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* memcg: synchronized LRUKAMEZAWA Hiroyuki2009-01-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A big patch for changing memcg's LRU semantics. Now, - page_cgroup is linked to mem_cgroup's its own LRU (per zone). - LRU of page_cgroup is not synchronous with global LRU. - page and page_cgroup is one-to-one and statically allocated. - To find page_cgroup is on what LRU, you have to check pc->mem_cgroup as - lru = page_cgroup_zoneinfo(pc, nid_of_pc, zid_of_pc); - SwapCache is handled. And, when we handle LRU list of page_cgroup, we do following. pc = lookup_page_cgroup(page); lock_page_cgroup(pc); .....................(1) mz = page_cgroup_zoneinfo(pc); spin_lock(&mz->lru_lock); .....add to LRU spin_unlock(&mz->lru_lock); unlock_page_cgroup(pc); But (1) is spin_lock and we have to be afraid of dead-lock with zone->lru_lock. So, trylock() is used at (1), now. Without (1), we can't trust "mz" is correct. This is a trial to remove this dirty nesting of locks. This patch changes mz->lru_lock to be zone->lru_lock. Then, above sequence will be written as spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU mem_cgroup_add/remove/etc_lru() { pc = lookup_page_cgroup(page); mz = page_cgroup_zoneinfo(pc); if (PageCgroupUsed(pc)) { ....add to LRU } spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU This is much simpler. (*) We're safe even if we don't take lock_page_cgroup(pc). Because.. 1. When pc->mem_cgroup can be modified. - at charge. - at account_move(). 2. at charge the PCG_USED bit is not set before pc->mem_cgroup is fixed. 3. at account_move() the page is isolated and not on LRU. Pros. - easy for maintenance. - memcg can make use of laziness of pagevec. - we don't have to duplicated LRU/Active/Unevictable bit in page_cgroup. - LRU status of memcg will be synchronized with global LRU's one. - # of locks are reduced. - account_move() is simplified very much. Cons. - may increase cost of LRU rotation. (no impact if memcg is not configured.) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: remove prepare_write/commit_writeNick Piggin2008-10-30
| | | | | | | | | | | Nothing uses prepare_write or commit_write. Remove them from the tree completely. [akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Don't allow splice() to files opened with O_APPENDLinus Torvalds2008-10-09
| | | | | | | | | | | | | | | | | | | | | This is debatable, but while we're debating it, let's disallow the combination of splice and an O_APPEND destination. It's not entirely clear what the semantics of O_APPEND should be, and POSIX apparently expects pwrite() to ignore O_APPEND, for example. So we could make up any semantics we want, including the old ones. But Miklos convinced me that we should at least give it some thought, and that accepting writes at arbitrary offsets is wrong at least for IS_APPEND() files (which always have O_APPEND set, even if the reverse isn't true: you can obviously have O_APPEND set on a regular file). So disallow O_APPEND entirely for now. I doubt anybody cares, and this way we have one less gray area to worry about. Reported-and-argued-for-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Jens Axboe <ens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: rename page trylockNick Piggin2008-08-05
| | | | | | | | | | | | | | | Converting page lock to new locking bitops requires a change of page flag operation naming, so we might as well convert it to something nicer (!TestSetPageLocked_Lock => trylock_page, SetPageLocked => set_page_locked). This also facilitates lockdeping of page lock. Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [patch 3/5] vfs: change remove_suid() to file_remove_suid()Miklos Szeredi2008-07-26
| | | | | | | | | All calls to remove_suid() are made with a file pointer, because (similarly to file_update_time) it is called when the file is written. Clean up callers by passing in a file instead of a dentry. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* splice: use get_user_pages_fastNick Piggin2008-07-26
| | | | | | | | | | | | | | | | | | | | | | Use get_user_pages_fast in splice. This reverts some mmap_sem batching there, however the biggest problem with mmap_sem tends to be hold times blocking out other threads rather than cacheline bouncing. Further: on architectures that implement get_user_pages_fast without locks, mmap_sem can be avoided completely anyway. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <andi@firstfloor.org> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Jens Axboe <jens.axboe@oracle.com> Reviewed-by: 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>
* splice: fix generic_file_splice_read() race with page invalidationMiklos Szeredi2008-07-04
| | | | | | | | | | | | | | | | | If a page was invalidated during splicing from file to a pipe, then generic_file_splice_read() could return a short or zero count. This manifested itself in rare I/O errors seen on nfs exported fuse filesystems. This is because nfsd uses splice_direct_to_actor() to read files, and fuse uses invalidate_inode_pages2() to invalidate stale data on open. Fix by redoing the page find/create if it was found to be truncated (invalidated). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: handle try_to_release_page() failureJens Axboe2008-05-28
| | | | | | | | splice currently assumes that try_to_release_page() always suceeds, but it can return failure. If it does, we cannot steal the page. Acked-by: Mingming Cao <cmm@us.ibm.com Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: fix sendfile() issue with relayTom Zanussi2008-05-28
| | | | | | | | | Splice isn't always incrementing the ppos correctly, which broke relay splice. Signed-off-by: Tom Zanussi <zanussi@comcast.net> Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Revert "relay: fix splice problem"Jens Axboe2008-05-08
| | | | This reverts commit c3270e577c18b3d0e984c3371493205a4807db9d.
