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path: root/fs/nfs/write.c
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2010-02-09NFS: Remove a redundant check for PageFsCache in nfs_migrate_page()Trond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: David Howells <dhowells@redhat.com>
2010-01-26NFS: Make nfs_commitdata_release staticH Hartley Sweeten
The symbol nfs_commitdata_release is only used locally in this file. Make it static to prevent the following sparse warning: warning: symbol 'nfs_commitdata_release' was not declared. Should it be static? Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
2010-01-26NFS: Fix a reference leak in nfs_wb_cancel_page()Trond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@kernel.org Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
2009-12-13Merge branch 'nfs-for-2.6.33'Trond Myklebust
2009-12-10NFS: Fix nfs_migrate_page()Trond Myklebust
The call to migrate_page() will cause the page->private field to be cleared. Also fix up the locking around the page->private transfer, so that we ensure that calls to nfs_page_find_request() don't end up racing. Finally, fix up a double free bug: nfs_unlock_request() already calls nfs_release_request() for us... Reported-by: Wu Fengguang <fengguang.wu@intel.com> Tested-by: Andi Kleen <andi@firstfloor.org> Cc: stable@kernel.org Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-10vfs: Implement proper O_SYNC semanticsChristoph Hellwig
While Linux provided an O_SYNC flag basically since day 1, it took until Linux 2.4.0-test12pre2 to actually get it implemented for filesystems, since that day we had generic_osync_around with only minor changes and the great "For now, when the user asks for O_SYNC, we'll actually give O_DSYNC" comment. This patch intends to actually give us real O_SYNC semantics in addition to the O_DSYNC semantics. After Jan's O_SYNC patches which are required before this patch it's actually surprisingly simple, we just need to figure out when to set the datasync flag to vfs_fsync_range and when not. This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's numerical value to keep binary compatibility, and adds a new real O_SYNC flag. To guarantee backwards compatiblity it is defined as expanding to both the O_DSYNC and the new additional binary flag (__O_SYNC) to make sure we are backwards-compatible when compiled against the new headers. This also means that all places that don't care about the differences can just check O_DSYNC and get the right behaviour for O_SYNC, too - only places that actuall care need to check __O_SYNC in addition. Drivers and network filesystems have been updated in a fail safe way to always do the full sync magic if O_DSYNC is set. The few places setting O_SYNC for lower layers are kept that way for now to stay failsafe. We enforce that O_DSYNC is set when __O_SYNC is set early in the open path to make sure we always get these sane options. Note that parisc really screwed up their headers as they already define a O_DSYNC that has always been a no-op. We try to repair it by using it for the new O_DSYNC and redefinining O_SYNC to send both the traditional O_SYNC numerical value _and_ the O_DSYNC one. Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jan Kara <jack@suse.cz>
2009-12-07NFS: Fix up the declaration of nfs4_restart_rpc when NFSv4 not configuredTrond Myklebust
Also rename it: it is used in generic code, and so should not have a 'nfs4' prefix. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05NFSv41: Clean up slot table managementTrond Myklebust
We no longer need to maintain a distinction between nfs41_sequence_done and nfs41_sequence_free_slot. This fixes a number of slot table leakages in the NFSv4.1 code. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04nfs41: call free slot from nfs4_restart_rpcAndy Adamson
nfs41_sequence_free_slot can be called multiple times on SEQUENCE operation errors. No reason to inline nfs4_restart_rpc Reported-by: Trond Myklebust <trond.myklebust@netapp.com> nfs_writeback_done and nfs_readpage_retry call nfs4_restart_rpc outside the error handler, and the slot is not freed prior to restarting in the rpc_prepare state during session reset. Fix this by moving the call to nfs41_sequence_free_slot from the error path of nfs41_sequence_done into nfs4_restart_rpc, and by removing the test for NFS4CLNT_SESSION_SETUP. Always free slot and goto the rpc prepare state on async errors. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03writeback: introduce wbc.for_backgroundWu Fengguang
It will lower the flush priority for NFS, and maybe more in future. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-16writeback: get rid of wbc->for_writepagesJens Axboe
