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2015-11-16dax: disable pmd mappingsDan Williams
While dax pmd mappings are functional in the nominal path they trigger kernel crashes in the following paths: BUG: unable to handle kernel paging request at ffffea0004098000 IP: [<ffffffff812362f7>] follow_trans_huge_pmd+0x117/0x3b0 [..] Call Trace: [<ffffffff811f6573>] follow_page_mask+0x2d3/0x380 [<ffffffff811f6708>] __get_user_pages+0xe8/0x6f0 [<ffffffff811f7045>] get_user_pages_unlocked+0x165/0x1e0 [<ffffffff8106f5b1>] get_user_pages_fast+0xa1/0x1b0 kernel BUG at arch/x86/mm/gup.c:131! [..] Call Trace: [<ffffffff8106f34c>] gup_pud_range+0x1bc/0x220 [<ffffffff8106f634>] get_user_pages_fast+0x124/0x1b0 BUG: unable to handle kernel paging request at ffffea0004088000 IP: [<ffffffff81235f49>] copy_huge_pmd+0x159/0x350 [..] Call Trace: [<ffffffff811fad3c>] copy_page_range+0x34c/0x9f0 [<ffffffff810a0daf>] copy_process+0x1b7f/0x1e10 [<ffffffff810a11c1>] _do_fork+0x91/0x590 All of these paths are interpreting a dax pmd mapping as a transparent huge page and making the assumption that the pfn is covered by the memmap, i.e. that the pfn has an associated struct page. PTE mappings do not suffer the same fate since they have the _PAGE_SPECIAL flag to cause the gup path to fault. We can do something similar for the PMD path, or otherwise defer pmd support for cases where a struct page is available. For now, 4.4-rc and -stable need to disable dax pmd support by default. For development the "depends on BROKEN" line can be removed from CONFIG_FS_DAX_PMD. Cc: <stable@vger.kernel.org> Cc: Jan Kara <jack@suse.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-11-13Merge branch 'libnvdimm-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm fixes from Dan Williams: - three fixes tagged for -stable including a crash fix, simple performance tweak, and an invalid i/o error. - build regression fix for the nvdimm unit tests - nvdimm documentation update * 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax: fix __dax_pmd_fault crash libnvdimm: documentation clarifications libnvdimm, pmem: fix size trim in pmem_direct_access() libnvdimm, e820: fix numa node for e820-type-12 pmem ranges tools/testing/nvdimm, acpica: fix flag rename build breakage
2015-11-12dax: fix __dax_pmd_fault crashDan Williams
Since 4.3 introduced devm_memremap_pages() the pfns handled by DAX may optionally have a struct page backing. When a mapped pfn reaches vmf_insert_pfn_pmd() it fails with a crash signature like the following: kernel BUG at mm/huge_memory.c:905! [..] Call Trace: [<ffffffff812a73ba>] __dax_pmd_fault+0x2ea/0x5b0 [<ffffffffa01a4182>] xfs_filemap_pmd_fault+0x92/0x150 [xfs] [<ffffffff811fbe02>] handle_mm_fault+0x312/0x1b50 Fix this by falling back to 4K mappings in the pfn_valid() case. Longer term, vmf_insert_pfn_pmd() needs to grow support for architectures that can provide a 'pmd_special' capability. Cc: <stable@vger.kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-11-12Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull misc block fixes from Jens Axboe: "Stuff that got collected after the merge window opened. This contains: - NVMe: - Fix for non-striped transfer size setting for NVMe from Sathyavathi. - (Some) support for the weird Apple nvme controller in the macbooks. From Stephan Günther. - The error value leak for dax from Al. - A few minor blk-mq tweaks from me. - Add the new linux-block@vger.kernel.org mailing list to the MAINTAINERS file. - Discard fix for brd, from Jan. - A kerneldoc warning for block core from Randy. - An older fix from Vivek, converting a WARN_ON() to a rate limited printk when a device is hot removed with dirty inodes" * 'for-linus' of git://git.kernel.dk/linux-block: block: don't hardcode blk_qc_t -> tag mask dax_io(): don't let non-error value escape via retval instead of EFAULT block: fix blk-core.c kernel-doc warning fs/block_dev.c: Remove WARN_ON() when inode writeback fails NVMe: add support for Apple NVMe controller NVMe: use split lo_hi_{read,write}q blk-mq: mark __blk_mq_complete_request() static MAINTAINERS: add reference to new linux-block list NVMe: Increase the max transfer size when mdts is 0 brd: Refuse improperly aligned discard requests
