- 07 12月, 2007 1 次提交
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由 Matthew Wilcox 提交于
This routine is like lock_page, but can be interrupted by a fatal signal Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
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- 01 11月, 2007 1 次提交
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由 Linus Torvalds 提交于
The kernel has for random historical reasons allowed ptrace() accesses to access (and insert) pages into the page cache above the size of the file. However, Nick broke that by mistake when doing the new fault handling in commit 54cb8821 ("mm: merge populate and nopage into fault (fixes nonlinear)". The breakage caused a hang with gdb when trying to access the invalid page. The ptrace "feature" really isn't worth resurrecting, since it really is wrong both from a portability _and_ from an internal page cache validity standpoint. So this removes those old broken remnants, and fixes the ptrace() hang in the process. Noticed and bisected by Duane Griffin, who also supplied a test-case (quoth Nick: "Well that's probably the best bug report I've ever had, thanks Duane!"). Cc: Duane Griffin <duaneg@dghda.com> Acked-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 31 10月, 2007 1 次提交
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由 Zach Brown 提交于
Commit commit 65b8291c ("dio: invalidate clean pages before dio write") introduced a bug which stopped dio from ever invalidating the page cache after writes. It still invalidated it before writes so most users were fine. Karl Schendel reported ( http://lkml.org/lkml/2007/10/26/481 ) hitting this bug when he had a buffered reader immediately reading file data after an O_DIRECT wirter had written the data. The kernel issued read-ahead beyond the position of the reader which overlapped with the O_DIRECT writer. The failure to invalidate after writes caused the reader to see stale data from the read-ahead. The following patch is originally from Karl. The following commentary is his: The below 3rd try takes on your suggestion of just invalidating no matter what the retval from the direct_IO call. I ran it thru the test-case several times and it has worked every time. The post-invalidate is probably still too early for async-directio, but I don't have a testcase for that; just sync. And, this won't be any worse in the async case. I added a test to the aio-dio-regress repository which mimics Karl's IO pattern. It verifed the bad behaviour and that the patch fixed it. I agree with Karl, this still doesn't help the case where a buffered reader follows an AIO O_DIRECT writer. That will require a bit more work. This gives up on the idea of returning EIO to indicate to userspace that stale data remains if the invalidation failed. Signed-off-by: NZach Brown <zach.brown@oracle.com> Cc: Karl Schendel <kschendel@datallegro.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Leonid Ananiev <leonid.i.ananiev@linux.intel.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 29 10月, 2007 1 次提交
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由 Emil Medve 提交于
mm/filemap.c: In function '__filemap_fdatawrite_range': mm/filemap.c:200: error: implicit declaration of function 'mapping_cap_writeback_dirty' This happens when we don't use/have any block devices and a NFS root filesystem is used. mapping_cap_writeback_dirty() is defined in linux/backing-dev.h which used to be provided in mm/filemap.c by linux/blkdev.h until commit f5ff8422 (Fix warnings with !CONFIG_BLOCK). Signed-off-by: NEmil Medve <Emilian.Medve@Freescale.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 20 10月, 2007 1 次提交
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由 Randy Dunlap 提交于
Fix kernel-api docbook contents problems. docproc: linux-2.6.23-git13/include/asm-x86/unaligned_32.h: No such file or directory Warning(linux-2.6.23-git13//include/linux/list.h:482): bad line: of list entry Warning(linux-2.6.23-git13//mm/filemap.c:864): No description found for parameter 'ra' Warning(linux-2.6.23-git13//block/ll_rw_blk.c:3760): No description found for parameter 'req' Warning(linux-2.6.23-git13//include/linux/input.h:1077): No description found for parameter 'private' Warning(linux-2.6.23-git13//include/linux/input.h:1077): No description found for parameter 'cdev' Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 19 10月, 2007 1 次提交
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由 Linus Torvalds 提交于
It gets it indirectly from blkdev.h when CONFIG_BLOCK is enabled, but it needs it unconditionally for the definition of mapping_cap_writeback_dirty. Noticed and bisected down to 4af3c9cc ("Drop some headers from mm.h") by Avuton Olrich. Cc: Avuton Olrich <avuton@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 10月, 2007 22 次提交
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由 Serge E. Hallyn 提交于
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: NSerge 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: NAndrew Morgan <morgan@kernel.org> Signed-off-by: NAdrian Bunk <bunk@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
zone->lock is quite an "inner" lock and mostly constrained to page alloc as well, so like slab locks, it probably isn't something that is critically important to document here. However unlike slab locks, zone lock could be used more widely in future, and page_alloc.c might possibly have more business to do tricky things with pagecache than does slab. So... I don't think it hurts to document it. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