It's only set, it's never checked. Kill it. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-19Merge branch 'nfsv4_xdr_cleanups-for-2.6.32' into nfs-for-2.6.32Trond Myklebust
Conflicts: fs/nfs/nfs4xdr.c
2009-08-12NFS: Fix an O_DIRECT Oops...Trond Myklebust
We can't call nfs_readdata_release()/nfs_writedata_release() without first initialising and referencing args.context. Doing so inside nfs_direct_read_schedule_segment()/nfs_direct_write_schedule_segment() causes an Oops. We should rather be calling nfs_readdata_free()/nfs_writedata_free() in those cases. Looking at the O_DIRECT code, the "struct nfs_direct_req" is already referencing the nfs_open_context for us. Since the readdata and writedata structures carry a reference to that, we can simplify things by getting rid of the extra nfs_open_context references, so that we can replace all instances of nfs_readdata_release()/nfs_writedata_release(). Reported-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Tested-by: Catalin Marinas <catalin.marinas@arm.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-10NFS: Add a ->migratepage() aop for NFSTrond Myklebust
Make NFS a bit more friendly to NUMA and memory hot removal... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-07-11Revert "fuse: Fix build error" as unnecessaryLinus Torvalds
This reverts commit 097041e576ee3a50d92dd643ee8ca65bf6a62e21. Trond had a better fix, which is the parent of this one ("Fix compile error due to congestion_wait() changes") Requested-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-10fuse: Fix build errorLarry Finger
When building v2.6.31-rc2-344-g69ca06c, the following build errors are found due to missing includes: CC [M] fs/fuse/dev.o fs/fuse/dev.c: In function ‘request_end’: fs/fuse/dev.c:289: error: ‘BLK_RW_SYNC’ undeclared (first use in this function) ... fs/nfs/write.c: In function ‘nfs_set_page_writeback’: fs/nfs/write.c:207: error: ‘BLK_RW_ASYNC’ undeclared (first use in this function) Signed-off-by: Larry Finger@lwfinger.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-10Fix congestion_wait() sync/async vs read/write confusionJens Axboe
Commit 1faa16d22877f4839bd433547d770c676d1d964c accidentally broke the bdi congestion wait queue logic, causing us to wait on congestion for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-17nfs41: use rpc prepare call state for session resetAndy Adamson
[nfs41: change nfs4_restart_rpc argument] [nfs41: check for session not minorversion] [nfs41: trigger the state manager for session reset] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [always define nfs4_restart_rpc] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17nfs41 commit sequence setup done supportAndy Adamson
Separate commit calls from nfs41: sequence setup/done support Implement the commit rpc_call_prepare method for asynchronuos nfs rpcs, call nfs41_setup_sequence from respective rpc_call_validate_args methods. Call nfs4_sequence_done from respective rpc_call_done methods. Note that we need to pass a pointer to the nfs_server in calls data for passing on to nfs4_sequence_done. Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [pnfs: client data server write validate and release] Signed-off-by: Andy Adamson<andros@umich.edu> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Support sessions with O_DIRECT.] Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: separate free slot from sequence done] [nfs41: nfs4_sequence_free_slot use nfs_client for data server] Signed-off-by: Andy Adamson<andros@umich.edu> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17nfs41 write sequence setup done supportAndy Adamson
Separate write calls from nfs41: sequence setup/done support Implement the write rpc_call_prepare method for asynchronuos nfs rpcs, call nfs41_setup_sequence from respective rpc_call_validate_args methods. Call nfs4_sequence_done from respective rpc_call_done methods. Note that we need to pass a pointer to the nfs_server in calls data for passing on to nfs4_sequence_done. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [pnfs: client data server write validate and release] Signed-off-by: Andy Adamson <andros@umich.edu> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [move the nfs4_sequence_free_slot call in nfs_readpage_retry from] [nfs41: separate free slot from sequence done Signed-off-by: Andy Adamson <andros@umich.edu> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Support sessions with O_DIRECT.] Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: nfs4_sequence_free_slot use nfs_client for data server] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17nfs41: set up seq_res.sr_slotidAndy Adamson
Initialize nfs4_sequence_res sr_slotid to NFS4_MAX_SLOT_TABLE. [was nfs41: sequence res use slotid] Signed-off-by: Andy Adamson <andros@netapp.com> [pulled definition of struct nfs4_sequence_res.sr_slotid to here] Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-03-19NFS: Fix up a mismerged patchTrond Myklebust