2015-11-11Merge tag 'xfs-for-linus-4.4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs Pull xfs updates from Dave Chinner: "There is nothing really major here - the only significant addition is the per-mount operation statistics infrastructure. Otherwises there's various ACL, xattr, DAX, AIO and logging fixes, and a smattering of small cleanups and fixes elsewhere. Summary: - per-mount operational statistics in sysfs - fixes for concurrent aio append write submission - various logging fixes - detection of zeroed logs and invalid log sequence numbers on v5 filesystems - memory allocation failure message improvements - a bunch of xattr/ACL fixes - fdatasync optimisation - miscellaneous other fixes and cleanups" * tag 'xfs-for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (39 commits) xfs: give all workqueues rescuer threads xfs: fix log recovery op header validation assert xfs: Fix error path in xfs_get_acl xfs: optimise away log forces on timestamp updates for fdatasync xfs: don't leak uuid table on rmmod xfs: invalidate cached acl if set via ioctl xfs: Plug memory leak in xfs_attrmulti_attr_set xfs: Validate the length of on-disk ACLs xfs: invalidate cached acl if set directly via xattr xfs: xfs_filemap_pmd_fault treats read faults as write faults xfs: add ->pfn_mkwrite support for DAX xfs: DAX does not use IO completion callbacks xfs: Don't use unwritten extents for DAX xfs: introduce BMAPI_ZERO for allocating zeroed extents xfs: fix inode size update overflow in xfs_map_direct() xfs: clear PF_NOFREEZE for xfsaild kthread xfs: fix an error code in xfs_fs_fill_super() xfs: stats are no longer dependent on CONFIG_PROC_FS xfs: simplify /proc teardown & error handling xfs: per-filesystem stats counter implementation ...
2015-11-11dax_io(): don't let non-error value escape via retval instead of EFAULTAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: stable@vger.kernel.org # 4.0+ Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-03xfs: Don't use unwritten extents for DAXDave Chinner
DAX has a page fault serialisation problem with block allocation. Because it allows concurrent page faults and does not have a page lock to serialise faults to the same page, it can get two concurrent faults to the page that race. When two read faults race, this isn't a huge problem as the data underlying the page is not changing and so "detect and drop" works just fine. The issues are to do with write faults. When two write faults occur, we serialise block allocation in get_blocks() so only one faul will allocate the extent. It will, however, be marked as an unwritten extent, and that is where the problem lies - the DAX fault code cannot differentiate between a block that was just allocated and a block that was preallocated and needs zeroing. The result is that both write faults end up zeroing the block and attempting to convert it back to written. The problem is that the first fault can zero and convert before the second fault starts zeroing, resulting in the zeroing for the second fault overwriting the data that the first fault wrote with zeros. The second fault then attempts to convert the unwritten extent, which is then a no-op because it's already written. Data loss occurs as a result of this race. Because there is no sane locking construct in the page fault code that we can use for serialisation across the page faults, we need to ensure block allocation and zeroing occurs atomically in the filesystem. This means we can still take concurrent page faults and the only time they will serialise is in the filesystem mapping/allocation callback. The page fault code will always see written, initialised extents, so we will be able to remove the unwritten extent handling from the DAX code when all filesystems are converted. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-10-16mm, dax: fix DAX deadlocksRoss Zwisler
