1 files changed, 85 insertions, 5 deletions

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 79babeac9d75..424861fbf1bd 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -19,6 +19,7 @@
 #include "xfs_ialloc.h"
 #include "xfs_dir2.h"
 #include "xfs_health.h"
+#include "xfs_metafile.h"
 
 #include <linux/iversion.h>
 
@@ -209,12 +210,15 @@ xfs_inode_from_disk(
 	 * They will also be unconditionally written back to disk as v2 inodes.
 	 */
 	if (unlikely(from->di_version == 1)) {
-		set_nlink(inode, be16_to_cpu(from->di_onlink));
+		/* di_metatype used to be di_onlink */
+		set_nlink(inode, be16_to_cpu(from->di_metatype));
 		ip->i_projid = 0;
 	} else {
 		set_nlink(inode, be32_to_cpu(from->di_nlink));
 		ip->i_projid = (prid_t)be16_to_cpu(from->di_projid_hi) << 16 |
 					be16_to_cpu(from->di_projid_lo);
+		if (xfs_dinode_is_metadir(from))
+			ip->i_metatype = be16_to_cpu(from->di_metatype);
 	}
 
 	i_uid_write(inode, be32_to_cpu(from->di_uid));
@@ -315,7 +319,10 @@ xfs_inode_to_disk(
 	struct inode		*inode = VFS_I(ip);
 
 	to->di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
-	to->di_onlink = 0;
+	if (xfs_is_metadir_inode(ip))
+		to->di_metatype = cpu_to_be16(ip->i_metatype);
+	else
+		to->di_metatype = 0;
 
 	to->di_format = xfs_ifork_format(&ip->i_df);
 	to->di_uid = cpu_to_be32(i_uid_read(inode));
@@ -483,6 +490,69 @@ xfs_dinode_verify_nrext64(
 	return NULL;
 }
 
+/*
+ * Validate all the picky requirements we have for a file that claims to be
+ * filesystem metadata.
+ */
+xfs_failaddr_t
+xfs_dinode_verify_metadir(
+	struct xfs_mount	*mp,
+	struct xfs_dinode	*dip,
+	uint16_t		mode,
+	uint16_t		flags,
+	uint64_t		flags2)
+{
+	if (!xfs_has_metadir(mp))
+		return __this_address;
+
+	/* V5 filesystem only */
+	if (dip->di_version < 3)
+		return __this_address;
+
+	if (be16_to_cpu(dip->di_metatype) >= XFS_METAFILE_MAX)
+		return __this_address;
+
+	/* V3 inode fields that are always zero */
+	if ((flags2 & XFS_DIFLAG2_NREXT64) && dip->di_nrext64_pad)
+		return __this_address;
+	if (!(flags2 & XFS_DIFLAG2_NREXT64) && dip->di_flushiter)
+		return __this_address;
+
+	/* Metadata files can only be directories or regular files */
+	if (!S_ISDIR(mode) && !S_ISREG(mode))
+		return __this_address;
+
+	/* They must have zero access permissions */
+	if (mode & 0777)
+		return __this_address;
+
+	/* DMAPI event and state masks are zero */
+	if (dip->di_dmevmask || dip->di_dmstate)
+		return __this_address;
+
+	/*
+	 * User and group IDs must be zero.  The project ID is used for
+	 * grouping inodes.  Metadata inodes are never accounted to quotas.
+	 */
+	if (dip->di_uid || dip->di_gid)
+		return __this_address;
+
+	/* Mandatory inode flags must be set */
+	if (S_ISDIR(mode)) {
+		if ((flags & XFS_METADIR_DIFLAGS) != XFS_METADIR_DIFLAGS)
+			return __this_address;
+	} else {
+		if ((flags & XFS_METAFILE_DIFLAGS) != XFS_METAFILE_DIFLAGS)
+			return __this_address;
+	}
+
+	/* dax flags2 must not be set */
+	if (flags2 & XFS_DIFLAG2_DAX)
+		return __this_address;
+
+	return NULL;
+}
+
 xfs_failaddr_t
 xfs_dinode_verify(
 	struct xfs_mount	*mp,
@@ -523,8 +593,11 @@ xfs_dinode_verify(
 	 * di_nlink==0 on a V1 inode.  V2/3 inodes would get written out with
 	 * di_onlink==0, so we can check that.
 	 */
-	if (dip->di_version >= 2) {
-		if (dip->di_onlink)
+	if (dip->di_version == 2) {
+		if (dip->di_metatype)
+			return __this_address;
+	} else if (dip->di_version >= 3) {
+		if (!xfs_dinode_is_metadir(dip) && dip->di_metatype)
 			return __this_address;
 	}
 
@@ -546,7 +619,8 @@ xfs_dinode_verify(
 			if (dip->di_nlink)
 				return __this_address;
 		} else {
-			if (dip->di_onlink)
+			/* di_metatype used to be di_onlink */
+			if (dip->di_metatype)
 				return __this_address;
 		}
 	}
@@ -663,6 +737,12 @@ xfs_dinode_verify(
 	    !xfs_has_bigtime(mp))
 		return __this_address;
 
+	if (flags2 & XFS_DIFLAG2_METADATA) {
+		fa = xfs_dinode_verify_metadir(mp, dip, mode, flags, flags2);
+		if (fa)
+			return fa;
+	}
+
 	return NULL;
 }