These will show up in the leaf bests table.
 	 */
 	while (dp->i_d.di_size > mp->m_dirblksize) {
+		int hdrsz;
+
+		hdrsz = xfs_dir3_data_hdr_size(xfs_sb_version_hascrc(&mp->m_sb));
 		bestsp = xfs_dir2_leaf_bests_p(ltp);
 		if (be16_to_cpu(bestsp[be32_to_cpu(ltp->bestcount) - 1]) ==
-		    mp->m_dirblksize - (uint)sizeof(*hdr)) {
+					    mp->m_dirblksize - hdrsz) {
 			if ((error =
 			    xfs_dir2_leaf_trim_data(args, lbp,
 				    (xfs_dir2_db_t)(be32_to_cpu(ltp->bestcount) - 1))))
@@ -1014,8 +1072,8 @@ xfs_dir2_leaf_to_block(
 	/*
 	 * Start converting it to block form.
 	 */
-	dbp->b_ops = &xfs_dir2_block_buf_ops;
-	hdr->magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
+	xfs_dir3_block_init(mp, dbp, dp);
+
 	needlog = 1;
 	needscan = 0;
 	/*
@@ -1137,16 +1195,16 @@ xfs_dir2_sf_to_block(
 		return error;
 	}
 	/*
-	 * Initialize the data block.
+	 * Initialize the data block, then convert it to block format.
 	 */
-	error = xfs_dir2_data_init(args, blkno, &bp);
+	error = xfs_dir3_data_init(args, blkno, &bp);
 	if (error) {
 		kmem_free(sfp);
 		return error;
 	}
-	bp->b_ops = &xfs_dir2_block_buf_ops;
+	xfs_dir3_block_init(mp, bp, dp);
 	hdr = bp->b_addr;
-	hdr->magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
+
 	/*
 	 * Compute size of block "tail" area.
 	 */
@@ -1156,7 +1214,7 @@ xfs_dir2_sf_to_block(
 	 * The whole thing is initialized to free by the init routine.
 	 * Say we're using the leaf and tail area.
 	 */
-	dup = (xfs_dir2_data_unused_t *)(hdr + 1);
+	dup = xfs_dir3_data_unused_p(hdr);
 	needlog = needscan = 0;
 	xfs_dir2_data_use_free(tp, bp, dup, mp->m_dirblksize - i, i, &needlog,
 		&needscan);
@@ -1178,8 +1236,7 @@ xfs_dir2_sf_to_block(
 	/*
 	 * Create entry for .
 	 */
-	dep = (xfs_dir2_data_entry_t *)
-	      ((char *)hdr + XFS_DIR2_DATA_DOT_OFFSET);
+	dep = xfs_dir3_data_dot_entry_p(hdr);
 	dep->inumber = cpu_to_be64(dp->i_ino);
 	dep->namelen = 1;
 	dep->name[0] = '.';
@@ -1192,8 +1249,7 @@ xfs_dir2_sf_to_block(
 	/*
 	 * Create entry for ..
 	 */
-	dep = (xfs_dir2_data_entry_t *)
-		((char *)hdr + XFS_DIR2_DATA_DOTDOT_OFFSET);
+	dep = xfs_dir3_data_dotdot_entry_p(hdr);
 	dep->inumber = cpu_to_be64(xfs_dir2_sf_get_parent_ino(sfp));
 	dep->namelen = 2;
 	dep->name[0] = dep->name[1] = '.';
@@ -1203,7 +1259,7 @@ xfs_dir2_sf_to_block(
 	blp[1].hashval = cpu_to_be32(xfs_dir_hash_dotdot);
 	blp[1].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
 				(char *)dep - (char *)hdr));
-	offset = XFS_DIR2_DATA_FIRST_OFFSET;
+	offset = xfs_dir3_data_first_offset(hdr);
 	/*
 	 * Loop over existing entries, stuff them in.
 	 */

fs/xfs/xfs_dir2_format.h

 /*
  * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2013 Red Hat, Inc.
  * All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or
@@ -35,6 +36,37 @@
 #define	XFS_DIR2_DATA_MAGIC	0x58443244	/* XD2D: multiblock dirs */
 #define	XFS_DIR2_FREE_MAGIC	0x58443246	/* XD2F: free index blocks */
 
