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2008-05-02Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: [PATCH] fix sysctl_nr_open bugs [PATCH] sanitize anon_inode_getfd() [PATCH] split linux/file.h [PATCH] make osf_select() use core_sys_select() [PATCH] remove horrors with irix tty ioctls handling [PATCH] fix file and descriptor handling in perfmon
2008-05-02netns: assign PDE->data before gluing entry into /proc treeDenis V. Lunev
In this unfortunate case, proc_mkdir_mode wrapper can't be used anymore and this is no way to reuse proc_create_data due to nlinks assignment. So, copy the code from proc_mkdir and assign PDE->data at the appropriate moment. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-01Merge git://git.infradead.org/mtd-2.6Linus Torvalds
* git://git.infradead.org/mtd-2.6: [MTD][NOR] Add physical address to point() method [JFFS2] Track parent inode for directories (for NFS export) [JFFS2] Invert last argument of jffs2_gc_fetch_inode(), make it boolean. [JFFS2] Quiet lockdep false positive. [JFFS2] Clean up jffs2_alloc_inode() and jffs2_i_init_once() [MTD] Delete long-unused jedec.h header file. [MTD] [NAND] at91_nand: use at91_nand_{en,dis}able consistently.
2008-05-01[MTD][NOR] Add physical address to point() methodJared Hulbert
Adding the ability to get a physical address from point() in addition to virtual address. This physical address is required for XIP of userspace code from flash. Signed-off-by: Jared Hulbert <jaredeh@gmail.com> Reviewed-by: Jörn Engel <joern@logfs.org> Acked-by: Nicolas Pitre <nico@cam.org> Acked-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-05-01[JFFS2] Track parent inode for directories (for NFS export)David Woodhouse
To support NFS export, we need to know the parent inode of directories. Rather than growing the jffs2_inode_cache structure, share space with the nlink field -- which was always set to 1 for directories anyway. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-05-01[PATCH] fix sysctl_nr_open bugsAl Viro
* if luser with root sets it to something that is not a multiple of BITS_PER_LONG, the system is screwed. * if it gets decreased at the wrong time, we can get expand_files() returning success and _not_ increasing the size of table as asked. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-01[PATCH] sanitize anon_inode_getfd()Al Viro
a) none of the callers even looks at inode or file returned by anon_inode_getfd() b) any caller that would try to look at those would be racy, since by the time it returns we might have raced with close() from another thread and that file would be pining for fjords. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-01[PATCH] split linux/file.hAl Viro
Initial splitoff of the low-level stuff; taken to fdtable.h Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-01[PATCH] make osf_select() use core_sys_select()Al Viro
... instead of open-coding it Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-01[JFFS2] Invert last argument of jffs2_gc_fetch_inode(), make it boolean.David Woodhouse
We don't actually care about nlink; we only care whether the inode in question is unlinked or not. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-05-01fuse: use clamp() rather than nested min/maxHarvey Harrison
clamp() exists for this use. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01autofs: path_{get,put}() cleanupsJan Blunck
Here are some more places where path_{get,put}() can be used instead of dput()/mntput() pair. Besides that it fixes a bug in autofs4_mount_busy() where mntput() was called before dput(). Signed-off-by: Jan Blunck <jblunck@suse.de> Cc: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01autofs4: fix incorrect return from root.c:try_to_fill_dentry()Jeff Moyer
Jeff Moyer has identified a case where the autofs4 function root.c:try_to_fill_dentry() can return -EBUSY when it should return 0. Jeff's description of the way this happens is: "automount starts an expire for directory d. after the callout to the daemon, but before the rmdir, another process tries to walk into the same directory. It puts itself onto the waitq, pending the expiration. When the expire finishes, the second process is woken up. In try_to_fill_dentry, it does this check: status = d_invalidate(dentry); if (status != -EBUSY) return -EAGAIN; And status is EBUSY. The dentry still has a non-zero d_inode, and the flags do not contain LOOKUP_CONTINUE or LOOKUP_DIRECTORY So, we fall through and return -EBUSY to the caller." Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01autofs4: fix execution order race in mount request codeJeff Moyer
