MAP_PRIVATE mmap could return stale data from the cache for
"direct_io" files. Fix this by flushing the cache on mmap.
Found with a slightly modified fsx-linux.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Fix the following warning:
fs/fuse/file.c: In function 'fuse_direct_io':
fs/fuse/file.c:1002: warning: passing argument 3 of 'fuse_get_user_pages' from incompatible pointer type
This was introduced by commit f4975c67 "fuse: allow kernel to access
"direct_io" files".
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Allow MAP_PRIVATE mmaps of "direct_io" files. This is necessary for
execute support.
MAP_SHARED mappings require some sort of coherency between the
underlying file and the mapping. With "direct_io" it is difficult to
provide this, so for the moment just disallow shared (read-write and
read-only) mappings altogether.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Allow the kernel read and write on "direct_io" files. This is
necessary for nfs export and execute support.
The implementation is simple: if an access from the kernel is
detected, don't perform get_user_pages(), just use the kernel address
provided by the requester to copy from/to the userspace filesystem.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Change the page_mkwrite prototype to take a struct vm_fault, and return
VM_FAULT_xxx flags. There should be no functional change.
This makes it possible to return much more detailed error information to
the VM (and also can provide more information eg. virtual_address to the
driver, which might be important in some special cases).
This is required for a subsequent fix. And will also make it easier to
merge page_mkwrite() with fault() in future.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This bug was found with smatch (http://repo.or.cz/w/smatch.git/). If
we return directly the inode->i_mutex lock doesn't get released.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org
ff is set to NULL and then dereferenced on line 65. Compile tested only.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org
With the write_begin/write_end aops, page_symlink was broken because it
could no longer pass a GFP_NOFS type mask into the point where the
allocations happened. They are done in write_begin, which would always
assume that the filesystem can be entered from reclaim. This bug could
cause filesystem deadlocks.
The funny thing with having a gfp_t mask there is that it doesn't really
allow the caller to arbitrarily tinker with the context in which it can be
called. It couldn't ever be GFP_ATOMIC, for example, because it needs to
take the page lock. The only thing any callers care about is __GFP_FS
anyway, so turn that into a single flag.
Add a new flag for write_begin, AOP_FLAG_NOFS. Filesystems can now act on
this flag in their write_begin function. Change __grab_cache_page to
accept a nofs argument as well, to honour that flag (while we're there,
change the name to grab_cache_page_write_begin which is more instructive
and does away with random leading underscores).
This is really a more flexible way to go in the end anyway -- if a
filesystem happens to want any extra allocations aside from the pagecache
ones in ints write_begin function, it may now use GFP_KERNEL (rather than
GFP_NOFS) for common case allocations (eg. ocfs2_alloc_write_ctxt, for a
random example).
[kosaki.motohiro@jp.fujitsu.com: fix ubifs]
[kosaki.motohiro@jp.fujitsu.com: fix fuse]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Cleaned up the calling convention: just pass in the AOP flags
untouched to the grab_cache_page_write_begin() function. That
just simplifies everybody, and may even allow future expansion of the
logic. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Makes the existing annotations match the more common one per line style
and adds a few missing annotations.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Add fuse_ prefix to request_send*() and get_root_inode() as some of
those functions will be exported for CUSE. With or without CUSE
export, having the function names scoped is a good idea for
debuggability.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Implement poll support. Polled files are indexed using kh in a RB
tree rooted at fuse_conn->polled_files.
Client should send FUSE_NOTIFY_POLL notification once after processing
FUSE_POLL which has FUSE_POLL_SCHEDULE_NOTIFY set. Sending
notification unconditionally after the latest poll or everytime file
content might have changed is inefficient but won't cause malfunction.
fuse_file_poll() can sleep and requires patches from the following
thread which allows f_op->poll() to sleep.
http://thread.gmane.org/gmane.linux.kernel/726176
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
The file handle, fuse_file->fh, is opaque value supplied by userland
FUSE server and uniqueness is not guaranteed. Add file kernel handle,
fuse_file->kh, which is allocated by the kernel on file allocation and
guaranteed to be unique.
This will be used by poll to match notification to the respective file
but can be used for other purposes where unique file handle is
necessary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Generic ioctl support is tricky to implement because only the ioctl
implementation itself knows which memory regions need to be read
and/or written. To support this, fuse client can request retry of
ioctl specifying memory regions to read and write. Deep copying
(nested pointers) can be implemented by retrying multiple times
resolving one depth of dereference at a time.
For security and cleanliness considerations, ioctl implementation has
restricted mode where the kernel determines data transfer directions
and sizes using the _IOC_*() macros on the ioctl command. In this
mode, retry is not allowed.
For all FUSE servers, restricted mode is enforced. Unrestricted ioctl
will be used by CUSE.
