@@ -3676,13 +3676,12 @@ static struct dentry *filename_create(int dfd, struct filename *name,
int type;
int err2;
int error;
- bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
/*
* Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any
* other flags passed in are ignored!
*/
- lookup_flags &= LOOKUP_REVAL;
+ lookup_flags &= LOOKUP_REVAL | LOOKUP_DIRECTORY;
error = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
if (error)
@@ -3698,9 +3697,11 @@ static struct dentry *filename_create(int dfd, struct filename *name,
/* don't fail immediately if it's r/o, at least try to report other errors */
err2 = mnt_want_write(path->mnt);
/*
- * Do the final lookup.
+ * Do the final lookup. Request 'create' only if there is no trailing
+ * '/', or if directory is requested.
*/
- lookup_flags |= LOOKUP_CREATE | LOOKUP_EXCL;
+ if (!last.name[last.len] || (lookup_flags & LOOKUP_DIRECTORY))
+ lookup_flags |= LOOKUP_CREATE | LOOKUP_EXCL;
inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
dentry = __lookup_hash(&last, path->dentry, lookup_flags);
if (IS_ERR(dentry))
@@ -3716,7 +3717,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
* all is fine. Let's be bastards - you had / on the end, you've
* been asking for (non-existent) directory. -ENOENT for you.
*/
- if (unlikely(!is_dir && last.name[last.len])) {
+ if (!likely(lookup_flags & LOOKUP_CREATE)) {
error = -ENOENT;
goto fail;
}
When asked to create a path ending '/', but which is not to be a directory (LOOKUP_DIRECTORY not set), filename_create() will never try to create the file. If it doesn't exist, -ENOENT is reported. However, it still passes LOOKUP_CREATE|LOOKUP_EXCL to the filesystems ->lookup() function, even though there is no intent to create. This is misleading and can cause incorrect behaviour. If you try ln -s foo /path/dir/ where 'dir' is a directory on an NFS filesystem which is not currently known in the dcache, this will fail with ENOENT. As the name is not in the dcache, nfs_lookup gets called with LOOKUP_CREATE|LOOKUP_EXCL and so it returns NULL without performing any lookup, with the expectation that as subsequent call to create the target will be made, and the lookup can be combined with the creation. In the case with a trailing '/' and no LOOKUP_DIRECTORY, that call is never made. Instead filename_create() sees that the dentry is not (yet) positive and returns -ENOENT - even though the directory actually exists. So only set LOOKUP_CREATE|LOOKUP_EXCL if there really is an intent to create, and use the absence of these flags to decide if -ENOENT should be returned. Note that we now leave LOOKUP_DIRECTORY in lookup_flags as passed to ->lookup etc. This seems more consistent with the comment which says that only LOOKUP_REVAL and LOOKUP_DIRECTORY are relevant, and makes the code a little cleaner. Signed-off-by: NeilBrown <neilb@suse.de> --- fs/namei.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)