diff options
Diffstat (limited to 'fs/sync.c')
| -rw-r--r-- | fs/sync.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/fs/sync.c b/fs/sync.c index 4487b5560dc..89c37f732af 100644 --- a/fs/sync.c +++ b/fs/sync.c @@ -51,6 +51,18 @@ int sync_filesystem(struct super_block *sb) { int ret; + /* + * We need to be protected against the filesystem going from + * r/o to r/w or vice versa. + */ + WARN_ON(!rwsem_is_locked(&sb->s_umount)); + + /* + * No point in syncing out anything if the filesystem is read-only. + */ + if (sb->s_flags & MS_RDONLY) + return 0; + ret = __sync_filesystem(sb, 0); if (ret < 0) return ret; @@ -79,25 +91,22 @@ static void sync_filesystems(int wait) mutex_lock(&mutex); /* Could be down_interruptible */ spin_lock(&sb_lock); - list_for_each_entry(sb, &super_blocks, s_list) { - if (sb->s_flags & MS_RDONLY) - continue; + list_for_each_entry(sb, &super_blocks, s_list) sb->s_need_sync = 1; - } restart: list_for_each_entry(sb, &super_blocks, s_list) { if (!sb->s_need_sync) continue; sb->s_need_sync = 0; - if (sb->s_flags & MS_RDONLY) - continue; /* hm. Was remounted r/o meanwhile */ sb->s_count++; spin_unlock(&sb_lock); + down_read(&sb->s_umount); - if (sb->s_root) + if (!(sb->s_flags & MS_RDONLY) && sb->s_root) __sync_filesystem(sb, wait); up_read(&sb->s_umount); + /* restart only when sb is no longer on the list */ spin_lock(&sb_lock); if (__put_super_and_need_restart(sb)) |