[PATCH v2 5/7] xfs_db: print attribute remote value blocks

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

Teach xfs_db how to print the contents of xattr remote value blocks.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
v2: update manpage, fix some field placement and function naming problems
---
 db/attr.c         |   63 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 db/attr.h         |    1 +
 db/field.c        |    3 +++
 db/field.h        |    1 +
 man/man8/xfs_db.8 |   38 ++++++++++++++++++++++++++++++--
 5 files changed, 104 insertions(+), 2 deletions(-)

diff --git a/db/attr.c b/db/attr.c
index 23ffcd5..0284fd4 100644
--- a/db/attr.c
+++ b/db/attr.c
@@ -41,6 +41,10 @@ static int	attr_leaf_nvlist_offset(void *obj, int startoff, int idx);
 static int	attr_node_btree_count(void *obj, int startoff);
 static int	attr_node_hdr_count(void *obj, int startoff);
 
+static int	attr_remote_data_count(void *obj, int startoff);
+static int	attr3_remote_hdr_count(void *obj, int startoff);
+static int	attr3_remote_data_count(void *obj, int startoff);
+
 const field_t	attr_hfld[] = {
 	{ "", FLDT_ATTR, OI(0), C1, 0, TYP_NONE },
 	{ NULL }
@@ -53,6 +57,8 @@ const field_t	attr_flds[] = {
 	  FLD_COUNT, TYP_NONE },
 	{ "hdr", FLDT_ATTR_NODE_HDR, OI(NOFF(hdr)), attr_node_hdr_count,
 	  FLD_COUNT, TYP_NONE },
+	{ "data", FLDT_CHARNS, OI(0), attr_remote_data_count, FLD_COUNT,
+	  TYP_NONE },
 	{ "entries", FLDT_ATTR_LEAF_ENTRY, OI(LOFF(entries)),
 	  attr_leaf_entries_count, FLD_ARRAY|FLD_COUNT, TYP_NONE },
 	{ "btree", FLDT_ATTR_NODE_ENTRY, OI(NOFF(__btree)), attr_node_btree_count,
@@ -197,6 +203,35 @@ attr3_leaf_hdr_count(
 	return be16_to_cpu(leaf->hdr.info.hdr.magic) == XFS_ATTR3_LEAF_MAGIC;
 }
 
+static int
+attr_remote_data_count(
+	void				*obj,
+	int				startoff)
+{
+	if (attr_leaf_hdr_count(obj, startoff) == 0 &&
+	    attr_node_hdr_count(obj, startoff) == 0)
+		return mp->m_sb.sb_blocksize;
+	return 0;
+}
+
+static int
+attr3_remote_data_count(
+	void				*obj,
+	int				startoff)
+{
+	struct xfs_attr3_rmt_hdr	*hdr = obj;
+	size_t				buf_space;
+
+	ASSERT(startoff == 0);
+
+	if (hdr->rm_magic != cpu_to_be32(XFS_ATTR3_RMT_MAGIC))
+		return 0;
+	buf_space = XFS_ATTR3_RMT_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
+	if (be32_to_cpu(hdr->rm_bytes) > buf_space)
+		return buf_space;
+	return be32_to_cpu(hdr->rm_bytes);
+}
+
 typedef int (*attr_leaf_entry_walk_f)(struct xfs_attr_leafblock *,
 				      struct xfs_attr_leaf_entry *, int);
 static int
@@ -477,6 +512,17 @@ attr3_node_hdr_count(
 	return be16_to_cpu(node->hdr.info.hdr.magic) == XFS_DA3_NODE_MAGIC;
 }
 
+static int
+attr3_remote_hdr_count(
+	void			*obj,
+	int			startoff)
+{
+	struct xfs_attr3_rmt_hdr	*node = obj;
+
+	ASSERT(startoff == 0);
+	return be32_to_cpu(node->rm_magic) == XFS_ATTR3_RMT_MAGIC;
+}
+
 int
 attr_size(
 	void	*obj,
@@ -501,6 +547,10 @@ const field_t	attr3_flds[] = {
 	  FLD_COUNT, TYP_NONE },
 	{ "hdr", FLDT_ATTR3_NODE_HDR, OI(N3OFF(hdr)), attr3_node_hdr_count,
 	  FLD_COUNT, TYP_NONE },
+	{ "hdr", FLDT_ATTR3_REMOTE_HDR, OI(0), attr3_remote_hdr_count,
+	  FLD_COUNT, TYP_NONE },
+	{ "data", FLDT_CHARNS, OI(bitize(sizeof(struct xfs_attr3_rmt_hdr))),
+	  attr3_remote_data_count, FLD_COUNT, TYP_NONE },
 	{ "entries", FLDT_ATTR_LEAF_ENTRY, OI(L3OFF(entries)),
 	  attr3_leaf_entries_count, FLD_ARRAY|FLD_COUNT, TYP_NONE },
 	{ "btree", FLDT_ATTR_NODE_ENTRY, OI(N3OFF(__btree)),
@@ -543,6 +593,19 @@ const field_t	attr3_node_hdr_flds[] = {
 	{ NULL }
 };
 
