[PATCH 1/2] fs: expose do_unlinkat for built-in callers

From: Christoph Hellwig
Date: Mon May 15 2017 - 11:59:32 EST


And make it take a struct filename instead of a user pointer.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/internal.h | 1 +
fs/namei.c | 12 +++++-------
2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 9676fe11c093..c127454fe4af 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -55,6 +55,7 @@ extern void __init chrdev_init(void);
extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
const char *, unsigned int, struct path *);
+long do_unlinkat(int dfd, struct filename *name);

/*
* namespace.c
diff --git a/fs/namei.c b/fs/namei.c
index 6571a5f5112e..75e90a083369 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4002,10 +4002,9 @@ EXPORT_SYMBOL(vfs_unlink);
* writeout happening, and we don't want to prevent access to the directory
* while waiting on the I/O.
*/
-static long do_unlinkat(int dfd, const char __user *pathname)
+long do_unlinkat(int dfd, struct filename *name)
{
int error;
- struct filename *name;
struct dentry *dentry;
struct path path;
struct qstr last;
@@ -4014,8 +4013,7 @@ static long do_unlinkat(int dfd, const char __user *pathname)
struct inode *delegated_inode = NULL;
unsigned int lookup_flags = 0;
retry:
- name = filename_parentat(dfd, getname(pathname), lookup_flags,
- &path, &last, &type);
+ name = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
if (IS_ERR(name))
return PTR_ERR(name);

@@ -4057,12 +4055,12 @@ static long do_unlinkat(int dfd, const char __user *pathname)
mnt_drop_write(path.mnt);
exit1:
path_put(&path);
- putname(name);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
inode = NULL;
goto retry;
}
+ putname(name);
return error;

slashes:
@@ -4083,12 +4081,12 @@ SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
if (flag & AT_REMOVEDIR)
return do_rmdir(dfd, pathname);

- return do_unlinkat(dfd, pathname);
+ return do_unlinkat(dfd, getname(pathname));
}

SYSCALL_DEFINE1(unlink, const char __user *, pathname)
{
- return do_unlinkat(AT_FDCWD, pathname);
+ return do_unlinkat(AT_FDCWD, getname(pathname));
}

int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
--
2.11.0