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2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-08Merge branch 'for-next' into for-linusJiri Kosina
Conflicts: Documentation/filesystems/proc.txt arch/arm/mach-u300/include/mach/debug-macro.S drivers/net/qlge/qlge_ethtool.c drivers/net/qlge/qlge_main.c drivers/net/typhoon.c
2010-03-03Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: fix large stack use fuse: cleanup in fuse_notify_inval_...()
2010-02-09tree-wide: Assorted spelling fixesDaniel Mack
In particular, several occurances of funny versions of 'success', 'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address', 'beginning', 'desirable', 'separate' and 'necessary' are fixed. Signed-off-by: Daniel Mack <daniel@caiaq.de> Cc: Joe Perches <joe@perches.com> Cc: Junio C Hamano <gitster@pobox.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-02-05fuse: fix large stack useFang Wenqi
gcc 4.4 warns about: fs/fuse/dev.c: In function ‘fuse_notify_inval_entry’: fs/fuse/dev.c:925: warning: the frame size of 1060 bytes is larger than 1024 bytes The problem is we declare two structures and a large array on the stack, I move the array alway from the stack and allocate memory for it dynamically. Signed-off-by: Fang Wenqi <antonf@turbolinux.com.cn> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-02-05fuse: cleanup in fuse_notify_inval_...()Miklos Szeredi
Small cleanup in fuse_notify_inval_inode() and fuse_notify_inval_entry(). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-02-03mm: flush dcache before writing into page to avoid aliasanfei zhou
The cache alias problem will happen if the changes of user shared mapping is not flushed before copying, then user and kernel mapping may be mapped into two different cache line, it is impossible to guarantee the coherence after iov_iter_copy_from_user_atomic. So the right steps should be: flush_dcache_page(page); kmap_atomic(page); write to page; kunmap_atomic(page); flush_dcache_page(page); More precisely, we might create two new APIs flush_dcache_user_page and flush_dcache_kern_page to replace the two flush_dcache_page accordingly. Here is a snippet tested on omap2430 with VIPT cache, and I think it is not ARM-specific: int val = 0x11111111; fd = open("abc", O_RDWR); addr = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); *(addr+0) = 0x44444444; tmp = *(addr+0); *(addr+1) = 0x77777777; write(fd, &val, sizeof(int)); close(fd); The results are not always 0x11111111 0x77777777 at the beginning as expected. Sometimes we see 0x44444444 0x77777777. Signed-off-by: Anfei <anfei.zhou@gmail.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: <linux-arch@vger.kernel.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-27fuse: reject O_DIRECT flag also in fuse_createCsaba Henk
The comment in fuse_open about O_DIRECT: "VFS checks this, but only _after_ ->open()" also holds for fuse_create, however, the same kind of check was missing there. As an impact of this bug, open(newfile, O_RDWR|O_CREAT|O_DIRECT) fails, but a stub newfile will remain if the fuse server handled the implied FUSE_CREATE request appropriately. Other impact: in the above situation ima_file_free() will complain to open/free imbalance if CONFIG_IMA is set. Signed-off-by: Csaba Henk <csaba@gluster.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Harshavardhana <harsha@gluster.com> Cc: stable@kernel.org
2009-11-04fuse: invalidate target of renameMiklos Szeredi
Invalidate the target's attributes, which may have changed (such as nlink, change time) so that they are refreshed on the next getattr(). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-11-04fuse: fix kunmap in fuse_ioctl_copy_userJens Axboe
Looks like another victim of the confusing kmap() vs kmap_atomic() API differences. Reported-by: Todor Gyumyushev <yodor1@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: stable@kernel.org
2009-11-04fuse: prevent fuse_put_request on invalid pointerAnand V. Avati
fuse_direct_io() has a loop where requests are allocated in each iteration. if allocation fails, the loop is broken out and follows into an unconditional fuse_put_request() on that invalid pointer. Signed-off-by: Anand V. Avati <avati@gluster.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: stable@kernel.org
2009-09-27const: mark struct vm_struct_operationsAlexey Dobriyan
* mark struct vm_area_struct::vm_ops as const * mark vm_ops in AGP code But leave TTM code alone, something is fishy there with global vm_ops being used. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24truncate: use new helpersnpiggin@suse.de
Update some fs code to make use of new helper functions introduced in the previous patch. Should be no significant change in behaviour (except CIFS now calls send_sig under i_lock, via inode_newsize_ok). Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Miklos Szeredi <miklos@szeredi.hu> Cc: linux-nfs@vger.kernel.org Cc: Trond.Myklebust@netapp.com Cc: linux-cifs-client@lists.samba.org Cc: sfrench@samba.org Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-09-18Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: add fusectl interface to max_background fuse: limit user-specified values of max background requests fuse: use drop_nlink() instead of direct nlink manipulation fuse: document protocol version negotiation fuse: make the number of max background requests and congestion threshold tunable
2009-09-16fs: Assign bdi in super_blockJens Axboe
We do this automatically in get_sb_bdev() from the set_bdev_super() callback. Filesystems that have their own private backing_dev_info must assign that in ->fill_super(). Note that ->s_bdi assignment is required for proper writeback! Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-16fuse: add fusectl interface to max_backgroundCsaba Henk
