mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-24 04:34:08 +08:00
merge d_materialise_unique() into d_splice_alias()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
154e80e4c3
commit
b5ae6b15bd
145
fs/dcache.c
145
fs/dcache.c
@ -2575,11 +2575,11 @@ struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
|
||||
* Note: If ever the locking in lock_rename() changes, then please
|
||||
* remember to update this too...
|
||||
*/
|
||||
static struct dentry *__d_unalias(struct inode *inode,
|
||||
static int __d_unalias(struct inode *inode,
|
||||
struct dentry *dentry, struct dentry *alias)
|
||||
{
|
||||
struct mutex *m1 = NULL, *m2 = NULL;
|
||||
struct dentry *ret = ERR_PTR(-EBUSY);
|
||||
int ret = -EBUSY;
|
||||
|
||||
/* If alias and dentry share a parent, then no extra locks required */
|
||||
if (alias->d_parent == dentry->d_parent)
|
||||
@ -2594,7 +2594,7 @@ static struct dentry *__d_unalias(struct inode *inode,
|
||||
m2 = &alias->d_parent->d_inode->i_mutex;
|
||||
out_unalias:
|
||||
__d_move(alias, dentry, false);
|
||||
ret = alias;
|
||||
ret = 0;
|
||||
out_err:
|
||||
spin_unlock(&inode->i_lock);
|
||||
if (m2)
|
||||
@ -2629,130 +2629,57 @@ out_err:
|
||||
*/
|
||||
struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
|
||||
{
|
||||
struct dentry *new = NULL;
|
||||
|
||||
if (IS_ERR(inode))
|
||||
return ERR_CAST(inode);
|
||||
|
||||
if (inode && S_ISDIR(inode->i_mode)) {
|
||||
spin_lock(&inode->i_lock);
|
||||
new = __d_find_any_alias(inode);
|
||||
if (new) {
|
||||
if (!IS_ROOT(new)) {
|
||||
spin_unlock(&inode->i_lock);
|
||||
dput(new);
|
||||
iput(inode);
|
||||
return ERR_PTR(-EIO);
|
||||
}
|
||||
if (d_ancestor(new, dentry)) {
|
||||
spin_unlock(&inode->i_lock);
|
||||
dput(new);
|
||||
iput(inode);
|
||||
return ERR_PTR(-EIO);
|
||||
}
|
||||
write_seqlock(&rename_lock);
|
||||
__d_move(new, dentry, false);
|
||||
write_sequnlock(&rename_lock);
|
||||
spin_unlock(&inode->i_lock);
|
||||
security_d_instantiate(new, inode);
|
||||
iput(inode);
|
||||
} else {
|
||||
/* already taking inode->i_lock, so d_add() by hand */
|
||||
__d_instantiate(dentry, inode);
|
||||
spin_unlock(&inode->i_lock);
|
||||
security_d_instantiate(dentry, inode);
|
||||
d_rehash(dentry);
|
||||
}
|
||||
} else {
|
||||
d_instantiate(dentry, inode);
|
||||
if (d_unhashed(dentry))
|
||||
d_rehash(dentry);
|
||||
}
|
||||
return new;
|
||||
}
|
||||
EXPORT_SYMBOL(d_splice_alias);
|
||||
|
||||
/**
|
||||
* d_materialise_unique - introduce an inode into the tree
|
||||
* @dentry: candidate dentry
|
||||
* @inode: inode to bind to the dentry, to which aliases may be attached
|
||||
*
|
||||
* Introduces an dentry into the tree, substituting an extant disconnected
|
||||
* root directory alias in its place if there is one. Caller must hold the
|
||||
* i_mutex of the parent directory.
