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2016-10-07thp: reduce usage of huge zero page's atomic counterAaron Lu1-1/+1
The global zero page is used to satisfy an anonymous read fault. If THP(Transparent HugePage) is enabled then the global huge zero page is used. The global huge zero page uses an atomic counter for reference counting and is allocated/freed dynamically according to its counter value. CPU time spent on that counter will greatly increase if there are a lot of processes doing anonymous read faults. This patch proposes a way to reduce the access to the global counter so that the CPU load can be reduced accordingly. To do this, a new flag of the mm_struct is introduced: MMF_USED_HUGE_ZERO_PAGE. With this flag, the process only need to touch the global counter in two cases: 1 The first time it uses the global huge zero page; 2 The time when mm_user of its mm_struct reaches zero. Note that right now, the huge zero page is eligible to be freed as soon as its last use goes away. With this patch, the page will not be eligible to be freed until the exit of the last process from which it was ever used. And with the use of mm_user, the kthread is not eligible to use huge zero page either. Since no kthread is using huge zero page today, there is no difference after applying this patch. But if that is not desired, I can change it to when mm_count reaches zero. Case used for test on Haswell EP: usemem -n 72 --readonly -j 0x200000 100G Which spawns 72 processes and each will mmap 100G anonymous space and then do read only access to that space sequentially with a step of 2MB. CPU cycles from perf report for base commit: 54.03% usemem [kernel.kallsyms] [k] get_huge_zero_page CPU cycles from perf report for this commit: 0.11% usemem [kernel.kallsyms] [k] mm_get_huge_zero_page Performance(throughput) of the workload for base commit: 1784430792 Performance(throughput) of the workload for this commit: 4726928591 164% increase. Runtime of the workload for base commit: 707592 us Runtime of the workload for this commit: 303970 us 50% drop. Link: http://lkml.kernel.org/r/fe51a88f-446a-4622-1363-ad1282d71385@intel.com Signed-off-by: Aaron Lu <aaron.lu@intel.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-19dax: provide an iomap based fault handlerChristoph Hellwig1-0/+114
Very similar to the existing dax_fault function, but instead of using the get_block callback we rely on the iomap_ops vector from iomap.c. That also avoids having to do two calls into the file system for write faults. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19dax: provide an iomap based dax read/write pathChristoph Hellwig1-0/+114
This is a much simpler implementation of the DAX read/write path that makes use of the iomap infrastructure. It does not try to mirror the direct I/O calling conventions and thus doesn't have to deal with i_dio_count or the end_io handler, but instead leaves locking and filesystem-specific I/O completion to the caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19dax: don't pass buffer_head to copy_user_daxChristoph Hellwig1-6/+6
This way we can use this helper for the iomap based DAX implementation as well. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19dax: don't pass buffer_head to dax_insert_mappingChristoph Hellwig1-6/+6
This way we can use this helper for the iomap based DAX implementation as well. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-28Merge tag 'libnvdimm-for-4.8' of ↵Linus Torvalds1-9/+4
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm updates from Dan Williams: - Replace pcommit with ADR / directed-flushing. The pcommit instruction, which has not shipped on any product, is deprecated. Instead, the requirement is that platforms implement either ADR, or provide one or more flush addresses per nvdimm. ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers to the memory controller on a power-fail event. Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware Interface Table (NFIT) sub-structure: "Flush Hint Address Structure". A flush hint is an mmio address that when written and fenced assures that all previous posted writes targeting a given dimm have been flushed to media. - On-demand ARS (address range scrub). Linux uses the results of the ACPI ARS commands to track bad blocks in pmem devices. When latent errors are detected we re-scrub the media to refresh the bad block list, userspace can also request a re-scrub at any time. - Support for the Microsoft DSM (device specific method) command format. - Support for EDK2/OVMF virtual disk device memory ranges. - Various fixes and cleanups across the subsystem. * tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits) libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register" nfit: do an ARS scrub on hitting a latent media error nfit: move to nfit/ sub-directory nfit, libnvdimm: allow an ARS scrub to be triggered on demand libnvdimm: register nvdimm_bus devices with an nd_bus driver pmem: clarify a debug print in pmem_clear_poison x86/insn: remove pcommit Revert "KVM: x86: add pcommit support" nfit, tools/testing/nvdimm/: unify shutdown paths libnvdimm: move ->module to struct nvdimm_bus_descriptor nfit: cleanup acpi_nfit_init calling convention nfit: fix _FIT evaluation memory leak + use after free tools/testing/nvdimm: add manufacturing_{date|location} dimm properties tools/testing/nvdimm: add virtual ramdisk range acpi, nfit: treat virtual ramdisk SPA as pmem region pmem: kill __pmem address space pmem: kill wmb_pmem() libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes fs/dax: remove wmb_pmem() libnvdimm, pmem: flush posted-write queues on shutdown ...