* vfs: splice remove_suid() cleanupMiklos Szeredi2008-05-07
| | | | | | | | | | | | generic_file_splice_write() duplicates remove_suid() just because it doesn't hold i_mutex. But it grabs i_mutex inside splice_from_pipe() anyway, so this is rather pointless. Move locking to generic_file_splice_write() and call remove_suid() and __splice_from_pipe() instead. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* relay: fix splice problemTom Zanussi2008-04-29
| | | | | | | | Splice isn't always incrementing the ppos correctly, which broke relay splice. Signed-off-by: Tom Zanussi <zanussi@comcast.net> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: fix infinite loop in generic_file_splice_read()Jens Axboe2008-04-10
| | | | | | | | | | There's a quirky loop in generic_file_splice_read() that could go on indefinitely, if the file splice returns 0 permanently (and not just as a temporary condition). Get rid of the loop and pass back -EAGAIN correctly from __generic_file_splice_read(), so we handle that condition properly as well. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: use mapping_gfp_maskHugh Dickins2008-04-03
| | | | | | | | | | | | The loop block driver is careful to mask __GFP_IO|__GFP_FS out of its mapping_gfp_mask, to avoid hangs under memory pressure. But nowadays it uses splice, usually going through __generic_file_splice_read. That must use mapping_gfp_mask instead of GFP_KERNEL to avoid those hangs. Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* splice: only return -EAGAIN if there's hope of more dataJens Axboe2008-03-04
| | | | | | | | | | | | | sys_tee() currently is a bit eager in returning -EAGAIN, it may do so even if we don't have a chance of anymore data becoming available. So improve the logic and only return -EAGAIN if we have an attached writer to the input pipe. Reported by Johann Felix Soden <johfel@gmx.de> and Patrick McManus <mcmanus@ducksong.com>. Tested-by: Johann Felix Soden <johfel@users.sourceforge.net> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: fix user pointer access in get_iovec_page_array()Bastian Blank2008-02-10
| | | | | | | | | | | | | | | | | Commit 8811930dc74a503415b35c4a79d14fb0b408a361 ("splice: missing user pointer access verification") added the proper access_ok() calls to copy_from_user_mmap_sem() which ensures we can copy the struct iovecs from userspace to the kernel. But we also must check whether we can access the actual memory region pointed to by the struct iovec to fix the access checks properly. Signed-off-by: Bastian Blank <waldi@debian.org> Acked-by: Oliver Pinter <oliver.pntr@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* splice: missing user pointer access verificationJens Axboe2008-02-08
| | | | | | | | | | | | vmsplice_to_user() must always check the user pointer and length with access_ok() before copying. Likewise, for the slow path of copy_from_user_mmap_sem() we need to check that we may read from the user region. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Cc: Wojciech Purczynski <cliph@research.coseinc.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* splice: always updated atime in direct spliceJens Axboe2008-02-01
| | | | | | | | | | Andre Majorel <aym-xunil@teaser.fr> points out that if we only updated the atime when we transfer some data, we deviate from the standard of always updating the atime. So change splice to always call file_accessed() even if splice_direct_to_actor() didn't transfer any data. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: fix problem with atime not being updatedJens Axboe2008-01-29
| | | | | | | | | A bug report on nfsd that states that since it was switched to use splice instead of sendfile, the atime was no longer being updated on the input file. do_generic_mapping_read() does this when accessing the file, make splice do it for the direct splice handler. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [SPLICE]: Don't assume regular pages in splice_to_pipe()Jens Axboe2008-01-28
| | | | | | | | | Allow caller to pass in a release function, there might be other resources that need releasing as well. Needed for network receive. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* security: call security_file_permission from rw_verify_areaJames Morris2008-01-24
