nilfs2: fix gc failure on volumes keeping numerous snapshots

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

diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
index 82462acd06eecb22ccd94353f0d8beab12a2a6b8..a4c9550fd7740522ee9f03a4dc24d036f3b787ad 100644 (file)
--- a/fs/nilfs2/cpfile.c
+++ b/fs/nilfs2/cpfile.c
@@ -422,20 +422,20 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 cno,
        return ret;
 }
 
-static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 cno,
+static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
                                          struct nilfs_cpinfo *ci, size_t nci)
 {
        struct buffer_head *bh;
        struct nilfs_cpfile_header *header;
        struct nilfs_checkpoint *cp;
-       __u64 curr, next;
+       __u64 curr = *cnop, next;
        unsigned long curr_blkoff, next_blkoff;
        void *kaddr;
        int n, ret;
 
        down_read(&NILFS_MDT(cpfile)->mi_sem);
 
-       if (cno == 0) {
+       if (curr == 0) {
                ret = nilfs_cpfile_get_header_block(cpfile, &bh);
                if (ret < 0)
                        goto out;
@@ -448,8 +448,11 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 cno,
                        ret = 0;
                        goto out;
                }
-       } else
-               curr = cno;
+       } else if (unlikely(curr == ~(__u64)0)) {
+               ret = 0;
+               goto out;
+       }
+
        curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
        ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
        if (ret < 0)
@@ -461,7 +464,7 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 cno,
                nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n]);
                next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
                if (next == 0) {
-                       curr = next;
+                       curr = ~(__u64)0; /* Terminator */
                        n++;
                        break;
                }
@@ -480,6 +483,7 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 cno,
        }
        kunmap_atomic(kaddr, KM_USER0);
        brelse(bh);
+       *cnop = curr;
        ret = n;
 
  out:
@@ -494,15 +498,15 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 cno,
  * @ci:
  * @nci:
  */
-ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile,
-                               __u64 cno, int mode,
+
+ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
                                struct nilfs_cpinfo *ci, size_t nci)
 {
        switch (mode) {
        case NILFS_CHECKPOINT:
-               return nilfs_cpfile_do_get_cpinfo(cpfile, cno, ci, nci);
+               return nilfs_cpfile_do_get_cpinfo(cpfile, *cnop, ci, nci);
        case NILFS_SNAPSHOT:
-               return nilfs_cpfile_do_get_ssinfo(cpfile, cno, ci, nci);
+               return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, nci);
        default:
                return -EINVAL;
        }