The following two locking commits in the DAX code: commit 843172978bb9 ("dax: fix race between simultaneous faults") commit 46c043ede471 ("mm: take i_mmap_lock in unmap_mapping_range() for DAX") introduced a number of deadlocks and other issues which need to be fixed for the v4.3 kernel. The list of issues in DAX after these commits (some newly introduced by the commits, some preexisting) can be found here: https://lkml.org/lkml/2015/9/25/602 (Subject: "Re: [PATCH] dax: fix deadlock in __dax_fault"). This undoes most of the changes introduced by those two commits, essentially returning us to the DAX locking scheme that was used in v4.2. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dan Williams <dan.j.williams@intel.com> Tested-by: Dave Chinner <dchinner@redhat.com> Cc: Jan Kara <jack@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-01dax: fix NULL pointer in __dax_pmd_fault()Ross Zwisler
Commit 46c043ede471 ("mm: take i_mmap_lock in unmap_mapping_range() for DAX") moved some code in __dax_pmd_fault() that was responsible for zeroing newly allocated PMD pages. The new location didn't properly set up 'kaddr', so when run this code resulted in a NULL pointer BUG. Fix this by getting the correct 'kaddr' via bdev_direct_access(). Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-15dax: fix O_DIRECT I/O to the last block of a blockdevJeff Moyer
commit bbab37ddc20b (block: Add support for DAX reads/writes to block devices) caused a regression in mkfs.xfs. That utility sets the block size of the device to the logical block size using the BLKBSZSET ioctl, and then issues a single sector read from the last sector of the device. This results in the dax_io code trying to do a page-sized read from 512 bytes from the end of the device. The result is -ERANGE being returned to userspace. The fix is to align the block to the page size before calling get_block. Thanks to willy for simplifying my original patch. Cc: <stable@vger.kernel.org> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Tested-by: Linda Knippers <linda.knippers@hp.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-09-09dax: update PMD fault handler with PMEM APIRoss Zwisler
As part of the v4.3 merge window the DAX code was updated by Matthew and Kirill to handle PMD pages. Also as part of the v4.3 merge window we updated the DAX code to do proper PMEM flushing (commit 2765cfbb342c: "dax: update I/O path to do proper PMEM flushing"). The additional code added by the DAX PMD patches also needs to be updated to properly use the PMEM API. This ensures that after a PMD fault is handled the zeros written to the newly allocated pages are durable on the DIMMs. linux/dax.h is included to get rid of a bunch of sparse warnings. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Matthew Wilcox <willy@linux.intel.com>, Cc: Dan Williams <dan.j.williams@intel.com> Cc: Kirill Shutemov <kirill@shutemov.name> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge second patch-bomb from Andrew Morton: "Almost all of the rest of MM. There was an unusually large amount of MM material this time" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (141 commits) zpool: remove no-op module init/exit mm: zbud: constify the zbud_ops mm: zpool: constify the zpool_ops mm: swap: zswap: maybe_preload & refactoring zram: unify error reporting zsmalloc: remove null check from destroy_handle_cache() zsmalloc: do not take class lock in zs_shrinker_count() zsmalloc: use class->pages_per_zspage zsmalloc: consider ZS_ALMOST_FULL as migrate source zsmalloc: partial page ordering within a fullness_list zsmalloc: use shrinker to trigger auto-compaction zsmalloc: account the number of compacted pages zsmalloc/zram: introduce zs_pool_stats api zsmalloc: cosmetic compaction code adjustments zsmalloc: introduce zs_can_compact() function zsmalloc: always keep per-class stats zsmalloc: drop unused variable `nr_to_migrate' mm/memblock.c: fix comment in __next_mem_range() mm/page_alloc.c: fix type information of memoryless node memory-hotplug: fix comments in zone_spanned_pages_in_node() and zone_spanned_pages_in_node() ...
