Just pass struct file *. Methods are happier that way...
There's no need to return struct file * from finish_open() now,
so let it return int. Next: saner prototypes for parts in
namei.c
Change-Id: I984f0f992330c959a2f9703d9e7647ef340e2845
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
make put_filp() conditional on flag set by finish_open()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I79833cd7a54d635bad80c6fca31eb55631e96c8b
Change of calling conventions:
old new
NULL 1
file 0
ERR_PTR(-ve) -ve
Caller *knows* that struct file *; no need to return it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I883d67181a0100447a2e077ed537ee393e862e0b
... and let finish_open() report having opened the file via that sucker.
Next step: don't modify od->filp at all.
[AV: FILE_CREATE was already used by cifs; Miklos' fix folded]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I6ea0f871fab215a2901710392abbda88c80008c1
Add an ->atomic_open implementation which replaces the atomic lookup+open+create
operation implemented via ->lookup and ->create operations.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I9cd73db22147a760ee2f69b498aacd16689908b1
What was the purpose of this?
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I5f994a7aa9edc51f6e7ec4f746bf51332d5b496b
Add an ->atomic_open implementation which replaces the atomic open+create
operation implemented via ->create. No functionality is changed.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I0c8c0998fcf940f603963a876ef2be825babf6a7
is_atomic_open() is now only used by nfs4_lookup_revalidate() to check whether
it's okay to skip normal revalidation.
It does a racy check for mount read-onlyness and falls back to normal
revalidation if the open would fail. This makes little sense now that this
function isn't used for determining whether to actually open the file or not.
The d_mountpoint() check still makes sense since it is an indication that we
might be following a mount and so open may not revalidate the dentry.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Ibad58603956e406c63b4b7c63243502eabe6febf
Instead check LOOKUP_EXCL in nd->flags, which is basically what the open intent
flags were used for.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I9afc0a255a45c8d976efdd17ab991b71fc3c41f3
Don't pass nfs_open_context() to ->create(). Only the NFS4 implementation
needed that and only because it wanted to return an open file using open
intents. That task has been replaced by ->atomic_open so it is not necessary
anymore to pass the context to the create rpc operation.
Despite nfs4_proc_create apparently being okay with a NULL context it Oopses
somewhere down the call chain. So allocate a context here.
Change-Id: I1241a81129cb80a7f06338969ea95f28e10d40f0
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Replace NFS4 specific ->lookup implementation with ->atomic_open impelementation
and use the generic nfs_lookup for other lookups.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I287cb7db22925d56e7f37c8ae8869086e9e17841
NFSv4 can't do reliable opens in d_revalidate, since it cannot know whether a
mount needs to be followed or not. It does check d_mountpoint() on the dentry,
which can result in a weird error if the VFS found that the mount does not in
fact need to be followed, e.g.:
# mount --bind /mnt/nfs /mnt/nfs-clone
# echo something > /mnt/nfs/tmp/bar
# echo x > /tmp/file
# mount --bind /tmp/file /mnt/nfs-clone/tmp/bar
# cat /mnt/nfs/tmp/bar
cat: /mnt/nfs/tmp/bar: Not a directory
Which should, by any sane filesystem, result in "something" being printed.
So instead do the open in f_op->open() and in the unlikely case that the cached
dentry turned out to be invalid, drop the dentry and return EOPENSTALE to let
the VFS retry.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I680d2732dd85ae175a2ad9142f42bb3db16dc533
Add an ->atomic_open implementation which replaces the atomic open+create
operation implemented via ->create. No functionality is changed.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I5d06b0b21d17a68854b2b2b22a15d25b75e07724
Add an ->atomic_open implementation which replaces the atomic lookup+open+create
operation implemented via ->lookup and ->create operations.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Steve French <sfrench@samba.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I8b39432768b5b6336ffb643026e565f1aefc40f5
Perform open_check_o_direct() in a common place in do_last after opening the
file.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Icce292d477d2cb452acedd08ed35df5207294c07
Move the lookup retry logic to the bottom of the function to make the normal
case simpler to read.
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I6f0d88aae8d935c1138b3170bf171a69d453ab32
Consistently use bool for boolean values in do_last().
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I25241ab09fa97c0b27c9006c34691faf2ff53989
All users of open intents have been converted to use ->atomic_{open,create}.
This patch gets rid of nd->intent.open and related infrastructure.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I9143c542eaa8f34e899e647d1e39fa289816639a
Add a new inode operation which is called on the last component of an open.
Using this the filesystem can look up, possibly create and open the file in one
atomic operation. If it cannot perform this (e.g. the file type turned out to
be wrong) it may signal this by returning NULL instead of an open struct file
pointer.
i_op->atomic_open() is only called if the last component is negative or needs
lookup. Handling cached positive dentries here doesn't add much value: these
can be opened using f_op->open(). If the cached file turns out to be invalid,
the open can be retried, this time using ->atomic_open() with a fresh dentry.