| | | | | | | | All instances of rw_verify_area() are followed by a call to security_file_permission(), so just call the latter from the former. Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
* Implement file posix capabilitiesSerge E. Hallyn2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement file posix capabilities. This allows programs to be given a subset of root's powers regardless of who runs them, without having to use setuid and giving the binary all of root's powers. This version works with Kaigai Kohei's userspace tools, found at http://www.kaigai.gr.jp/index.php. For more information on how to use this patch, Chris Friedhoff has posted a nice page at http://www.friedhoff.org/fscaps.html. Changelog: Nov 27: Incorporate fixes from Andrew Morton (security-introduce-file-caps-tweaks and security-introduce-file-caps-warning-fix) Fix Kconfig dependency. Fix change signaling behavior when file caps are not compiled in. Nov 13: Integrate comments from Alexey: Remove CONFIG_ ifdef from capability.h, and use %zd for printing a size_t. Nov 13: Fix endianness warnings by sparse as suggested by Alexey Dobriyan. Nov 09: Address warnings of unused variables at cap_bprm_set_security when file capabilities are disabled, and simultaneously clean up the code a little, by pulling the new code into a helper function. Nov 08: For pointers to required userspace tools and how to use them, see http://www.friedhoff.org/fscaps.html. Nov 07: Fix the calculation of the highest bit checked in check_cap_sanity(). Nov 07: Allow file caps to be enabled without CONFIG_SECURITY, since capabilities are the default. Hook cap_task_setscheduler when !CONFIG_SECURITY. Move capable(TASK_KILL) to end of cap_task_kill to reduce audit messages. Nov 05: Add secondary calls in selinux/hooks.c to task_setioprio and task_setscheduler so that selinux and capabilities with file cap support can be stacked. Sep 05: As Seth Arnold points out, uid checks are out of place for capability code. Sep 01: Define task_setscheduler, task_setioprio, cap_task_kill, and task_setnice to make sure a user cannot affect a process in which they called a program with some fscaps. One remaining question is the note under task_setscheduler: are we ok with CAP_SYS_NICE being sufficient to confine a process to a cpuset? It is a semantic change, as without fsccaps, attach_task doesn't allow CAP_SYS_NICE to override the uid equivalence check. But since it uses security_task_setscheduler, which elsewhere is used where CAP_SYS_NICE can be used to override the uid equivalence check, fixing it might be tough. task_setscheduler note: this also controls cpuset:attach_task. Are we ok with CAP_SYS_NICE being used to confine to a cpuset? task_setioprio task_setnice sys_setpriority uses this (through set_one_prio) for another process. Need same checks as setrlimit Aug 21: Updated secureexec implementation to reflect the fact that euid and uid might be the same and nonzero, but the process might still have elevated caps. Aug 15: Handle endianness of xattrs. Enforce capability version match between kernel and disk. Enforce that no bits beyond the known max capability are set, else return -EPERM. With this extra processing, it may be worth reconsidering doing all the work at bprm_set_security rather than d_instantiate. Aug 10: Always call getxattr at bprm_set_security, rather than caching it at d_instantiate. [morgan@kernel.org: file-caps clean up for linux/capability.h] [bunk@kernel.org: unexport cap_inode_killpriv] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Andrew Morgan <morgan@kernel.org> Signed-off-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-blockLinus Torvalds2007-10-16
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block: (63 commits) Fix memory leak in dm-crypt SPARC64: sg chaining support SPARC: sg chaining support PPC: sg chaining support PS3: sg chaining support IA64: sg chaining support x86-64: enable sg chaining x86-64: update pci-gart iommu to sg helpers x86-64: update nommu to sg helpers x86-64: update calgary iommu to sg helpers swiotlb: sg chaining support i386: enable sg chaining i386 dma_map_sg: convert to using sg helpers mmc: need to zero sglist on init Panic in blk_rq_map_sg() from CCISS driver remove sglist_len remove blk_queue_max_phys_segments in libata revert sg segment size ifdefs Fixup u14-34f ENABLE_SG_CHAINING qla1280: enable use_sg_chaining option ...
