[GFS2] Make sentinel dirents compatible with gfs1

When deleting directory entries, we set the inum.no_addr to zero
in a dirent when its the first dirent in a block and thus cannot
be merged into the previous dirent as is the usual case. In gfs1,
inum.no_formal_ino was used instead.

This patch changes gfs2 to set both inum.no_addr and inum.no_formal_ino
to zero. It also changes the test from just looking at inum.no_addr to
look at both inum.no_addr and inum.no_formal_ino and a sentinel is
now considered to be a dirent in which _either_ (or both) of them
is set to zero.

This resolves Red Hat bugzillas: #215809, #211465

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 16 insertions, 10 deletions

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index a2923fb91bba..0fdcb7713cd9 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -340,10 +340,15 @@ fail:
         return (copied) ? copied : error;
 }
 
+static inline int gfs2_dirent_sentinel(const struct gfs2_dirent *dent)
+{
+        return dent->de_inum.no_addr == 0 || dent->de_inum.no_formal_ino == 0;
+}
+
 static inline int __gfs2_dirent_find(const struct gfs2_dirent *dent,
                                      const struct qstr *name, int ret)
 {
-        if (dent->de_inum.no_addr != 0 &&
+        if (!gfs2_dirent_sentinel(dent) &&
             be32_to_cpu(dent->de_hash) == name->hash &&
             be16_to_cpu(dent->de_name_len) == name->len &&
             memcmp(dent+1, name->name, name->len) == 0)
@@ -388,7 +393,7 @@ static int gfs2_dirent_find_space(const struct gfs2_dirent *dent,
         unsigned actual = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
         unsigned totlen = be16_to_cpu(dent->de_rec_len);
 
-        if (!dent->de_inum.no_addr)
+        if (gfs2_dirent_sentinel(dent))
                 actual = GFS2_DIRENT_SIZE(0);
         if (totlen - actual >= required)
                 return 1;
@@ -405,7 +410,7 @@ static int gfs2_dirent_gather(const struct gfs2_dirent *dent,
                               void *opaque)
 {
         struct dirent_gather *g = opaque;
-        if (dent->de_inum.no_addr) {
+        if (!gfs2_dirent_sentinel(dent)) {
                 g->pdent[g->offset++] = dent;
         }
         return 0;
@@ -433,10 +438,10 @@ static int gfs2_check_dirent(struct gfs2_dirent *dent, unsigned int offset,
         if (unlikely(offset + size > len))
                 goto error;
         msg = "zero inode number";
-        if (unlikely(!first && !dent->de_inum.no_addr))
+        if (unlikely(!first && gfs2_dirent_sentinel(dent)))
                 goto error;
         msg = "name length is greater than space in dirent";
-        if (dent->de_inum.no_addr &&
+        if (!gfs2_dirent_sentinel(dent) &&
             unlikely(sizeof(struct gfs2_dirent)+be16_to_cpu(dent->de_name_len) >
                      size))
                 goto error;
@@ -598,7 +603,7 @@ static int dirent_next(struct gfs2_inode *dip, struct buffer_head *bh,
                 return ret;
 
         /* Only the first dent could ever have de_inum.no_addr == 0 */
-        if (!tmp->de_inum.no_addr) {
+        if (gfs2_dirent_sentinel(tmp)) {
                 gfs2_consist_inode(dip);
                 return -EIO;
         }
@@ -621,7 +626,7 @@ static void dirent_del(struct gfs2_inode *dip, struct buffer_head *bh,
 {
         u16 cur_rec_len, prev_rec_len;
 
-        if (!cur->de_inum.no_addr) {
+        if (gfs2_dirent_sentinel(cur)) {
                 gfs2_consist_inode(dip);
                 return;
         }
@@ -633,7 +638,8 @@ static void dirent_del(struct gfs2_inode *dip, struct buffer_head *bh,
            out the inode number and return.  */
 
         if (!prev) {
-                cur->de_inum.no_addr = 0;       /* No endianess worries */
+                cur->de_inum.no_addr = 0;
+                cur->de_inum.no_formal_ino = 0;
                 return;
         }
 
@@ -664,7 +670,7 @@ static struct gfs2_dirent *gfs2_init_dirent(struct inode *inode,
         struct gfs2_dirent *ndent;
         unsigned offset = 0, totlen;
 
-        if (dent->de_inum.no_addr)
+        if (!gfs2_dirent_sentinel(dent))
                 offset = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
         totlen = be16_to_cpu(dent->de_rec_len);
         BUG_ON(offset + name->len > totlen);
@@ -1002,7 +1008,7 @@ static int dir_split_leaf(struct inode *inode, const struct qstr *name)
                 if (dirent_next(dip, obh, &next))
                         next = NULL;
 
-                if (dent->de_inum.no_addr &&
+                if (!gfs2_dirent_sentinel(dent) &&
                     be32_to_cpu(dent->de_hash) < divider) {
                         struct qstr str;
                         str.name = (char*)(dent+1);