2015-09-08mm: take i_mmap_lock in unmap_mapping_range() for DAXKirill A. Shutemov
DAX is not so special: we need i_mmap_lock to protect mapping->i_mmap. __dax_pmd_fault() uses unmap_mapping_range() shoot out zero page from all mappings. We need to drop i_mmap_lock there to avoid lock deadlock. Re-aquiring the lock should be fine since we check i_size after the point. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08dax: use linear_page_index()Matthew Wilcox
I was basically open-coding it (thanks to copying code from do_fault() which probably also needs to be fixed). Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08dax: ensure that zero pages are removed from other processesMatthew Wilcox
If the first access to a huge page was a store, there would be no existing zero pmd in this process's page tables. There could be a zero pmd in another process's page tables, if it had done a load. We can detect this case by noticing that the buffer_head returned from the filesystem is New, and ensure that other processes mapping this huge page have their page tables flushed. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08dax: don't use set_huge_zero_page()Kirill A. Shutemov
This is another place where DAX assumed that pgtable_t was a pointer. Open code the important parts of set_huge_zero_page() in DAX and make set_huge_zero_page() static again. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08dax: fix race between simultaneous faultsMatthew Wilcox
If two threads write-fault on the same hole at the same time, the winner of the race will return to userspace and complete their store, only to have the loser overwrite their store with zeroes. Fix this for now by taking the i_mmap_sem for write instead of read, and do so outside the call to get_block(). Now the loser of the race will see the block has already been zeroed, and will not zero it again. This severely limits our scalability. I have ideas for improving it, but those can wait for a later patch. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08dax: improve comment about truncate raceMatthew Wilcox
Jan Kara pointed out I should be more explicit here about the perils of racing against truncate. The comment is mostly the same as for the PTE case. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08fs/dax.c: fix typo in #endif commentValentin Rothberg
Fix typo s/CONFIG_TRANSPARENT_HUGEPAGES/CONFIG_TRANSPARENT_HUGEPAGE/ in #endif comment introduced by commit 2b26a9206d6a ("dax: add huge page fault support"). Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08dax: add huge page fault supportMatthew Wilcox
This is the support code for DAX-enabled filesystems to allow them to provide huge pages in response to faults. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08Merge tag 'libnvdimm-for-4.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm updates from Dan Williams: "This update has successfully completed a 0day-kbuild run and has appeared in a linux-next release. The changes outside of the typical drivers/nvdimm/ and drivers/acpi/nfit.[ch] paths are related to the removal of IORESOURCE_CACHEABLE, the introduction of memremap(), and the introduction of ZONE_DEVICE + devm_memremap_pages(). Summary: - Introduce ZONE_DEVICE and devm_memremap_pages() as a generic mechanism for adding device-driver-discovered memory regions to the kernel's direct map. This facility is used by the pmem driver to enable pfn_to_page() operations on the page frames returned by DAX ('direct_access' in 'struct block_device_operations'). For now, the 'memmap' allocation for these "device" pages comes from "System RAM". Support for allocating the memmap from device memory will arrive in a later kernel. - Introduce memremap() to replace usages of ioremap_cache() and ioremap_wt(). memremap() drops the __iomem annotation for these mappings to memory that do not have i/o side effects. The replacement of ioremap_cache() with memremap() is limited to the pmem driver to ease merging the api change in v4.3. Completion of the conversion is targeted for v4.4. - Similar to the usage of memcpy_to_pmem() + wmb_pmem() in the pmem driver, update the VFS DAX implementation and PMEM api to provide persistence guarantees for kernel operations on a DAX mapping. - Convert the ACPI NFIT 'BLK' driver to map the block apertures as cacheable to improve performance. - Miscellaneous updates and fixes to libnvdimm including support for issuing "address range scrub" commands, clarifying the optimal 'sector size' of pmem devices, a clarification of the usage of the ACPI '_STA' (status) property for DIMM devices, and other minor fixes" * tag 'libnvdimm-for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (34 commits) libnvdimm, pmem: direct map legacy pmem by default libnvdimm, pmem: 'struct page' for pmem libnvdimm, pfn: 'struct page' provider infrastructure x86, pmem: clarify that ARCH_HAS_PMEM_API implies PMEM mapped WB add devm_memremap_pages mm: ZONE_DEVICE for "device memory" mm: move __phys_to_pfn and __pfn_to_phys to asm/generic/memory_model.h dax: drop size parameter to ->direct_access() nd_blk: change aperture mapping from WC to WB nvdimm: change to use generic kvfree() pmem, dax: have direct_access use __pmem annotation dax: update I/O path to do proper PMEM flushing pmem: add copy_from_iter_pmem() and clear_pmem() pmem, x86: clean up conditional pmem includes pmem: remove layer when calling arch_has_wmb_pmem() pmem, x86: move x86 PMEM API to new pmem.h header libnvdimm, e820: make CONFIG_X86_PMEM_LEGACY a tristate option pmem: switch to devm_ allocations devres: add devm_memremap libnvdimm, btt: write and validate parent_uuid ...