Jeff Moyer has identified a race in due to an execution order dependency in the autofs4 function root.c:try_to_fill_dentry(). Jeff's description of this race is: "P1 does a lookup of /mount/submount/foo. Since the VFS can't find an entry for "foo" under /mount/submount, it calls into the autofs4 kernel module to allocate a new dentry, D1. The kernel creates a new waitq for this lookup and calls the daemon to perform the mount. The daemon performs a mkdir of the "foo" directory under /mount/submount, which ends up creating a *new* dentry, D2. Then, P2 does a lookup of /mount/submount/foo. The VFS path walking logic finds a dentry in the dcache, D2, and calls the revalidate function with this. In the autofs4 revalidate code, we then trigger a mount, since the dentry is an empty directory that isn't a mountpoint, and so set DCACHE_AUTOFS_PENDING and call into the wait code to trigger the mount. The wait code finds our existing waitq entry (since it is keyed off of the directory name) and adds itself to the list of waiters. After the daemon finishes the mount, it calls back into the kernel to release the waiters. When this happens, P1 is woken up and goes about clearing the DCACHE_AUTOFS_PENDING flag, but it does this in D1! So, given that P1 in our case is a program that will immediately try to access a file under /mount/submount/foo, we end up finding the dentry D2 which still has the pending flag set, and we set out to wait for a mount *again*! So, one way to address this is to re-do the lookup at the end of try_to_fill_dentry, and to clear the pending flag on the hashed dentry. This seems a sane approach to me." And Jeff's patch does this. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01autofs4: check for invalid dentry in getpathIan Kent
Catch invalid dentry when calculating its path. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01autofs4: fix sparse warning in waitq.c:autofs4_expire_indirect()Ian Kent
Re-order some code in expire.c:autofs4_expire_indirect() to avoid compile warning, reported by Harvey Harrison: CHECK fs/autofs4/expire.c fs/autofs4/expire.c:383:2: warning: context imbalance in 'autofs4_expire_indirect' - unexpected unlock Signed-off-by: Ian Kent <raven@themaw.net> Reviewed-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01vfs: fix permission checking in sys_utimensatMiklos Szeredi
If utimensat() is called with both times set to UTIME_NOW or one of them to UTIME_NOW and the other to UTIME_OMIT, then it will update the file time without any permission checking. I don't think this can be used for anything other than a local DoS, but could be quite bewildering at that (e.g. "Why was that large source tree rebuilt when I didn't modify anything???") This affects all kernels from 2.6.22, when the utimensat() syscall was introduced. Fix by doing the same permission checking as for the "times == NULL" case. Thanks to Michael Kerrisk, whose utimensat-non-conformances-and-fixes.patch in -mm also fixes this (and breaks other stuff), only he didn't realize the security implications of this bug. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01[JFFS2] Quiet lockdep false positive.David Woodhouse
Don't hold f->sem while calling into jffs2_do_create(). It makes lockdep unhappy, and we don't really need it -- the _reason_ it's a false positive is because nobody else can see this inode yet and so nobody will be trying to lock it anyway. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-05-01[JFFS2] Clean up jffs2_alloc_inode() and jffs2_i_init_once()David Woodhouse
Ditch a couple of pointless casts from void *, and use the normal variable name 'f' for jffs2_inode_info pointers -- especially since it actually shows up in lockdep reports. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-04-30Fix dnotify/close raceAl Viro
We have a race between fcntl() and close() that can lead to dnotify_struct inserted into inode's list *after* the last descriptor had been gone from current->files. Since that's the only point where dnotify_struct gets evicted, we are screwed - it will stick around indefinitely. Even after struct file in question is gone and freed. Worse, we can trigger send_sigio() on it at any later point, which allows to send an arbitrary signal to arbitrary process if we manage to apply enough memory pressure to get the page that used to host that struct file and fill it with the right pattern... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30ocfs2: Use GFP_NOFS in kmalloc during localalloc window moveSunil Mushran
