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authorAl Viro <viro@zeniv.linux.org.uk>2014-10-12 22:16:02 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2014-11-19 13:01:19 -0500
commitb5ae6b15bd73e35b129408755a0804287a87e041 (patch)
treebc674dfb16177844acf90fed70320dd641fe77cd /fs
parentMerge branch 'for-gfs2' into for-next (diff)
downloadlinux-dev-b5ae6b15bd73e35b129408755a0804287a87e041.tar.xz
linux-dev-b5ae6b15bd73e35b129408755a0804287a87e041.zip
merge d_materialise_unique() into d_splice_alias()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
-rw-r--r--fs/dcache.c143
1 files changed, 35 insertions, 108 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index e605e90d0f0a..435991eada1e 100644
--- a/fs/dcache.c
+++ b/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);
+ if (unlikely(d_ancestor(new, dentry))) {
+ write_sequnlock(&rename_lock);
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);
+ 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);
- goto found;
+ 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);
- }
- 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);
+ __d_move(new, dentry, false);
+ write_sequnlock(&rename_lock);
+ spin_unlock(&inode->i_lock);
+ security_d_instantiate(new, inode);
}
- 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)
{