diff options
Diffstat (limited to 'fs/nilfs2/the_nilfs.c')
| -rw-r--r-- | fs/nilfs2/the_nilfs.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 45dbf6a6174..221953bfc85 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -664,6 +664,56 @@ int nilfs_near_disk_full(struct the_nilfs *nilfs) return ret; } +/** + * nilfs_find_sbinfo - find existing nilfs_sb_info structure + * @nilfs: nilfs object + * @rw_mount: mount type (non-zero value for read/write mount) + * @cno: checkpoint number (zero for read-only mount) + * + * nilfs_find_sbinfo() returns the nilfs_sb_info structure which + * @rw_mount and @cno (in case of snapshots) matched. If no instance + * was found, NULL is returned. Although the super block instance can + * be unmounted after this function returns, the nilfs_sb_info struct + * is kept on memory until nilfs_put_sbinfo() is called. + */ +struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *nilfs, + int rw_mount, __u64 cno) +{ + struct nilfs_sb_info *sbi; + + down_read(&nilfs->ns_sem); + /* + * The SNAPSHOT flag and sb->s_flags are supposed to be + * protected with nilfs->ns_sem. + */ + sbi = nilfs->ns_current; + if (rw_mount) { + if (sbi && !(sbi->s_super->s_flags & MS_RDONLY)) + goto found; /* read/write mount */ + else + goto out; + } else if (cno == 0) { + if (sbi && (sbi->s_super->s_flags & MS_RDONLY)) + goto found; /* read-only mount */ + else + goto out; + } + + list_for_each_entry(sbi, &nilfs->ns_supers, s_list) { + if (nilfs_test_opt(sbi, SNAPSHOT) && + sbi->s_snapshot_cno == cno) + goto found; /* snapshot mount */ + } + out: + up_read(&nilfs->ns_sem); + return NULL; + + found: + atomic_inc(&sbi->s_count); + up_read(&nilfs->ns_sem); + return sbi; +} + int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno, int snapshot_mount) { |