kmalloc() during a localalloc window move can trigger the mm to prune the dcache which inturn can trigger the fs to delete an inode causing it start a recursive transaction. The fix also makes the change in kmalloc during localalloc shutdown just to be safe. Fixes oss bugzilla#901 http://oss.oracle.com/bugzilla/show_bug.cgi?id=901 Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-30ocfs2: Allow uid/gid/perm changes of symlinksSunil Mushran
This patch adds the ability to change attributes of a symlink. Fixes oss bugzilla#963 http://oss.oracle.com/bugzilla/show_bug.cgi?id=963 Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-30ocfs2/dlm: dlmdebug.c: make 2 functions staticAdrian Bunk
This patch makes the following needlessly global functions static: - stringify_lockname() - dlm_debug_put() Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-30ocfs2: make struct o2cb_stack_ops staticAdrian Bunk
This patch makes the needlessly global struct o2cb_stack_ops static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-30ocfs2: make struct ocfs2_control_device staticAdrian Bunk
This patch makes the needlessly global struct ocfs2_control_device static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-30ocfs2: Correct merge of 52f7c21 (Move /sys/o2cb to /sys/fs/o2cb)Joel Becker
Commit 52f7c21b613f80cb425d115c9e5b4ed958a133c0 was intended to move /sys/o2cb to /sys/fs/o2cb, providing /sys/o2cb as a symlink for backwards compatibility. However, the merge apparently added the symlink but failed to move the directory, resulting in a duplicate filename error. It's a one-line change that was missing. Signed-off-by: Joel Becker <joel.becker@oracle.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-30DEBUGFS: Correct location of debugfs API documentation.Robert P. J. Day
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-30sysfs: Disallow truncation of files in sysfsBen Hutchings
sysfs allows attribute files to be truncated, e.g. using ftruncate(), with the expected effect on their inode. For most attributes, this doesn't change the "real" size of the file i.e. how much can be read from it. However, the parameter validation for reading and writing binary attribute files is based on the inode size and not the size specified in the file's bin_attribute, so it can be broken by this. For example, if we try using dd to write to such a file: # pwd /sys/bus/pci/devices/0000:08:00.0 # ls -l config -rw-r--r-- 1 root root 4096 Feb 1 17:35 config # dd if=/dev/zero of=config bs=4 count=1 1+0 records in 1+0 records out # ls -l config -rw-r--r-- 1 root root 0 Feb 1 17:50 config # dd if=/dev/zero of=config bs=4 count=1 seek=128 dd: writing `config': No space left on device 1+0 records in 0+0 records out Also, after truncation to 0, parameter validation for read and write is disabled. Most bin_attribute read and write methods also validate the size and offset, but for some this will allow out-of-range access. This may be a security issue, though access to such files is often limited to root. In any case, the validation should remain for safety's sake!) This was previously reported in Bugzilla as bug 9867. sysfs should ignore size changes or else refuse them (by returning -EINVAL). This patch makes it ignore them. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-30Merge branch 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6Linus Torvalds
* 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6: [S390] Update default configuration. [S390] use generic sys_ptrace [S390] Remove self ptrace IEEE_IP hack. [S390] Convert to SPARSEMEM & SPARSEMEM_VMEMMAP [S390] System z large page support. [S390] Convert machine feature detection code to C. [S390] vmemmap: use clear_table to initialise page tables. [S390] Move stfl to system.h and delete duplicated version. [S390] uaccess_mvcos: #ifdef config dependent code. [S390] cpu topology: Fix possible deadlock. [S390] Add topology_core_siblings to topology.h [S390] cio: Make isc handling more robust. [S390] remove -traditional [S390] Automatically detect added cpus. [S390] smp: Fix locking order. [S390] Add missing ifndef/define to include/asm-s390/sysinfo.h. [S390] Move show_regs to traps.c. [S390] cio: Use strict_strtoul() for attributes.