Move the definition of nfs_need_commit() into the #ifdef CONFIG_NFS_V3 section as originally intended in the patch "NFS: cleanup - remove struct nfs_inode->ncommit" Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-03-11NFS: Throttle page dirtying while we're flushing to diskTrond Myklebust
The following patch is a combination of a patch by myself and Peter Staubach. Trond: If we allow other processes to dirty pages while a process is doing a consistency sync to disk, we can end up never making progress. Peter: Attached is a patch which addresses a continuing problem with the NFS client generating out of order WRITE requests. While this is compliant with all of the current protocol specifications, there are servers in the market which can not handle out of order WRITE requests very well. Also, this may lead to sub-optimal block allocations in the underlying file system on the server. This may cause the read throughputs to be reduced when reading the file from the server. Peter: There has been a lot of work recently done to address out of order issues on a systemic level. However, the NFS client is still susceptible to the problem. Out of order WRITE requests can occur when pdflush is in the middle of writing out pages while the process dirtying the pages calls generic_file_buffered_write which calls generic_perform_write which calls balance_dirty_pages_rate_limited which ends up calling writeback_inodes which ends up calling back into the NFS client to writes out dirty pages for the same file that pdflush happens to be working with. Signed-off-by: Peter Staubach <staubach@redhat.com> [modification by Trond to merge the two similar patches] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-03-11NFS: cleanup - remove struct nfs_inode->ncommitTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-10-07NFS: Don't use range_cyclic for data integrity syncsTrond Myklebust
It is more efficient to write linearly starting from the beginning of the file. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-07-15NFS: Remove BKL requirement from attribute updatesTrond Myklebust
The main problem is dealing with inode->i_size: we need to set the inode->i_lock on all attribute updates, and so vmtruncate won't cut it. Make an NFS-private version of vmtruncate that has the necessary locking semantics. The result should be that the following inode attribute updates are protected by inode->i_lock nfsi->cache_validity nfsi->read_cache_jiffies nfsi->attrtimeo nfsi->attrtimeo_timestamp nfsi->change_attr nfsi->last_updated nfsi->cache_change_attribute nfsi->access_cache nfsi->access_cache_entry_lru nfsi->access_cache_inode_lru nfsi->acl_access nfsi->acl_default nfsi->nfs_page_tree nfsi->ncommit nfsi->npages nfsi->open_files nfsi->silly_list nfsi->acl nfsi->open_states inode->i_size inode->i_atime inode->i_mtime inode->i_ctime inode->i_nlink inode->i_uid inode->i_gid The following is protected by dir->i_mutex nfsi->cookieverf Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-07-09NFS: Allow redirtying of a completed unstable write.Trond Myklebust
Currently, if an unstable write completes, we cannot redirty the page in order to reflect a new change in the page data until after we've sent a COMMIT request. This patch allows a page rewrite to proceed without the unnecessary COMMIT step, putting it immediately back onto the dirty page list, undoing the VM unstable write accounting, and removing the NFS_PAGE_TAG_COMMIT tag from the NFS radix tree. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-07-09NFS: Clean up nfs_update_request()Trond Myklebust
Simplify the loop in nfs_update_request by moving into a separate function the code that attempts to update an existing cached NFS write. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-07-09NFS: Fix trace debugging nits in write.cChuck Lever
Clean up: fix a few dprintk messages that still need to show the RPC task ID correctly, and be sure we use the preferred %lld or %llu instead of %Ld or %Lu. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-07-09NFS: Revert commit 44dd151dTrond Myklebust
Revert commit 44dd151d "NFS: Don't mark a written page as uptodate until it is on disk". While it is true that the write may fail, that is always the case. There is no reason why we should treat data on pages that are not already marked as PG_uptodate as being special. The only thing we gain is a noticeable slowdown when re-reading these pages. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-07-09NFS: Optimise append writes with holesTrond Myklebust
