[2/7] mkfs: check root inode location

Commit Message

Darrick J. Wong Feb. 5, 2020, 12:46 a.m. UTC

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

Make sure the root inode gets created where repair thinks it should be
created.

Signed-off-by: Darrick J. Wong <[e-mail]>
Reviewed-by: Eric Sandeen <[e-mail]>
---
 libxfs/libxfs_api_defs.h |    1 +
 mkfs/xfs_mkfs.c          |   39 +++++++++++++++++++++++++++++++++------
 2 files changed, 34 insertions(+), 6 deletions(-)

Comments

Christoph Hellwig Feb. 17, 2020, 1:50 p.m. UTC | #1

On Tue, Feb 04, 2020 at 04:46:50PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <[e-mail]>
> 
> Make sure the root inode gets created where repair thinks it should be
> created.
> 
> Signed-off-by: Darrick J. Wong <[e-mail]>
> Reviewed-by: Eric Sandeen <[e-mail]>

Looks good,

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/libxfs/libxfs_api_defs.h b/libxfs/libxfs_api_defs.h
index 9daf2635..7c629c62 100644
--- a/libxfs/libxfs_api_defs.h
+++ b/libxfs/libxfs_api_defs.h
@@ -98,6 +98,7 @@ 
 #define xfs_fs_geometry			libxfs_fs_geometry
 #define xfs_highbit32			libxfs_highbit32
 #define xfs_highbit64			libxfs_highbit64
+#define xfs_ialloc_calc_rootino		libxfs_ialloc_calc_rootino
 #define xfs_idata_realloc		libxfs_idata_realloc
 #define xfs_idestroy_fork		libxfs_idestroy_fork
 #define xfs_iext_lookup_extent		libxfs_iext_lookup_extent
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 606f79da..cc71fd39 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -3549,6 +3549,38 @@  rewrite_secondary_superblocks(
 	libxfs_writebuf(buf, LIBXFS_EXIT_ON_FAILURE);
 }
 
+static void
+check_root_ino(
+	struct xfs_mount	*mp)
+{
+	xfs_ino_t		ino;
+
+	if (XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino) != 0) {
+		fprintf(stderr,
+			_("%s: root inode created in AG %u, not AG 0\n"),
+			progname, XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino));
+		exit(1);
+	}
+
+	/*
+	 * The superblock points to the root directory inode, but xfs_repair
+	 * expects to find the root inode in a very specific location computed
+	 * from the filesystem geometry for an extra level of verification.
+	 *
+	 * Fail the format immediately if those assumptions ever break, because
+	 * repair will toss the root directory.
+	 */
+	ino = libxfs_ialloc_calc_rootino(mp, mp->m_sb.sb_unit);
+	if (mp->m_sb.sb_rootino != ino) {
+		fprintf(stderr,
+	_("%s: root inode (%llu) not allocated in expected location (%llu)\n"),
+			progname,
+			(unsigned long long)mp->m_sb.sb_rootino,
+			(unsigned long long)ino);
+		exit(1);
+	}
+}
+
 int
 main(
 	int			argc,
@@ -3835,12 +3867,7 @@  main(
 	/*
 	 * Protect ourselves against possible stupidity
 	 */
-	if (XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino) != 0) {
-		fprintf(stderr,
-			_("%s: root inode created in AG %u, not AG 0\n"),
-			progname, XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino));
-		exit(1);
-	}
+	check_root_ino(mp);
 
 	/*
 	 * Re-write multiple secondary superblocks with rootinode field set