2008-04-30fs: replace remaining __FUNCTION__ occurrencesHarvey Harrison
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30afs: replace remaining __FUNCTION__ occurrencesHarvey Harrison
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30debugobjects: add timer specific object debugging codeThomas Gleixner
Add calls to the generic object debugging infrastructure and provide fixup functions which allow to keep the system alive when recoverable problems have been detected by the object debugging core code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Greg KH <greg@kroah.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30hfsplus: fix warning with 64k PAGE_SIZEAndrew Morton
fs/hfsplus/btree.c: In function 'hfsplus_bmap_alloc': fs/hfsplus/btree.c:239: warning: comparison is always false due to limited range of data type But this might hide a real bug? Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30hfs: fix warning with 64k PAGE_SIZEAndrew Morton
fs/hfs/btree.c: In function 'hfs_bmap_alloc': fs/hfs/btree.c:263: warning: comparison is always false due to limited range of data type The patch makes the warning go away, but the code might actually be buggy? Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30sysv: [bl]e*_add_cpu conversionMarcin Slusarz
replace all: big/little_endian_variable = cpu_to_[bl]eX([bl]eX_to_cpu(big/little_endian_variable) + expression_in_cpu_byteorder); with: [bl]eX_add_cpu(&big/little_endian_variable, expression_in_cpu_byteorder); generated with semantic patch Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30quota: le*_add_cpu conversionMarcin Slusarz
replace all: little_endian_variable = cpu_to_leX(leX_to_cpu(little_endian_variable) + expression_in_cpu_byteorder); with: leX_add_cpu(&little_endian_variable, expression_in_cpu_byteorder); generated with semantic patch Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30hfs/hfsplus: be*_add_cpu conversionMarcin Slusarz
replace all: big_endian_variable = cpu_to_beX(beX_to_cpu(big_endian_variable) + expression_in_cpu_byteorder); with: beX_add_cpu(&big_endian_variable, expression_in_cpu_byteorder); generated with semantic patch Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30affs: be*_add_cpu conversionMarcin Slusarz
replace all: big_endian_variable = cpu_to_beX(beX_to_cpu(big_endian_variable) + expression_in_cpu_byteorder); with: beX_add_cpu(&big_endian_variable, expression_in_cpu_byteorder); generated with semantic patch Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30reiserfs: use open_bdev_exclChristoph Hellwig
Use the proper helper to open a blockdevice by name for filesystem use, this makes sure it's properly claimed (also added for open-by-number) and gets rid of the struct file abuse. Tested by mounting a reiserfs filesystem with external journal. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Chris Mason <chris.mason@oracle.com> Cc: Jeff Mahoney <jeffm@suse.com> Acked-by: Edward Shishkin <edward.shishkin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30fuse: fix sparse warningsMiklos Szeredi
fs/fuse/dev.c:306:2: warning: context imbalance in 'wait_answer_interruptible' - unexpected unlock fs/fuse/dev.c:361:2: warning: context imbalance in 'request_wait_answer' - unexpected unlock fs/fuse/dev.c:1002:4: warning: context imbalance in 'end_io_requests' - unexpected unlock 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>
2008-04-30fuse: fix race in llseekMiklos Szeredi
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>
2008-04-30fuse: fix node ID typeMiklos Szeredi
Node ID is 64bit but it is passed as unsigned long to some functions. This breakage wasn't noticed, because libfuse uses unsigned long too. 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>
2008-04-30fuse: fix max i/o size calculationMiklos Szeredi
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>
2008-04-30fuse: update file size on short readMiklos Szeredi
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>
2008-04-30fuse: implement perform_writeNick Piggin
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>
2008-04-30fuse: clean up setting i_size in writeMiklos Szeredi
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>
2008-04-30fuse: support writable mmapMiklos Szeredi
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>
2008-04-30mm: Add NR_WRITEBACK_TEMP counterMiklos Szeredi
Fuse will use temporary buffers to write back dirty data from memory mappings (normal writes are done synchronously). This is needed, because there cannot be any guarantee about the time in which a write will complete. By using temporary buffers, from the MM's point if view the page is written back immediately. If the writeout was due to memory pressure, this effectively migrates data from a full zone to a less full zone. This patch adds a new counter (NR_WRITEBACK_TEMP) for the number of pages used as temporary buffers. [Lee.Schermerhorn@hp.com: add vmstat_text for NR_WRITEBACK_TEMP] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30mm: bdi: add separate writeback accounting capabilityMiklos Szeredi
Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether 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>
2008-04-30mm: bdi: expose the BDI object in sysfs for FUSEMiklos Szeredi
Register FUSE's backing_dev_info under sysfs with the name "fuse-MAJOR:MINOR" Make the fuse control filesystem use s_dev instead of a fuse specific ID. This makes it easier to match directories under /sys/fs/fuse/connections/ with directories under /sys/class/bdi, and with actual mounts. 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>