1 files changed, 512 insertions, 4 deletions

diff --git a/fs/xfs/libxfs/xfs_imeta.c b/fs/xfs/libxfs/xfs_imeta.c
index ca62ef6255eb..59193eb834ee 100644
--- a/fs/xfs/libxfs/xfs_imeta.c
+++ b/fs/xfs/libxfs/xfs_imeta.c
@@ -21,6 +21,7 @@
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
 #include "xfs_trans_space.h"
+#include "xfs_dir2.h"
 
 /*
  * Metadata Inode Number Management
@@ -41,9 +42,16 @@
  * this structure must be passed to xfs_imeta_end_update to free resources that
  * cannot be freed during the transaction.
  *
- * Right now we only support callers passing in the predefined metadata inode
- * paths; the goal is that callers will some day locate metadata inodes based
- * on a metadata inode directory structure.
+ * When the metadata inode directory (metadir) feature is enabled, we can
+ * create a complex directory tree in which to store metadata inodes.  Inodes
+ * within the metadata directory tree should have the "metadata" inode flag set
+ * to prevent them from being exposed to the outside world.
+ *
+ * Within the metadata directory tree, we avoid taking the directory IOLOCK
+ * (like the VFS does for user directories) because we assume that the higher
+ * level XFS code already controls against concurrent updates of the
+ * corresponding part of the directory tree.  We do take metadata inodes' ILOCK
+ * during updates due to the locking requirements of the bmap code.
  */
 
 /* Static metadata inode paths */
@@ -59,6 +67,10 @@ XFS_IMETA_DEFINE_PATH(XFS_IMETA_USRQUOTA,	usrquota_path);
 XFS_IMETA_DEFINE_PATH(XFS_IMETA_GRPQUOTA,	grpquota_path);
 XFS_IMETA_DEFINE_PATH(XFS_IMETA_PRJQUOTA,	prjquota_path);
 
+const struct xfs_imeta_path XFS_IMETA_METADIR = {
+	.im_depth = 0,
+};
+
 /* Are these two paths equal? */
 STATIC bool
 xfs_imeta_path_compare(
@@ -116,6 +128,10 @@ static const struct xfs_imeta_sbmap {
 		.path	= &XFS_IMETA_PRJQUOTA,
 		.offset	= offsetof(struct xfs_sb, sb_pquotino),
 	},
+	{
+		.path	= &XFS_IMETA_METADIR,
+		.offset	= offsetof(struct xfs_sb, sb_metadirino),
+	},
 	{ NULL, 0 },
 };
 
