[RFC][PATCH v4 63/69] take post-lookup part of do_last() out of loop

Al Viro
2020-03-13T23:55:00Z

now we can have open_last_lookups() directly from the loop in
path_openat() - the rest of do_last() never returns a symlink
to follow, so we can bloody well leave the loop first.

Rename the rest of that thing from do_last() to do_open() and
make it return an int.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index aa1a74c5f52d..da64fa0b2f6d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3219,31 +3219,26 @@ static const char *open_last_lookups(struct nameidata *nd,
/*
* Handle the last step of open()
*/
-static const char *do_last(struct nameidata *nd,
+static int do_open(struct nameidata *nd,
struct file *file, const struct open_flags *op)
{
int open_flag = op->open_flag;
bool do_truncate;
int acc_mode;
- const char *link;
int error;

- link = open_last_lookups(nd, file, op);
- if (unlikely(link))
- return link;
-
if (!(file->f_mode & FMODE_CREATED))
audit_inode(nd->name, nd->path.dentry, 0);
if (open_flag & O_CREAT) {
if (d_is_dir(nd->path.dentry))
- return ERR_PTR(-EISDIR);
+ return -EISDIR;
error = may_create_in_sticky(nd->dir_mode, nd->dir_uid,
d_backing_inode(nd->path.dentry));
if (unlikely(error))
- return ERR_PTR(error);
+ return error;
}
if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
- return ERR_PTR(-ENOTDIR);
+ return -ENOTDIR;

do_truncate = false;
acc_mode = op->acc_mode;
@@ -3254,7 +3249,7 @@ static const char *do_last(struct nameidata *nd,
} else if (d_is_reg(nd->path.dentry) && open_flag & O_TRUNC) {
error = mnt_want_write(nd->path.mnt);
if (error)
- return ERR_PTR(error);
+ return error;
do_truncate = true;
}
error = may_open(&nd->path, acc_mode, open_flag);
@@ -3270,7 +3265,7 @@ static const char *do_last(struct nameidata *nd,
}
if (do_truncate)
mnt_drop_write(nd->path.mnt);
- return ERR_PTR(error);
+ return error;
}

struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
@@ -3373,8 +3368,10 @@ static struct file *path_openat(struct nameidata *nd,
} else {
const char *s = path_init(nd, flags);
while (!(error = link_path_walk(s, nd)) &&
- (s = do_last(nd, file, op)) != NULL)
+ (s = open_last_lookups(nd, file, op)) != NULL)
;
+ if (!error)
+ error = do_open(nd, file, op);
terminate_walk(nd);
}
if (likely(!error)) {
--
2.11.0