simple_start_creating() now uses start_dirop(), which further
centralised locking rules.
start_dirop() and lookup_noperm_common() are not available
via fs/internal.h.
Signed-off-by: NeilBrown <neil@brown.name>
---
fs/internal.h | 3 +++
fs/libfs.c | 36 +++++++++++++++++-------------------
fs/namei.c | 6 +++---
3 files changed, 23 insertions(+), 22 deletions(-)
diff --git a/fs/internal.h b/fs/internal.h
index 38e8aab27bbd..baeaaf3747e3 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -67,6 +67,9 @@ int vfs_tmpfile(struct mnt_idmap *idmap,
const struct path *parentpath,
struct file *file, umode_t mode);
struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
+struct dentry *start_dirop(struct dentry *parent, struct qstr *name,
+ unsigned int lookup_flags);
+int lookup_noperm_common(struct qstr *qname, struct dentry *base);
/*
* namespace.c
diff --git a/fs/libfs.c b/fs/libfs.c
index ce8c496a6940..63c1a4186206 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -2289,27 +2289,25 @@ void stashed_dentry_prune(struct dentry *dentry)
cmpxchg(stashed, dentry, NULL);
}
-/* parent must be held exclusive */
+/**
+ * simple_start_creating - prepare to create a given name
+ * @parent - directory in which to prepare to create the name
+ * @name - the name to be created
+ *
+ * Locks are taken and a lookup in performed prior to creating
+ * an object in a directory. No permission checking is performed.
+ *
+ * Returns: a negative dentry on which vfs_create() or similar may
+ * be attempted, or an error.
+ */
struct dentry *simple_start_creating(struct dentry *parent, const char *name)
{
- struct dentry *dentry;
- struct inode *dir = d_inode(parent);
+ struct qstr qname = QSTR(name);
+ int err;
- inode_lock(dir);
- if (unlikely(IS_DEADDIR(dir))) {
- inode_unlock(dir);
- return ERR_PTR(-ENOENT);
- }
- dentry = lookup_noperm(&QSTR(name), parent);
- if (IS_ERR(dentry)) {
- inode_unlock(dir);
- return dentry;
- }
- if (dentry->d_inode) {
- dput(dentry);
- inode_unlock(dir);
- return ERR_PTR(-EEXIST);
- }
- return dentry;
+ err = lookup_noperm_common(&qname, parent);
+ if (err)
+ return ERR_PTR(err);
+ return start_dirop(parent, &qname, LOOKUP_CREATE | LOOKUP_EXCL);
}
EXPORT_SYMBOL(simple_start_creating);
diff --git a/fs/namei.c b/fs/namei.c
index 8121550f20aa..c1e39c985f1f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2765,8 +2765,8 @@ static int filename_parentat(int dfd, struct filename *name,
* Returns: a locked dentry, or an error.
*
*/
-static struct dentry *start_dirop(struct dentry *parent, struct qstr *name,
- unsigned int lookup_flags)
+struct dentry *start_dirop(struct dentry *parent, struct qstr *name,
+ unsigned int lookup_flags)
{
struct dentry *dentry;
struct inode *dir = d_inode(parent);
@@ -2931,7 +2931,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
}
EXPORT_SYMBOL(vfs_path_lookup);
-static int lookup_noperm_common(struct qstr *qname, struct dentry *base)
+int lookup_noperm_common(struct qstr *qname, struct dentry *base)
{
const char *name = qname->name;
u32 len = qname->len;
--
2.50.0.107.gf914562f5916.dirty