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namei: saner calling conventions for mountpoint_last()

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leave the result in nd->path, have caller do follow_mount() and
copy it to the final destination.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-11-14 00:40:33 -05:00
parent c1d4dd2767
commit ba8f46135a
1 changed files with 25 additions and 25 deletions
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50
fs/namei.c
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@ -2561,7 +2561,6 @@ EXPORT_SYMBOL(user_path_at_empty);
/**
* mountpoint_last - look up last component for umount
* @nd: pathwalk nameidata - currently pointing at parent directory of "last"
* @path: pointer to container for result
*
* This is a special lookup_last function just for umount. In this case, we
* need to resolve the path without doing any revalidation.
@ -2574,23 +2573,20 @@ EXPORT_SYMBOL(user_path_at_empty);
*
* Returns:
* -error: if there was an error during lookup. This includes -ENOENT if the
* lookup found a negative dentry. The nd->path reference will also be
* put in this case.
* lookup found a negative dentry.
*
* 0: if we successfully resolved nd->path and found it to not to be a
* symlink that needs to be followed. "path" will also be populated.
* The nd->path reference will also be put.
* 0: if we successfully resolved nd->last and found it to not to be a
* symlink that needs to be followed.
*
* 1: if we successfully resolved nd->last and found it to be a symlink
* that needs to be followed. "path" will be populated with the path
* to the link, and nd->path will *not* be put.
* that needs to be followed.
*/
static int
mountpoint_last(struct nameidata *nd, struct path *path)
mountpoint_last(struct nameidata *nd)
{
int error = 0;
struct dentry *dentry;
struct dentry *dir = nd->path.dentry;
struct path path;
/* If we're in rcuwalk, drop out of it to handle last component */
if (nd->flags & LOOKUP_RCU) {
@ -2604,36 +2600,34 @@ mountpoint_last(struct nameidata *nd, struct path *path)
error = handle_dots(nd, nd->last_type);
if (error)
return error;
dentry = dget(nd->path.dentry);
path.dentry = dget(nd->path.dentry);
} else {
dentry = d_lookup(dir, &nd->last);
if (!dentry) {
path.dentry = d_lookup(dir, &nd->last);
if (!path.dentry) {
/*
* No cached dentry. Mounted dentries are pinned in the
* cache, so that means that this dentry is probably
* a symlink or the path doesn't actually point
* to a mounted dentry.
*/
dentry = lookup_slow(&nd->last, dir,
path.dentry = lookup_slow(&nd->last, dir,
nd->flags | LOOKUP_NO_REVAL);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (IS_ERR(path.dentry))
return PTR_ERR(path.dentry);
}
}
if (d_is_negative(dentry)) {
dput(dentry);
if (d_is_negative(path.dentry)) {
dput(path.dentry);
return -ENOENT;
}
if (nd->depth)
put_link(nd);
path->dentry = dentry;
path->mnt = nd->path.mnt;
error = should_follow_link(nd, path, nd->flags & LOOKUP_FOLLOW,
d_backing_inode(dentry), 0);
path.mnt = nd->path.mnt;
error = should_follow_link(nd, &path, nd->flags & LOOKUP_FOLLOW,
d_backing_inode(path.dentry), 0);
if (unlikely(error))
return error;
mntget(path->mnt);
follow_mount(path);
path_to_nameidata(&path, nd);
return 0;
}
@ -2654,13 +2648,19 @@ path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path)
if (IS_ERR(s))
return PTR_ERR(s);
while (!(err = link_path_walk(s, nd)) &&
(err = mountpoint_last(nd, path)) > 0) {
(err = mountpoint_last(nd)) > 0) {
s = trailing_symlink(nd);
if (IS_ERR(s)) {
err = PTR_ERR(s);
break;
}
}
if (!err) {
*path = nd->path;
nd->path.mnt = NULL;
nd->path.dentry = NULL;
follow_mount(path);
}
terminate_walk(nd);
return err;
}