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* Merge git://git.infradead.org/mtd-2.6Linus Torvalds2008-05-0114-68/+108
|\ | | | | | | | | | | | | | | | | | | | | * 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.
| * [MTD][NOR] Add physical address to point() methodJared Hulbert2008-05-013-10/+13
| | | | | | | | | | | | | | | | | | | | | | | | 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>
| * [JFFS2] Track parent inode for directories (for NFS export)David Woodhouse2008-05-0112-42/+70
| | | | | | | | | | | | | | | | 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>
| * [JFFS2] Invert last argument of jffs2_gc_fetch_inode(), make it boolean.David Woodhouse2008-05-014-7/+8
| | | | | | | | | | | | | | 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>
| * [JFFS2] Quiet lockdep false positive.David Woodhouse2008-05-012-3/+10
| | | | | | | | | | | | | | | | | | 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>
| * [JFFS2] Clean up jffs2_alloc_inode() and jffs2_i_init_once()David Woodhouse2008-05-011-7/+8
| | | | | | | | | | | | | | | | 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>
* | fuse: use clamp() rather than nested min/maxHarvey Harrison2008-05-011-1/+1
| | | | | | | | | | | | | | | | | | 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>
* | autofs: path_{get,put}() cleanupsJan Blunck2008-05-012-7/+7
| | | | | | | | | | | | | | | | | | | | | | 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>
* | autofs4: fix incorrect return from root.c:try_to_fill_dentry()Jeff Moyer2008-05-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | autofs4: fix execution order race in mount request codeJeff Moyer2008-05-011-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | autofs4: check for invalid dentry in getpathIan Kent2008-05-011-1/+1
| | | | | | | | | | | | | | | | 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>
* | autofs4: fix sparse warning in waitq.c:autofs4_expire_indirect()Ian Kent2008-05-011-13/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | vfs: fix permission checking in sys_utimensatMiklos Szeredi2008-05-011-2/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Fix dnotify/close raceAl Viro2008-04-301-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | DEBUGFS: Correct location of debugfs API documentation.Robert P. J. Day2008-04-301-1/+1
| | | | | | | | | | | | Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | sysfs: Disallow truncation of files in sysfsBen Hutchings2008-04-301-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Merge branch 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6Linus Torvalds2008-04-301-1/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * '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.
| * | [S390] System z large page support.Gerald Schaefer2008-04-301-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds hugetlbfs support on System z, using both hardware large page support if available and software large page emulation on older hardware. Shared (large) page tables are implemented in software emulation mode, by using page->index of the first tail page from a compound large page to store page table information. Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | | fs: replace remaining __FUNCTION__ occurrencesHarvey Harrison2008-04-3028-57/+57
| | | | | | | | | | | | | | | | | | | | | | | | __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>
* | | afs: replace remaining __FUNCTION__ occurrencesHarvey Harrison2008-04-302-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | __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>
* | | debugobjects: add timer specific object debugging codeThomas Gleixner2008-04-301-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | hfsplus: fix warning with 64k PAGE_SIZEAndrew Morton2008-04-301-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | hfs: fix warning with 64k PAGE_SIZEAndrew Morton2008-04-301-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | sysv: [bl]e*_add_cpu conversionMarcin Slusarz2008-04-301-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | quota: le*_add_cpu conversionMarcin Slusarz2008-04-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | hfs/hfsplus: be*_add_cpu conversionMarcin Slusarz2008-04-302-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | affs: be*_add_cpu conversionMarcin Slusarz2008-04-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | reiserfs: use open_bdev_exclChristoph Hellwig2008-04-301-27/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: fix sparse warningsMiklos Szeredi2008-04-301-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: fix race in llseekMiklos Szeredi2008-04-301-2/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: fix node ID typeMiklos Szeredi2008-04-302-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: fix max i/o size calculationMiklos Szeredi2008-04-302-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: update file size on short readMiklos Szeredi2008-04-303-8/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: implement perform_writeNick Piggin2008-04-301-1/+193
