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* exportfs: Return the minimum required handle sizeAneesh Kumar K.V2011-03-141-1/+3
| | | | | | | | | | | The exportfs encode handle function should return the minimum required handle size. This helps user to find out the handle size by passing 0 handle size in the first step and then redoing to the call again with the returned handle size value. Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch fuseAl Viro2011-01-131-6/+4
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2011-01-101-19/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | 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 ioctl ABI fuse: allow batching of FORGET requests fuse: separate queue for FORGET requests fuse: ioctl cleanup Fix up trivial conflict in fs/fuse/inode.c due to RCU lookup having done the RCU-freeing of the inode in fuse_destroy_inode().
| * fuse: separate queue for FORGET requestsMiklos Szeredi2010-12-071-19/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Terje Malmedal reports that a fuse filesystem with 32 million inodes on a machine with lots of memory can go unresponsive for up to 30 minutes when all those inodes are evicted from the icache. The reason is that FORGET messages, sent when the inode is evicted, are queued up together with regular filesystem requests, and while the huge queue of FORGET messages are processed no other filesystem operation can proceed. Since a full fuse request structure is allocated for each inode, these take up quite a bit of memory as well. To solve these issues, create a slim 'fuse_forget_link' structure containing just the minimum of information required to send the FORGET request and chain these on a separate queue. When userspace is asking for a request make sure that FORGET and non-FORGET requests are selected fairly: for each 8 non-FORGET allow 16 FORGET requests. This will make sure FORGETs do not pile up, yet other requests are also allowed to proceed while the queued FORGETs are processed. Reported-by: Terje Malmedal <terje.malmedal@usit.uio.no> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* | fs: dcache reduce branches in lookup pathNick Piggin2011-01-071-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Reduce some branches and memory accesses in dcache lookup by adding dentry flags to indicate common d_ops are set, rather than having to check them. This saves a pointer memory access (dentry->d_op) in common path lookup situations, and saves another pointer load and branch in cases where we have d_op but not the particular operation. Patched with: git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* | fs: icache RCU free inodesNick Piggin2011-01-071-1/+8
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | RCU free the struct inode. This will allow: - Subsequent store-free path walking patch. The inode must be consulted for permissions when walking, so an RCU inode reference is a must. - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want to take i_lock no longer need to take sb_inode_list_lock to walk the list in the first place. This will simplify and optimize locking. - Could remove some nested trylock loops in dcache code - Could potentially simplify things a bit in VM land. Do not need to take the page lock to follow page->mapping. The downsides of this is the performance cost of using RCU. In a simple creat/unlink microbenchmark, performance drops by about 10% due to inability to reuse cache-hot slab objects. As iterations increase and RCU freeing starts kicking over, this increases to about 20%. In cases where inode lifetimes are longer (ie. many inodes may be allocated during the average life span of a single inode), a lot of this cache reuse is not applicable, so the regression caused by this patch is smaller. The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU, however this adds some complexity to list walking and store-free path walking, so I prefer to implement this at a later date, if it is shown to be a win in real situations. I haven't found a regression in any non-micro benchmark so I doubt it will be a problem. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* convert get_sb_nodev() usersAl Viro2010-10-291-4/+4
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: mount_bdev()Al Viro2010-10-291-5/+4
| | | | | | ... and switch of the obvious get_sb_bdev() users to ->mount() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* convert remaining ->clear_inode() to ->evict_inode()Al Viro2010-08-091-2/+4
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* tree-wide: Assorted spelling fixesDaniel Mack2010-02-091-1/+1
| | | | | | | | | | | 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>
* truncate: use new helpersnpiggin@suse.de2009-09-241-10/+1
| | | | | | | | | | | | | | | 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>
* Merge branch 'for-linus' of ↵Linus Torvalds2009-09-181-0/+80
|\ | | | | | | | | | | | | | | | | | | | | 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
| * fuse: add fusectl interface to max_backgroundCsaba Henk2009-09-161-2/+2