@@ -246,6 +262,459 @@ xfs_imeta_sb_zap(
 	return 0;
 }
 
+/* Functions for storing and retrieving metadata directory inode values. */
+
+/*
+ * Given a parent directory @dp, a metadata inode @path and component
+ * @path_idx, and the expected file type @ftype of the path component, fill out
+ * the @xname and look up the inode number in the directory, returning it in
+ * @ino.
+ */
+static inline int
+xfs_imeta_dir_lookup_component(
+	struct xfs_inode		*dp,
+	const struct xfs_imeta_path	*path,
+	unsigned int			path_idx,
+	unsigned char			ftype,
+	struct xfs_name			*xname,
+	xfs_ino_t			*ino)
+{
+	int				error;
+
+	xname->name = (const unsigned char *)path->im_path[path_idx];
+	xname->len = strlen(path->im_path[path_idx]);
+	xname->type = ftype;
+
+	trace_xfs_imeta_dir_lookup_component(dp, xname);
+
+	error = xfs_dir_lookup(NULL, dp, xname, ino, NULL);
+	if (error)
+		return error;
+	if (!xfs_verify_ino(dp->i_mount, *ino))
+		return -EFSCORRUPTED;
+	return 0;
+}
+
+/*
+ * Traverse a metadata directory tree path, returning the inode corresponding
+ * to the parent of the last path component.  If any of the path components do
+ * not exist, return -ENOENT.
+ */
+STATIC int
+xfs_imeta_dir_parent(
+	struct xfs_mount		*mp,
+	const struct xfs_imeta_path	*path,
+	struct xfs_inode		**dpp)
+{
+	struct xfs_name			xname;
+	struct xfs_inode		*dp;
+	xfs_ino_t			ino;
+	unsigned int			i;
+	int				error;
+
+	if (mp->m_metadirip == NULL)
+		return -ENOENT;
+
+	/* Grab the metadir root. */
+	error = xfs_imeta_iget(mp, mp->m_metadirip->i_ino, XFS_DIR3_FT_DIR,
+			&dp);
+	if (error)
+		return error;
+
+	/* Caller wanted the root, we're done! */
+	if (path->im_depth == 0) {
+		*dpp = dp;
+		return 0;
+	}
+
+	for (i = 0; i < path->im_depth - 1; i++) {
+		/* Look up the name in the current directory. */
+		error = xfs_imeta_dir_lookup_component(dp, path, i,
+				XFS_DIR3_FT_DIR, &xname, &ino);
+		if (error)
+			goto out_rele;
+
+		/* Drop the existing dp and pick up the new one. */
+		xfs_imeta_irele(dp);
+		error = xfs_imeta_iget(mp, ino, XFS_DIR3_FT_DIR, &dp);
+		if (error)
+			goto out_rele;
+	}
+
+	*dpp = dp;
+	return 0;
+
+out_rele:
+	xfs_imeta_irele(dp);
+	return error;
+}
+
+/*
+ * Look up a metadata inode from the metadata inode directory.  If the last
+ * path component doesn't exist, return NULLFSINO.  If any other part of the
+ * path does not exist, return -ENOENT so we can distinguish the two.
+ */
+STATIC int
+xfs_imeta_dir_lookup_int(
+	struct xfs_mount		*mp,
+	const struct xfs_imeta_path	*path,
+	xfs_ino_t			*inop)
+{
+	struct xfs_name			xname;
+	struct xfs_inode		*dp = NULL;
+	xfs_ino_t			ino;
+	int				error;
+
+	/* metadir ino is recorded in superblock */
+	if (xfs_imeta_path_compare(path, &XFS_IMETA_METADIR))
+		return xfs_imeta_sb_lookup(mp, path, inop);
+
+	ASSERT(path->im_depth > 0);
+
+	/* Find the parent of the last path component. */
+	error = xfs_imeta_dir_parent(mp, path, &dp);
+	if (error)
+		return error;
+
+	/* Look up the name in the current directory. */
+	error = xfs_imeta_dir_lookup_component(dp, path, path->im_depth - 1,
+			XFS_DIR3_FT_UNKNOWN, &xname, &ino);
+	switch (error) {
+	case 0:
+		*inop = ino;
+		break;
+	case -ENOENT:
+		*inop = NULLFSINO;
+		error = 0;
+		break;
+	}
+
+	xfs_imeta_irele(dp);
+	return error;
+}
+
+/*
+ * Look up a metadata inode from the metadata inode directory.  If any of the
+ * middle path components do not exist, we consider this corruption because
+ * only the last component is allowed to not exist.
+ */
+STATIC int
+xfs_imeta_dir_lookup(
+	struct xfs_mount		*mp,
+	const struct xfs_imeta_path	*path,
+	xfs_ino_t			*inop)
+{
+	int				error;
+
+	error = xfs_imeta_dir_lookup_int(mp, path, inop);
+	if (error == -ENOENT)
+		return -EFSCORRUPTED;
+	return error;
+}
+
+/*
+ * Load all the metadata inode pointers that are cached in the in-core
+ * superblock but live somewhere in the metadata directory tree.
+ */
+STATIC int
+xfs_imeta_dir_mount(
+	struct xfs_mount		*mp)
+{
+	const struct xfs_imeta_sbmap	*p;