prepare/commit_write no longer returns AOP_TRUNCATED_PAGE since OCFS2 and GFS2 were converted to the new aops, so we can make some simplifications for that. [michal.k.k.piotrowski@gmail.com: fix warning] Signed-off-by: NNick Piggin <npiggin@suse.de> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: NMichal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Rework the generic block "cont" routines to handle the new aops. Supporting cont_prepare_write would take quite a lot of code to support, so remove it instead (and we later convert all filesystems to use it). write_begin gets passed AOP_FLAG_CONT_EXPAND when called from generic_cont_expand, so filesystems can avoid the old hacks they used. Signed-off-by: NNick Piggin <npiggin@suse.de> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Restore the KERNEL_DS optimisation, especially helpful to the 2copy write path. This may be a pretty questionable gain in most cases, especially after the legacy 2copy write path is removed, but it doesn't cost much. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
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: NNick Piggin <npiggin@suse.de> Signed-off-by: NMark Fasheh <mark.fasheh@oracle.com> Signed-off-by: NDmitriy Monakhov <dmonakhov@openvz.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Add an iterator data structure to operate over an iovec. Add usercopy operators needed by generic_file_buffered_write, and convert that function over. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Modify the core write() code so that it won't take a pagefault while holding a lock on the pagecache page. There are a number of different deadlocks possible if we try to do such a thing: 1. generic_buffered_write 2. lock_page 3. prepare_write 4. unlock_page+vmtruncate 5. copy_from_user 6. mmap_sem(r) 7. handle_mm_fault 8. lock_page (filemap_nopage) 9. commit_write 10. unlock_page a. sys_munmap / sys_mlock / others b. mmap_sem(w) c. make_pages_present d. get_user_pages e. handle_mm_fault f. lock_page (filemap_nopage) 2,8 - recursive deadlock if page is same 2,8;2,8 - ABBA deadlock is page is different 2,6;b,f - ABBA deadlock if page is same The solution is as follows: 1. If we find the destination page is uptodate, continue as normal, but use atomic usercopies which do not take pagefaults and do not zero the uncopied tail of the destination. The destination is already uptodate, so we can commit_write the full length even if there was a partial copy: it does not matter that the tail was not modified, because if it is dirtied and written back to disk it will not cause any problems (uptodate *means* that the destination page is as new or newer than the copy on disk). 1a. The above requires that fault_in_pages_readable correctly returns access information, because atomic usercopies cannot distinguish between non-present pages in a readable mapping, from lack of a readable mapping. 2. If we find the destination page is non uptodate, unlock it (this could be made slightly more optimal), then allocate a temporary page to copy the source data into. Relock the destination page and continue with the copy. However, instead of a usercopy (which might take a fault), copy the data from the pinned temporary page via the kernel address space. (also, rename maxlen to seglen, because it was confusing) This increases the CPU/memory copy cost by almost 50% on the affected workloads. That will be solved by introducing a new set of pagecache write aops in a subsequent patch. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Hide some of the open-coded nr_segs tests into the iovec helpers. This is all to simplify generic_file_buffered_write, because that gets more complex in the next patch. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Quite a bit of code is used in maintaining these "cached pages" that are probably pretty unlikely to get used. It would require a narrow race where the page is inserted concurrently while this process is allocating a page in order to create the spare page. Then a multi-page write into an uncached part of the file, to make use of it. Next, the buffered write path (and others) uses its own LRU pagevec when it should be just using the per-CPU LRU pagevec (which will cut down on both data and code size cacheline footprint). Also, these private LRU pagevecs are emptied after just a very short time, in contrast with the per-CPU pagevecs that are persistent. Net result: 7.3 times fewer lru_lock acquisitions required to add the pages to pagecache for a bulk write (in 4K chunks). [this gets rid of some cond_resched() calls in readahead.c and mpage.c due to clashes in -mm. What put them there, and why? ] Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
If prepare_write fails with AOP_TRUNCATED_PAGE, or if commit_write fails, then we may have failed the write operation despite prepare_write having instantiated blocks past i_size. Fix this, and consolidate the trimming into one place. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Allow CONFIG_DEBUG_VM to switch off the prefaulting logic, to simulate the Makes the race much easier to hit. This is useful for demonstration and testing purposes, but is removed in a subsequent patch. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrew Morton 提交于
Rename some variables and fix some types. Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrew Morton 提交于
This reverts commit 6527c2bd, which fixed the following bug: When prefaulting in the pages in generic_file_buffered_write(), we only faulted in the pages for the firts segment of the iovec. If the second of successive segment described a mmapping of the page into which we're write()ing, and that page is not up-to-date, the fault handler tries to lock the already-locked page (to bring it up to date) and deadlocks. An exploit for this bug is in writev-deadlock-demo.c, in http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz. (These demos assume blocksize < PAGE_CACHE_SIZE). The problem with this fix is that it takes the kernel back to doing a single prepare_write()/commit_write() per iovec segment. So in the worst case we'll run prepare_write+commit_write 1024 times where we previously would have run it once. The other problem with the fix is that it fix all the locking problems. <insert numbers obtained via ext3-tools's writev-speed.c here> And apparently this change killed NFS overwrite performance, because, I suppose, it talks to the server for each prepare_write+commit_write. So just back that patch out - we'll be fixing the deadlock by other means. Nick says: also it only ever actually papered over the bug, because after faulting in the pages, they might be unmapped or reclaimed. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrew Morton 提交于
