Array of MAX_NESTED_LINKS + 1 elements put into nameidata;
what used to be a local array in link_path_walk() occupies
entries 1 .. MAX_NESTED_LINKS in it, link and cookie from
the trailing symlink handling loops - entry 0.
This is _not_ the final arrangement; just an easily verified
incremental step.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Deal with skipping leading slashes before what used to be the
recursive call. That way we can get rid of that goto completely.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
absolutely straightforward now - the only variables we need to preserve
across the recursive call are name, link and cookie, and recursion depth
is limited (and can is equal to nd->depth). So arrange an array of
triples to hold instances of those and be done with that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
reduce the number of returns in there - turn all places
where it returns zero into goto OK and places where it
returns non-zero into goto Err. The only non-trivial
detail is that all breaks in the loop are guaranteed
to be with non-zero err.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
What we do after the second walk_component() + put_link() + depth
decrement in there is exactly equivalent to what's done right
after the first walk_component(). Easy to verify and not at all
surprising, seeing that there we have just walked the last
component of nested symlink.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull the block after the if-else in the end of what used to be do-while
body into all branches there. We are almost done with the massage...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
If we get ERR_PTR() from get_link(), we are guaranteed to get err != 0
when we break out of do-while, so we are going to hit if (err) return err;
shortly after it. Pull that into the if (IS_ERR(s)) body.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and strip __always_inline from follow_link() - remaining callers
don't need that.
Now link_path_walk() recursion is a direct one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
shares space with nameidata->next, walk_component() et.al. store
the struct path of symlink instead of returning it into a variable
passed by caller.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Split a piece of fs/namei.c:follow_link() that does obtaining the link
body into a separate function. follow_link() itself is converted to
calling get_link() and then doing the body traversal (if any).
The next step will expand follow_link() call in link_path_walk()
and this helps to keep the size down...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
a) instead of storing the symlink body (via nd_set_link()) and returning
an opaque pointer later passed to ->put_link(), ->follow_link() _stores_
that opaque pointer (into void * passed by address by caller) and returns
the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic
symlinks) and pointer to symlink body for normal symlinks. Stored pointer
is ignored in all cases except the last one.
Storing NULL for opaque pointer (or not storing it at all) means no call
of ->put_link().
b) the body used to be passed to ->put_link() implicitly (via nameidata).
Now only the opaque pointer is. In the cases when we used the symlink body
to free stuff, ->follow_link() now should store it as opaque pointer in addition
to returning it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
when we go for on-demand allocation of saved state in
link_path_walk(), we'll want nameidata to stay around
for all 3 calls of path_mountpoint().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
that avoids having nameidata on stack during the calls of
->rmdir()/->unlink() and *two* of those during the calls
of ->rename().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
it's a convenient helper, but we'll want to shift nameidata
down the call chain, so it won't be available there...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
With LOOKUP_FOLLOW we unlazy and return 1; without it we either
fail with ELOOP or, for O_PATH opens, succeed. No need to mix
those cases...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When O_PATH is present, O_CREAT isn't, so symlink_ok is always equal to
(open_flags & O_PATH) && !(nd->flags & LOOKUP_FOLLOW).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
No ->inode_follow_link() methods use the nameidata arg, and
it is about to become private to namei.c.
So remove from all inode_follow_link() functions.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
let "fast" symlinks store the pointer to the body into ->i_link and
use simple_follow_link for ->follow_link()
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ovl_follow_link current calls ->put_link on an error path.
However ->put_link is about to change in a way that it will be
impossible to call it from ovl_follow_link.
So rearrange the code to avoid the need for that error path.
Specifically: move the kmalloc() call before the ->follow_link()
call to the subordinate filesystem.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We copy there a kmalloc'ed string and proceed to kfree that string immediately
after that. Easier to just feed that string to nd_set_link() and _not_
kfree it until ->put_link() (which becomes kfree_put_link() in that case).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Doing a readdir on a dfs root can result in the dentries for directories
with a dfs share mounted being replaced by new dentries for objects
returned by the readdir call. These new dentries on shares mounted with
unix extenstions show up as symlinks pointing to the dfs share.
# mount -t cifs -o sec=none //vm140-31/dfsroot cifs
# stat cifs/testlink/testfile; ls -l cifs
File: ‘cifs/testlink/testfile’
Size: 0 Blocks: 0 IO Block: 16384 regular
empty file
Device: 27h/39d Inode: 130120 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2015-03-31 13:55:50.106018200 +0100
Modify: 2015-03-31 13:55:50.106018200 +0100
Change: 2015-03-31 13:55:50.106018200 +0100
Birth: -
total 0
drwxr-xr-x 2 root root 0 Mar 31 13:54 testdir
lrwxrwxrwx 1 root root 19 Mar 24 14:25 testlink -> \vm140-31\test
In the example above, the stat command mounts the dfs share at
cifs/testlink. The subsequent ls on the dfsroot directory replaces the
dentry for testlink with a symlink.
In the earlier code, the d_invalidate command returned an -EBUSY error
when attempting to invalidate directories. This stopped the code from
replacing the directories with symlinks returned by the readdir call.
Changes were recently made to the d_invalidate() command so
that it no longer returns an error code. This results in the directory
with the mounted dfs share being replaced by a symlink which denotes a
dfs share.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Pull user-namespace fix from Eric Biederman:
"Eric Windish recently reported a really bug that allows mounting fresh
copies of proc and sysfs when it really should not be allowed. The
code attempted to verify that proc and sysfs were fully visible but
there is a test missing to ensure that the root of the filesystem is
visible. Doh!
The following patch fixes that.
This fixes a containment issue that the docker folks are seeing"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
mnt: Fix fs_fully_visible to verify the root directory is visible
This fixes a dumb bug in fs_fully_visible that allows proc or sys to
be mounted if there is a bind mount of part of /proc/ or /sys/ visible.
Cc: stable@vger.kernel.org
Reported-by: Eric Windisch <ewindisch@docker.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