| * splice: fix double kunmap() in vmsplice copy pathJens Axboe2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The out label should not include the unmap, the only way to jump there already has unmapped the source. 00002000 f7c21a00 00000000 00000000 c0489036 00018e32 00000002 00000000 00001000 Call Trace: [<c0487dd9>] pipe_to_user+0xca/0xd3 [<c0488233>] __splice_from_pipe+0x53/0x1bd [<c0454947>] ------------[ cut here ]------------ filemap_fault+0x221/0x380 [<c0487d0f>] pipe_to_user+0x0/0xd3 [<c0489036>] sys_vmsplice+0x3b7/0x422 [<c045ec3f>] kernel BUG at mm/highmem.c:206! handle_mm_fault+0x4d5/0x8eb [<c041ed5b>] kmap_atomic+0x1c/0x20 [<c045d33d>] unmap_vmas+0x3d1/0x584 [<c045f717>] free_pgtables+0x90/0xa0 [<c041d84b>] pgd_dtor+0x0/0x1 [<c044d665>] audit_syscall_exit+0x2aa/0x2c6 [<c0407817>] do_syscall_trace+0x124/0x169 [<c0404df2>] syscall_call+0x7/0xb ======================= Code: 2d 00 d0 5b 00 25 00 00 e0 ff 29 invalid opcode: 0000 [#1] c2 89 d0 c1 e8 0c 8b 14 85 a0 6c 7c c0 4a 85 d2 89 14 85 a0 6c 7c c0 74 07 31 c9 4a 75 15 eb 04 <0f> 0b eb fe 31 c9 81 3d 78 38 6d c0 78 38 6d c0 0f 95 c1 b0 01 EIP: [<c045bbc3>] kunmap_high+0x51/0x8e SS:ESP 0068:f5960df0 SMP Modules linked in: netconsole autofs4 hidp nfs lockd nfs_acl rfcomm l2cap bluetooth sunrpc ipv6 ib_iser rdma_cm ib_cm iw_cmib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi scsi_transport_iscsi dm_mirror dm_multipath dm_mod video output sbs batteryac parport_pc lp parport sg i2c_piix4 i2c_core floppy cfi_probe gen_probe scb2_flash mtd chipreg tg3 e1000 button ide_cd serio_raw cdrom aic7xxx scsi_transport_spi sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd uhci_hcd CPU: 3 EIP: 0060:[<c045bbc3>] Not tainted VLI EFLAGS: 00010246 (2.6.23 #1) EIP is at kunmap_high+0x51/0x8e Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | fs: introduce write_begin, write_end, and perform_write aopsNick Piggin2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These are intended to replace prepare_write and commit_write with more flexible alternatives that are also able to avoid the buffered write deadlock problems efficiently (which prepare_write is unable to do). [mark.fasheh@oracle.com: API design contributions, code review and fixes] [akpm@linux-foundation.org: various fixes] [dmonakhov@sw.ru: new aop block_write_begin fix] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | readahead: combine file_ra_state.prev_index/prev_offset into prev_posFengguang Wu2007-10-16
|/ | | | | | | | | | | | | | | | | | | Combine the file_ra_state members unsigned long prev_index unsigned int prev_offset into loff_t prev_pos It is more consistent and better supports huge files. Thanks to Peter for the nice proposal! [akpm@linux-foundation.org: fix shift overflow] Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix possible splice() mmap_sem deadlockLinus Torvalds2007-10-01
| | | | | | | | | | | | | | | | Nick Piggin points out that splice isn't being good about the mmap semaphore: while two readers can nest inside each others, it does leave a possible deadlock if a writer (ie a new mmap()) comes in during that nesting. Original "just move the locking" patch by Nick, replaced by one by me based on an optimistic pagefault_disable(). And then Jens tested and updated that patch. Reported-by: Nick Piggin <npiggin@suse.de> Tested-by: Jens Axboe <jens.axboe@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* docbook: add pipes, other fixesRandy Dunlap2007-07-27
| | | | | | | | Fix some typos in pipe.c and splice.c. Add pipes API to kernel-api.tmpl. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: fix bad unlock_page() in error caseJens Axboe2007-07-20
| | | | | | | | | | | | | If add_to_page_cache_lru() fails, the page will not be locked. But splice jumps to an error path that does a page release and unlock, causing a BUG() in unlock_page(). Fix this by adding one more label that just releases the page. This bug was actually triggered on EL5 by gurudas pai <gurudas.pai@oracle.com> using fio. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* readahead: split ondemand readahead interface into two functionsRusty Russell2007-07-19
| | | | | | | | | | | | | Split ondemand readahead interface into two functions. I think this makes it a little clearer for non-readahead experts (like Rusty). Internally they both call ondemand_readahead(), but the page argument is changed to an obvious boolean flag. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* readahead: pass real splice sizeFengguang Wu2007-07-19