If a file is being extended, and we're creating a hole, we might as well declare the entire page to be up to date. This patch significantly improves the write performance for sparse files in the case where lseek(SEEK_END) is used to append several non-contiguous writes at intervals of < PAGE_SIZE. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-07-09NFS: Fix a preemption count leak in nfs_update_requestTrond Myklebust
The commit 2785259631697ebb0749a3782cca206e2e542939 (nfs: use GFP_NOFS preloads for radix-tree insertion) appears to have introduced a bug: We only want to call radix_tree_preload() once after creating a request. Calling it every time we loop after we created the request, will cause preemption count leaks. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Nick Piggin <npiggin@suse.de>
2008-06-23NFS: nfs_updatepage(): don't mark page as dirty if an error occurredTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-05-16nfs: fix race in nfs_dirty_requestFred Isaman
When called from nfs_flush_incompatible, the req is not locked, so req->wb_page might be set to NULL before it is used by PageWriteback. Signed-off-by: Fred Isaman <iisaman@citi.umich.edu> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-04-19NFS: Ensure that rpc_run_task() errors are propagated back to the callerTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-04-19NFS: Ensure that the write code cleans up properly when rpc_run_task() failsTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-04-19NFS: Fix nfs_wb_page() to always exit with an error or a clean pageTrond Myklebust
It is possible for nfs_wb_page() to sometimes exit with 0 return value, yet the page is left in a dirty state. For instance in the case where the server rebooted, and the COMMIT request failed, then all the previously "clean" pages which were cached by the server, but were not guaranteed to have been writted out to disk, have to be redirtied and resent to the server. The fix is to have nfs_wb_page_priority() check that the page is clean before it exits... This fixes a condition that triggers the BUG_ON(PagePrivate(page)) in nfs_create_request() when we're in the nfs_readpage() path. Also eliminate a redundant BUG_ON(!PageLocked(page)) while we're at it. It turns out that clear_page_dirty_for_io() has the exact same test. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-03-19nfs: nfs_redirty_requestFred
Both flush functions have the same error handling routine. Pull it out as a function. Signed-off-by: Fred Isaman <iisaman@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-03-19Merge branch 'hotfixes' into develTrond Myklebust
2008-03-19nfs: don't ignore return value from nfs_pageio_add_requestFred Isaman
Ignoring the return value from nfs_pageio_add_request can cause deadlocks. In read path: call nfs_pageio_add_request from readpage_async_filler assume at this point that there are requests already in desc, that can't be merged with the current request. so nfs_pageio_doio is fired up to clear out desc. assume something goes wrong in setting up the io, so desc->pg_error is set. This causes nfs_pageio_add_request to return 0, *WITHOUT* adding the original request. BUT, since return code is ignored, readpage_async_filler assumes it has been added, and does nothing further, leaving page locked. do_generic_mapping_read will eventually call lock_page, resulting in deadlock In write path: page is marked dirty by generic_perform_write nfs_writepages is called call nfs_pageio_add_request from nfs_page_async_flush assume at this point that there are requests already in desc, that can't be merged with the current request. so nfs_pageio_doio is fired up to clear out desc. assume something goes wrong in setting up the io, so desc->pg_error is set. This causes nfs_page_async_flush to return 0, *WITHOUT* adding the original request, yet marking the request as locked (PG_BUSY) and in writeback, clearing dirty marks. The next time a write is done to the page, deadlock will result as nfs_write_end calls nfs_update_request Signed-off-by: Fred Isaman <iisaman@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-03-07NFS: Fix an f_mode/f_flags confusion in fs/nfs/write.cTrond Myklebust
O_SYNC is stored in filp->f_flags. Thanks to Al Viro for pointing out the bug. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-02-28Merge branch 'cleanups' into nextTrond Myklebust
2008-02-28SUNRPC: Remove now-redundant RCU-safe rpc_task free pathTrond Myklebust
Now that we've tightened up the locking rules for RPC queue wakeups, we can remove the RCU-safe kfree calls... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-02-25NFS: Ensure that the asynchronous RPC calls complete on nfsiod.Trond Myklebust