2016-07-26dax: remote unused fault wrappersRoss Zwisler1-59/+14
Remove the unused wrappers dax_fault() and dax_pmd_fault(). After this removal, rename __dax_fault() and __dax_pmd_fault() to dax_fault() and dax_pmd_fault() respectively, and update all callers. The dax_fault() and dax_pmd_fault() wrappers were initially intended to capture some filesystem independent functionality around page faults (calling sb_start_pagefault() & sb_end_pagefault(), updating file mtime and ctime). However, the following commits: 5726b27b09cc ("ext2: Add locking for DAX faults") ea3d7209ca01 ("ext4: fix races between page faults and hole punching") added locking to the ext2 and ext4 filesystems after these common operations but before __dax_fault() and __dax_pmd_fault() were called. This means that these wrappers are no longer used, and are unlikely to be used in the future. XFS has had locking analogous to what was recently added to ext2 and ext4 since DAX support was initially introduced by: 6b698edeeef0 ("xfs: add DAX file operations support") Link: http://lkml.kernel.org/r/20160714214049.20075-2-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-24Merge branch 'for-4.8/libnvdimm' into libnvdimm-for-nextDan Williams1-9/+4
2016-07-12pmem: kill __pmem address spaceDan Williams1-3/+3
The __pmem address space was meant to annotate codepaths that touch persistent memory and need to coordinate a call to wmb_pmem(). Now that wmb_pmem() is gone, there is little need to keep this annotation. Cc: Christoph Hellwig <hch@lst.de> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-12fs/dax: remove wmb_pmem()Dan Williams1-6/+1
Flushing posted-write queues is now deferred to REQ_FLUSH context, or otherwise handled by an ADR event at the platform level. Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-06-27dax: fix offset overflow in dax_ioEric Sandeen1-1/+6
This isn't functionally apparent for some reason, but when we test io at extreme offsets at the end of the loff_t rang, such as in fstests xfs/071, the calculation of "max" in dax_io() can be wrong due to pos + size overflowing. For example, # xfs_io -c "pwrite 9223372036854771712 512" /mnt/test/file enters dax_io with: start 0x7ffffffffffff000 end 0x7ffffffffffff200 and the rounded up "size" variable is 0x1000. This yields: pos + size 0x8000000000000000 (overflows loff_t) end 0x7ffffffffffff200 Due to the overflow, the min() function picks the wrong value for the "max" variable, and when we send (max - pos) into i.e. copy_from_iter_pmem() it is also the wrong value. This somehow(tm) gets magically absorbed without incident, probably because iter->count is correct. But it seems best to fix it up properly by comparing the two values as unsigned. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-05-26Merge tag 'dax-locking-for-4.7' of ↵Linus Torvalds1-171/+421
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull DAX locking updates from Ross Zwisler: "Filesystem DAX locking for 4.7 - We use a bit in an exceptional radix tree entry as a lock bit and use it similarly to how page lock is used for normal faults. This fixes races between hole instantiation and read faults of the same index. - Filesystem DAX PMD faults are disabled, and will be re-enabled when PMD locking is implemented" * tag 'dax-locking-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax: Remove i_mmap_lock protection dax: Use radix tree entry lock to protect cow faults dax: New fault locking dax: Allow DAX code to replace exceptional entries dax: Define DAX lock bit for radix tree exceptional entry dax: Make huge page handling depend of CONFIG_BROKEN dax: Fix condition for filling of PMD holes
2016-05-26Merge tag 'dax-misc-for-4.7' of ↵Linus Torvalds1-194/+63