+/*
+ * Directory Version 3 With CRCs.
+ *
+ * The tree formats are the same as for version 2 directories.  The difference
+ * is in the block header and dirent formats. In many cases the v3 structures
+ * use v2 definitions as they are no different and this makes code sharing much
+ * easier.
+ *
+ * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the
+ * format is v2 then they switch to the existing v2 code, or the format is v3
+ * they implement the v3 functionality. This means the existing dir2 is a mix of
+ * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called
+ * where there is a difference in the formats, otherwise the code is unchanged.
+ *
+ * Where it is possible, the code decides what to do based on the magic numbers
+ * in the blocks rather than feature bits in the superblock. This means the code
+ * is as independent of the external XFS code as possible as doesn't require
+ * passing struct xfs_mount pointers into places where it isn't really
+ * necessary.
+ *
+ * Version 3 includes:
+ *
+ *	- a larger block header for CRC and identification purposes and so the
+ *	offsets of all the structures inside the blocks are different.
+ *
+ *	- new magic numbers to be able to detect the v2/v3 types on the fly.
+ */
+
+#define	XFS_DIR3_BLOCK_MAGIC	0x58444233	/* XDB3: single block dirs */
+#define	XFS_DIR3_DATA_MAGIC	0x58444433	/* XDD3: multiblock dirs */
+
 /*
  * Byte offset in data block and shortform entry.
  */
@@ -225,6 +257,38 @@ typedef struct xfs_dir2_data_hdr {
 	xfs_dir2_data_free_t	bestfree[XFS_DIR2_DATA_FD_COUNT];
 } xfs_dir2_data_hdr_t;
 
+/*
+ * define a structure for all the verification fields we are adding to the
+ * directory block structures. This will be used in several structures.
+ * The magic number must be the first entry to align with all the dir2
+ * structures so we determine how to decode them just by the magic number.
+ */
+struct xfs_dir3_blk_hdr {
+	__be32			magic;	/* magic number */
+	__be32			crc;	/* CRC of block */
+	__be64			blkno;	/* first block of the buffer */
+	__be64			lsn;	/* sequence number of last write */
+	uuid_t			uuid;	/* filesystem we belong to */
+	__be64			owner;	/* inode that owns the block */
+};
+
+struct xfs_dir3_data_hdr {
+	struct xfs_dir3_blk_hdr	hdr;
+	xfs_dir2_data_free_t	best_free[XFS_DIR2_DATA_FD_COUNT];
+};
+
+#define XFS_DIR3_DATA_CRC_OFF  offsetof(struct xfs_dir3_data_hdr, hdr.crc)
+
+static inline struct xfs_dir2_data_free *
+xfs_dir3_data_bestfree_p(struct xfs_dir2_data_hdr *hdr)
+{
+	if (hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
+		struct xfs_dir3_data_hdr *hdr3 = (struct xfs_dir3_data_hdr *)hdr;
+		return hdr3->best_free;
+	}
+	return hdr->bestfree;
+}
+
 /*
  * Active entry in a data block.
  *
@@ -280,6 +344,85 @@ xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
 			be16_to_cpu(dup->length) - sizeof(__be16));
 }
 
+static inline struct xfs_dir2_data_unused *
+xfs_dir3_data_unused_p(struct xfs_dir2_data_hdr *hdr)
+{
+	if (hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
+		return (struct xfs_dir2_data_unused *)
+			((char *)hdr + sizeof(struct xfs_dir3_data_hdr));
+	}
+	return (struct xfs_dir2_data_unused *)
+		((char *)hdr + sizeof(struct xfs_dir2_data_hdr));
+}
+
+static inline size_t
+xfs_dir3_data_hdr_size(bool dir3)
+{
+	if (dir3)
+		return sizeof(struct xfs_dir3_data_hdr);
+	return sizeof(struct xfs_dir2_data_hdr);
+}
+
+static inline size_t
+xfs_dir3_data_entry_offset(struct xfs_dir2_data_hdr *hdr)
+{
+	bool dir3 = hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+		    hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
+	return xfs_dir3_data_hdr_size(dir3);
+}
+
+static inline struct xfs_dir2_data_entry *
+xfs_dir3_data_entry_p(struct xfs_dir2_data_hdr *hdr)
+{
+	return (struct xfs_dir2_data_entry *)
+		((char *)hdr + xfs_dir3_data_entry_offset(hdr));
+}
+
+/*
+ * Offsets of . and .. in data space (always block 0)
+ */
+static inline xfs_dir2_data_aoff_t
+xfs_dir3_data_dot_offset(struct xfs_dir2_data_hdr *hdr)
+{
+	return xfs_dir3_data_entry_offset(hdr);
+}
+
+static inline xfs_dir2_data_aoff_t
+xfs_dir3_data_dotdot_offset(struct xfs_dir2_data_hdr *hdr)
+{
+	return xfs_dir3_data_dot_offset(hdr) + xfs_dir2_data_entsize(1);
+}
+
+static inline xfs_dir2_data_aoff_t
+xfs_dir3_data_first_offset(struct xfs_dir2_data_hdr *hdr)
+{
+	return xfs_dir3_data_dotdot_offset(hdr) + xfs_dir2_data_entsize(2);
+}
+
+/*
+ * location of . and .. in data space (always block 0)
+ */
+static inline struct xfs_dir2_data_entry *
+xfs_dir3_data_dot_entry_p(struct xfs_dir2_data_hdr *hdr)
+{
+	return (struct xfs_dir2_data_entry *)
+		((char *)hdr + xfs_dir3_data_dot_offset(hdr));
+}
+
+static inline struct xfs_dir2_data_entry *
+xfs_dir3_data_dotdot_entry_p(struct xfs_dir2_data_hdr *hdr)
+{
+	return (struct xfs_dir2_data_entry *)
+		((char *)hdr + xfs_dir3_data_dotdot_offset(hdr));
+}
+
+static inline struct xfs_dir2_data_entry *
+xfs_dir3_data_first_entry_p(struct xfs_dir2_data_hdr *hdr)
+{
+	return (struct xfs_dir2_data_entry *)
+		((char *)hdr + xfs_dir3_data_first_offset(hdr));
+}
+
 /*
  * Leaf block structures.
  *