|
||||
*/
|
||||
struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
|
||||
{
|
||||
struct dentry *actual;
|
||||
|
||||
BUG_ON(!d_unhashed(dentry));
|
||||
|
||||
if (!inode) {
|
||||
actual = dentry;
|
||||
__d_instantiate(dentry, NULL);
|
||||
d_rehash(actual);
|
||||
goto out_nolock;
|
||||
goto out;
|
||||
}
|
||||
|
||||
spin_lock(&inode->i_lock);
|
||||
|
||||
if (S_ISDIR(inode->i_mode)) {
|
||||
struct dentry *alias;
|
||||
|
||||
/* Does an aliased dentry already exist? */
|
||||
alias = __d_find_alias(inode);
|
||||
if (alias) {
|
||||
actual = alias;
|
||||
struct dentry *new = __d_find_any_alias(inode);
|
||||
if (unlikely(new)) {
|
||||
write_seqlock(&rename_lock);
|
||||
|
||||
if (d_ancestor(alias, dentry)) {
|
||||
/* Check for loops */
|
||||
actual = ERR_PTR(-ELOOP);
|
||||
spin_unlock(&inode->i_lock);
|
||||
} else if (IS_ROOT(alias)) {
|
||||
/* Is this an anonymous mountpoint that we
|
||||
* could splice into our tree? */
|
||||
__d_move(alias, dentry, false);
|
||||
if (unlikely(d_ancestor(new, dentry))) {
|
||||
write_sequnlock(&rename_lock);
|
||||
goto found;
|
||||
spin_unlock(&inode->i_lock);
|
||||
dput(new);
|
||||
new = ERR_PTR(-ELOOP);
|
||||
pr_warn_ratelimited(
|
||||
"VFS: Lookup of '%s' in %s %s"
|
||||
" would have caused loop\n",
|
||||
dentry->d_name.name,
|
||||
inode->i_sb->s_type->name,
|
||||
inode->i_sb->s_id);
|
||||
} else if (!IS_ROOT(new)) {
|
||||
int err = __d_unalias(inode, dentry, new);
|
||||
write_sequnlock(&rename_lock);
|
||||
if (err) {
|
||||
dput(new);
|
||||
new = ERR_PTR(err);
|
||||
}
|
||||
} else {
|
||||
/* Nope, but we must(!) avoid directory
|
||||
* aliasing. This drops inode->i_lock */
|
||||
actual = __d_unalias(inode, dentry, alias);
|
||||
__d_move(new, dentry, false);
|
||||
write_sequnlock(&rename_lock);
|
||||
spin_unlock(&inode->i_lock);
|
||||
security_d_instantiate(new, inode);
|
||||
}
|
||||
write_sequnlock(&rename_lock);
|
||||
if (IS_ERR(actual)) {
|
||||
if (PTR_ERR(actual) == -ELOOP)
|
||||
pr_warn_ratelimited(
|
||||
"VFS: Lookup of '%s' in %s %s"
|
||||
" would have caused loop\n",
|
||||
dentry->d_name.name,
|
||||
inode->i_sb->s_type->name,
|
||||
inode->i_sb->s_id);
|
||||
dput(alias);
|
||||
}
|
||||
goto out_nolock;
|
||||
iput(inode);
|
||||
return new;
|
||||
}
|
||||
}
|
||||
|
||||
/* Add a unique reference */
|
||||
actual = __d_instantiate_unique(dentry, inode);
|
||||
if (!actual)
|
||||
actual = dentry;
|
||||
|
||||
d_rehash(actual);
|
||||
found:
|
||||
/* already taking inode->i_lock, so d_add() by hand */
|
||||
__d_instantiate(dentry, inode);
|
||||
spin_unlock(&inode->i_lock);
|
||||
out_nolock:
|
||||
if (actual == dentry) {
|
||||
security_d_instantiate(dentry, inode);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
iput(inode);
|
||||
return actual;
|
||||
out:
|
||||
security_d_instantiate(dentry, inode);
|
||||
d_rehash(dentry);
|
||||
return NULL;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(d_materialise_unique);
|
||||
EXPORT_SYMBOL(d_splice_alias);
|
||||
|
||||
static int prepend(char **buffer, int *buflen, const char *str, int namelen)
|
||||
{
|
||||
|
||||
@ -230,7 +230,7 @@ extern seqlock_t rename_lock;
|
||||
*/
|
||||
extern void d_instantiate(struct dentry *, struct inode *);
|
||||
extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
|
||||
extern struct dentry * d_materialise_unique(struct dentry *, struct inode *);
|
||||
#define d_materialise_unique(d, i) d_splice_alias(i, d)
|
||||
extern int d_instantiate_no_diralias(struct dentry *, struct inode *);
|
||||
extern void __d_drop(struct dentry *dentry);
|
||||
extern void d_drop(struct dentry *dentry);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user