+	xfs_ino_t			*sb_inop;
+	int				err2;
+	int				error = 0;
+
+	for (p = xfs_imeta_sbmaps; p->path && p->path->im_depth > 0; p++) {
+		if (p->path == &XFS_IMETA_METADIR)
+			continue;
+		sb_inop = xfs_imeta_sbmap_to_inop(mp, p);
+		err2 = xfs_imeta_dir_lookup_int(mp, p->path, sb_inop);
+		if (err2 == -ENOENT) {
+			*sb_inop = NULLFSINO;
+			continue;
+		}
+		if (!error && err2)
+			error = err2;
+	}
+
+	return error;
+}
+
+/*
+ * Create a new metadata inode and a metadata directory entry to this new
+ * inode.  There must not already be a directory entry.
+ */
+STATIC int
+xfs_imeta_dir_create(
+	struct xfs_trans		**tpp,
+	const struct xfs_imeta_path	*path,
+	umode_t				mode,
+	struct xfs_inode		**ipp,
+	struct xfs_imeta_end		*cleanup)
+{
+	struct xfs_ialloc_args args = {
+		.nlink			= S_ISDIR(mode) ? 2 : 1,
+		.mode			= mode,
+	};
+	struct xfs_name			xname;
+	struct xfs_mount		*mp = (*tpp)->t_mountp;
+	struct xfs_inode		*dp = NULL;
+	xfs_ino_t			*sb_inop;
+	xfs_ino_t			ino;
+	unsigned int			resblks;
+	int				error;
+
+	/* metadir ino is recorded in superblock */
+	if (xfs_imeta_path_compare(path, &XFS_IMETA_METADIR)) {
+		error = xfs_imeta_sb_create(tpp, path, mode, ipp);
+		if (error)
+			return error;
+
+		/* Set the metadata iflag, initialize directory. */
+		(*ipp)->i_d.di_flags2 |= XFS_DIFLAG2_METADATA;
+		return xfs_dir_init(*tpp, *ipp, *ipp);
+	}
+
+	ASSERT(path->im_depth > 0);
+
+	/*
+	 * Find the parent of the last path component.  If the parent path does
+	 * not exist, we consider this corruption because paths are supposed
+	 * to exist.
+	 */
+	error = xfs_imeta_dir_parent(mp, path, &dp);
+	if (error == -ENOENT)
+		return -EFSCORRUPTED;
+	if (error)
+		return error;
+
+	/* Check that the name does not already exist in the directory. */
+	error = xfs_imeta_dir_lookup_component(dp, path, path->im_depth - 1,
+			XFS_DIR3_FT_UNKNOWN, &xname, &ino);
+	switch (error) {
+	case 0:
+		error = -EEXIST;
+		break;
+	case -ENOENT:
+		error = 0;
+		break;
+	}
+	if (error)
+		goto out_rele;
+
+	xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
+
+	/*
+	 * A newly created regular or special file just has one directory
+	 * entry pointing to them, but a directory also the "." entry
+	 * pointing to itself.
+	 */
+	args.pip = dp;
+	error = xfs_dir_ialloc(tpp, &args, ipp);
+	if (error)
+		goto out_ilock;
+
+	/* Set the metadata iflag */
+	(*ipp)->i_d.di_flags2 |= XFS_DIFLAG2_METADATA;
+	xfs_trans_log_inode(*tpp, *ipp, XFS_ILOG_CORE);
+
+	/*
+	 * Once we join the parent directory to the transaction we can't
+	 * release it until after the transaction commits or cancels, so we
+	 * must defer releasing it to end_update.  This is different from
+	 * regular file creation, where the vfs holds the parent dir reference
+	 * and will free it.  The caller is always responsible for releasing
+	 * ipp, even if we failed.
+	 */
+	xfs_trans_ijoin(*tpp, dp, XFS_ILOCK_EXCL);
+	cleanup->dp = dp;
+
+	/* Create the entry. */
+	if (S_ISDIR(args.mode))
+		resblks = XFS_MKDIR_SPACE_RES(mp, xname.len);
+	else
+		resblks = XFS_CREATE_SPACE_RES(mp, xname.len);
+	xname.type = xfs_mode_to_ftype(args.mode);
+	trace_xfs_imeta_dir_try_create(dp, &xname);
+	error = xfs_dir_create_new_child(*tpp, resblks, dp, &xname, *ipp);
+	if (error)
+		return error;
+	trace_xfs_imeta_dir_created(*ipp, &xname);
+
+	/* Update the in-core superblock value if there is one. */
+	sb_inop = xfs_imeta_path_to_sb_inop(mp, path);
+	if (sb_inop)
+		*sb_inop = (*ipp)->i_ino;
+	return 0;
+
+out_ilock:
+	xfs_iunlock(dp, XFS_ILOCK_EXCL);
+out_rele:
+	xfs_imeta_irele(dp);
+	return error;
+}
+
+/*
+ * Remove the given entry from the metadata directory and drop the link count
+ * of the metadata inode.
+ */
+STATIC int
+xfs_imeta_dir_unlink(
+	struct xfs_trans		**tpp,
+	const struct xfs_imeta_path	*path,
+	struct xfs_inode		*ip,
+	struct xfs_imeta_end		*cleanup)
+{
+	struct xfs_name			xname;
+	struct xfs_mount		*mp = (*tpp)->t_mountp;
+	struct xfs_inode		*dp = NULL;
+	xfs_ino_t			*sb_inop;
+	xfs_ino_t			ino;
+	unsigned int			resblks;
