@@ -1562,7 +1562,13 @@ static struct dentry *lookup_dcache(const struct qstr *name,
{
struct dentry *dentry = d_lookup(dir, name);
if (dentry) {
- int error = d_revalidate(dentry, flags);
+ int error;
+ /* Some filesystems assume EXCL -> CREATE, so make
+ * sure it does.
+ */
+ if (!(flags & LOOKUP_CREATE))
+ flags &= ~LOOKUP_EXCL;
+ error = d_revalidate(dentry, flags);
if (unlikely(error <= 0)) {
if (!error)
d_invalidate(dentry);
@@ -1621,6 +1627,8 @@ static struct dentry *__lookup_hash(const struct qstr *name,
* or shared lock depending on the fs preference, then do a lookup,
* and then set the DCACHE_PAR_UPDATE bit on the child if a shared lock
* was taken on the parent.
+ * If LOOKUP_EXCL, name should not already exist, else -EEXIST
+ * If not LOOKUP_CREATE, name should already exist, else -ENOENT
*/
static struct dentry *lookup_hash_update(
const struct qstr *name,
@@ -1651,6 +1659,24 @@ static struct dentry *lookup_hash_update(
dput(dentry);
goto retry;
}
+ if (flags & LOOKUP_EXCL) {
+ if (d_is_positive(dentry)) {
+ d_lookup_done(dentry);
+ d_unlock_update(dentry);
+ dput(dentry);
+ err = -EEXIST;
+ goto out_err;
+ }
+ }
+ if (!(flags & LOOKUP_CREATE)) {
+ if (!dentry->d_inode) {
+ d_lookup_done(dentry);
+ d_unlock_update(dentry);
+ dput(dentry);
+ err = -ENOENT;
+ goto out_err;
+ }
+ }
return dentry;
out_err:
@@ -3868,7 +3894,7 @@ static struct dentry *filename_create_one(struct qstr *last, struct path *path,
struct dentry *dentry;
bool want_dir = lookup_flags & LOOKUP_DIRECTORY;
unsigned int reval_flag = lookup_flags & LOOKUP_REVAL;
- unsigned int create_flags = LOOKUP_CREATE | LOOKUP_EXCL;
+ unsigned int create_flag = LOOKUP_CREATE;
int err2;
int error;
@@ -3879,26 +3905,16 @@ static struct dentry *filename_create_one(struct qstr *last, struct path *path,
* '/', and a directory wasn't requested.
*/
if (last->name[last->len] && !want_dir)
- create_flags = 0;
+ /* Name was foo/bar/ but not creating a directory, so
+ * we won't try to create - result will be either -ENOENT
+ * or -EEXIST.
+ */
+ create_flag = 0;
dentry = lookup_hash_update(last, path->dentry,
- reval_flag | create_flags, wq);
+ reval_flag | create_flag | LOOKUP_EXCL, wq);
if (IS_ERR(dentry))
goto drop_write;
- error = -EEXIST;
- if (d_is_positive(dentry))
- goto fail;
-
- /*
- * Special case - lookup gave negative, but... we had foo/bar/
- * From the vfs_mknod() POV we just have a negative dentry -
- * 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(!create_flags)) {
- error = -ENOENT;
- goto fail;
- }
if (unlikely(err2)) {
error = err2;
goto fail;
@@ -4292,10 +4308,6 @@ int do_rmdir(int dfd, struct filename *name)
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto exit3;
- if (!dentry->d_inode) {
- error = -ENOENT;
- goto exit4;
- }
error = security_path_rmdir(&path, dentry);
if (error)
goto exit4;
@@ -4435,8 +4447,6 @@ int do_unlinkat(int dfd, struct filename *name)
if (last.name[last.len])
goto slashes;
inode = dentry->d_inode;
- if (d_is_negative(dentry))
- goto slashes;
ihold(inode);
error = security_path_unlink(&path, dentry);
if (error)
Moving common error handling into lookup_hash_update() simplifies callers. A future patch will export this functionality to nfsd, and the more code we put in the interface, the less code will be needed in nfsd. EEXIST is returned if LOOKUP_EXCL is set and dentry is positivie. ENOENT is returned if LOOKUP_CREAT is NOT set and dentry is negative. This involves seting LOOKUP_EXCL in cases where it wasn't before. In particular, when creating a non-dir named "foo/", we want the EEXIST error, but don't want to actually create anything. Some filesystems assume LOOKUP_EXCL implies LOOKUP_CREATE, so ensure it does when calling ->lookup(). Signed-off-by: NeilBrown <neilb@suse.de> --- fs/namei.c | 58 ++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 34 insertions(+), 24 deletions(-)