Plese read the comment on top of fs/fuse/file.c::fuse_file_do_ioctl()
for more information.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
fuse_req->end() was supposed to be put the base reference but there's
no reason why it should. It only makes things more complex. Move it
out of ->end() and make it the responsibility of request_end().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Let the client request nonseekable open using FOPEN_NONSEEKABLE and
call nonseekable_open() on the file if requested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Update file size before using it in lseek(..., SEEK_END).
Reported-by: Amnon Shiloh <u3557@miso.sublimeip.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
All calls to remove_suid() are made with a file pointer, because
(similarly to file_update_time) it is called when the file is written.
Clean up callers by passing in a file instead of a dentry.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
If fuse filesystem doesn't define it's own lock operations, then allow the
lock manager to work with fuse.
Adding lockd support for remote locking is also possible, but more rarely
used, so leave it till later.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: David Teigland <teigland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Prior to 2.6.26 fuse only supported single page write requests. In theory all
fuse filesystem should be able support bigger than 4k writes, as there's
nothing in the API to prevent it. Unfortunately there's a known case in
NTFS-3G where big writes cause filesystem corruption. There could also be
other filesystems, where the lack of testing with big write requests would
result in bugs.
To prevent such problems on a kernel upgrade, disable big writes by default,
but let filesystems set a flag to turn it on.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Szabolcs Szakacsits <szaka@ntfs-3g.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fuse doesn't use i_mutex to protect setting i_size, and so
generic_file_llseek() can be racy: it doesn't use i_size_read().
So do a fuse specific llseek method, which does use i_size_read().
[akpm@linux-foundation.org: make `retval' loff_t]
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a bug that Werner Baumann reported: fuse can send a bigger write request
than the maximum specified. This only affected direct_io operation.
In addition set a sane minimum for the max_read and max_write tunables, so I/O
always makes some progress.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the READ request returned a short count, then either
- cached size is incorrect
- filesystem is buggy, as short reads are only allowed on EOF
So assume that the size is wrong and refresh it, so that cached read() doesn't
zero fill the missing chunk.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce fuse_perform_write. With fusexmp (a passthrough filesystem), large
(1MB) writes into a backing tmpfs filesystem are sped up by almost 4 times
(256MB/s vs 71MB/s).
[mszeredi@suse.cz]:
- split into smaller functions
- testing
- duplicate generic_file_aio_write(), so that there's no need to add a
new ->perform_write() a_op. Comment from hch.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Extract common code for setting i_size in write functions into a common
helper.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quoting Linus (3 years ago, FUSE inclusion discussions):
"User-space filesystems are hard to get right. I'd claim that they
are almost impossible, unless you limit them somehow (shared
writable mappings are the nastiest part - if you don't have those,
you can reasonably limit your problems by limiting the number of
dirty pages you accept through normal "write()" calls)."
Instead of attempting the impossible, I've just waited for the dirty page
accounting infrastructure to materialize (thanks to Peter Zijlstra and
others). This nicely solved the biggest problem: limiting the number of pages
used for write caching.
Some small details remained, however, which this largish patch attempts to
address. It provides a page writeback implementation for fuse, which is
completely safe against VM related deadlocks. Performance may not be very
good for certain usage patterns, but generally it should be acceptable.
It has been tested extensively with fsx-linux and bash-shared-mapping.
Fuse page writeback design
--------------------------
fuse_writepage() allocates a new temporary page with GFP_NOFS|__GFP_HIGHMEM.
It copies the contents of the original page, and queues a WRITE request to the
userspace filesystem using this temp page.
The writeback is finished instantly from the MM's point of view: the page is
removed from the radix trees, and the PageDirty and PageWriteback flags are
cleared.
For the duration of the actual write, the NR_WRITEBACK_TEMP counter is
incremented. The per-bdi writeback count is not decremented until the actual
write completes.
On dirtying the page, fuse waits for a previous write to finish before
proceeding. This makes sure, there can only be one temporary page used at a
time for one cached page.
This approach is wasteful in both memory and CPU bandwidth, so why is this
complication needed?
The basic problem is that there can be no guarantee about the time in which
the userspace filesystem will complete a write. It may be buggy or even
malicious, and fail to complete WRITE requests. We don't want unrelated parts
of the system to grind to a halt in such cases.
Also a filesystem may need additional resources (particularly memory) to
complete a WRITE request. There's a great danger of a deadlock if that
allocation may wait for the writepage to finish.
Currently there are several cases where the kernel can block on page
writeback:
- allocation order is larger than PAGE_ALLOC_COSTLY_ORDER
- page migration
- throttle_vm_writeout (through NR_WRITEBACK)
- sync(2)
Of course in some cases (fsync, msync) we explicitly want to allow blocking.
So for these cases new code has to be added to fuse, since the VM is not
tracking writeback pages for us any more.
