ext2: Implement freezing
The only missing piece to make freezing work reliably with ext2 is to
stop iput() of unlinked inode from deleting the inode on frozen filesystem.
So add a necessary protection to ext2_evict_inode().
We also provide appropriate ->freeze_fs and ->unfreeze_fs functions.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 5df3d2d..15761e6 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -42,6 +42,8 @@
static int ext2_remount (struct super_block * sb, int * flags, char * data);
static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
static int ext2_sync_fs(struct super_block *sb, int wait);
+static int ext2_freeze(struct super_block *sb);
+static int ext2_unfreeze(struct super_block *sb);
void ext2_error(struct super_block *sb, const char *function,
const char *fmt, ...)
@@ -305,6 +307,8 @@
.evict_inode = ext2_evict_inode,
.put_super = ext2_put_super,
.sync_fs = ext2_sync_fs,
+ .freeze_fs = ext2_freeze,
+ .unfreeze_fs = ext2_unfreeze,
.statfs = ext2_statfs,
.remount_fs = ext2_remount,
.show_options = ext2_show_options,
@@ -1200,6 +1204,35 @@
return 0;
}
+static int ext2_freeze(struct super_block *sb)
+{
+ struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+ /*
+ * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
+ * because we have unattached inodes and thus filesystem is not fully
+ * consistent.
+ */
+ if (atomic_long_read(&sb->s_remove_count)) {
+ ext2_sync_fs(sb, 1);
+ return 0;
+ }
+ /* Set EXT2_FS_VALID flag */
+ spin_lock(&sbi->s_lock);
+ sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
+ spin_unlock(&sbi->s_lock);
+ ext2_sync_super(sb, sbi->s_es, 1);
+
+ return 0;
+}
+
+static int ext2_unfreeze(struct super_block *sb)
+{
+ /* Just write sb to clear EXT2_VALID_FS flag */
+ ext2_write_super(sb);
+
+ return 0;
+}
void ext2_write_super(struct super_block *sb)
{