2015-08-20pmem, dax: have direct_access use __pmem annotationRoss Zwisler
Update the annotation for the kaddr pointer returned by direct_access() so that it is a __pmem pointer. This is consistent with the PMEM driver and with how this direct_access() pointer is used in the DAX code. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-08-20dax: update I/O path to do proper PMEM flushingRoss Zwisler
Update the DAX I/O path so that all operations that store data (I/O writes, zeroing blocks, punching holes, etc.) properly synchronize the stores to media using the PMEM API. This ensures that the data DAX is writing is durable on media before the operation completes. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-07-29xfs: call dax_fault on read page faults for DAXDave Chinner
When modifying the patch series to handle the XFS MMAP_LOCK nesting of page faults, I botched the conversion of the read page fault path, and so it is only every calling through the page cache. Re-add the necessary __dax_fault() call for such files. Because the get_blocks callback on read faults may not set up the mapping buffer correctly to allow unwritten extent completion to be run, we need to allow callers of __dax_fault() to pass a null complete_unwritten() callback. The DAX code always zeros the unwritten page when it is read faulted so there are no stale data exposure issues with not doing the conversion. The only downside will be the potential for increased CPU overhead on repeated read faults of the same page. If this proves to be a problem, then the filesystem needs to fix it's get_block callback and provide a convert_unwritten() callback to the read fault path. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-07-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
2015-07-04block: Add support for DAX reads/writes to block devicesMatthew Wilcox
If a block device supports the ->direct_access methods, bypass the normal DIO path and use DAX to go straight to memcpy() instead of allocating a DIO and a BIO. Includes support for the DIO_SKIP_DIO_COUNT flag in DAX, as is done in do_blockdev_direct_IO(). Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-07-04dax: Use copy_from_iter_nocacheMatthew Wilcox
When userspace does a write, there's no need for the written data to pollute the CPU cache. This matches the original XIP code. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-06-04dax: expose __dax_fault for filesystems with locking constraintsDave Chinner
Some filesystems cannot call dax_fault() directly because they have different locking and/or allocation constraints in the page fault IO path. To handle this, we need to follow the same model as the generic block_page_mkwrite code, where the internals are exposed via __block_page_mkwrite() so that filesystems can wrap the correct locking and operations around the outside. This is loosely based on a patch originally from Matthew Willcox. Unlike the original patch, it does not change ext4 code, error returns or unwritten extent conversion handling. It also adds a __dax_mkwrite() wrapper for .page_mkwrite implementations to do the right thing, too. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-06-04dax: don't abuse get_block mapping for endio callbacksDave Chinner
dax_fault() currently relies on the get_block callback to attach an io completion callback to the mapping buffer head so that it can run unwritten extent conversion after zeroing allocated blocks. Instead of this hack, pass the conversion callback directly into dax_fault() similar to the get_block callback. When the filesystem allocates unwritten extents, it will set the buffer_unwritten() flag, and hence the dax_fault code can call the completion function in the contexts where it is necessary without overloading the mapping buffer head. Note: The changes to ext4 to use this interface are suspect at best. In fact, the way ext4 