All callers of path_init() proceed to do the identical cleanup when
they are done with nameidata. Don't open-code it...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
As it is, default ->i_fop has NULL ->open() (along with all other methods).
The only case where it matters is reopening (via procfs symlink) a file that
didn't get its ->f_op from ->i_fop - anything else will have ->i_fop assigned
to something sane (default would fail on read/write/ioctl/etc.).
Unfortunately, such case exists - alloc_file() users, especially
anon_get_file() ones. There we have tons of opened files of very different
kinds sharing the same inode. As the result, attempt to reopen those via
procfs succeeds and you get a descriptor you can't do anything with.
Moreover, in case of sockets we set ->i_fop that will only be used
on such reopen attempts - and put a failing ->open() into it to make sure
those do not succeed.
It would be simpler to put such ->open() into default ->i_fop and leave
it unchanged both for anon inode (as we do anyway) and for socket ones. Result:
* everything going through do_dentry_open() works as it used to
* sock_no_open() kludge is gone
* attempts to reopen anon-inode files fail as they really ought to
* ditto for aio_private_file()
* ditto for perfmon - this one actually tried to imitate sock_no_open()
trick, but failed to set ->i_fop, so in the current tree reopens succeed and
yield completely useless descriptor. Intent clearly had been to fail with
-ENXIO on such reopens; now it actually does.
* everything else that used alloc_file() keeps working - it has ->i_fop
set for its inodes anyway
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
New pseudo-filesystem: nsfs. Targets of /proc/*/ns/* live there now.
It's not mountable (not even registered, so it's not in /proc/filesystems,
etc.). Files on it *are* bindable - we explicitly permit that in do_loopback().
This stuff lives in fs/nsfs.c now; proc_ns_fget() moved there as well.
get_proc_ns() is a macro now (it's simply returning ->i_private; would
have been an inline, if not for header ordering headache).
proc_ns_inode() is an ex-parrot. The interface used in procfs is
ns_get_path(path, task, ops) and ns_get_name(buf, size, task, ops).
Dentries and inodes are never hashed; a non-counting reference to dentry
is stashed in ns_common (removed by ->d_prune()) and reused by ns_get_path()
if present. See ns_get_path()/ns_prune_dentry/nsfs_evict() for details
of that mechanism.
As the result, proc_ns_follow_link() has stopped poking in nd->path.mnt;
it does nd_jump_link() on a consistent <vfsmount,dentry> pair it gets
from ns_get_path().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
a) make get_proc_ns() return a pointer to struct ns_common
b) mirror ns_ops in dentry->d_fsdata of ns dentries, so that
is_mnt_ns_file() could get away with fewer dereferences.
That way struct proc_ns becomes invisible outside of fs/proc/*.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
for now - just move corresponding ->proc_inum instances over there
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull btrfs deadlock fix from Chris Mason:
"This has a fix for a long standing deadlock that we've been trying to
nail down for a while. It ended up being a bad interaction with the
fair reader/writer locks and the order btrfs reacquires locks in the
btree"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
btrfs: fix lockups from btrfs_clear_path_blocking
"The biggest change is to rename the filesystem from "overlayfs" to "overlay".
This will allow legacy overlayfs to be easily carried by distros alongside the
new mainline one. Also fix a couple of copy-up races and allow escaping comma
character in filenames."
The last bit is about commas in pathname mount options...
Check against !OVL_PATH_LOWER instead of OVL_PATH_MERGE. For a copied up
directory the two are currently equivalent.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Pass dentry into ovl_dir_read_merged() insted of upperpath and lowerpath.
This cleans up callers and paves the way for multi-layer directory reads.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Xattr operations can race with copy up. This does not matter as long as
we consistently fiter out "trunsted.overlay.opaque" attribute on upper
directories.
Previously we checked parent against OVL_PATH_MERGE. This is too general,
and prone to race with copy-up. I.e. we found the parent to be on the
lower layer but ovl_dentry_real() would return the copied-up dentry,
possibly with the "opaque" attribute.
So instead use ovl_path_real() and decide to filter the attributes based on
the actual type of the dentry we'll use.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
ovl_remove_and_whiteout() needs to check if upper dentry exists or not
after having locked upper parent directory.