| | | | | | | | | | | | | | | | | | 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>
| * fuse: limit user-specified values of max background requestsCsaba Henk2009-09-161-6/+72
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * fuse: make the number of max background requests and congestion threshold ↵Csaba Henk2009-07-071-0/+14
| | | | | | | | | | | | | | | | | | | | 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>
* | fs: Assign bdi in super_blockJens Axboe2009-09-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | 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>
* | writeback: add name to backing_dev_infoJens Axboe2009-09-111-0/+1
|/ | | | | | | | 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>
* fuse: invalidation reverse callsJohn Muir2009-06-301-3/+56
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* fuse: allow umask processing in userspaceMiklos Szeredi2009-06-301-1/+8
| | | | | | | | | | | | | | 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>
* fuse doesn't need BKL in ->umount_begin()Al Viro2009-06-171-3/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'cuse' of ↵Linus Torvalds2009-06-121-50/+68
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * fuse: export symbols to be used by CUSETejun Heo2009-04-281-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * fuse: update fuse_conn_init() and separate out fuse_conn_kill()Tejun Heo2009-04-281-50/+65
| | | | | | | | | | | | | | | | | | | | | | 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>
* | Merge branch 'for-linus' of ↵Linus Torvalds2009-05-141-0/+1
|\| | | | | | | | | | | | | 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
| * fuse: destroy bdi on errorMiklos Szeredi2009-04-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | 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
* | vfs: umount_begin BKL pushdownAlessio Igor Bogani2009-05-091-0/+3
|/ | | | | | | 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>
* fuse: destroy bdi on umountMiklos Szeredi2009-01-261-1/+1
| | | | | | | | | | | | | | | | | If a fuse filesystem is unmounted but the device file descriptor remains open and a new mount reuses the old device number, then the mount fails with EEXIST and the following warning is printed in the kernel log: WARNING: at fs/sysfs/dir.c:462 sysfs_add_one+0x35/0x3d() sysfs: duplicate filename '0:15' can not be created The cause is that the bdi belonging to the fuse filesystem was destoryed only after the device file was released. Fix this by calling bdi_destroy() from fuse_put_super() instead. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org
* fuse: fuse_fill_super error handling cleanupMiklos Szeredi2009-01-261-18/+19
| | | | | | Clean up error handling for the whole of fuse_fill_super() function. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: fix missing fput on errorMiklos Szeredi2009-01-261-2/+7
| | | | | | | | Fix the leaking file reference if allocation or initialization of fuse_conn failed. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org
* fuse: add fuse_conn->release()Tejun Heo2008-11-261-1/+7
| | | | | | | | Add fuse_conn->release() so that fuse_conn can be embedded in other structures. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: separate out fuse_conn_init() from new_conn()Tejun Heo2008-11-261-57/+62
| | | | | | | | | | Separate out fuse_conn_init() from new_conn() and while at it initialize fuse_conn->entry during conn initialization. This will be used by CUSE. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: add fuse_ prefix to several functionsTejun Heo2008-11-261-6/+6
| | | | | | | | | | 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>
* fuse: implement poll supportTejun Heo2008-11-261-0/+1
| | | | | | | | | | | | | | | | | | 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>
* fuse: add file kernel handleTejun Heo2008-11-261-0/+1
| | | | | | | | | | | | | | 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>
* fuse: don't let fuse_req->end() put the base referenceTejun Heo2008-11-261-1/+0
| | | | | | | | | 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>
* fuse: style fixesMiklos Szeredi2008-11-261-10/+9
| | | | | | | Fix coding style errors reported by checkpatch and others. Uptdate copyright date to 2008. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* [PATCH] switch all filesystems over to d_obtain_aliasChristoph Hellwig2008-10-231-15/+8
| | | | | | | Switch all users of d_alloc_anon to d_obtain_alias. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fuse: add missing fuse_request_freeJulia Lawall2008-10-161-1/+2
| | | | | | | | | | | | The error handling code for the second call to fuse_request_alloc should include freeing the result of the first one. This bug was found by the Coccinelle project: http://www.emn.fr/x-info/coccinelle/ Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* vfs: Use const for kernel parser tableSteven Whitehouse2008-10-131-1/+1
