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ext2: Implement freezing

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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>
This commit is contained in:
Jan Kara 2012-06-12 16:20:46 +02:00 committed by Al Viro
parent b2b5ef5c8e
commit 1e8b212fe5
2 changed files with 37 additions and 1 deletions
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5
fs/ext2/inode.c
View file

@ -79,6 +79,7 @@ void ext2_evict_inode(struct inode * inode)
truncate_inode_pages(&inode->i_data, 0);
if (want_delete) {
sb_start_intwrite(inode->i_sb);
/* set dtime */
EXT2_I(inode)->i_dtime = get_seconds();
mark_inode_dirty(inode);
@ -98,8 +99,10 @@ void ext2_evict_inode(struct inode * inode)
if (unlikely(rsv))
kfree(rsv);
if (want_delete)
if (want_delete) {
ext2_free_inode(inode);
sb_end_intwrite(inode->i_sb);
}
}
typedef struct {

33
fs/ext2/super.c
View file

@ -42,6 +42,8 @@ static void ext2_sync_super(struct super_block *sb,
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 @@ static const struct super_operations ext2_sops = {
.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 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
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)
{