[05/14] xfs: allow xattr matching on name and value for local/sf attrs

Commit Message

Darrick J. Wong Dec. 31, 2023, 8:46 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Add a new NVLOOKUP flag to signal that the caller wants to look up an
extended attribute by name and value.  This only works with shortform
and local attributes.  Only parent pointers need this functionality
and parent pointers cannot be remote xattrs, so this limitation is ok
for now.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 fs/xfs/libxfs/xfs_attr_leaf.c |   45 ++++++++++++++++++++++++++++++++++-------
 fs/xfs/libxfs/xfs_da_btree.h  |    4 +++-
 2 files changed, 40 insertions(+), 9 deletions(-)

Patch

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 3face870b4dac..f7a4839e93e3f 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -508,10 +508,12 @@  xfs_attr3_leaf_read(
  */
 static bool
 xfs_attr_match(
-	struct xfs_da_args	*args,
-	uint8_t			namelen,
-	unsigned char		*name,
-	int			flags)
+	const struct xfs_da_args	*args,
+	uint8_t				namelen,
+	const unsigned char		*name,
+	unsigned int			valuelen,
+	const void			*value,
+	int				flags)
 {
 
 	if (args->namelen != namelen)
@@ -519,6 +521,23 @@  xfs_attr_match(
 	if (memcmp(args->name, name, namelen) != 0)
 		return false;
 
+	if (args->op_flags & XFS_DA_OP_NVLOOKUP) {
+		if (args->valuelen != valuelen)
+			return false;
+		if (args->valuelen && !value) {
+			/* not implemented for remote values */
+			ASSERT(0);
+			return false;
+		}
+		if (valuelen && !args->value) {
+			/* caller gave us valuelen > 0 but no value?? */
+			ASSERT(0);
+			return false;
+		}
+		if (valuelen > 0 && memcmp(args->value, value, valuelen) != 0)
+			return false;
+	}
+
 	/* Recovery ignores the INCOMPLETE flag. */
 	if ((args->op_flags & XFS_DA_OP_RECOVERY) &&
 	    args->attr_filter == (flags & XFS_ATTR_NSP_ONDISK_MASK))
@@ -537,6 +556,10 @@  xfs_attr_copy_value(
 	unsigned char		*value,
 	int			valuelen)
 {
+	/* vlookups already supplied the attr value; don't copy anything */
+	if (args->op_flags & XFS_DA_OP_NVLOOKUP)
+		return 0;
+
 	/*
 	 * No copy if all we have to do is get the length
 	 */
@@ -761,6 +784,7 @@  xfs_attr_sf_findname(
 			     base += size, i++) {
 		size = xfs_attr_sf_entsize(sfe);
 		if (!xfs_attr_match(args, sfe->namelen, sfe->nameval,
+				    sfe->valuelen, &sfe->nameval[sfe->namelen],
 				    sfe->flags))
 			continue;
 		break;
@@ -929,6 +953,7 @@  xfs_attr_shortform_lookup(xfs_da_args_t *args)
 	for (i = 0; i < sf->hdr.count;
 				sfe = xfs_attr_sf_nextentry(sfe), i++) {
 		if (xfs_attr_match(args, sfe->namelen, sfe->nameval,
+				sfe->valuelen, &sfe->nameval[sfe->namelen],
 				sfe->flags))
 			return -EEXIST;
 	}
@@ -956,6 +981,7 @@  xfs_attr_shortform_getvalue(
 	for (i = 0; i < sf->hdr.count;
 				sfe = xfs_attr_sf_nextentry(sfe), i++) {
 		if (xfs_attr_match(args, sfe->namelen, sfe->nameval,
+				sfe->valuelen, &sfe->nameval[sfe->namelen],
 				sfe->flags))
 			return xfs_attr_copy_value(args,
 				&sfe->nameval[args->namelen], sfe->valuelen);
@@ -1008,7 +1034,7 @@  xfs_attr_shortform_to_leaf(
 	nargs.total = args->total;
 	nargs.whichfork = XFS_ATTR_FORK;
 	nargs.trans = args->trans;
-	nargs.op_flags = XFS_DA_OP_OKNOENT;
+	nargs.op_flags = XFS_DA_OP_OKNOENT | XFS_DA_OP_NVLOOKUP;
 	nargs.owner = args->owner;
 
 	sfe = &sf->list[0];
@@ -1212,7 +1238,7 @@  xfs_attr3_leaf_to_shortform(
 	nargs.total = args->total;
 	nargs.whichfork = XFS_ATTR_FORK;
 	nargs.trans = args->trans;
-	nargs.op_flags = XFS_DA_OP_OKNOENT;
+	nargs.op_flags = XFS_DA_OP_OKNOENT | XFS_DA_OP_NVLOOKUP;
 	nargs.owner = args->owner;
 
 	for (i = 0; i < ichdr.count; entry++, i++) {
@@ -2509,14 +2535,17 @@  xfs_attr3_leaf_lookup_int(
 		if (entry->flags & XFS_ATTR_LOCAL) {
 			name_loc = xfs_attr3_leaf_name_local(leaf, probe);
 			if (!xfs_attr_match(args, name_loc->namelen,
-					name_loc->nameval, entry->flags))
+					name_loc->nameval,
+					be16_to_cpu(name_loc->valuelen),
+					&name_loc->nameval[name_loc->namelen],
+					entry->flags))
 				continue;
 			args->index = probe;
 			return -EEXIST;
 		} else {
 			name_rmt = xfs_attr3_leaf_name_remote(leaf, probe);
 			if (!xfs_attr_match(args, name_rmt->namelen,
-					name_rmt->name, entry->flags))
+					name_rmt->name, 0, NULL, entry->flags))
 				continue;
 			args->index = probe;
 			args->rmtvaluelen = be32_to_cpu(name_rmt->valuelen);
diff --git a/fs/xfs/libxfs/xfs_da_btree.h b/fs/xfs/libxfs/xfs_da_btree.h
index 7a004786ee0a2..1bcb291150eb5 100644
--- a/fs/xfs/libxfs/xfs_da_btree.h
+++ b/fs/xfs/libxfs/xfs_da_btree.h
@@ -94,6 +94,7 @@  typedef struct xfs_da_args {
 #define XFS_DA_OP_REMOVE	(1u << 6) /* this is a remove operation */
 #define XFS_DA_OP_RECOVERY	(1u << 7) /* Log recovery operation */
 #define XFS_DA_OP_LOGGED	(1u << 8) /* Use intent items to track op */
+#define XFS_DA_OP_NVLOOKUP	(1u << 9) /* Match local attr on name+value */
 
 #define XFS_DA_OP_FLAGS \
 	{ XFS_DA_OP_JUSTCHECK,	"JUSTCHECK" }, \
@@ -104,7 +105,8 @@  typedef struct xfs_da_args {
 	{ XFS_DA_OP_NOTIME,	"NOTIME" }, \
 	{ XFS_DA_OP_REMOVE,	"REMOVE" }, \
 	{ XFS_DA_OP_RECOVERY,	"RECOVERY" }, \
-	{ XFS_DA_OP_LOGGED,	"LOGGED" }
+	{ XFS_DA_OP_LOGGED,	"LOGGED" }, \
+	{ XFS_DA_OP_NVLOOKUP,	"NVLOOKUP" }
 
 /*
  * Storage for holding state during Btree searches and split/join ops.