nilfs2: get rid of BUG_ON use in btree lookup routines

[safe/jmp/linux-2.6] / fs / nilfs2 / cpfile.c

diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
index cadd36b..3f5d5d0 100644 (file)
--- a/fs/nilfs2/cpfile.c
+++ b/fs/nilfs2/cpfile.c
@@ -295,10 +295,6 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
                return -EINVAL;
        }
 
-       /* cannot delete the latest checkpoint */
-       if (start == nilfs_mdt_cno(cpfile) - 1)
-               return -EPERM;
-
        down_write(&NILFS_MDT(cpfile)->mi_sem);
 
        ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
@@ -311,7 +307,7 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
                ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
                if (ret < 0) {
                        if (ret != -ENOENT)
-                               goto out_header;
+                               break;
                        /* skip hole */
                        ret = 0;
                        continue;
@@ -344,7 +340,7 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
                                        continue;
                                printk(KERN_ERR "%s: cannot delete block\n",
                                       __func__);
-                               goto out_header;
+                               break;
                        }
                }
 
@@ -362,7 +358,6 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
                kunmap_atomic(kaddr, KM_USER0);
        }
 
- out_header:
        brelse(header_bh);
 
  out_sem:
@@ -384,9 +379,10 @@ static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
 }
 
 static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
-                                         struct nilfs_cpinfo *ci, size_t nci)
+                                         void *buf, unsigned cisz, size_t nci)
 {
        struct nilfs_checkpoint *cp;
+       struct nilfs_cpinfo *ci = buf;
        struct buffer_head *bh;
        size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
        __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
@@ -410,17 +406,22 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
                kaddr = kmap_atomic(bh->b_page, KM_USER0);
                cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
                for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
-                       if (!nilfs_checkpoint_invalid(cp))
-                               nilfs_cpfile_checkpoint_to_cpinfo(
-                                       cpfile, cp, &ci[n++]);
+                       if (!nilfs_checkpoint_invalid(cp)) {
+                               nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
+                                                                 ci);
+                               ci = (void *)ci + cisz;
+                               n++;
+                       }
                }
                kunmap_atomic(kaddr, KM_USER0);
                brelse(bh);
        }
 
        ret = n;
-       if (n > 0)
-               *cnop = ci[n - 1].ci_cno + 1;
+       if (n > 0) {
+               ci = (void *)ci - cisz;
+               *cnop = ci->ci_cno + 1;
+       }
 
  out:
        up_read(&NILFS_MDT(cpfile)->mi_sem);
@@ -428,11 +429,12 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
 }
 
 static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
-                                         struct nilfs_cpinfo *ci, size_t nci)
+                                         void *buf, unsigned cisz, size_t nci)
 {
        struct buffer_head *bh;
        struct nilfs_cpfile_header *header;
        struct nilfs_checkpoint *cp;
+       struct nilfs_cpinfo *ci = buf;
        __u64 curr = *cnop, next;
        unsigned long curr_blkoff, next_blkoff;
        void *kaddr;
@@ -472,7 +474,9 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
                if (unlikely(nilfs_checkpoint_invalid(cp) ||
                             !nilfs_checkpoint_snapshot(cp)))
                        break;
-               nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n++]);
+               nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
+               ci = (void *)ci + cisz;
+               n++;
                next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
                if (next == 0)
                        break; /* reach end of the snapshot list */
@@ -511,13 +515,13 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
  */
 
 ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
-                               struct nilfs_cpinfo *ci, size_t nci)
+                               void *buf, unsigned cisz, size_t nci)
 {
        switch (mode) {
        case NILFS_CHECKPOINT:
-               return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, ci, nci);
+               return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
        case NILFS_SNAPSHOT:
-               return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, nci);
+               return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
        default:
                return -EINVAL;
        }
@@ -533,20 +537,14 @@ int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
        struct nilfs_cpinfo ci;
        __u64 tcno = cno;
        ssize_t nci;
-       int ret;
 
-       nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1);
+       nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
        if (nci < 0)
                return nci;
        else if (nci == 0 || ci.ci_cno != cno)
                return -ENOENT;
-
-       /* cannot delete the latest checkpoint nor snapshots */
-       ret = nilfs_cpinfo_snapshot(&ci);
-       if (ret < 0)
-               return ret;
-       else if (ret > 0 || cno == nilfs_mdt_cno(cpfile) - 1)
-               return -EPERM;
+       else if (nilfs_cpinfo_snapshot(&ci))
+               return -EBUSY;
 
        return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
 }
@@ -817,8 +815,10 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
        void *kaddr;
        int ret;
 
-       if (cno == 0)
-               return -ENOENT; /* checkpoint number 0 is invalid */
+       /* CP number is invalid if it's zero or larger than the
+       largest exist one.*/
+       if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
+               return -ENOENT;
        down_read(&NILFS_MDT(cpfile)->mi_sem);
 
        ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
@@ -826,7 +826,10 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
                goto out;
        kaddr = kmap_atomic(bh->b_page, KM_USER0);
        cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
-       ret = nilfs_checkpoint_snapshot(cp);
+       if (nilfs_checkpoint_invalid(cp))
+               ret = -ENOENT;
+       else
+               ret = nilfs_checkpoint_snapshot(cp);
        kunmap_atomic(kaddr, KM_USER0);
        brelse(bh);
 
@@ -868,7 +871,6 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
                 * exclusive with a new mount job.  Though it doesn't cover
                 * umount, it's enough for the purpose.
                 */
-               mutex_lock(&nilfs->ns_mount_mutex);
                if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {
                        /* Current implementation does not have to protect
                           plain read-only mounts since they are exclusive
@@ -877,7 +879,6 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
                        ret = -EBUSY;
                } else
                        ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
-               mutex_unlock(&nilfs->ns_mount_mutex);
                return ret;
        case NILFS_SNAPSHOT:
                return nilfs_cpfile_set_snapshot(cpfile, cno);