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull misc DAX updates from Vishal Verma: "DAX error handling for 4.7 - Until now, dax has been disabled if media errors were found on any device. This enables the use of DAX in the presence of these errors by making all sector-aligned zeroing go through the driver. - The driver (already) has the ability to clear errors on writes that are sent through the block layer using 'DSMs' defined in ACPI 6.1. Other misc changes: - When mounting DAX filesystems, check to make sure the partition is page aligned. This is a requirement for DAX, and previously, we allowed such unaligned mounts to succeed, but subsequent reads/writes would fail. - Misc/cleanup fixes from Jan that remove unused code from DAX related to zeroing, writeback, and some size checks" * tag 'dax-misc-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax: fix a comment in dax_zero_page_range and dax_truncate_page dax: for truncate/hole-punch, do zeroing through the driver if possible dax: export a low-level __dax_zero_page_range helper dax: use sb_issue_zerout instead of calling dax_clear_sectors dax: enable dax in the presence of known media errors (badblocks) dax: fallback from pmd to pte on error block: Update blkdev_dax_capable() for consistency xfs: Add alignment check for DAX mount ext2: Add alignment check for DAX mount ext4: Add alignment check for DAX mount block: Add bdev_dax_supported() for dax mount checks block: Add vfs_msg() interface dax: Remove redundant inode size checks dax: Remove pointless writeback from dax_do_io() dax: Remove zeroing from dax_io() dax: Remove dead zeroing code from fault handlers ext2: Avoid DAX zeroing to corrupt data ext2: Fix block zeroing in ext2_get_blocks() for DAX dax: Remove complete_unwritten argument DAX: move RADIX_DAX_ definitions to dax.c
2016-05-24Merge tag 'ext4_for_linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Fix a number of bugs, most notably a potential stale data exposure after a crash and a potential BUG_ON crash if a file has the data journalling flag enabled while it has dirty delayed allocation blocks that haven't been written yet. Also fix a potential crash in the new project quota code and a maliciously corrupted file system. In addition, fix some DAX-specific bugs, including when there is a transient ENOSPC situation and races between writes via direct I/O and an mmap'ed segment that could lead to lost I/O. Finally the usual set of miscellaneous cleanups" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (23 commits) ext4: pre-zero allocated blocks for DAX IO ext4: refactor direct IO code ext4: fix race in transient ENOSPC detection ext4: handle transient ENOSPC properly for DAX dax: call get_blocks() with create == 1 for write faults to unwritten extents ext4: remove unmeetable inconsisteny check from ext4_find_extent() jbd2: remove excess descriptions for handle_s ext4: remove unnecessary bio get/put ext4: silence UBSAN in ext4_mb_init() ext4: address UBSAN warning in mb_find_order_for_block() ext4: fix oops on corrupted filesystem ext4: fix check of dqget() return value in ext4_ioctl_setproject() ext4: clean up error handling when orphan list is corrupted ext4: fix hang when processing corrupted orphaned inode list ext4: remove trailing \n from ext4_warning/ext4_error calls ext4: fix races between changing inode journal mode and ext4_writepages ext4: handle unwritten or delalloc buffers before enabling data journaling ext4: fix jbd2 handle extension in ext4_ext_truncate_extend_restart() ext4: do not ask jbd2 to write data for delalloc buffers jbd2: add support for avoiding data writes during transaction commits ...