| | | | | | | | | | | | | | | | | Pass real splice size to page_cache_readahead_ondemand(). The splice code works in chunks of 16 pages internally. The readahead code should be told of the overall splice size, instead of the internal chunk size. Otherwize bad things may happen. Imagine some 17-page random splice reads. The code before this patch will result in two readahead calls: readahead(16); readahead(1); That leads to one 16-page I/O and one 32-page I/O: one extra I/O and 31 readahead miss pages. Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* readahead: move synchronous readahead call out of splice loopFengguang Wu2007-07-19
| | | | | | | | | | | | | | | | | Move synchronous page_cache_readahead_ondemand() call out of splice loop. This avoids one pointless page allocation/insertion in case of non-zero ra_pages, or many pointless readahead calls in case of zero ra_pages. Note that if a user sets ra_pages to less than PIPE_BUFFERS=16 pages, he will not get expected readahead behavior anyway. The splice code works in batches of 16 pages, which can be taken as another form of synchronous readahead. Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* readahead: convert splice invocationsFengguang Wu2007-07-19
| | | | | | | | | | | | Convert splice reads to use on-demand readahead. Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Steven Pratt <slpratt@austin.ibm.com> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Jens Axboe <axboe@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* splice: direct splicing updates ppos twiceJens Axboe2007-07-16
| | | | | | | | | | | | | | | | | | | | | | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> reported that he's noticed nfsd read corruption in recent kernels, and did the hard work of discovering that it's due to splice updating the file position twice. This means that the next operation would start further ahead than it should. nfsd_vfs_read() splice_direct_to_actor() while(len) { do_splice_to() [update sd->pos] -> generic_file_splice_read() [read from sd->pos] nfsd_direct_splice_actor() -> __splice_from_pipe() [update sd->pos] There's nothing wrong with the core splice code, but the direct splicing is an addon that calls both input and output paths. So it has to take care in locally caching offset so it remains correct. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: fix offset mangling with direct splicing (sendfile)Jens Axboe2007-07-13
| | | | | | | | | | | | | | | If the output actor doesn't transfer the full amount of data, we will increment ppos too much. Two related bugs in there: - We need to break out and return actor() retval if it is shorted than what we spliced into the pipe. - Adjust ppos only according to actor() return. Also fix loop problem in generic_file_splice_read(), it should not keep going when data has already been transferred. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* security: revalidate rw permissions for sys_splice and sys_vmspliceJames Morris2007-07-13
| | | | | | | | | Revalidate read/write permissions for splice(2) and vmslice(2), in case security policy has changed since the files were opened. Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* pipe: add documentation and commentsJens Axboe2007-07-10
| | | | | | | | As per Andrew Mortons request, here's a set of documentation for the generic pipe_buf_operations hooks, the pipe, and pipe_buffer structures. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* pipe: change the ->pin() operation to ->confirm()Jens Axboe2007-07-10
| | | | | | | | | | | | The name 'pin' was badly chosen, it doesn't pin a pipe buffer in the most commonly used sense in the kernel. So change the name to 'confirm', after debating this issue with Hugh Dickins a bit. A good return from ->confirm() means that the buffer is really there, and that the contents are good. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: completely document external interface with kerneldocJens Axboe2007-07-10
| | | | | | | Also add fs/splice.c as a kerneldoc target with a smaller blurb that should be expanded to better explain the overview of splice. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* pipe: allow passing around of ops private pointerJens Axboe2007-07-10