Make the max_background and congestion_threshold parameters of a FUSE mount tunable at runtime by adding the respective knobs to its directory within the fusectl filesystem. Signed-off-by: Csaba Henk <csaba@gluster.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-09-16fuse: limit user-specified values of max background requestsCsaba Henk
An untrusted user could DoS the system if s/he were allowed to accumulate an arbitrary number of pending background requests by setting the above limits to extremely high values in INIT. This patch excludes this possibility by imposing global upper limits on the possible values of per-mount "max background requests" and "congestion threshold" parameters for unprivileged FUSE filesystems. These global limits are implemented as module parameters. Signed-off-by: Csaba Henk <csaba@gluster.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-09-16fuse: use drop_nlink() instead of direct nlink manipulationCsaba Henk
drop_nlink() is the API function to decrease the link count of an inode. However, at a place the control filesystem used the decrement operator on i_nlink directly. Fix this. Cc: Anand Avati <avati@gluster.com> Signed-off-by: Csaba Henk <csaba@gluster.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-09-11writeback: add name to backing_dev_infoJens Axboe
This enables us to track who does what and print info. Its main use is catching dirty inodes on the default_backing_dev_info, so we can fix that up. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-11Revert "fuse: Fix build error" as unnecessaryLinus Torvalds
This reverts commit 097041e576ee3a50d92dd643ee8ca65bf6a62e21. Trond had a better fix, which is the parent of this one ("Fix compile error due to congestion_wait() changes") Requested-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-11fuse: Fix build errorLarry Finger
When building v2.6.31-rc2-344-g69ca06c, the following build errors are found due to missing includes: CC [M] fs/fuse/dev.o fs/fuse/dev.c: In function ‘request_end’: fs/fuse/dev.c:289: error: ‘BLK_RW_SYNC’ undeclared (first use in this function) ... fs/nfs/write.c: In function ‘nfs_set_page_writeback’: fs/nfs/write.c:207: error: ‘BLK_RW_ASYNC’ undeclared (first use in this function) Signed-off-by: Larry Finger@lwfinger.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-10Fix congestion_wait() sync/async vs read/write confusionJens Axboe
Commit 1faa16d22877f4839bd433547d770c676d1d964c accidentally broke the bdi congestion wait queue logic, causing us to wait on congestion for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-07fuse: make the number of max background requests and congestion threshold ↵Csaba Henk
tunable The practical values for these limits depend on the design of the filesystem server so let userspace set them at initialization time. Signed-off-by: Csaba Henk <csaba@gluster.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-06-30fuse: invalidation reverse callsJohn Muir
Add notification messages that allow the filesystem to invalidate VFS caches. Two notifications are added: 1) inode invalidation - invalidate cached attributes - invalidate a range of pages in the page cache (this is optional) 2) dentry invalidation - try to invalidate a subtree in the dentry cache Care must be taken while accessing the 'struct super_block' for the mount, as it can go away while an invalidation is in progress. To prevent this, introduce a rw-semaphore, that is taken for read during the invalidation and taken for write in the ->kill_sb callback. Cc: Csaba Henk <csaba@gluster.com> Cc: Anand Avati <avati@zresearch.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-06-30fuse: allow umask processing in userspaceMiklos Szeredi
This patch lets filesystems handle masking the file mode on creation. This is needed if filesystem is using ACLs. - The CREATE, MKDIR and MKNOD requests are extended with a "umask" parameter. - A new FUSE_DONT_MASK flag is added to the INIT request/reply. With this the filesystem may request that the create mode is not masked. CC: Jean-Pierre André <jean-pierre.andre@wanadoo.fr> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-06-30fuse: fix bad return value in fuse_file_poll()Miklos Szeredi
Fix fuse_file_poll() which returned a -errno value instead of a poll mask. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org
2009-06-30fuse: fix return value of fuse_dev_write()Csaba Henk
On 64 bit systems -- where sizeof(ssize_t) > sizeof(int) -- the following test exposes a bug due to a non-careful return of an int or unsigned value: implement a FUSE filesystem which sends an unsolicited notification to the kernel with invalid opcode. The respective write to /dev/fuse will return (1 << 32) - EINVAL with errno == 0 instead of -1 with errno == EINVAL. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org
2009-06-17fuse doesn't need BKL in ->umount_begin()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-12Merge branch 'cuse' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse * 'cuse' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: CUSE: implement CUSE - Character device in Userspace fuse: export symbols to be used by CUSE fuse: update fuse_conn_init() and separate out fuse_conn_kill() fuse: don't use inode in fuse_file_poll fuse: don't use inode in fuse_do_ioctl() helper fuse: don't use inode in fuse_sync_release() fuse: create fuse_do_open() helper for CUSE fuse: clean up args in fuse_finish_open() and fuse_release_fill() fuse: don't use inode in helpers called by fuse_direct_io() fuse: add members to struct fuse_file fuse: prepare fuse_direct_io() for CUSE fuse: clean up fuse_write_fill() fuse: use struct path in release structure fuse: misc cleanups
2009-06-09CUSE: implement CUSE - Character device in UserspaceTejun Heo
