diff options
| -rw-r--r-- | fs/dcache.c | 125 | ||||
| -rw-r--r-- | fs/nfs/nfs4proc.c | 13 | ||||
| -rw-r--r-- | include/linux/dcache.h | 18 |
3 files changed, 58 insertions, 98 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 2398f9f94337..4d20bf5c609b 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1782,81 +1782,6 @@ void d_instantiate(struct dentry *entry, struct inode * inode) EXPORT_SYMBOL(d_instantiate); /** - * d_instantiate_unique - instantiate a non-aliased dentry - * @entry: dentry to instantiate - * @inode: inode to attach to this dentry - * - * Fill in inode information in the entry. On success, it returns NULL. - * If an unhashed alias of "entry" already exists, then we return the - * aliased dentry instead and drop one reference to inode. - * - * Note that in order to avoid conflicts with rename() etc, the caller - * had better be holding the parent directory semaphore. - * - * This also assumes that the inode count has been incremented - * (or otherwise set) by the caller to indicate that it is now - * in use by the dcache. - */ -static struct dentry *__d_instantiate_unique(struct dentry *entry, - struct inode *inode) -{ - struct dentry *alias; - int len = entry->d_name.len; - const char *name = entry->d_name.name; - unsigned int hash = entry->d_name.hash; - - if (!inode) { - __d_instantiate(entry, NULL); - return NULL; - } - - hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { - /* - * Don't need alias->d_lock here, because aliases with - * d_parent == entry->d_parent are not subject to name or - * parent changes, because the parent inode i_mutex is held. - */ - if (alias->d_name.hash != hash) - continue; - if (alias->d_parent != entry->d_parent) - continue; - if (alias->d_name.len != len) - continue; - if (dentry_cmp(alias, name, len)) - continue; - __dget(alias); - return alias; - } - - __d_instantiate(entry, inode); - return NULL; -} - -struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) -{ - struct dentry *result; - - BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); - - if (inode) - spin_lock(&inode->i_lock); - result = __d_instantiate_unique(entry, inode); - if (inode) - spin_unlock(&inode->i_lock); - - if (!result) { - security_d_instantiate(entry, inode); - return NULL; - } - - BUG_ON(!d_unhashed(result)); - iput(inode); - return result; -} - -EXPORT_SYMBOL(d_instantiate_unique); - -/** * d_instantiate_no_diralias - instantiate a non-aliased dentry * @entry: dentry to complete * @inode: inode to attach to this dentry @@ -2437,6 +2362,56 @@ void d_rehash(struct dentry * entry) EXPORT_SYMBOL(d_rehash); /** + * d_exact_alias - find and hash an exact unhashed alias + * @entry: dentry to add + * @inode: The inode to go with this dentry + * + * If an unhashed dentry with the same name/parent and desired + * inode already exists, hash and return it. Otherwise, return + * NULL. + * + * Parent directory should be locked. + */ +struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode) +{ + struct dentry *alias; + int len = entry->d_name.len; + const char *name = entry->d_name.name; + unsigned int hash = entry->d_name.hash; + + spin_lock(&inode->i_lock); + hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { + /* + * Don't need alias->d_lock here, because aliases with + * d_parent == entry->d_parent are not subject to name or + * parent changes, because the parent inode i_mutex is held. + */ + if (alias->d_name.hash != hash) + continue; + if (alias->d_parent != entry->d_parent) + continue; + if (alias->d_name.len != len) + continue; + if (dentry_cmp(alias, name, len)) + continue; + spin_lock(&alias->d_lock); + if (!d_unhashed(alias)) { + spin_unlock(&alias->d_lock); + alias = NULL; + } else { + __dget_dlock(alias); + _d_rehash(alias); + spin_unlock(&alias->d_lock); + } + spin_unlock(&inode->i_lock); + return alias; + } + spin_unlock(&inode->i_lock); + return NULL; +} +EXPORT_SYMBOL(d_exact_alias); + +/** * dentry_update_name_case - update case insensitive dentry with a new name * @dentry: dentry to be updated * @name: new name diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 4bfc33ad0563..400a70b3be7b 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -2461,14 +2461,15 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata, dentry = opendata->dentry; if (d_really_is_negative(dentry)) { - /* FIXME: Is this d_drop() ever needed? */ + struct dentry *alias; d_drop(dentry); - dentry = d_add_unique(dentry, igrab(state->inode)); - if (dentry == NULL) { - dentry = opendata->dentry; - } else if (dentry != ctx->dentry) { + alias = d_exact_alias(dentry, state->inode); + if (!alias) + alias = d_splice_alias(igrab(state->inode), dentry); + /* d_splice_alias() can't fail here - it's a non-directory */ + if (alias) { dput(ctx->dentry); - ctx->dentry = dget(dentry); + ctx->dentry = dentry = alias; } nfs_set_verifier(dentry, nfs_save_change_attribute(d_inode(opendata->dir))); diff --git a/include/linux/dcache.h b/include/linux/dcache.h index c4b5f4b3f8f8..bda4ec53886b 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -246,6 +246,7 @@ extern struct dentry * d_alloc(struct dentry *, const struct qstr *); extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); extern struct dentry * d_splice_alias(struct inode *, struct dentry *); extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); +extern struct dentry * d_exact_alias(struct dentry *, struct inode *); extern struct dentry *d_find_any_alias(struct inode *inode); extern struct dentry * d_obtain_alias(struct inode *); extern struct dentry * d_obtain_root(struct inode *); @@ -288,23 +289,6 @@ static inline void d_add(struct dentry *entry, struct inode *inode) d_rehash(entry); } -/** - * d_add_unique - add dentry to hash queues without aliasing - * @entry: dentry to add - * @inode: The inode to attach to this dentry - * - * This adds the entry to the hash queues and initializes @inode. - * The entry was actually filled in earlier during d_alloc(). - */ -static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode) -{ - struct dentry *res; - - res = d_instantiate_unique(entry, inode); - d_rehash(res != NULL ? res : entry); - return res; -} - extern void dentry_update_name_case(struct dentry *, struct qstr *); /* used for rename() and baskets */ |