1 files changed, 82 insertions, 60 deletions

diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index 9d884c127bb9..c7142a064c48 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -1203,6 +1203,63 @@ error0:
         return error;
 }
 
+STATIC int
+xfs_imap_lookup(
+        struct xfs_mount        *mp,
+        struct xfs_trans        *tp,
+        xfs_agnumber_t          agno,
+        xfs_agino_t             agino,
+        xfs_agblock_t           agbno,
+        xfs_agblock_t           *chunk_agbno,
+        xfs_agblock_t           *offset_agbno,
+        int                     flags)
+{
+        struct xfs_inobt_rec_incore rec;
+        struct xfs_btree_cur    *cur;
+        struct xfs_buf          *agbp;
+        xfs_agino_t             startino;
+        int                     error;
+        int                     i;
+
+        error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
+        if (error) {
+                xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
+                                "xfs_ialloc_read_agi() returned "
+                                "error %d, agno %d",
+                                error, agno);
+                return error;
+        }
+
+        /*
+         * derive and lookup the exact inode record for the given agino. If the
+         * record cannot be found, then it's an invalid inode number and we
+         * should abort.
+         */
+        cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
+        startino = agino & ~(XFS_IALLOC_INODES(mp) - 1);
+        error = xfs_inobt_lookup(cur, startino, XFS_LOOKUP_EQ, &i);
+        if (!error) {
+                if (i)
+                        error = xfs_inobt_get_rec(cur, &rec, &i);
+                if (!error && i == 0)
+                        error = EINVAL;
+        }
+
+        xfs_trans_brelse(tp, agbp);
+        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
+        if (error)
+                return error;
+
+        /* for untrusted inodes check it is allocated first */
+        if ((flags & XFS_IGET_UNTRUSTED) &&
+            (rec.ir_free & XFS_INOBT_MASK(agino - rec.ir_startino)))
+                return EINVAL;
+
+        *chunk_agbno = XFS_AGINO_TO_AGBNO(mp, rec.ir_startino);
+        *offset_agbno = agbno - *chunk_agbno;
+        return 0;
+}
+
 /*
  * Return the location of the inode in imap, for mapping it into a buffer.
  */
@@ -1235,8 +1292,11 @@ xfs_imap(
         if (agno >= mp->m_sb.sb_agcount || agbno >= mp->m_sb.sb_agblocks ||
             ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
 #ifdef DEBUG
-                /* no diagnostics for bulkstat, ino comes from userspace */
-                if (flags & XFS_IGET_BULKSTAT)
+                /*
+                 * Don't output diagnostic information for untrusted inodes
+                 * as they can be invalid without implying corruption.
+                 */
+                if (flags & XFS_IGET_UNTRUSTED)
                         return XFS_ERROR(EINVAL);
                 if (agno >= mp->m_sb.sb_agcount) {
                         xfs_fs_cmn_err(CE_ALERT, mp,
@@ -1263,6 +1323,23 @@ xfs_imap(
                 return XFS_ERROR(EINVAL);
         }
 
+        blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_blocklog;
+
+        /*
+         * For bulkstat and handle lookups, we have an untrusted inode number
+         * that we have to verify is valid. We cannot do this just by reading
+         * the inode buffer as it may have been unlinked and removed leaving
+         * inodes in stale state on disk. Hence we have to do a btree lookup
+         * in all cases where an untrusted inode number is passed.
+         */
+        if (flags & XFS_IGET_UNTRUSTED) {
+                error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
+                                        &chunk_agbno, &offset_agbno, flags);
+                if (error)
+                        return error;
+                goto out_map;
+        }
+
         /*
          * If the inode cluster size is the same as the blocksize or
          * smaller we get to the buffer by simple arithmetics.
@@ -1277,24 +1354,6 @@ xfs_imap(
                 return 0;
         }
 
-        blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_blocklog;
-
-        /*
-         * If we get a block number passed from bulkstat we can use it to
-         * find the buffer easily.
-         */
-        if (imap->im_blkno) {
-                offset = XFS_INO_TO_OFFSET(mp, ino);
-                ASSERT(offset < mp->m_sb.sb_inopblock);
-
-                cluster_agbno = xfs_daddr_to_agbno(mp, imap->im_blkno);
-                offset += (agbno - cluster_agbno) * mp->m_sb.sb_inopblock;
-
-                imap->im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
-                imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
-                return 0;
-        }
-
         /*
          * If the inode chunks are aligned then use simple maths to
          * find the location. Otherwise we have to do a btree
@@ -1304,50 +1363,13 @@ xfs_imap(
                 offset_agbno = agbno & mp->m_inoalign_mask;
                 chunk_agbno = agbno - offset_agbno;
         } else {
-                xfs_btree_cur_t *cur;   /* inode btree cursor */
-                xfs_inobt_rec_incore_t chunk_rec;
-                xfs_buf_t       *agbp;  /* agi buffer */
-                int             i;      /* temp state */
-
-                error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
-                if (error) {
-                        xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
-                                        "xfs_ialloc_read_agi() returned "
-                                        "error %d, agno %d",
-                                        error, agno);
-                        return error;
-                }
-
-                cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
-                error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i);
-                if (error) {
-                        xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
-                                        "xfs_inobt_lookup() failed");
-                        goto error0;
-                }
-
-                error = xfs_inobt_get_rec(cur, &chunk_rec, &i);
-                if (error) {
-                        xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
-                                        "xfs_inobt_get_rec() failed");
-                        goto error0;
-                }
-                if (i == 0) {
-#ifdef DEBUG
-                        xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
-                                        "xfs_inobt_get_rec() failed");
-#endif /* DEBUG */
-                        error = XFS_ERROR(EINVAL);
-                }
- error0:
-                xfs_trans_brelse(tp, agbp);
-                xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
+                error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
+                                        &chunk_agbno, &offset_agbno, flags);
                 if (error)
                         return error;
-                chunk_agbno = XFS_AGINO_TO_AGBNO(mp, chunk_rec.ir_startino);
-                offset_agbno = agbno - chunk_agbno;
         }
 
+out_map:
         ASSERT(agbno >= chunk_agbno);
         cluster_agbno = chunk_agbno +
                 ((offset_agbno / blks_per_cluster) * blks_per_cluster);