[XFS] Fix CI lookup in leaf-form directories

Instead of comparing buffer pointers, compare buffer block numbers and
don't keep buff

SGI-PV: 983564

SGI-Modid: xfs-linux-melb:xfs-kern:31346a

Signed-off-by: Barry Naujok <bnaujok@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

1 files changed, 25 insertions, 24 deletions

diff --git a/fs/xfs/xfs_dir2_leaf.c b/fs/xfs/xfs_dir2_leaf.c
index f110242d6dfc..93535992cb60 100644
--- a/fs/xfs/xfs_dir2_leaf.c
+++ b/fs/xfs/xfs_dir2_leaf.c
@@ -1321,8 +1321,8 @@ xfs_dir2_leaf_lookup_int(
         int                     *indexp,        /* out: index in leaf block */
         xfs_dabuf_t             **dbpp)         /* out: data buffer */
 {
-        xfs_dir2_db_t           curdb;          /* current data block number */
-        xfs_dabuf_t             *dbp;           /* data buffer */
+        xfs_dir2_db_t           curdb = -1;     /* current data block number */
+        xfs_dabuf_t             *dbp = NULL;    /* data buffer */
         xfs_dir2_data_entry_t   *dep;           /* data entry */
         xfs_inode_t             *dp;            /* incore directory inode */
         int                     error;          /* error return code */
@@ -1333,7 +1333,7 @@ xfs_dir2_leaf_lookup_int(
         xfs_mount_t             *mp;            /* filesystem mount point */
         xfs_dir2_db_t           newdb;          /* new data block number */
         xfs_trans_t             *tp;            /* transaction pointer */
-        xfs_dabuf_t             *cbp;           /* case match data buffer */
+        xfs_dir2_db_t           cidb = -1;      /* case match data block no. */
         enum xfs_dacmp          cmp;            /* name compare result */
 
         dp = args->dp;
@@ -1342,11 +1342,10 @@ xfs_dir2_leaf_lookup_int(
         /*
          * Read the leaf block into the buffer.
          */
-        if ((error =
-            xfs_da_read_buf(tp, dp, mp->m_dirleafblk, -1, &lbp,
-                    XFS_DATA_FORK))) {
+        error = xfs_da_read_buf(tp, dp, mp->m_dirleafblk, -1, &lbp,
+                                                        XFS_DATA_FORK);
+        if (error)
                 return error;
-        }
         *lbpp = lbp;
         leaf = lbp->data;
         xfs_dir2_leaf_check(dp, lbp);
@@ -1358,9 +1357,7 @@ xfs_dir2_leaf_lookup_int(
          * Loop over all the entries with the right hash value
          * looking to match the name.
          */
-        cbp = NULL;
-        for (lep = &leaf->ents[index], dbp = NULL, curdb = -1;
-                                index < be16_to_cpu(leaf->hdr.count) &&
+        for (lep = &leaf->ents[index]; index < be16_to_cpu(leaf->hdr.count) &&
                                 be32_to_cpu(lep->hashval) == args->hashval;
                                 lep++, index++) {
                 /*
@@ -1377,7 +1374,7 @@ xfs_dir2_leaf_lookup_int(
                  * need to pitch the old one and read the new one.
                  */
                 if (newdb != curdb) {
-                        if (dbp != cbp)
+                        if (dbp)
                                 xfs_da_brelse(tp, dbp);
                         error = xfs_da_read_buf(tp, dp,
                                                 xfs_dir2_db_to_da(mp, newdb),
@@ -1403,35 +1400,39 @@ xfs_dir2_leaf_lookup_int(
                 if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
                         args->cmpresult = cmp;
                         *indexp = index;
-                        /*
-                         * case exact match: release the stored CI buffer if it
-                         * exists and return the current buffer.
-                         */
+                        /* case exact match: return the current buffer. */
                         if (cmp == XFS_CMP_EXACT) {
-                                if (cbp && cbp != dbp)
-                                        xfs_da_brelse(tp, cbp);
                                 *dbpp = dbp;
                                 return 0;
                         }
-                        cbp = dbp;
+                        cidb = curdb;
                 }
         }
         ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);
         /*
-         * Here, we can only be doing a lookup (not a rename or replace).
-         * If a case-insensitive match was found earlier, release the current
-         * buffer and return the stored CI matching buffer.
+         * Here, we can only be doing a lookup (not a rename or remove).
+         * If a case-insensitive match was found earlier, re-read the
+         * appropriate data block if required and return it.
          */
         if (args->cmpresult == XFS_CMP_CASE) {
-                if (cbp != dbp)
+                ASSERT(cidb != -1);
+                if (cidb != curdb) {
                         xfs_da_brelse(tp, dbp);
-                *dbpp = cbp;
+                        error = xfs_da_read_buf(tp, dp,
+                                                xfs_dir2_db_to_da(mp, cidb),
+                                                -1, &dbp, XFS_DATA_FORK);
+                        if (error) {
+                                xfs_da_brelse(tp, lbp);
+                                return error;
+                        }
+                }
+                *dbpp = dbp;
                 return 0;
         }
         /*
          * No match found, return ENOENT.
          */
-        ASSERT(cbp == NULL);
+        ASSERT(cidb == -1);
         if (dbp)
                 xfs_da_brelse(tp, dbp);
         xfs_da_brelse(tp, lbp);