This reverts commit 81b0c871, which was a bugfix against 6527c2bd ("[PATCH] generic_file_buffered_write(): deadlock on vectored write"), which we also revert. Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Revert the patch from Neil Brown to optimise NFSD writev handling. Cc: Neil Brown <neilb@suse.de> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
find_lock_page does not need to recheck ->index because if the page is in the right mapping then the index must be the same. Also, tree_lock does not need to be retaken after the page is locked in order to test that ->mapping has not changed, because holding the page lock pins its mapping. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Fengguang Wu 提交于
Convert some 'unsigned long' to pgoff_t. Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Fengguang Wu 提交于
- remove unused local next_index in do_generic_mapping_read() - remove a redudant page_cache_read() declaration Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Fengguang Wu 提交于
The local copy of ra in do_generic_mapping_read() can now go away. It predates readanead(req_size). In a time when the readahead code was called on *every* single page. Hence a local has to be made to reduce the chance of the readahead state being overwritten by a concurrent reader. More details in: Linux: Random File I/O Regressions In 2.6 <http://kerneltrap.org/node/3039> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Fengguang Wu 提交于
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: NFengguang Wu <wfg@mail.ustc.edu.cn> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Fengguang Wu 提交于
Fold file_ra_state.mmap_hit into file_ra_state.mmap_miss and make it an int. Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 10月, 2007 1 次提交
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由 Yan Zheng 提交于
find_lock_page increases page's usage count, we should decrease it before return VM_FAULT_SIGBUS Signed-off-by: Yan Zheng<yanzheng@21cn.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 12 8月, 2007 2 次提交
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由 Stephen Hemminger 提交于
Minor docbook error since argument name in comment doesn't match function Signed-off-by: NStephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Adrian Bunk 提交于
This patch removes the no longer used file_send_actor(). Signed-off-by: NAdrian Bunk <bunk@stusta.de> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 01 8月, 2007 1 次提交
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由 Randy Dunlap 提交于
Fix kernel-doc warning: Warning(linux-2.6.23-rc1-mm1//mm/filemap.c:864): No description found for parameter 'ra' Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 20 7月, 2007 6 次提交
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由 Rusty Russell 提交于
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: NRusty Russell <rusty@rustcorp.com.au> Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Fengguang Wu 提交于
Convert filemap reads to use on-demand readahead. The new call scheme is to - call readahead on non-cached page - call readahead on look-ahead page - update prev_index when finished with the read request Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn> Cc: Steven Pratt <slpratt@austin.ibm.com> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
This patch completes Linus's wish that the fault return codes be made into bit flags, which I agree makes everything nicer. This requires requires all handle_mm_fault callers to be modified (possibly the modifications should go further and do things like fault accounting in handle_mm_fault -- however that would be for another patch). [akpm@linux-foundation.org: fix alpha build] [akpm@linux-foundation.org: fix s390 build] [akpm@linux-foundation.org: fix sparc build] [akpm@linux-foundation.org: fix sparc64 build] [akpm@linux-foundation.org: fix ia64 build] Signed-off-by: NNick Piggin <npiggin@suse.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Acked-by: NKyle McMartin <kyle@mcmartin.ca> Acked-by: NHaavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: NRalf Baechle <ralf@linux-mips.org> Acked-by: NAndi Kleen <ak@muc.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> [ Still apparently needs some ARM and PPC loving - Linus ] Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Change ->fault prototype. We now return an int, which contains VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte. FAULT_RET_ code tells the VM whether a page was found, whether it has been locked, and potentially other things. This is not quite the way he wanted it yet, but that's changed in the next patch (which requires changes to arch code). This means we no longer set VM_CAN_INVALIDATE in the vma in order to say that a page is locked which requires filemap_nopage to go away (because we can no longer remain backward compatible without that flag), but we were going to do that anyway. struct fault_data is renamed to struct vm_fault as Linus asked. address is now a void __user * that we should firmly encourage drivers not to use without really good reason. The page is now returned via a page pointer in the vm_fault struct. