From d635711daa98be86d4c7fd01499c34f566b54ccb Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Fri, 10 Jun 2016 05:30:17 -0300 Subject: Linux-libre 4.6.2-gnu --- fs/dcache.c | 177 ++++++++++++++++++++++++++++++------------------------------ 1 file changed, 88 insertions(+), 89 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index 6bdabe2fc..0dd0237f8 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1749,13 +1749,12 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) unsigned add_flags = d_flags_for_inode(inode); spin_lock(&dentry->d_lock); - if (inode) - hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); + hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); raw_write_seqcount_begin(&dentry->d_seq); __d_set_inode_and_type(dentry, inode, add_flags); raw_write_seqcount_end(&dentry->d_seq); + __fsnotify_d_instantiate(dentry); spin_unlock(&dentry->d_lock); - fsnotify_d_instantiate(dentry, inode); } /** @@ -1776,90 +1775,15 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) void d_instantiate(struct dentry *entry, struct inode * inode) { BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); - if (inode) + if (inode) { spin_lock(&inode->i_lock); - __d_instantiate(entry, inode); - if (inode) + __d_instantiate(entry, inode); spin_unlock(&inode->i_lock); + } security_d_instantiate(entry, 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 @@ -2440,6 +2364,86 @@ void d_rehash(struct dentry * entry) } EXPORT_SYMBOL(d_rehash); + +/* inode->i_lock held if inode is non-NULL */ + +static inline void __d_add(struct dentry *dentry, struct inode *inode) +{ + if (inode) { + __d_instantiate(dentry, inode); + spin_unlock(&inode->i_lock); + } + security_d_instantiate(dentry, inode); + d_rehash(dentry); +} + +/** + * d_add - add dentry to hash queues + * @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(). + */ + +void d_add(struct dentry *entry, struct inode *inode) +{ + if (inode) + spin_lock(&inode->i_lock); + __d_add(entry, inode); +} +EXPORT_SYMBOL(d_add); + +/** + * 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 @@ -2776,10 +2780,9 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) BUG_ON(!d_unhashed(dentry)); - if (!inode) { - __d_instantiate(dentry, NULL); + if (!inode) goto out; - } + spin_lock(&inode->i_lock); if (S_ISDIR(inode->i_mode)) { struct dentry *new = __d_find_any_alias(inode); @@ -2813,12 +2816,8 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) return new; } } - /* already taking inode->i_lock, so d_add() by hand */ - __d_instantiate(dentry, inode); - spin_unlock(&inode->i_lock); out: - security_d_instantiate(dentry, inode); - d_rehash(dentry); + __d_add(dentry, inode); return NULL; } EXPORT_SYMBOL(d_splice_alias); -- cgit v1.2.3-54-g00ecf