We want to ensure that rpc_call_ops that involve mntput() are run on nfsiod rather than on rpciod, so that they don't deadlock when the resulting umount calls rpc_shutdown_client(). Hence we specify that read, write and commit calls must complete on nfsiod. Ditto for NFSv4 open, lock, locku and close asynchronous calls. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-02-25NFS: Fix a deadlock with lazy umountTrond Myklebust
We can't allow rpc callback functions like task->tk_ops->rpc_call_prepare() and task->tk_ops->rpc_call_done() to call mntput() in any way, since that will cause a deadlock when the call to rpc_shutdown_client() attempts to wait on 'task' to complete. We can avoid the above deadlock by moving calls to mntput to task->tk_ops->rpc_release() callback, since at that time the task will be marked as completed, and so rpc_shutdown_client won't attempt to wait on it. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-02-25NFS: Fix an f_mode/f_flags confusion in fs/nfs/write.cTrond Myklebust
O_SYNC is stored in filp->f_flags. Thanks to Al Viro for pointing out the bug. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-02-13nfs: use GFP_NOFS preloads for radix-tree insertionNick Piggin
NFS should use GFP_NOFS mode radix tree preloads rather than GFP_ATOMIC allocations at radix-tree insertion-time. This is important to reduce the atomic memory requirement. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-02-07NFS: Fix a potential file corruption issue when writingTrond Myklebust
If the inode is flagged as having an invalid mapping, then we can't rely on the PageUptodate() flag. Ensure that we don't use the "anti-fragmentation" write optimisation in nfs_updatepage(), since that will cause NFS to write out areas of the page that are no longer guaranteed to be up to date. A potential corruption could occur in the following scenario: client 1 client 2 =============== =============== fd=open("f",O_CREAT|O_WRONLY,0644); write(fd,"fubar\n",6); // cache last page close(fd); fd=open("f",O_WRONLY|O_APPEND); write(fd,"foo\n",4); close(fd); fd=open("f",O_WRONLY|O_APPEND); write(fd,"bar\n",4); close(fd); ----- The bug may lead to the file "f" reading 'fubar\n\0\0\0\nbar\n' because client 2 does not update the cached page after re-opening the file for write. Instead it keeps it marked as PageUptodate() until someone calls invaldate_inode_pages2() (typically by calling read()). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-02-05Pagecache zeroing: zero_user_segment, zero_user_segments and zero_userChristoph Lameter
Simplify page cache zeroing of segments of pages through 3 functions zero_user_segments(page, start1, end1, start2, end2) Zeros two segments of the page. It takes the position where to start and end the zeroing which avoids length calculations and makes code clearer. zero_user_segment(page, start, end) Same for a single segment. zero_user(page, start, length) Length variant for the case where we know the length. We remove the zero_user_page macro. Issues: 1. Its a macro. Inline functions are preferable. 2. The KM_USER0 macro is only defined for HIGHMEM. Having to treat this special case everywhere makes the code needlessly complex. The parameter for zeroing is always KM_USER0 except in one single case that we open code. Avoiding KM_USER0 makes a lot of code not having to be dealing with the special casing for HIGHMEM anymore. Dealing with kmap is only necessary for HIGHMEM configurations. In those configurations we use KM_USER0 like we do for a series of other functions defined in highmem.h. Since KM_USER0 is depends on HIGHMEM the existing zero_user_page function could not be a macro. zero_user_* functions introduced here can be be inline because that constant is not used when these functions are called. Also extract the flushing of the caches to be outside of the kmap. [akpm@linux-foundation.org: fix nfs and ntfs build] [akpm@linux-foundation.org: fix ntfs build some more] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: <linux-ext4@vger.kernel.org> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: David Chinner <dgc@sgi.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-01Merge branch 'task_killable' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc * 'task_killable' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: (22 commits) Remove commented-out code copied from NFS NFS: Switch from intr mount option to TASK_KILLABLE Add wait_for_completion_killable Add wait_event_killable Add schedule_timeout_killable Use mutex_lock_killable in vfs_readdir Add mutex_lock_killable Use lock_page_killable Add lock_page_killable Add fatal_signal_pending Add TASK_WAKEKILL exit: Use task_is_* signal: Use task_is_* sched: Use task_contributes_to_load, TASK_ALL and TASK_NORMAL ptrace: Use task_is_* power: Use task_is_* wait: Use TASK_NORMAL proc/base.c: Use task_is_* proc/array.c: Use TASK_REPORT perfmon: Use task_is_* ... Fixed up conflicts in NFS/sunrpc manually..