nilfs2: fix improper return values of nilfs_get_cpinfo ioctl

[linux-2.6-omap-h63xx.git] / fs / nilfs2 / cpfile.c

diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
index a4c9550fd7740522ee9f03a4dc24d036f3b787ad..50dff147744f52491ca61d1d7a26f8095dbf6d24 100644 (file)
--- a/fs/nilfs2/cpfile.c
+++ b/fs/nilfs2/cpfile.c
@@ -431,7 +431,7 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
        __u64 curr = *cnop, next;
        unsigned long curr_blkoff, next_blkoff;
        void *kaddr;
-       int n, ret;
+       int n = 0, ret;
 
        down_read(&NILFS_MDT(cpfile)->mi_sem);
 
@@ -455,27 +455,33 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
 
        curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
        ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
-       if (ret < 0)
+       if (unlikely(ret < 0)) {
+               if (ret == -ENOENT)
+                       ret = 0; /* No snapshots (started from a hole block) */
                goto out;
+       }
        kaddr = kmap_atomic(bh->b_page, KM_USER0);
-       for (n = 0; n < nci; n++) {
-               cp = nilfs_cpfile_block_get_checkpoint(
-                       cpfile, curr, bh, kaddr);
-               nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n]);
-               next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
-               if (next == 0) {
-                       curr = ~(__u64)0; /* Terminator */
-                       n++;
+       while (n < nci) {
+               cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
+               curr = ~(__u64)0; /* Terminator */
+               if (unlikely(nilfs_checkpoint_invalid(cp) ||
+                            !nilfs_checkpoint_snapshot(cp)))
                        break;
-               }
+               nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n++]);
+               next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
+               if (next == 0)
+                       break; /* reach end of the snapshot list */
+
                next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
                if (curr_blkoff != next_blkoff) {
                        kunmap_atomic(kaddr, KM_USER0);
                        brelse(bh);
                        ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
                                                                0, &bh);
-                       if (ret < 0)
+                       if (unlikely(ret < 0)) {
+                               WARN_ON(ret == -ENOENT);
                                goto out;
+                       }
                        kaddr = kmap_atomic(bh->b_page, KM_USER0);
                }
                curr = next;