2016-05-20dax: move RADIX_DAX_ definitions to dax.cNeilBrown1-0/+9
These don't belong in radix-tree.h any more than PAGECACHE_TAG_* do. Let's try to maintain the idea that radix-tree simply implements an abstract data type. Signed-off-by: NeilBrown <neilb@suse.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19dax: Remove i_mmap_lock protectionJan Kara1-19/+5
Currently faults are protected against truncate by filesystem specific i_mmap_sem and page lock in case of hole page. Cow faults are protected DAX radix tree entry locking. So there's no need for i_mmap_lock in DAX code. Remove it. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
2016-05-19dax: Use radix tree entry lock to protect cow faultsJan Kara1-7/+5
When doing cow faults, we cannot directly fill in PTE as we do for other faults as we rely on generic code to do proper accounting of the cowed page. We also have no page to lock to protect against races with truncate as other faults have and we need the protection to extend until the moment generic code inserts cowed page into PTE thus at that point we have no protection of fs-specific i_mmap_sem. So far we relied on using i_mmap_lock for the protection however that is completely special to cow faults. To make fault locking more uniform use DAX entry lock instead. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
2016-05-19dax: New fault lockingJan Kara1-146/+407
Currently DAX page fault locking is racy. CPU0 (write fault) CPU1 (read fault) __dax_fault() __dax_fault() get_block(inode, block, &bh, 0) -> not mapped get_block(inode, block, &bh, 0) -> not mapped if (!buffer_mapped(&bh)) if (vmf->flags & FAULT_FLAG_WRITE) get_block(inode, block, &bh, 1) -> allocates blocks if (page) -> no if (!buffer_mapped(&bh)) if (vmf->flags & FAULT_FLAG_WRITE) { } else { dax_load_hole(); } dax_insert_mapping() And we are in a situation where we fail in dax_radix_entry() with -EIO. Another problem with the current DAX page fault locking is that there is no race-free way to clear dirty tag in the radix tree. We can always end up with clean radix tree and dirty data in CPU cache. We fix the first problem by introducing locking of exceptional radix tree entries in DAX mappings acting very similarly to page lock and thus synchronizing properly faults against the same mapping index. The same lock can later be used to avoid races when clearing radix tree dirty tag. Reviewed-by: NeilBrown <neilb@suse.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
2016-05-19dax: Define DAX lock bit for radix tree exceptional entryJan Kara1-6/+11
We will use lowest available bit in the radix tree exceptional entry for locking of the entry. Define it. Also clean up definitions of DAX entry type bits in DAX exceptional entries to use defined constants instead of hardcoding numbers and cleanup checking of these bits to not rely on how other bits in the entry are set. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
2016-05-19dax: Make huge page handling depend of CONFIG_BROKENJan Kara1-1/+1
Currently the handling of huge pages for DAX is racy. For example the following can happen: CPU0 (THP write fault) CPU1 (normal read fault) __dax_pmd_fault() __dax_fault() get_block(inode, block, &bh, 0) -> not mapped get_block(inode, block, &bh, 0) -> not mapped if (!buffer_mapped(&bh) && write) get_block(inode, block, &bh, 1) -> allocates blocks truncate_pagecache_range(inode, lstart, lend); dax_load_hole(); This results in data corruption since process on CPU1 won't see changes into the file done by CPU0. The race can happen even if two normal faults race however with THP the situation is even worse because the two faults don't operate on the same entries in the radix tree and we want to use these entries for serialization. So make THP support in DAX code depend on CONFIG_BROKEN for now. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
2016-05-19dax: Fix condition for filling of PMD holesJan Kara1-1/+1
Currently dax_pmd_fault() decides to fill a PMD-sized hole only if returned buffer has BH_Uptodate set. However that doesn't get set for any mapping buffer so that branch is actually a dead code. The BH_Uptodate check doesn't make any sense so just remove it. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
2016-05-18dax: fix a comment in dax_zero_page_range and dax_truncate_pageVishal Verma1-12/+0
The distinction between PAGE_SIZE and PAGE_CACHE_SIZE was removed in 09cbfea mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros The comments for the above functions described a distinction between those, that is now redundant, so remove those paragraphs Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-18dax: for truncate/hole-punch, do zeroing through the driver if possibleVishal Verma1-5/+25