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: clean up setting i_size in writeMiklos Szeredi2008-04-301-13/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | fuse: support writable mmapMiklos Szeredi2008-04-305-29/+481
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | mm: Add NR_WRITEBACK_TEMP counterMiklos Szeredi2008-04-301-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | mm: bdi: add separate writeback accounting capabilityMiklos Szeredi2008-04-305-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | mm: bdi: expose the BDI object in sysfs for FUSEMiklos Szeredi2008-04-303-18/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | mm: bdi: expose the BDI object in sysfs for NFSMiklos Szeredi2008-04-301-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Register NFS' backing_dev_info under sysfs with the name "nfs-MAJOR:MINOR" Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | devpts: factor out PTY index allocationSukadev Bhattiprolu2008-04-301-1/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Factor out the code used to allocate/free a pts index into new interfaces, devpts_new_index() and devpts_kill_index(). This localizes the external data structures used in managing the pts indices. [akpm@linux-foundation.org: undo accidental mutex2sem conversion] Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | tty: The big operations reworkAlan Cox2008-04-302-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Operations are now a shared const function block as with most other Linux objects - Introduce wrappers for some optional functions to get consistent behaviour - Wrap put_char which used to be patched by the tty layer - Document which functions are needed/optional - Make put_char report success/fail - Cache the driver->ops pointer in the tty as tty->ops - Remove various surplus lock calls we no longer need - Remove proc_write method as noted by Alexey Dobriyan - Introduce some missing sanity checks where certain driver/ldisc combinations would oops as they didn't check needed methods were present [akpm@linux-foundation.org: fix fs/compat_ioctl.c build] [akpm@linux-foundation.org: fix isicom] [akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build] [akpm@linux-foundation.org: fix kgdb] Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | tty_io: fix remaining pid struct lockingAlan Cox2008-04-301-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes the last couple of pid struct locking failures I know about. [oleg@tv-sign.ru: clean up do_task_stat()] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | tty: BKL pushdownAlan Cox2008-04-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | document de_thread() with exit_notify() connectionOleg Nesterov2008-04-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Add a couple of small comments, it is not easy to see what this code does. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | signals: use HAVE_SET_RESTORE_SIGMASKRoland McGrath2008-04-303-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change all the #ifdef TIF_RESTORE_SIGMASK conditionals in non-arch code to #ifdef HAVE_SET_RESTORE_SIGMASK. If arch code defines it first, the generic set_restore_sigmask() using TIF_RESTORE_SIGMASK is not defined. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | signals: add set_restore_sigmaskRoland McGrath2008-04-303-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds the set_restore_sigmask() inline in <linux/thread_info.h> and replaces every set_thread_flag(TIF_RESTORE_SIGMASK) with a call to it. No change, but abstracts the details of the flag protocol from all the calls. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | signals: de_thread: simplify the ->child_reaper switchingOleg Nesterov2008-04-301-13/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we rely on SIGNAL_UNKILLABLE flag, de_thread() doesn't need the nasty hack to kill the old ->child_reaper during the mt-exec. This also means we can avoid taking tasklist_lock around zap_other_threads(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | do_task_stat: don't take rcu_read_lock()Oleg Nesterov2008-04-301-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lock_task_sighand() was changed, and do_task_stat() doesn't need rcu_read_lock any longer. sighand->siglock protects all "interesting" fields. Except: it doesn't protect ->tty->pgrp, but neither does rcu_read_lock(), this should be fixed. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Pavel Emelyanov <xemul@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | isofs: fix access to unallocated memory when reading corrupted filesystemJan Kara2008-04-302-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a directory on isofs is corrupted, we did not check whether length of the name in a directory entry and the length of the directory entry itself are consistent. This could lead to possible access beyond the end of buffer when the length of the name was too big. Add this sanity check to directory reading code. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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