As an extra safetly measure, the maximum dirty ratio allocated to a single
fuse filesystem is set to 1% by default. This way one (or several) buggy or
malicious fuse filesystems cannot slow down the rest of the system by hogging
dirty memory.
With appropriate privileges, this limit can be raised through
'/sys/class/bdi/<bdi>/max_ratio'.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the fields 'dentry' and 'vfsmount' into the request specific union, since
these are only used for the RELEASE request.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some open flags (O_APPEND, O_DIRECT) can be changed with fcntl(F_SETFL, ...)
after open, but fuse currently only sends the flags to userspace in open.
To make it possible to correcly handle changing flags, send the
current value to userspace in each read and write.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently reading a fuse file will stop at cached i_size and return
EOF, even though the file might have grown since the attributes were
last updated.
So detect if trying to read past EOF, and refresh the attributes
before continuing with the read.
Thanks to mpb for the report.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For mandatory locking the userspace filesystem needs to know the lock
ownership for read, write and truncate operations.
This patch adds the necessary fields to the protocol.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds a new helper function fuse_write_fill() which makes it
possible to send WRITE requests asynchronously.
A new flag for WRITE requests is also added which indicates that this a write
from the page cache, and not a "normal" file write.
This patch is in preparation for writable mmap support.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Each WRITE request must carry a valid file descriptor. When a page is written
back from a memory mapping, the file through which the page was dirtied is not
available, so a new mechananism is needed to find a suitable file in
->writepage(s).
A list of fuse_files is added to fuse_inode. The file is removed from the
list in fuse_release().
This patch is in preparation for writable mmap support.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is trivial to add support for flock(2) semantics to the existing protocol,
by setting the lock owner field to the file pointer, and passing a new
FUSE_LK_FLOCK flag with the locking request.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch allows fuse filesystems to implement open(..., O_TRUNC) as a single
request, instead of separate truncate and open requests.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Getattr and lookup operations can be running in parallel to attribute changing
operations, such as write and setattr.
This means, that if for example getattr was slower than a write, the cached
size attribute could be set to a stale value.
To prevent this race, introduce a per-filesystem attribute version counter.
This counter is incremented whenever cached attributes are modified, and the
incremented value stored in the inode.
Before storing new attributes in the cache, getattr and lookup check, using
the version number, whether the attributes have been modified during the
request's lifetime. If so, the returned attributes are not cached, because
they might be stale.
Thanks to Jakub Bogusz for the bug report and test program.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Jakub Bogusz <jakub.bogusz@gemius.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move dput/mntput pair from request_end() to fuse_release_end(), because
there's no other place they are used.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fuse_permission() didn't refresh inode attributes before using them, even if
the validity has already expired.
Thanks to Junjiro Okajima for spotting this.
Also remove some old code to unconditionally refresh the attributes on the
root inode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Other than truncate, there are two cases, when fuse tries to get rid
of cached pages:
a) in open, if KEEP_CACHE flag is not set
b) in getattr, if file size changed spontaneously
Until now invalidate_mapping_pages() were used, which didn't get rid
of mapped pages. This is wrong, and becomes more wrong as dirty pages
are introduced. So instead properly invalidate all pages with
invalidate_inode_pages2().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make lifetime of 'struct fuse_file' independent from 'struct file' by adding a
reference counter and destructor.
This will enable asynchronous page writeback, where it cannot be guaranteed,
that the file is not released while a request with this file handle is being
served.
The actual RELEASE request is only sent when there are no more references to
the fuse_file.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[mszeredi]
- don't send zero length write requests
- it is not legal for the filesystem to return with zero written bytes
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They can use generic_file_splice_read() instead. Since sys_sendfile() now
prefers that, there should be no change in behaviour.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This fixes O_APPEND in direct IO mode. Also checks writes against file size
limits, notably rlimits.
Reported by Greg Bruno.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.
This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
getting them indirectly
Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
they don't need sched.h
b) sched.h stops being dependency for significant number of files:
on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
after patch it's only 3744 (-8.3%).
Cross-compile tested on
all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
alpha alpha-up
arm
i386 i386-up i386-defconfig i386-allnoconfig
ia64 ia64-up
m68k
mips
parisc parisc-up
powerpc powerpc-up
s390 s390-up
sparc sparc-up
sparc64 sparc64-up
um-x86_64
x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig
as well as my two usual configs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
posix_test_lock() and ->lock() do the same job but have gratuitously
different interfaces. Modify posix_test_lock() so the two agree,
simplifying some code in the process.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Convert all calls to invalidate_inode_pages() into open-coded calls to
invalidate_mapping_pages().
Leave the invalidate_inode_pages() wrapper in place for now, marked as
deprecated.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The use by FUSE was just a remnant of an optimization from the time
when writable mappings were supported.
Now FUSE never actually allows the creation of dirty pages, so this
invocation of clear_page_dirty() is effectively a no-op.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Miklos Szeredi