In the truncate or hole-punch path in dax, we clear out sub-page ranges. If these sub-page ranges are sector aligned and sized, we can do the zeroing through the driver instead so that error-clearing is handled automatically. For sub-sector ranges, we still have to rely on clear_pmem and have the possibility of tripping over errors. Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-18dax: export a low-level __dax_zero_page_range helperChristoph Hellwig1-15/+20
This allows XFS to perform zeroing using the iomap infrastructure and avoid buffer heads. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christoph Hellwig <hch@lst.de> [vishal: fix conflicts with dax-error-handling] Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-18dax: use sb_issue_zerout instead of calling dax_clear_sectorsMatthew Wilcox1-32/+0
dax_clear_sectors() cannot handle poisoned blocks. These must be zeroed using the BIO interface instead. Convert ext2 and XFS to use only sb_issue_zerout(). Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> [vishal: Also remove the dax_clear_sectors function entirely] Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-17dax: fallback from pmd to pte on errorDan Williams1-2/+2
In preparation for consulting a badblocks list in pmem_direct_access(), teach dax_pmd_fault() to fallback rather than fail immediately upon encountering an error. The thought being that reducing the span of the dax request may avoid the error region. Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-17dax: Remove redundant inode size checksJan Kara1-59/+1
Callers of dax fault handlers must make sure these calls cannot race with truncate. Thus it is enough to check inode size when entering the function and we don't have to recheck it again later in the handler. Note that inode size itself can be decreased while the fault handler runs but filesystem locking prevents against any radix tree or block mapping information changes resulting from the truncate and that is what we really care about. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-17dax: Remove pointless writeback from dax_do_io()Jan Kara1-9/+1
dax_do_io() is calling filemap_write_and_wait() if DIO_LOCKING flags is set. Presumably this was copied over from direct IO code. However DAX inodes have no pagecache pages to write so the call is pointless. Remove it. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-17dax: Remove zeroing from dax_io()Jan Kara1-18/+10
All the filesystems are now zeroing blocks themselves for DAX IO to avoid races between dax_io() and dax_fault(). Remove the zeroing code from dax_io() and add warning to catch the case when somebody unexpectedly returns new or unwritten buffer. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-17dax: Remove dead zeroing code from fault handlersJan Kara1-15/+2
Now that all filesystems zero out blocks allocated for a fault handler, we can just remove the zeroing from the handler itself. Also add checks that no filesystem returns to us unwritten or new buffer. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-16dax: Remove complete_unwritten argumentJan Kara1-34/+9
Fault handlers currently take complete_unwritten argument to convert unwritten extents after PTEs are updated. However no filesystem uses this anymore as the code is racy. Remove the unused argument. Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-16DAX: move RADIX_DAX_ definitions to dax.cNeilBrown1-0/+9
These don't belong in radix-tree.c any more than PAGECACHE_TAG_* do. Let's try to maintain the idea that radix-tree simply implements an abstract data type. Acked-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2016-05-13dax: call get_blocks() with create == 1 for write faults to unwritten extentsJan Kara1-1/+1
Currently, __dax_fault() does not call get_blocks() callback with create argument set, when we got back unwritten extent from the initial get_blocks() call during a write fault. This is because originally filesystems were supposed to convert unwritten extents to written ones using complete_unwritten() callback. Later this was abandoned in favor of using pre-zeroed blocks however the condition whether get_blocks() needs to be called with create == 1 remained. Fix the condition so that filesystems are not forced to zero-out and convert unwritten extents when get_blocks() is called with create == 0 (which introduces unnecessary overhead for read faults and can be problematic as the filesystem may possibly be read-only). Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-05-01direct-io: eliminate the offset argument to ->direct_IOChristoph Hellwig1-2/+2
