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nilfs2: see state of root dentry for mount check of snapshots

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After applied the patch that unified sb instances, root dentry of
snapshots can be left in dcache even after their trees are unmounted.

The orphan root dentry/inode keeps a root object, and this causes
false positive of nilfs_checkpoint_is_mounted function.

This resolves the issue by having nilfs_checkpoint_is_mounted test
whether the root dentry is busy or not.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Ryusuke Konishi 2010-09-13 11:16:34 +09:00
parent f1e89c86fd
commit 032dbb3b50
6 changed files with 53 additions and 37 deletions
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23
fs/nilfs2/cpfile.c
View File

@ -863,26 +863,19 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
*/
int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
{
struct the_nilfs *nilfs;
int ret;
nilfs = NILFS_MDT(cpfile)->mi_nilfs;
switch (mode) {
case NILFS_CHECKPOINT:
/*
* Check for protecting existing snapshot mounts:
* ns_mount_mutex is used to make this operation atomic and
* exclusive with a new mount job. Though it doesn't cover
* umount, it's enough for the purpose.
*/
if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {
/* Current implementation does not have to protect
plain read-only mounts since they are exclusive
with a read/write mount and are protected from the
cleaner. */
if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
/*
* Current implementation does not have to protect
* plain read-only mounts since they are exclusive
* with a read/write mount and are protected from the
* cleaner.
*/
ret = -EBUSY;
} else
else
ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
return ret;
case NILFS_SNAPSHOT:

10
fs/nilfs2/inode.c
View File

@ -506,6 +506,16 @@ static int nilfs_iget_set(struct inode *inode, void *opaque)
return 0;
}
struct inode *nilfs_ilookup(struct super_block *sb, struct nilfs_root *root,
unsigned long ino)
{
struct nilfs_iget_args args = {
.ino = ino, .root = root, .cno = 0, .for_gc = 0
};
return ilookup5(sb, ino, nilfs_iget_test, &args);
}
struct inode *nilfs_iget_locked(struct super_block *sb, struct nilfs_root *root,
unsigned long ino)
{

3
fs/nilfs2/nilfs.h
View File

@ -244,6 +244,8 @@ extern int nilfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
extern void nilfs_set_inode_flags(struct inode *);
extern int nilfs_read_inode_common(struct inode *, struct nilfs_inode *);
extern void nilfs_write_inode_common(struct inode *, struct nilfs_inode *, int);
struct inode *nilfs_ilookup(struct super_block *sb, struct nilfs_root *root,
unsigned long ino);
struct inode *nilfs_iget_locked(struct super_block *sb, struct nilfs_root *root,
unsigned long ino);
struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
@ -285,6 +287,7 @@ extern int nilfs_commit_super(struct nilfs_sb_info *, int);
extern int nilfs_cleanup_super(struct nilfs_sb_info *);
int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
struct nilfs_root **root);
int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno);
/* gcinode.c */
int nilfs_gccache_submit_read_data(struct inode *, sector_t, sector_t, __u64,

32
fs/nilfs2/super.c
View File

@ -833,6 +833,38 @@ static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
return nilfs_tree_was_touched(root_dentry);
}
int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
{
struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
struct nilfs_root *root;
struct inode *inode;
struct dentry *dentry;
int ret;
if (cno < 0 || cno > nilfs->ns_cno)
return false;
if (cno >= nilfs_last_cno(nilfs))
return true; /* protect recent checkpoints */
ret = false;
root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
if (root) {
inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
if (inode) {
dentry = d_find_alias(inode);
if (dentry) {
if (nilfs_tree_was_touched(dentry))
ret = nilfs_try_to_shrink_tree(dentry);
dput(dentry);
}
iput(inode);
}
nilfs_put_root(root);
}
return ret;
}
/**
* nilfs_fill_super() - initialize a super block instance
* @sb: super_block

21
fs/nilfs2/the_nilfs.c
View File

@ -769,24 +769,3 @@ void nilfs_put_root(struct nilfs_root *root)
kfree(root);
}
}
int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
int snapshot_mount)
{
struct nilfs_root *root;
int ret;
if (cno < 0 || cno > nilfs->ns_cno)
return false;
if (cno >= nilfs_last_cno(nilfs))
return true; /* protect recent checkpoints */
ret = false;
root = nilfs_lookup_root(nilfs, cno);
if (root) {
ret = true;
nilfs_put_root(root);
}
return ret;
}

1
fs/nilfs2/the_nilfs.h
View File

@ -242,7 +242,6 @@ struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
__u64 cno);
void nilfs_put_root(struct nilfs_root *root);
struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
int nilfs_near_disk_full(struct the_nilfs *);
void nilfs_fall_back_super_block(struct the_nilfs *);
void nilfs_swap_super_block(struct the_nilfs *);