xfs: create inode pointer verifiers

Create some helper functions to check that inode pointers point to
somewhere within the filesystem and not at the static AG metadata.
Move xfs_internal_inum and create a directory inode check function.
We will use these functions in scrub and elsewhere.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

5 files changed, 100 insertions, 28 deletions

diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
index ccf9783fd3f0..ee5e9160eb01 100644
--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -30,6 +30,7 @@
 #include "xfs_bmap.h"
 #include "xfs_dir2.h"
 #include "xfs_dir2_priv.h"
+#include "xfs_ialloc.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
 
@@ -202,22 +203,8 @@ xfs_dir_ino_validate(
         xfs_mount_t     *mp,
         xfs_ino_t       ino)
 {
-        xfs_agblock_t   agblkno;
-        xfs_agino_t     agino;
-        xfs_agnumber_t  agno;
-        int             ino_ok;
-        int             ioff;
-
-        agno = XFS_INO_TO_AGNO(mp, ino);
-        agblkno = XFS_INO_TO_AGBNO(mp, ino);
-        ioff = XFS_INO_TO_OFFSET(mp, ino);
-        agino = XFS_OFFBNO_TO_AGINO(mp, agblkno, ioff);
-        ino_ok =
-                agno < mp->m_sb.sb_agcount &&
-                agblkno < mp->m_sb.sb_agblocks &&
-                agblkno != 0 &&
-                ioff < (1 << mp->m_sb.sb_inopblog) &&
-                XFS_AGINO_TO_INO(mp, agno, agino) == ino;
+        bool            ino_ok = xfs_verify_dir_ino(mp, ino);
+
         if (unlikely(XFS_TEST_ERROR(!ino_ok, mp, XFS_ERRTAG_DIR_INO_VALIDATE))) {
                 xfs_warn(mp, "Invalid inode number 0x%Lx",
                                 (unsigned long long) ino);
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index dfd643909f85..e11f8af8a725 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -2664,3 +2664,93 @@ xfs_ialloc_pagi_init(
                 xfs_trans_brelse(tp, bp);
         return 0;
 }
+
+/* Calculate the first and last possible inode number in an AG. */
+void
+xfs_ialloc_agino_range(
+        struct xfs_mount        *mp,
+        xfs_agnumber_t          agno,
+        xfs_agino_t             *first,
+        xfs_agino_t             *last)
+{
+        xfs_agblock_t           bno;
+        xfs_agblock_t           eoag;
+
+        eoag = xfs_ag_block_count(mp, agno);
+
+        /*
+         * Calculate the first inode, which will be in the first
+         * cluster-aligned block after the AGFL.
+         */
+        bno = round_up(XFS_AGFL_BLOCK(mp) + 1,
+                        xfs_ialloc_cluster_alignment(mp));
+        *first = XFS_OFFBNO_TO_AGINO(mp, bno, 0);
+
+        /*
+         * Calculate the last inode, which will be at the end of the
+         * last (aligned) cluster that can be allocated in the AG.
+         */
+        bno = round_down(eoag, xfs_ialloc_cluster_alignment(mp));
+        *last = XFS_OFFBNO_TO_AGINO(mp, bno, 0) - 1;
+}
+
+/*
+ * Verify that an AG inode number pointer neither points outside the AG
+ * nor points at static metadata.
+ */
+bool
+xfs_verify_agino(
+        struct xfs_mount        *mp,
+        xfs_agnumber_t          agno,
+        xfs_agino_t             agino)
+{
+        xfs_agino_t             first;
+        xfs_agino_t             last;
+
+        xfs_ialloc_agino_range(mp, agno, &first, &last);
+        return agino >= first && agino <= last;
+}
+
+/*
+ * Verify that an FS inode number pointer neither points outside the
+ * filesystem nor points at static AG metadata.
+ */
+bool
+xfs_verify_ino(
+        struct xfs_mount        *mp,
+        xfs_ino_t               ino)
+{
+        xfs_agnumber_t          agno = XFS_INO_TO_AGNO(mp, ino);
+        xfs_agino_t             agino = XFS_INO_TO_AGINO(mp, ino);
+
+        if (agno >= mp->m_sb.sb_agcount)
+                return false;
+        if (XFS_AGINO_TO_INO(mp, agno, agino) != ino)
+                return false;
+        return xfs_verify_agino(mp, agno, agino);
+}
+
+/* Is this an internal inode number? */
+bool
+xfs_internal_inum(
+        struct xfs_mount        *mp,
+        xfs_ino_t               ino)
+{
+        return ino == mp->m_sb.sb_rbmino || ino == mp->m_sb.sb_rsumino ||
+                (xfs_sb_version_hasquota(&mp->m_sb) &&
+                 xfs_is_quota_inode(&mp->m_sb, ino));
+}
+
+/*
+ * Verify that a directory entry's inode number doesn't point at an internal
+ * inode, empty space, or static AG metadata.
+ */
+bool
+xfs_verify_dir_ino(
+        struct xfs_mount        *mp,
+        xfs_ino_t               ino)
+{
+        if (xfs_internal_inum(mp, ino))
+                return false;
+        return xfs_verify_ino(mp, ino);
+}
diff --git a/fs/xfs/libxfs/xfs_ialloc.h b/fs/xfs/libxfs/xfs_ialloc.h
index b32cfb5aeb5b..d2bdcd5e7312 100644
--- a/fs/xfs/libxfs/xfs_ialloc.h
+++ b/fs/xfs/libxfs/xfs_ialloc.h
@@ -173,5 +173,12 @@ void xfs_inobt_btrec_to_irec(struct xfs_mount *mp, union xfs_btree_rec *rec,
                 struct xfs_inobt_rec_incore *irec);
 
 int xfs_ialloc_cluster_alignment(struct xfs_mount *mp);
+void xfs_ialloc_agino_range(struct xfs_mount *mp, xfs_agnumber_t agno,
+                xfs_agino_t *first, xfs_agino_t *last);
+bool xfs_verify_agino(struct xfs_mount *mp, xfs_agnumber_t agno,
+                xfs_agino_t agino);
+bool xfs_verify_ino(struct xfs_mount *mp, xfs_ino_t ino);
+bool xfs_internal_inum(struct xfs_mount *mp, xfs_ino_t ino);
+bool xfs_verify_dir_ino(struct xfs_mount *mp, xfs_ino_t ino);
 
 #endif  /* __XFS_IALLOC_H__ */
diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index c393a2f6d8c3..0172d0b72c95 100644
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -31,16 +31,6 @@
 #include "xfs_trace.h"
 #include "xfs_icache.h"
 
-int
-xfs_internal_inum(
-        xfs_mount_t     *mp,
-        xfs_ino_t       ino)
-{
-        return (ino == mp->m_sb.sb_rbmino || ino == mp->m_sb.sb_rsumino ||
-                (xfs_sb_version_hasquota(&mp->m_sb) &&
-                 xfs_is_quota_inode(&mp->m_sb, ino)));
-}
-
 /*
  * Return stat information for one inode.
  * Return 0 if ok, else errno.
diff --git a/fs/xfs/xfs_itable.h b/fs/xfs/xfs_itable.h
index 17e86e0541af..6ea8b3912fa4 100644
--- a/fs/xfs/xfs_itable.h
+++ b/fs/xfs/xfs_itable.h
@@ -96,6 +96,4 @@ xfs_inumbers(
         void                    __user *buffer, /* buffer with inode info */
         inumbers_fmt_pf         formatter);
 
-int xfs_internal_inum(struct xfs_mount *mp, xfs_ino_t ino);
-
 #endif  /* __XFS_ITABLE_H__ */