For now leave the old way of using open intents in lookup and revalidate in
place. This will be removed once all the users are converted.
David Howells noticed that if ->atomic_open() opens the file but does not create
it, handle_truncate() will be called on it even if it is not a regular file.
Fix this by checking the file type in this case too.
Change-Id: Ic8ccf5b34eb678bec8ab12ea2f5aebbf79f8473b
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Copy __lookup_hash() into lookup_open(). The next patch will insert the atomic
open call just before the real lookup.
Change-Id: I0764bfb794f152e95f3592a3c8171f3935ab7101
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Split out lookup + maybe create from do_last(). This is the part under i_mutex
protection.
The function is called lookup_open() and returns a filp even though the open
part is not used yet.
Change-Id: If0cfeff6b9a91306c1e3ad98ad7168e50308aea6
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Miklos Szeredi points out that we need to also worry about memory
odering when doing the dentry name comparison asynchronously with RCU.
In particular, doing a rename can do a memcpy() of one dentry name over
another, and we want to make sure that any unlocked reader will always
see the proper terminating NUL character, so that it won't ever run off
the allocation.
Rather than having to be extra careful with the name copy or at lookup
time for each character, this resolves the issue by making sure that all
names that are inlined in the dentry always have a NUL character at the
end of the name allocation. If we do that at dentry allocation time, we
know that no future name copy will ever change that final NUL to
anything else, so there are no memory ordering issues.
So even if a concurrent rename ends up overwriting the NUL character
that terminates the original name, we always know that there is one
final NUL at the end, and there is no worry about the lockless RCU
lookup traversing the name too far.
The out-of-line allocations are never copied over, so we can just make
sure that we write the name (with terminating NULL) and do a write
barrier before we expose the name to anything else by setting it in the
dentry.
Reported-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I5890f1c8d9d207dcf508aa17b373a6d7e6d4e586
This allows comparing hash and len in one operation on 64-bit
architectures. Right now only __d_lookup_rcu() takes advantage of this,
since that is the case we care most about.
The use of anonymous struct/unions hides the alternate 64-bit approach
from most users, the exception being a few cases where we initialize a
'struct qstr' with a static initializer. This makes the problematic
cases use a new QSTR_INIT() helper function for that (but initializing
just the name pointer with a "{ .name = xyzzy }" initializer remains
valid, as does just copying another qstr structure).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I710810eb8717563264428e39c99e62599d31907e
All callers do want to check the dentry length, but some of them can
check the length and the hash together, so doing it in dentry_cmp() can
be counter-productive.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I19bda91a21594b0150f8eecef0f2738984c3b13e
Commit 12f8ad4b05 ("vfs: clean up __d_lookup_rcu() and dentry_cmp()
interfaces") did the careful ACCESS_ONCE() of the dentry name only for
the word-at-a-time case, even though the issue is generic.
Admittedly I don't really see gcc ever reloading the value in the middle
of the loop, so the ACCESS_ONCE() protects us from a fairly theoretical
issue. But better safe than sorry.
Also, this consolidates the common parts of the word-at-a-time and
bytewise logic, which includes checking the length. We'll be changing
that later.
Change-Id: Icd5773ff1910d0509e250eb65a469e99d0145795
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make the slow lookup part of O_CREAT and non-O_CREAT opens common.
This allows atomic_open to be hooked into the slow lookup part.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I1e3c97737246f53fb4e33d2df5586e0b422aa30e
Check O_CREAT on the slow lookup paths where necessary. This allows the rest to
be shared with plain open.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I498c7daabc652b940d2618f95580a97ed16fe129
no need for kludgy "set cookie to ERR_PTR(...) because we failed
before we did actual ->follow_link() and want to suppress put_link()",
no pointless check in put_link() itself.
Callers checked if follow_link() has failed anyway; might as well
break out of their loops if that happened, without bothering
to call put_link() first.
[AV: folded fixes from hch]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I240bcdcbf8a89b925716e69610def8c341dd2419
NFS optimizes away d_revalidates for last component of open. This means that
open itself can find the dentry stale.
This patch allows the filesystem to return EOPENSTALE and the VFS will retry the
lookup on just the last component if possible.
