提交 fb2d5b86 编写于 作者: N Nick Piggin

fs: name case update method

smpfs and ncpfs want to update a live dentry name in-place. Rather than
have them open code the locking, provide a documented dcache API.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>
上级 2bc334dc
......@@ -145,8 +145,8 @@ smb_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
goto end_advance;
} else {
hashed = 1;
memcpy((char *) newdent->d_name.name, qname->name,
newdent->d_name.len);
/* dir i_mutex is locked because we're in readdir */
dentry_update_name_case(newdent, qname);
}
if (!newdent->d_inode) {
......
......@@ -1589,6 +1589,33 @@ void d_rehash(struct dentry * entry)
}
EXPORT_SYMBOL(d_rehash);
/**
* dentry_update_name_case - update case insensitive dentry with a new name
* @dentry: dentry to be updated
* @name: new name
*
* Update a case insensitive dentry with new case of name.
*
* dentry must have been returned by d_lookup with name @name. Old and new
* name lengths must match (ie. no d_compare which allows mismatched name
* lengths).
*
* Parent inode i_mutex must be held over d_lookup and into this call (to
* keep renames and concurrent inserts, and readdir(2) away).
*/
void dentry_update_name_case(struct dentry *dentry, struct qstr *name)
{
BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
memcpy((unsigned char *)dentry->d_name.name, name->name, name->len);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
}
EXPORT_SYMBOL(dentry_update_name_case);
/*
* When switching names, the actual string doesn't strictly have to
* be preserved in the target - because we're dropping the target
......
......@@ -611,35 +611,12 @@ ncp_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
shrink_dcache_parent(newdent);
/*
* It is not as dangerous as it looks. NetWare's OS2 namespace is
* case preserving yet case insensitive. So we update dentry's name
* as received from server. We found dentry via d_lookup with our
* hash, so we know that hash does not change, and so replacing name
* should be reasonably safe.
* NetWare's OS2 namespace is case preserving yet case
* insensitive. So we update dentry's name as received from
* server. Parent dir's i_mutex is locked because we're in
* readdir.
*/
if (qname.len == newdent->d_name.len &&
memcmp(newdent->d_name.name, qname.name, newdent->d_name.len)) {
struct inode *inode = newdent->d_inode;
/*
* Inside ncpfs all uses of d_name are either for debugging,
* or on functions which acquire inode mutex (mknod, creat,
* lookup). So grab i_mutex here, to be sure. d_path
* uses dcache_lock when generating path, so we should too.
* And finally d_compare is protected by dentry's d_lock, so
* here we go.
*/
if (inode)
mutex_lock(&inode->i_mutex);
spin_lock(&dcache_lock);
spin_lock(&newdent->d_lock);
memcpy((char *) newdent->d_name.name, qname.name,
newdent->d_name.len);
spin_unlock(&newdent->d_lock);
spin_unlock(&dcache_lock);
if (inode)
mutex_unlock(&inode->i_mutex);
}
dentry_update_name_case(newdent, &qname);
}
if (!newdent->d_inode) {
......@@ -657,7 +634,7 @@ ncp_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
} else {
struct inode *inode = newdent->d_inode;
mutex_lock(&inode->i_mutex);
mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
ncp_update_inode2(inode, entry);
mutex_unlock(&inode->i_mutex);
}
......
......@@ -290,6 +290,8 @@ static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *in
return res;
}
extern void dentry_update_name_case(struct dentry *, struct qstr *);
/* used for rename() and baskets */
extern void d_move(struct dentry *, struct dentry *);
extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
......
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