did this end_io assignment in the first place looks suspect because it only set a completion callback when there wasn't already some other write() call taking place on the same inode. The ext4 end_io code looks rather intricate and fragile with all it's reference counting and passing to different contexts for modification via inode private pointers that aren't protected by locks... Signed-off-by: Dave Chinner <dchinner@redhat.com> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-04-26Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull fourth vfs update from Al Viro: "d_inode() annotations from David Howells (sat in for-next since before the beginning of merge window) + four assorted fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: RCU pathwalk breakage when running into a symlink overmounting something fix I_DIO_WAKEUP definition direct-io: only inc/dec inode->i_dio_count for file systems fs/9p: fix readdir() VFS: assorted d_backing_inode() annotations VFS: fs/inode.c helpers: d_inode() annotations VFS: fs/cachefiles: d_backing_inode() annotations VFS: fs library helpers: d_inode() annotations VFS: assorted weird filesystems: d_inode() annotations VFS: normal filesystems (and lustre): d_inode() annotations VFS: security/: d_inode() annotations VFS: security/: d_backing_inode() annotations VFS: net/: d_inode() annotations VFS: net/unix: d_backing_inode() annotations VFS: kernel/: d_inode() annotations VFS: audit: d_backing_inode() annotations VFS: Fix up some ->d_inode accesses in the chelsio driver VFS: Cachefiles should perform fs modifications on the top layer only VFS: AF_UNIX sockets should call mknod on the top layer only
2015-04-24direct-io: only inc/dec inode->i_dio_count for file systemsJens Axboe
do_blockdev_direct_IO() increments and decrements the inode ->i_dio_count for each IO operation. It does this to protect against truncate of a file. Block devices don't need this sort of protection. For a capable multiqueue setup, this atomic int is the only shared state between applications accessing the device for O_DIRECT, and it presents a scaling wall for that. In my testing, as much as 30% of system time is spent incrementing and decrementing this value. A mixed read/write workload improved from ~2.5M IOPS to ~9.6M IOPS, with better latencies too. Before: clat percentiles (usec): | 1.00th=[ 33], 5.00th=[ 34], 10.00th=[ 34], 20.00th=[ 34], | 30.00th=[ 34], 40.00th=[ 34], 50.00th=[ 35], 60.00th=[ 35], | 70.00th=[ 35], 80.00th=[ 35], 90.00th=[ 37], 95.00th=[ 80], | 99.00th=[ 98], 99.50th=[ 151], 99.90th=[ 155], 99.95th=[ 155], | 99.99th=[ 165] After: clat percentiles (usec): | 1.00th=[ 95], 5.00th=[ 108], 10.00th=[ 129], 20.00th=[ 149], | 30.00th=[ 155], 40.00th=[ 161], 50.00th=[ 167], 60.00th=[ 171], | 70.00th=[ 177], 80.00th=[ 185], 90.00th=[ 201], 95.00th=[ 270], | 99.00th=[ 390], 99.50th=[ 398], 99.90th=[ 418], 99.95th=[ 422], | 99.99th=[ 438] In other setups, Robert Elliott reported seeing good performance improvements: https://lkml.org/lkml/2015/4/3/557 The more applications accessing the device, the worse it gets. Add a new direct-io flags, DIO_SKIP_DIO_COUNT, which tells do_blockdev_direct_IO() that it need not worry about incrementing or decrementing the inode i_dio_count for this caller. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Elliott, Robert (Server Storage) <elliott@hp.