diff options
| -rw-r--r-- | fs/dcache.c | 143 | ||||
| -rw-r--r-- | include/linux/dcache.h | 2 |
2 files changed, 36 insertions, 109 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) { diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 1c2f1b84468b..ee569da27b72 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -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); |