If the lookup was done using RCU mode, including the last component, then this
is not possible since the parent dentry is lost. In this case fall back to
non-RCU lookup. Currently this is not used since NFS will always leave RCU
mode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Ie1f7465757dc9086ef0ffefe22c969ef3c6ddedb
Now the post lookup code can be shared between O_CREAT and plain opens since
they are essentially the same.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Ia366d92c0e4edc183bfa23218676083872ef10f0
This allows this code to be shared between O_CREAT and plain opens.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I07469a80d749749e2b161ef500afd98895b33e6a
This allows this code to be shared between O_CREAT and plain opens.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I74a1b2a53fe009245bfce52dfc17f7628ac6d9c0
Check for ENOTDIR before finishing open. This allows this code to be shared
between O_CREAT and plain opens.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Ib5bcfc2548d45b8c632bb11aecb3f5618887d3d1
This will allow this code to be used in RCU mode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I72145c85cd20934d00bc9cbcb20efe42a636d592
This will allow this code to be used in RCU mode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I16990161f7e02dcdfd8979cb5594fe4a8207fca1
Use helper variable instead of path->dentry->d_inode before complete_walk().
This will allow this code to be used in RCU mode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I8fd1525e9d0efd992451664c0fb545bbd4bb40d3
Allow returning from do_last() with LOOKUP_RCU still set on the "out:" and
"exit:" labels.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Ic63718547582cf09a2c0bbc86dcc9084bd080ffc
Split do_lookup() into two functions:
lookup_fast() - does cached lookup without i_mutex
lookup_slow() - does lookup with i_mutex
Both follow managed dentries.
The new functions are needed by atomic_open.
Change-Id: Ic32255a88ff82a92622a20135eb034ad3fa1d5a7
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The calling conventions for __d_lookup_rcu() and dentry_cmp() are
annoying in different ways, and there is actually one single underlying
reason for both of the annoyances.
The fundamental reason is that we do the returned dentry sequence number
check inside __d_lookup_rcu() instead of doing it in the caller. This
results in two annoyances:
- __d_lookup_rcu() now not only needs to return the dentry and the
sequence number that goes along with the lookup, it also needs to
return the inode pointer that was validated by that sequence number
check.
- and because we did the sequence number check early (to validate the
name pointer and length) we also couldn't just pass the dentry itself
to dentry_cmp(), we had to pass the counted string that contained the
name.
So that sequence number decision caused two separate ugly calling
conventions.
Both of these problems would be solved if we just did the sequence
number check in the caller instead. There's only one caller, and that
caller already has to do the sequence number check for the parent
anyway, so just do that.
That allows us to stop returning the dentry->d_inode in that in-out
argument (pointer-to-pointer-to-inode), so we can make the inode
argument just a regular input inode pointer. The caller can just load
the inode from dentry->d_inode, and then do the sequence number check
after that to make sure that it's synchronized with the name we looked
up.
And it allows us to just pass in the dentry to dentry_cmp(), which is
what all the callers really wanted. Sure, dentry_cmp() has to be a bit
careful about the dentry (which is not stable during RCU lookup), but
that's actually very simple.
And now that dentry_cmp() can clearly see that the first string argument
is a dentry, we can use the direct word access for that, instead of the
careful unaligned zero-padding. The dentry name is always properly
aligned, since it is a single path component that is either embedded
into the dentry itself, or was allocated with kmalloc() (see __d_alloc).
Finally, this also uninlines the nasty slow-case for dentry comparisons:
that one *does* need to do a sequence number check, since it will call
in to the low-level filesystems, and we want to give those a stable
inode pointer and path component length/start arguments. Doing an extra
sequence check for that slow case is not a problem, though.
Change-Id: If75355452c45e51c72838fa50e914df017b42531
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes a number of silly games around strncpy_from_user() in
do_getname(), and removes that helper function entirely. We instead
make getname_flags() just use strncpy_from_user() properly directly.
Removing the wrapper function simplifies things noticeably, mostly
because we no longer play the unnecessary games with segments (x86
strncpy_from_user() no longer needs the hack), but also because the
empty path handling is just much more obvious. The return value of
"strncpy_to_user()" is much more obvious than checking an odd error
return case from do_getname().
[ non-x86 architectures were notified of this change several weeks ago,
since it is possible that they have copied the old broken x86
strncpy_from_user. But nobody reacted, so .. See
http://www.spinics.net/lists/linux-arch/msg17313.html
for details ]
Cc: linux-arch@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: Ic049b87071c10330b1cd3f864dd0c4c5d98464df
Safely making device nodes in a container is solvable but simply
having the capability in a user namespace is not sufficient to make
this work.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Change-Id: I4eb0afd78bb4a8b106dca3002c11ae81caae9e1d
If open fails, don't put the file. This allows it to be reused if open needs to
be retried.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: I78695bdf3ab30e2f313f1fb5ec79c9cd572f4c55
Move put_filp() out to __dentry_open(), the only caller now.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Ica706ac4611a66cd6e637650bd8143148fa95e44
Split __dentry_open() into two functions:
do_dentry_open() - does most of the actual work, doesn't put file on failure
open_check_o_direct() - after a successful open, checks direct_IO method
This will allow i_op->atomic_open to do just the file initialization and leave
the direct_IO checking to the VFS.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Change-Id: Ieb8a4e7c4ec9a12636c184d757a5f7a49c5e75df
