[RFC][PATCH v3 07/55] atomic_open(): saner calling conventions (return dentry on success)

Al Viro
2020-03-01T21:52:47Z

Currently it either returns -E... or puts (nd->path.mnt,dentry)
into *path and returns 0. Make it return ERR_PTR(-E...) or
dentry; adjust the caller. Fewer arguments and it's easier
to keep track of *path contents that way.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 41 ++++++++++++++++++++++++-----------------
1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c104ec75faef..5f8b791a6d6e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3087,10 +3087,10 @@ static int may_o_create(const struct path *dir, struct dentry *dentry, umode_t m
*
* Returns an error code otherwise.
*/
-static int atomic_open(struct nameidata *nd, struct dentry *dentry,
- struct path *path, struct file *file,
- const struct open_flags *op,
- int open_flag, umode_t mode)
+static struct dentry *atomic_open(struct nameidata *nd, struct dentry *dentry,
+ struct file *file,
+ const struct open_flags *op,
+ int open_flag, umode_t mode)
{
struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
struct inode *dir = nd->path.dentry->d_inode;
@@ -3131,17 +3131,15 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
}
if (file->f_mode & FMODE_CREATED)
fsnotify_create(dir, dentry);
- if (unlikely(d_is_negative(dentry))) {
+ if (unlikely(d_is_negative(dentry)))
error = -ENOENT;
- } else {
- path->dentry = dentry;
- path->mnt = nd->path.mnt;
- return 0;
- }
}
}
- dput(dentry);
- return error;
+ if (error) {
+ dput(dentry);
+ dentry = ERR_PTR(error);
+ }
+ return dentry;
}

/*
@@ -3236,11 +3234,20 @@ static int lookup_open(struct nameidata *nd, struct path *path,
}

if (dir_inode->i_op->atomic_open) {
- error = atomic_open(nd, dentry, path, file, op, open_flag,
- mode);
- if (unlikely(error == -ENOENT) && create_error)
- error = create_error;
- return error;
+ dentry = atomic_open(nd, dentry, file, op, open_flag, mode);
+ if (IS_ERR(dentry)) {
+ error = PTR_ERR(dentry);
+ if (unlikely(error == -ENOENT) && create_error)
+ error = create_error;
+ return error;
+ }
+ if (file->f_mode & FMODE_OPENED) {
+ dput(dentry);
+ return 0;
+ }
+ path->mnt = nd->path.mnt;
+ path->dentry = dentry;
+ return 0;
}

no_open:
--
2.11.0