| | | | | | | | relay needs this for proper consumption handling, and the network receive support needs it as well to lookup the sk_buff on pipe release. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: divorce the splice structure/function definitions from the pipe headerJens Axboe2007-07-10
| | | | | | | | | We need to move even more stuff into the header so that folks can use the splice_to_pipe() implementation instead of open-coding a lot of pipe knowledge (see relay implementation), so move to our own header file finally. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* vmsplice: add vmsplice-to-user supportJens Axboe2007-07-10
| | | | | | | | A bit of a cheat, it actually just copies the data to userspace. But this makes the interface nice and symmetric and enables people to build on splice, with room for future improvement in performance. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: abstract out actor dataJens Axboe2007-07-10
| | | | | | | | | | | | For direct splicing (or private splicing), the output may not be a file. So abstract out the handling into a specified actor function and put the data in the splice_desc structure earlier, so we can build on top of that. This is the first step in better splice handling for drivers, and also for implementing vmsplice _to_ user memory. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: only check do_wakeup in splice_to_pipe() for a real pipeJens Axboe2007-06-15
| | | | | | | | We only ever set do_wakeup to non-zero if the pipe has an inode backing, so it's pointless to check outside the pipe->inode check. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: fix leak of pages on short splice to pipeJens Axboe2007-06-15
| | | | | | | | | | | | | If the destination pipe is full and we already transferred data, we break out instead of waiting for more pipe room. The exit logic looks at spd->nr_pages to see if we moved everything inside the spd container, but we decrement that variable in the loop to decide when spd has emptied. Instead we want to compare to the original page count in the spd, so cache that in a local variable. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: adjust balance_dirty_pages_ratelimited() callJens Axboe2007-06-15
| | | | | | | | | As we have potentially dirtied more than 1 page, we should indicate as such to the dirty page balancing. So call balance_dirty_pages_ratelimited_nr() and pass in the approximate number of pages we dirtied. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: __generic_file_splice_read: fix read/truncate raceJens Axboe2007-06-08
| | | | | | | | | | | | | | | | | | | | | | | Original patch and description from Neil Brown <neilb@suse.de>, merged and adapted to splice branch by me. Neils text follows: __generic_file_splice_read() currently samples the i_size at the start and doesn't do so again unless it needs to call ->readpage to load a page. After ->readpage it has to re-sample i_size as a truncate may have caused that page to be filled with zeros, and the read() call should not see these. However there are other activities that might cause ->readpage to be called on a page between the time that __generic_file_splice_read() samples i_size and when it finds that it has an uptodate page. These include at least read-ahead and possibly another thread performing a read So we must sample i_size *after* it has an uptodate page. Thus the current sampling at the start and after a read can be replaced with a sampling before page addition into spd. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: __generic_file_splice_read: fix i_size_read() length checksHugh Dickins2007-06-08
| | | | | | | | | | __generic_file_splice_read's partial page check, at eof after readpage, not only got its calculations wrong, but also reused the loff variable: causing data corruption when splicing from a non-0 offset in the file's last page (revealed by ext2 -b 1024 testing on a loop of a tmpfs file). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: move balance_dirty_pages_ratelimited() outside of splice actorJens Axboe2007-06-08
| | | | | | | I've seen inode related deadlocks, so move this call outside of the actor itself, which may hold the inode lock. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* splice: remove do_splice_direct() symbol exportJens Axboe2007-06-08
| | | | | | | It's only supposed to be used by do_sendfile(), which is never modular. So kill the export. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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