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-16Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull third hunk of vfs changes from Al Viro: "This contains the ->direct_IO() changes from Omar + saner generic_write_checks() + dealing with fcntl()/{read,write}() races (mirroring O_APPEND/O_DIRECT into iocb->ki_flags and instead of repeatedly looking at ->f_flags, which can be changed by fcntl(2), check ->ki_flags - which cannot) + infrastructure bits for dhowells' d_inode annotations + Christophs switch of /dev/loop to vfs_iter_write()" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (30 commits) block: loop: switch to VFS ITER_BVEC configfs: Fix inconsistent use of file_inode() vs file->f_path.dentry->d_inode VFS: Make pathwalk use d_is_reg() rather than S_ISREG() VFS: Fix up debugfs to use d_is_dir() in place of S_ISDIR() VFS: Combine inode checks with d_is_negative() and d_is_positive() in pathwalk NFS: Don't use d_inode as a variable name VFS: Impose ordering on accesses of d_inode and d_flags VFS: Add owner-filesystem positive/negative dentry checks nfs: generic_write_checks() shouldn't be done on swapout... ocfs2: use __generic_file_write_iter() mirror O_APPEND and O_DIRECT into iocb->ki_flags switch generic_write_checks() to iocb and iter ocfs2: move generic_write_checks() before the alignment checks ocfs2_file_write_iter: stop messing with ppos udf_file_write_iter: reorder and simplify fuse: ->direct_IO() doesn't need generic_write_checks() ext4_file_write_iter: move generic_write_checks() up xfs_file_aio_write_checks: switch to iocb/iov_iter generic_write_checks(): drop isblk argument blkdev_write_iter: expand generic_file_checks() call in there ...
2015-04-15dax: use pfn_mkwrite to update c/mtime + freeze protectionBoaz Harrosh
From: Yigal Korman <yigal@plexistor.com> [v1] Without this patch, c/mtime is not updated correctly when mmap'ed page is first read from and then written to. A new xfstest is submitted for testing this (generic/080) [v2] Jan Kara has pointed out that if we add the sb_start/end_pagefault pair in the new pfn_mkwrite we are then fixing another bug where: A user could start writing to the page while filesystem is frozen. Signed-off-by: Yigal Korman <yigal@plexistor.com> Signed-off-by: Boaz Harrosh <boaz@plexistor.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-11Remove rw from dax_{do_,}io()Omar Sandoval
And use iov_iter_rw() instead. Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-02-16dax: add dax_zero_page_rangeMatthew Wilcox
This new function allows us to support hole-punch for DAX files by zeroing a partial page, as opposed to the dax_truncate_page() function which can only truncate to the end of the page. Reimplement dax_truncate_page() to call dax_zero_page_range(). [ross.zwisler@linux.intel.com: ported to 3.13-rc2] [akpm@linux-foundation.org: fix typos in comments] Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-16dax,ext2: replace xip_truncate_page with dax_truncate_pageMatthew Wilcox
It takes a get_block parameter just like nobh_truncate_page() and block_truncate_page() Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-16dax,ext2: replace the XIP page fault handler with the DAX page fault handlerMatthew Wilcox
Instead of calling aops->get_xip_mem from the fault handler, the filesystem passes a get_block_t that is used to find the appropriate blocks. This requires that all architectures implement copy_user_page(). At the time of writing, mips and arm do not. Patches exist and are in progress. [akpm@linux-foundation.org: remap_file_pages went away] Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-16dax,ext2: replace ext2_clear_xip_target with dax_clear_blocksMatthew Wilcox
This is practically generic code; other filesystems will want to call it from other places, but there's nothing ext2-specific about it. Make it a little more generic by allowing it to take a count of the number of bytes to zero rather than fixing it to a single page. Thanks to Dave Hansen for suggesting that I need to call cond_resched() if zeroing more than one page. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-16dax,ext2: replace XIP read and write with DAX I/OMatthew Wilcox
Use the generic AIO infrastructure instead of custom read and write methods. In addition to giving us support for AIO, this adds the missing locking between read() and truncate(). Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>