Previously we used a "type" value computed before locking the upper parent
directory, which is susceptible to racing with copy-up.
There's a similar check in ovl_check_empty_and_clear(). This one is not
actually racy, since copy-up doesn't change the "emptyness" property of a
directory. Add a comment to this effect, and check the existence of upper
dentry locally to make the code cleaner.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Some distributions carry an "old" format of overlayfs while mainline has a
"new" format.
The distros will possibly want to keep the old overlayfs alongside the new
for compatibility reasons.
To make it possible to differentiate the two versions change the name of
the new one from "overlayfs" to "overlay".
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reported-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Andy Whitcroft <apw@canonical.com>
The fair reader/writer locks mean that btrfs_clear_path_blocking needs
to strictly follow lock ordering rules even when we already have
blocking locks on a given path.
Before we can clear a blocking lock on the path, we need to make sure
all of the locks have been converted to blocking. This will remove lock
inversions against anyone spinning in write_lock() against the buffers
we're trying to get read locks on. These inversions didn't exist before
the fair read/writer locks, but now we need to be more careful.
We papered over this deadlock in the past by changing
btrfs_try_read_lock() to be a true trylock against both the spinlock and
the blocking lock. This was slower, and not sufficient to fix all the
deadlocks. This patch adds a btrfs_tree_read_lock_atomic(), which
basically means get the spinlock but trylock on the blocking lock.
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reported-by: Patrick Schmid <schmid@phys.ethz.ch>
cc: stable@vger.kernel.org #v3.15+
With the isofs_hash() function removed, isofs_hash_ms() is the only user
of isofs_hash_common(), but it's defined inside of an #ifdef, which triggers
this gcc warning in ARM axm55xx_defconfig starting with v3.18-rc3:
fs/isofs/inode.c:177:1: warning: 'isofs_hash_common' defined but not used [-Wunused-function]
This patch moves the function inside of the same #ifdef section to avoid that
warning, which seems the best compromise of a relatively harmless patch for
a late -rc.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: b0afd8e5db ("isofs: don't bother with ->d_op for normal case")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In "d_prune_alias(): just lock the parent and call __dentry_kill()" the old
dget + d_drop + dput has been replaced with lock_parent + __dentry_kill;
unfortunately, dput() does more than just killing dentry - it also drops the
reference to parent. New variant leaks that reference and needs dput(parent)
after killing the child off.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull the beginning of seq_file cleanup from Steven:
"I'm looking to clean up the seq_file code and to eventually merge the
trace_seq code with seq_file as well, since they basically do the same thing.
Part of this process is to remove the return code of seq_printf() and friends
as they are rather inconsistent. It is better to use the new function
seq_has_overflowed() if you want to stop processing when the buffer
is full. Note, if the buffer is full, the seq_file code will throw away
the contents, allocate a bigger buffer, and then call your code again
to fill in the data. The only thing that breaking out of the function
early does is to save a little time which is probably never noticed.
I started with patches from Joe Perches and modified them as well.
There's many more places that need to be updated before we can convert
seq_printf() and friends to return void. But this patch set introduces
the seq_has_overflowed() and does some initial updates."
This patch fixes kmemcheck warning in switch_names. The function
switch_names swaps inline names of two dentries. It swaps full arrays
d_iname, no matter how many bytes are really used by the strings. Reading
data beyond string ends results in kmemcheck warning.
We fix the bug by marking both arrays as fully initialized.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org # v3.15
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... for situations when we don't have any candidate in pathnames - basically,
in descriptor-based syscalls.
[Folded the build fix for !CONFIG_AUDITSYSCALL configs from Chen Gang]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In ->atomic_open(inode, dentry, file, opened) calling finish_no_open(file, NULL)
is equivalent to dget(dentry); return finish_no_open(file, dentry);
No need to open-code that...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
dentry is always hashed and negative, inode - non-error, non-NULL and
non-directory. In such conditions d_splice_alias() is equivalent to
"d_instantiate(dentry, inode) and return NULL", which simplifies the
downstream code and is consistent with the "have to create a new object"
case.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
