1 files changed, 33 insertions, 5 deletions

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 82a1ac7895a2..a96fa07b3f3b 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -1262,9 +1262,10 @@ static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
                               u64 leaf_no)
 {
         struct gfs2_inode *ip = GFS2_I(inode);
+        struct gfs2_sbd *sdp = GFS2_SB(inode);
         struct buffer_head *bh;
         struct gfs2_leaf *lf;
-        unsigned entries = 0;
+        unsigned entries = 0, entries2 = 0;
         unsigned leaves = 0;
         const struct gfs2_dirent **darr, *dent;
         struct dirent_gather g;
@@ -1290,7 +1291,13 @@ static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
                 return 0;
 
         error = -ENOMEM;
-        larr = vmalloc((leaves + entries) * sizeof(void *));
+        /*
+         * The extra 99 entries are not normally used, but are a buffer
+         * zone in case the number of entries in the leaf is corrupt.
+         * 99 is the maximum number of entries that can fit in a single
+         * leaf block.
+         */
+        larr = vmalloc((leaves + entries + 99) * sizeof(void *));
         if (!larr)
                 goto out;
         darr = (const struct gfs2_dirent **)(larr + leaves);
@@ -1305,10 +1312,20 @@ static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
                 lf = (struct gfs2_leaf *)bh->b_data;
                 lfn = be64_to_cpu(lf->lf_next);
                 if (lf->lf_entries) {
+                        entries2 += be16_to_cpu(lf->lf_entries);
                         dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
                                                 gfs2_dirent_gather, NULL, &g);
                         error = PTR_ERR(dent);
-                        if (IS_ERR(dent)) {
+                        if (IS_ERR(dent))
+                                goto out_kfree;
+                        if (entries2 != g.offset) {
+                                fs_warn(sdp, "Number of entries corrupt in dir "
+                                                "leaf %llu, entries2 (%u) != "
+                                                "g.offset (%u)\n",
+                                        (unsigned long long)bh->b_blocknr,
+                                        entries2, g.offset);
+                                        
+                                error = -EIO;
                                 goto out_kfree;
                         }
                         error = 0;
@@ -1318,6 +1335,7 @@ static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
                 }
         } while(lfn);
 
+        BUG_ON(entries2 != entries);
         error = do_filldir_main(ip, offset, opaque, filldir, darr,
                                 entries, copied);
 out_kfree:
@@ -1401,6 +1419,7 @@ int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
                   filldir_t filldir)
 {
         struct gfs2_inode *dip = GFS2_I(inode);
+        struct gfs2_sbd *sdp = GFS2_SB(inode);
         struct dirent_gather g;
         const struct gfs2_dirent **darr, *dent;
         struct buffer_head *dibh;
@@ -1423,8 +1442,8 @@ int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
                 return error;
 
         error = -ENOMEM;
-        darr = kmalloc(dip->i_di.di_entries * sizeof(struct gfs2_dirent *),
-                       GFP_KERNEL);
+        /* 96 is max number of dirents which can be stuffed into an inode */
+        darr = kmalloc(96 * sizeof(struct gfs2_dirent *), GFP_KERNEL);
         if (darr) {
                 g.pdent = darr;
                 g.offset = 0;
@@ -1434,6 +1453,15 @@ int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
                         error = PTR_ERR(dent);
                         goto out;
                 }
+                if (dip->i_di.di_entries != g.offset) {
+                        fs_warn(sdp, "Number of entries corrupt in dir %llu, "
+                                "ip->i_di.di_entries (%u) != g.offset (%u)\n",
+                                (unsigned long long)dip->i_num.no_addr,
+                                dip->i_di.di_entries,
+                                g.offset);
+                        error = -EIO;
+                        goto out;
+                }
                 error = do_filldir_main(dip, offset, opaque, filldir, darr,
                                         dip->i_di.di_entries, &copied);
 out: