xfs: iget for metadata inodes

Create a xfs_trans_metafile_iget function for metadata inodes to ensure
that when we try to iget a metadata file, the inode is allocated and its
file mode matches the metadata file type the caller expects.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 65 insertions, 0 deletions

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 383c24548202..aa645e357812 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -25,6 +25,9 @@
 #include "xfs_ag.h"
 #include "xfs_log_priv.h"
 #include "xfs_health.h"
+#include "xfs_da_format.h"
+#include "xfs_dir2.h"
+#include "xfs_metafile.h"
 
 #include <linux/iversion.h>
 
@@ -829,6 +832,68 @@ out_error_or_again:
 }
 
 /*
+ * Get a metadata inode.
+ *
+ * The metafile type must match the file mode exactly.
+ */
+int
+xfs_trans_metafile_iget(
+	struct xfs_trans	*tp,
+	xfs_ino_t		ino,
+	enum xfs_metafile_type	metafile_type,
+	struct xfs_inode	**ipp)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	struct xfs_inode	*ip;
+	umode_t			mode;
+	int			error;
+
+	error = xfs_iget(mp, tp, ino, 0, 0, &ip);
+	if (error == -EFSCORRUPTED)
+		goto whine;
+	if (error)
+		return error;
+
+	if (VFS_I(ip)->i_nlink == 0)
+		goto bad_rele;
+
+	if (metafile_type == XFS_METAFILE_DIR)
+		mode = S_IFDIR;
+	else
+		mode = S_IFREG;
+	if (inode_wrong_type(VFS_I(ip), mode))
+		goto bad_rele;
+
+	*ipp = ip;
+	return 0;
+bad_rele:
+	xfs_irele(ip);
+whine:
+	xfs_err(mp, "metadata inode 0x%llx is corrupt", ino);
+	return -EFSCORRUPTED;
+}
+
+/* Grab a metadata file if the caller doesn't already have a transaction. */
+int
+xfs_metafile_iget(
+	struct xfs_mount	*mp,
+	xfs_ino_t		ino,
+	enum xfs_metafile_type	metafile_type,
+	struct xfs_inode	**ipp)
+{
+	struct xfs_trans	*tp;
+	int			error;
+
+	error = xfs_trans_alloc_empty(mp, &tp);
+	if (error)
+		return error;
+
+	error = xfs_trans_metafile_iget(tp, ino, metafile_type, ipp);
+	xfs_trans_cancel(tp);
+	return error;
+}
+
+/*
  * Grab the inode for reclaim exclusively.
  *
  * We have found this inode via a lookup under RCU, so the inode may have