CUSE enables implementing character devices in userspace. With recent additions of ioctl and poll support, FUSE already has most of what's necessary to implement character devices. All CUSE has to do is bonding all those components - FUSE, chardev and the driver model - nicely. When client opens /dev/cuse, kernel starts conversation with CUSE_INIT. The client tells CUSE which device it wants to create. As the previous patch made fuse_file usable without associated fuse_inode, CUSE doesn't create super block or inodes. It attaches fuse_file to cdev file->private_data during open and set ff->fi to NULL. The rest of the operation is almost identical to FUSE direct IO case. Each CUSE device has a corresponding directory /sys/class/cuse/DEVNAME (which is symlink to /sys/devices/virtual/class/DEVNAME if SYSFS_DEPRECATED is turned off) which hosts "waiting" and "abort" among other things. Those two files have the same meaning as the FUSE control files. The only notable lacking feature compared to in-kernel implementation is mmap support. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-05-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: destroy bdi on error
2009-05-09vfs: umount_begin BKL pushdownAlessio Igor Bogani
Push BKL down into ->umount_begin() Signed-off-by: Alessio Igor Bogani <abogani@texware.it> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-04-28fuse: export symbols to be used by CUSETejun Heo
Export the following symbols for CUSE. fuse_conn_put() fuse_conn_get() fuse_conn_kill() fuse_send_init() fuse_do_open() fuse_sync_release() fuse_direct_io() fuse_do_ioctl() fuse_file_poll() fuse_request_alloc() fuse_get_req() fuse_put_request() fuse_request_send() fuse_abort_conn() fuse_dev_release() fuse_dev_operations Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: update fuse_conn_init() and separate out fuse_conn_kill()Tejun Heo
Update fuse_conn_init() such that it doesn't take @sb and move bdi registration into a separate function. Also separate out fuse_conn_kill() from fuse_put_super(). These will be used to implement cuse. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: don't use inode in fuse_file_pollMiklos Szeredi
Use ff->fc and ff->nodeid instead of file->f_dentry->d_inode in the fuse_file_poll() implementation. This prepares this function for use by CUSE, where the inode is not owned by a fuse filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: don't use inode in fuse_do_ioctl() helperMiklos Szeredi
Create a helper for sending an IOCTL request that doesn't use a struct inode. This prepares this function for use by CUSE, where the inode is not owned by a fuse filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: don't use inode in fuse_sync_release()Miklos Szeredi
Make fuse_sync_release() a generic helper function that doesn't need a struct inode pointer. This makes it suitable for use by CUSE. Change return value of fuse_release_common() from int to void. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: create fuse_do_open() helper for CUSEMiklos Szeredi
Create a helper for sending an OPEN request that doesn't need a struct inode pointer. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: clean up args in fuse_finish_open() and fuse_release_fill()Miklos Szeredi
Move setting ff->fh, ff->nodeid and file->private_data outside fuse_finish_open(). Add ->open_flags member to struct fuse_file. This simplifies the argument passing to fuse_finish_open() and fuse_release_fill(), and paves the way for creating an open helper that doesn't need an inode pointer. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: don't use inode in helpers called by fuse_direct_io()Miklos Szeredi
Use ff->fc and ff->nodeid instead of passing down the inode. This prepares this function for use by CUSE, where the inode is not owned by a fuse filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: add members to struct fuse_fileMiklos Szeredi
Add new members ->fc and ->nodeid to struct fuse_file. This will aid in converting functions for use by CUSE, where the inode is not owned by a fuse filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: prepare fuse_direct_io() for CUSEMiklos Szeredi
Move code operating on the inode out from fuse_direct_io(). This prepares this function for use by CUSE, where the inode is not owned by a fuse filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: clean up fuse_write_fill()Miklos Szeredi
Move out code from fuse_write_fill() which is not common to all callers. Remove two function arguments which become unnecessary. Also remove unnecessary memset(), the request is already initialized to zero. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: use struct path in release structureMiklos Szeredi
Use struct path instead of separate dentry and vfsmount in req->misc.release. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-28fuse: destroy bdi on errorMiklos Szeredi
Destroy bdi on error in fuse_fill_super(). This was an omission from commit 26c3679101dbccc054dcf370143941844ba70531 "fuse: destroy bdi on umount", which moved the bdi_destroy() call from fuse_conn_put() to fuse_put_super(). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org
2009-04-28fuse: misc cleanupsTejun Heo
* fuse_file_alloc() was structured in weird way. The success path was split between else block and code following the block. Restructure the code such that it's easier to read and modify. * Unindent success path of fuse_release_common() to ease future changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2009-04-09fuse: fix "direct_io" private mmapMiklos Szeredi
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>
2009-04-09fuse: fix argument type in fuse_get_user_pages()Miklos Szeredi
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>
2009-04-02fuse: allow private mappings of "direct_io" filesMiklos Szeredi
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>
2009-04-02fuse: allow kernel to access "direct_io" filesMiklos Szeredi
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>