nilfs2: return EBUSY against delete request on snapshot

This helps userland programs like the rmcp command to distinguish
error codes returned against a checkpoint removal request.

Previously -EPERM was returned, and not discriminable from real
permission errors.  This also allows removal of the latest checkpoint
because the deletion leads to create a new checkpoint, and thus it's
harmless for the filesystem.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 2 insertions, 12 deletions

diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
index b5a8cd6b474f..4184c1c2992c 100644
--- 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);
@@ -542,20 +538,14 @@ 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, 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);
 }