fs/xfs/xfs_dir2_leaf.c

@@ -149,6 +149,7 @@ xfs_dir2_block_to_leaf(
 	int			needlog;	/* need to log block header */
 	int			needscan;	/* need to rescan bestfree */
 	xfs_trans_t		*tp;		/* transaction pointer */
+	struct xfs_dir2_data_free	*bf;
 
 	trace_xfs_dir2_block_to_leaf(args);
 
@@ -177,6 +178,7 @@ xfs_dir2_block_to_leaf(
 	xfs_dir2_data_check(dp, dbp);
 	btp = xfs_dir2_block_tail_p(mp, hdr);
 	blp = xfs_dir2_block_leaf_p(btp);
+	bf = xfs_dir3_data_bestfree_p(hdr);
 	/*
 	 * Set the counts in the leaf header.
 	 */
@@ -212,7 +214,7 @@ xfs_dir2_block_to_leaf(
 	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
 	ltp->bestcount = cpu_to_be32(1);
 	bestsp = xfs_dir2_leaf_bests_p(ltp);
-	bestsp[0] =  hdr->bestfree[0].length;
+	bestsp[0] =  bf[0].length;
 	/*
 	 * Log the data header and leaf bests table.
 	 */
@@ -544,7 +546,7 @@ xfs_dir2_leaf_addname(
 		/*
 		 * Initialize the block.
 		 */
-		if ((error = xfs_dir2_data_init(args, use_block, &dbp))) {
+		if ((error = xfs_dir3_data_init(args, use_block, &dbp))) {
 			xfs_trans_brelse(tp, lbp);
 			return error;
 		}

fs/xfs/xfs_dir2_node.c

@@ -1588,7 +1588,7 @@ xfs_dir2_node_addname_int(
 		if (unlikely((error = xfs_dir2_grow_inode(args,
 							 XFS_DIR2_DATA_SPACE,
 							 &dbno)) ||
-		    (error = xfs_dir2_data_init(args, dbno, &dbp))))
+		    (error = xfs_dir3_data_init(args, dbno, &dbp))))
 			return error;
 
 		/*

fs/xfs/xfs_dir2_priv.h

@@ -30,7 +30,7 @@ extern int xfs_dir_cilookup_result(struct xfs_da_args *args,
 				const unsigned char *name, int len);
 
 /* xfs_dir2_block.c */
-extern const struct xfs_buf_ops xfs_dir2_block_buf_ops;
+extern const struct xfs_buf_ops xfs_dir3_block_buf_ops;
 
 extern int xfs_dir2_block_addname(struct xfs_da_args *args);
 extern int xfs_dir2_block_getdents(struct xfs_inode *dp, void *dirent,
@@ -61,7 +61,7 @@ xfs_dir2_data_freeinsert(struct xfs_dir2_data_hdr *hdr,
 		struct xfs_dir2_data_unused *dup, int *loghead);
 extern void xfs_dir2_data_freescan(struct xfs_mount *mp,
 		struct xfs_dir2_data_hdr *hdr, int *loghead);
-extern int xfs_dir2_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
+extern int xfs_dir3_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
 		struct xfs_buf **bpp);
 extern void xfs_dir2_data_log_entry(struct xfs_trans *tp, struct xfs_buf *bp,
 		struct xfs_dir2_data_entry *dep);

fs/xfs/xfs_dir2_sf.c

@@ -278,7 +278,7 @@ xfs_dir2_block_to_sf(
 	 * Set up to loop over the block's entries.
 	 */
 	btp = xfs_dir2_block_tail_p(mp, hdr);
-	ptr = (char *)(hdr + 1);
+	ptr = (char *)xfs_dir3_data_entry_p(hdr);
 	endptr = (char *)xfs_dir2_block_leaf_p(btp);
 	sfep = xfs_dir2_sf_firstentry(sfp);
 	/*