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes the virtual address -> file offset differently from linear mappings. ->populate is a layering violation because the filesystem/pagecache code should need to know anything about the virtual memory mapping. The hitch here is that the ->nopage handler didn't pass down enough information (ie. pgoff). But it is more logical to pass pgoff rather than have the ->nopage function calculate it itself anyway (because that's a similar layering violation). Having the populate handler install the pte itself is likewise a nasty thing to be doing. This patch introduces a new fault handler that replaces ->nopage and ->populate and (later) ->nopfn. Most of the old mechanism is still in place so there is a lot of duplication and nice cleanups that can be removed if everyone switches over. The rationale for doing this in the first place is that nonlinear mappings are subject to the pagefault vs invalidate/truncate race too, and it seemed stupid to duplicate the synchronisation logic rather than just consolidate the two. After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in pagecache. Seems like a fringe functionality anyway. NOPAGE_REFAULT is removed. This should be implemented with ->fault, and no users have hit mainline yet. [akpm@linux-foundation.org: cleanup] [randy.dunlap@oracle.com: doc. fixes for readahead] [akpm@linux-foundation.org: build fix] Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Cc: Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Fix the race between invalidate_inode_pages and do_no_page. Andrea Arcangeli identified a subtle race between invalidation of pages from pagecache with userspace mappings, and do_no_page. The issue is that invalidation has to shoot down all mappings to the page, before it can be discarded from the pagecache. Between shooting down ptes to a particular page, and actually dropping the struct page from the pagecache, do_no_page from any process might fault on that page and establish a new mapping to the page just before it gets discarded from the pagecache. The most common case where such invalidation is used is in file truncation. This case was catered for by doing a sort of open-coded seqlock between the file's i_size, and its truncate_count. Truncation will decrease i_size, then increment truncate_count before unmapping userspace pages; do_no_page will read truncate_count, then find the page if it is within i_size, and then check truncate_count under the page table lock and back out and retry if it had subsequently been changed (ptl will serialise against unmapping, and ensure a potentially updated truncate_count is actually visible). Complexity and documentation issues aside, the locking protocol fails in the case where we would like to invalidate pagecache inside i_size. do_no_page can come in anytime and filemap_nopage is not aware of the invalidation in progress (as it is when it is outside i_size). The end result is that dangling (->mapping == NULL) pages that appear to be from a particular file may be mapped into userspace with nonsense data. Valid mappings to the same place will see a different page. Andrea implemented two working fixes, one using a real seqlock, another using a page->flags bit. He also proposed using the page lock in do_no_page, but that was initially considered too heavyweight. However, it is not a global or per-file lock, and the page cacheline is modified in do_no_page to increment _count and _mapcount anyway, so a further modification should not be a large performance hit. Scalability is not an issue. This patch implements this latter approach. ->nopage implementations return with the page locked if it is possible for their underlying file to be invalidated (in that case, they must set a special vm_flags bit to indicate so). do_no_page only unlocks the page after setting up the mapping completely. invalidation is excluded because it holds the page lock during invalidation of each page (and ensures that the page is not mapped while holding the lock). This also allows significant simplifications in do_no_page, because we have the page locked in the right place in the pagecache from the start. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 7月, 2007 1 次提交
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由 NeilBrown 提交于
do_generic_mapping_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 do_generic_mapping_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 do_generic_mapping_read 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 the copy-out. The same change applied to __generic_file_splice_read. Note that this fixes any race with truncate_complete_page, but does not fix a possible race with truncate_partial_page. If a partial truncate happens after do_generic_mapping_read samples i_size and before the copy_out, the nuls that truncate_partial_page place in the page could be copied out incorrectly. I think the best fix for that is to *not* zero out parts of the page in truncate_partial_page, but rather to zero out the tail of a page when increasing i_size. Signed-off-by: NNeil Brown <neilb@suse.de> Cc: Jens Axboe <jens.axboe@oracle.com> Acked-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 7月, 2007 1 次提交
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由 Micah Cowan 提交于
Some users have been having problems with utilities like cp or dd dumping core when they try to copy a file that's too large for the destination filesystem (typically, > 4gb). Apparently, some defunct standards required SIGXFSZ to be sent in such circumstances, but SUS only requires/allows it for when a written file exceeds the process's resource limits. I'd like to limit SIGXFSZs to the bare minimum required by SUS. Patch sent per http://lkml.org/lkml/2007/4/10/302Signed-off-by: NMicah Cowan <micahcowan@ubuntu.com> Acked-by: NAlan Cox <alan@redhat.com> Cc: <reiserfs-dev@namesys.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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