+	int				error;
+
+	/* metadir ino is recorded in superblock */
+	if (xfs_imeta_path_compare(path, &XFS_IMETA_METADIR))
+		return xfs_imeta_sb_unlink(tpp, path, ip);
+
+	ASSERT(path->im_depth > 0);
+
+	/*
+	 * Find the parent of the last path component.  If the parent path does
+	 * not exist, we consider this corruption because paths are supposed
+	 * to exist.
+	 */
+	error = xfs_imeta_dir_parent(mp, path, &dp);
+	if (error == -ENOENT)
+		return -EFSCORRUPTED;
+	if (error)
+		return error;
+
+	/* Look up the name in the current directory. */
+	error = xfs_imeta_dir_lookup_component(dp, path, path->im_depth - 1,
+			xfs_mode_to_ftype(VFS_I(ip)->i_mode), &xname, &ino);
+	switch (error) {
+	case 0:
+		if (ino != ip->i_ino)
+			error = -ENOENT;
+		break;
+	case -ENOENT:
+		error = -EFSCORRUPTED;
+		break;
+	}
+	if (error)
+		goto out_rele;
+
+	xfs_lock_two_inodes(dp, XFS_ILOCK_EXCL, ip, XFS_ILOCK_EXCL);
+
+	/*
+	 * Once we join the parent directory to the transaction we can't
+	 * release it until after the transaction commits or cancels, so we
+	 * must defer releasing it to end_update.  This is different from
+	 * regular file removal, where the vfs holds the parent dir reference
+	 * and will free it.  The unlink caller is always responsible for
+	 * releasing ip, so we don't need to take care of that.
+	 */
+	xfs_trans_ijoin(*tpp, dp, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(*tpp, ip, XFS_ILOCK_EXCL);
+	cleanup->dp = dp;
+
+	resblks = XFS_REMOVE_SPACE_RES(mp);
+	error = xfs_dir_remove_child(*tpp, resblks, dp, &xname, ip);
+	if (error)
+		return error;
+	trace_xfs_imeta_dir_unlinked(dp, &xname);
+
+	/* Update the in-core superblock value if there is one. */
+	sb_inop = xfs_imeta_path_to_sb_inop(mp, path);
+	if (sb_inop)
+		*sb_inop = NULLFSINO;
+	return 0;
+
+out_rele:
+	xfs_imeta_irele(dp);
+	return error;
+}
+
+/*
+ * Remove the given entry from the metadata directory, which effectively sets
+ * it to NULL.
+ */
+STATIC int
+xfs_imeta_dir_zap(
+	struct xfs_trans		**tpp,
+	const struct xfs_imeta_path	*path,
+	struct xfs_imeta_end		*cleanup)
+{
+	struct xfs_name			xname;
+	struct xfs_mount		*mp = (*tpp)->t_mountp;
+	struct xfs_inode		*dp = NULL;
+	xfs_ino_t			*sb_inop;
+	xfs_ino_t			ino;
+	unsigned int			resblks;
+	int				error;
+
+	/* metadir ino is recorded in superblock */
+	if (xfs_imeta_path_compare(path, &XFS_IMETA_METADIR))
+		return xfs_imeta_sb_zap(tpp, path);
+
+	ASSERT(path->im_depth > 0);
+
+	/*
+	 * Find the parent of the last path component.  If the parent path does
+	 * not exist, we consider this corruption because paths are supposed
+	 * to exist.
+	 */
+	error = xfs_imeta_dir_parent(mp, path, &dp);
+	if (error == -ENOENT)
+		return -EFSCORRUPTED;
+	if (error)
+		return error;
+
+	/* Look up the name in the current directory. */
+	error = xfs_imeta_dir_lookup_component(dp, path, path->im_depth - 1,
+			XFS_DIR3_FT_UNKNOWN, &xname, &ino);
+	switch (error) {
+	case 0:
+		break;
+	case -ENOENT:
+		error = 0;
+		/* fall through */
+	default:
+		goto out_rele;
+	}
+
+	xfs_ilock(dp, XFS_ILOCK_EXCL);
+
+	/*
+	 * Once we join the parent directory to the transaction we can't
+	 * release it until after the transaction commits or cancels, so we
+	 * must defer releasing it to end_update.  This is different from
+	 * regular file removal, where the vfs holds the parent dir reference
+	 * and will free it.  The unlink caller is always responsible for
+	 * releasing ip, so we don't need to take care of that.
+	 */
+	xfs_trans_ijoin(*tpp, dp, XFS_ILOCK_EXCL);
+	cleanup->dp = dp;
+
+	resblks = XFS_REMOVE_SPACE_RES(mp);
+	error = xfs_dir_removename(*tpp, dp, &xname, ino, resblks);
+	if (error)
+		return error;
+	trace_xfs_imeta_dir_zap(dp, &xname);
+
+	/* Update the in-core superblock value if there is one. */
+	sb_inop = xfs_imeta_path_to_sb_inop(mp, path);
+	if (sb_inop)
+		*sb_inop = NULLFSINO;
+	return 0;
+
+out_rele:
+	xfs_imeta_irele(dp);
+	return error;
+}
+
 /* General functions for managing metadata inode pointers */
 