+#define	RM3OFF(f)	bitize(offsetof(struct xfs_attr3_rmt_hdr, rm_ ## f))
+const struct field	attr3_remote_crc_flds[] = {
+	{ "magic", FLDT_UINT32X, OI(RM3OFF(magic)), C1, 0, TYP_NONE },
+	{ "offset", FLDT_UINT32D, OI(RM3OFF(offset)), C1, 0, TYP_NONE },
+	{ "bytes", FLDT_UINT32D, OI(RM3OFF(bytes)), C1, 0, TYP_NONE },
+	{ "crc", FLDT_CRC, OI(RM3OFF(crc)), C1, 0, TYP_NONE },
+	{ "uuid", FLDT_UUID, OI(RM3OFF(uuid)), C1, 0, TYP_NONE },
+	{ "owner", FLDT_INO, OI(RM3OFF(owner)), C1, 0, TYP_NONE },
+	{ "bno", FLDT_DFSBNO, OI(RM3OFF(blkno)), C1, 0, TYP_BMAPBTD },
+	{ "lsn", FLDT_UINT64X, OI(RM3OFF(lsn)), C1, 0, TYP_NONE },
+	{ NULL }
+};
+
 /*
  * Special read verifier for attribute buffers. Detect the magic number
  * appropriately and set the correct verifier and call it.
diff --git a/db/attr.h b/db/attr.h
index 21848c1..565d6d8 100644
--- a/db/attr.h
+++ b/db/attr.h
@@ -32,6 +32,7 @@ extern const field_t	attr3_leaf_hdr_flds[];
 extern const field_t	attr3_node_hdr_flds[];
 extern const field_t	attr3_blkinfo_flds[];
 extern const field_t	attr3_node_hdr_flds[];
+extern const field_t	attr3_remote_crc_flds[];
 
 extern int	attr_leaf_name_size(void *obj, int startoff, int idx);
 extern int	attr_size(void *obj, int startoff, int idx);
diff --git a/db/field.c b/db/field.c
index f1e5f35..ae4c805 100644
--- a/db/field.c
+++ b/db/field.c
@@ -99,6 +99,9 @@ const ftattr_t	ftattrtab[] = {
 	{ FLDT_ATTR3_NODE_HDR, "attr3_node_hdr", NULL,
 	  (char *)attr3_node_hdr_flds, SI(bitsz(struct xfs_da3_node_hdr)),
 	  0, NULL, attr3_node_hdr_flds },
+	{ FLDT_ATTR3_REMOTE_HDR, "attr3_remote_hdr", NULL,
+	  (char *)attr3_remote_crc_flds, attr_size, FTARG_SIZE, NULL,
+	  attr3_remote_crc_flds },
 
 	{ FLDT_BMAPBTA, "bmapbta", NULL, (char *)bmapbta_flds, btblock_size,
 	  FTARG_SIZE, NULL, bmapbta_flds },
diff --git a/db/field.h b/db/field.h
index d1a7095..a8df29b 100644
--- a/db/field.h
+++ b/db/field.h
@@ -47,6 +47,7 @@ typedef enum fldt	{
 	FLDT_ATTR3_BLKINFO,
 	FLDT_ATTR3_LEAF_HDR,
 	FLDT_ATTR3_NODE_HDR,
+	FLDT_ATTR3_REMOTE_HDR,
 
 	FLDT_BMAPBTA,
 	FLDT_BMAPBTA_CRC,
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index b3129f7..043985e 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -940,8 +940,7 @@ version 1 and version 2 directories, see type
 .B dir
 for a description. Leaf blocks can refer to "local" or "remote" attribute
 values. Local values are stored directly in the leaf block.
-Remote values are stored in an independent block in the attribute fork
-(with no structure). Leaf blocks contain the following fields:
+Leaf blocks contain the following fields:
 .RS 1.4i
 .PD 0
 .TP 1.2i
@@ -989,6 +988,41 @@ Fields present for local values:
 (fork block number of containing the value).
 .PD
 .RE
+.IP
+Remote values are stored in an independent block in the attribute fork.
+Prior to v5, value blocks had no structure, but in v5 they acquired a header
+structure with the following fields:
+.RS 1.4i
+.PD 0
+.TP 1.2i
+.B magic
+attr3 remote block magic number, 0x5841524d ('XARM').
+.TP
+.B offset
+Byte offset of this data block within the overall attribute value.
+.TP
+.B bytes
+Number of bytes stored in this block.
+.TP
+.B crc
+Checksum of the attribute block contents.
+.TP
+.B uuid
+Filesystem UUID.
+.TP
+.B owner
+Inode that owns this attribute value.
+.TP
+.B bno
+Block offset of this block within the inode's attribute fork.
+.TP
+.B lsn
+Log serial number of the last time this block was logged.
+.TP
+.B data
+The attribute value data.
+.PD
+.RE
 .TP
 .B bmapbt
 Files with many extents in their data or attribute fork will have the