| | | | | | | | | | | | | | This is a much better version of a previous patch to make the parser tables constant. Rather than changing the typedef, we put the "const" in all the various places where its required, allowing the __initconst exception for nfsroot which was the cause of the previous trouble. This was posted for review some time ago and I believe its been in -mm since then. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Alexander Viro <aviro@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SL*B: drop kmem cache argument from constructorAlexey Dobriyan2008-07-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Kmem cache passed to constructor is only needed for constructors that are themselves multiplexeres. Nobody uses this "feature", nor does anybody uses passed kmem cache in non-trivial way, so pass only pointer to object. Non-trivial places are: arch/powerpc/mm/init_64.c arch/powerpc/mm/hugetlbpage.c This is flag day, yes. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Christoph Lameter <cl@linux-foundation.org> Cc: Jon Tollefson <kniht@linux.vnet.ibm.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Matt Mackall <mpm@selenic.com> [akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c] [akpm@linux-foundation.org: fix mm/slab.c] [akpm@linux-foundation.org: fix ubifs] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fuse: nfs export special lookupsMiklos Szeredi2008-07-251-3/+63
| | | | | | | | | | | | | | | | | | | | | | | Implement the get_parent export operation by sending a LOOKUP request with ".." as the name. Implement looking up an inode by node ID after it has been evicted from the cache. This is done by seding a LOOKUP request with "." as the name (for all file types, not just directories). The filesystem can set the FUSE_EXPORT_SUPPORT flag in the INIT reply, to indicate that it supports these special lookups. Thanks to John Muir for the original implementation of this feature. 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>
* fuse: add export operationsMiklos Szeredi2008-07-251-0/+115
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement export_operations, to allow fuse filesystems to be exported to NFS. This feature has been in the out-of-tree fuse module, and is widely used and tested. It has not been originally merged into mainline, because doing the NFS export in userspace was thought to be a cleaner and more efficient way of doing it, than through the kernel. While that is true, it would also have involved a lot of duplicated effort at reimplementing NFS exporting (all the different versions of the protocol). This effort was unfortunately not undertaken by anyone, so we are left with doing it the easy but less efficient way. If this feature goes in, the out-of-tree fuse module can go away, which would have several advantages: - not having to maintain two versions - less confusion for users - no bugs due to kernel API changes Comment from hch: - Use the same fh_type values as XFS, since we use the same fh encoding. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fuse: fix thinko in max I/O size calucationMiklos Szeredi2008-06-181-2/+2
| | | | | | | | | | | | | | Use max not min to enforce a lower limit on the max I/O size. This bug was introduced by "fuse: fix max i/o size calculation" (commit e5d9a0df07484d6d191756878c974e4307fb24ce). Thanks to Brian Wang for noticing. Reported-by: Brian Wang <ywang221@hotmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Szabolcs Szakacsits <szaka@ntfs-3g.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fuse: fix bdi naming conflictMiklos Szeredi2008-05-241-1/+6
| | | | | | | | | | | | | | | | | | | Fuse allocates a separate bdi for each filesystem, and registers them in sysfs with "MAJOR:MINOR" of sb->s_dev (st_dev). This works fine for anon devices normally used by fuse, but can conflict with an already registered BDI for "fuseblk" filesystems, where sb->s_dev represents a real block device. In particularl this happens if a non-partitioned device is being mounted. Fix by registering with a different name for "fuseblk" filesystems. Thanks to Ioan Ionita for the bug report. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reported-by: Ioan Ionita <opslynx@gmail.com> Tested-by: Ioan Ionita <opslynx@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fuse: add flag to turn on big writesMiklos Szeredi2008-05-131-1/+4
| | | | | | | | | | | | | | | | | 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: fix node ID typeMiklos Szeredi2008-04-301-4/+4
| | | | | | | | | 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 Szeredi2008-04-301-1/+2
| | | | | | | | | | | | 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: support writable mmapMiklos Szeredi2008-04-301-10/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: bdi: expose the BDI object in sysfs for FUSEMiklos Szeredi2008-04-301-15/+15
| | | | | | | | | | | | | 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>
* [PATCH] restore sane ->umount_begin() APIAl Viro2008-04-251-3/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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