 /*
@@ -275,7 +744,10 @@ xfs_imeta_lookup(
 
 	ASSERT(xfs_imeta_path_check(path));
 
-	error = xfs_imeta_sb_lookup(mp, path, &ino);
+	if (xfs_sb_version_hasmetadir(&mp->m_sb))
+		error = xfs_imeta_dir_lookup(mp, path, &ino);
+	else
+		error = xfs_imeta_sb_lookup(mp, path, &ino);
 	if (error)
 		return error;
 
@@ -305,9 +777,14 @@ xfs_imeta_create(
 	struct xfs_inode		**ipp,
 	struct xfs_imeta_end		*cleanup)
 {
+	struct xfs_mount		*mp = (*tpp)->t_mountp;
+
 	ASSERT(xfs_imeta_path_check(path));
 	*ipp = NULL;
+	cleanup->dp = NULL;
 
+	if (xfs_sb_version_hasmetadir(&mp->m_sb))
+		return xfs_imeta_dir_create(tpp, path, mode, ipp, cleanup);
 	return xfs_imeta_sb_create(tpp, path, mode, ipp);
 }
 
@@ -324,9 +801,14 @@ xfs_imeta_unlink(
 	struct xfs_inode		*ip,
 	struct xfs_imeta_end		*cleanup)
 {
+	struct xfs_mount		*mp = (*tpp)->t_mountp;
+	cleanup->dp = NULL;
+
 	ASSERT(xfs_imeta_path_check(path));
 	ASSERT(xfs_imeta_verify((*tpp)->t_mountp, ip->i_ino));
 
+	if (xfs_sb_version_hasmetadir(&mp->m_sb))
+		return xfs_imeta_dir_unlink(tpp, path, ip, cleanup);
 	return xfs_imeta_sb_unlink(tpp, path, ip);
 }
 
@@ -343,8 +825,13 @@ xfs_imeta_zap(
 	const struct xfs_imeta_path	*path,
 	struct xfs_imeta_end		*cleanup)
 {
+	struct xfs_mount		*mp = (*tpp)->t_mountp;
+	cleanup->dp = NULL;
+
 	ASSERT(xfs_imeta_path_check(path));
 
+	if (xfs_sb_version_hasmetadir(&mp->m_sb))
+		return xfs_imeta_dir_zap(tpp, path, cleanup);
 	return xfs_imeta_sb_zap(tpp, path);
 }
 
@@ -359,6 +846,10 @@ xfs_imeta_end_update(
 	int				error)
 {
 	trace_xfs_imeta_end_update(mp, 0, error, _RET_IP_);
+
+	if (cleanup->dp)
+		xfs_imeta_irele(cleanup->dp);
+	cleanup->dp = NULL;
 }
 
 /* Does this inode number refer to a static metadata inode? */
@@ -384,6 +875,9 @@ int
 xfs_imeta_mount(
 	struct xfs_mount	*mp)
 {
+	if (xfs_sb_version_hasmetadir(&mp->m_sb))
+		return xfs_imeta_dir_mount(mp);
+
 	return 0;
 }
 
@@ -392,6 +886,9 @@ unsigned int
 xfs_imeta_create_space_res(
 	struct xfs_mount	*mp)
 {
+	if (xfs_sb_version_hasmetadir(&mp->m_sb))
+		return max(XFS_MKDIR_SPACE_RES(mp, NAME_MAX),
+			   XFS_CREATE_SPACE_RES(mp, NAME_MAX));
 	return XFS_IALLOC_SPACE_RES(mp);
 }
 
@@ -402,3 +899,14 @@ xfs_imeta_unlink_space_res(
 {
 	return XFS_REMOVE_SPACE_RES(mp);
 }
+
+/* Clear the metadata iflag if we're unlinking this inode. */
+void
+xfs_imeta_droplink(
+	struct xfs_inode	*ip)
+{
+	if (VFS_I(ip)->i_nlink == 0 &&
+	    xfs_sb_version_hasmetadir(&ip->i_mount->m_sb) &&
+	    xfs_is_metadata_inode(ip))
+		ip->i_d.di_flags2 &= ~XFS_DIFLAG2_METADATA;
+}