Including blkdev_direct_IO and dax_do_io. It has to be ki_pos to actually work, so eliminate the superflous argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-04mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usageKirill A. Shutemov1-2/+2
Mostly direct substitution with occasional adjustment or removing outdated comments. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-15/+15
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-21Merge tag 'xfs-for-linus-4.6-rc1' of ↵Linus Torvalds1-2/+7
git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs Pull xfs updates from Dave Chinner: "There's quite a lot in this request, and there's some cross-over with ext4, dax and quota code due to the nature of the changes being made. As for the rest of the XFS changes, there are lots of little things all over the place, which add up to a lot of changes in the end. The major changes are that we've reduced the size of the struct xfs_inode by ~100 bytes (gives an inode cache footprint reduction of >10%), the writepage code now only does a single set of mapping tree lockups so uses less CPU, delayed allocation reservations won't overrun under random write loads anymore, and we added compile time verification for on-disk structure sizes so we find out when a commit or platform/compiler change breaks the on disk structure as early as possible. Change summary: - error propagation for direct IO failures fixes for both XFS and ext4 - new quota interfaces and XFS implementation for iterating all the quota IDs in the filesystem - locking fixes for real-time device extent allocation - reduction of duplicate information in the xfs and vfs inode, saving roughly 100 bytes of memory per cached inode. - buffer flag cleanup - rework of the writepage code to use the generic write clustering mechanisms - several fixes for inode flag based DAX enablement - rework of remount option parsing - compile time verification of on-disk format structure sizes - delayed allocation reservation overrun fixes - lots of little error handling fixes - small memory leak fixes - enable xfsaild freezing again" * tag 'xfs-for-linus-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (66 commits) xfs: always set rvalp in xfs_dir2_node_trim_free xfs: ensure committed is initialized in xfs_trans_roll xfs: borrow indirect blocks from freed extent when available xfs: refactor delalloc indlen reservation split into helper xfs: update freeblocks counter after extent deletion xfs: debug mode forced buffered write failure xfs: remove impossible condition xfs: check sizes of XFS on-disk structures at compile time xfs: ioends require logically contiguous file offsets xfs: use named array initializers for log item dumping xfs: fix computation of inode btree maxlevels xfs: reinitialise per-AG structures if geometry changes during recovery xfs: remove xfs_trans_get_block_res xfs: fix up inode32/64 (re)mount handling xfs: fix format specifier , should be %llx and not %llu xfs: sanitize remount options xfs: convert mount option parsing to tokens xfs: fix two memory leaks in xfs_attr_list.c error paths xfs: XFS_DIFLAG2_DAX limited by PAGE_SIZE xfs: dynamically switch modes when XFS_DIFLAG2_DAX is set/cleared ...
2016-03-09dax: check return value of dax_radix_entry()Ross Zwisler1-1/+8
dax_pfn_mkwrite() previously wasn't checking the return value of the call to dax_radix_entry(), which was a mistake. Instead, capture this return value and return the appropriate VM_FAULT_ value. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Matthew Wilcox <willy@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>
2016-02-27dax: move writeback calls into the filesystemsRoss Zwisler1-5/+7
Previously calls to dax_writeback_mapping_range() for all DAX filesystems (ext2, ext4 & xfs) were centralized in filemap_write_and_wait_range(). dax_writeback_mapping_range() needs a struct block_device, and it used to get that from inode->i_sb->s_bdev. This is correct for normal inodes mounted on ext2, ext4 and XFS filesystems, but is incorrect for DAX raw block devices and for XFS real-time files. Instead, call dax_writeback_mapping_range() directly from the filesystem ->writepages function so that it can supply us with a valid block device. This also fixes DAX code to properly flush caches in response to sync(2). Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@fb.com> Cc: Matthew Wilcox <matthew.r.wilcox@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>
2016-02-27dax: give DAX clearing code correct bdevRoss Zwisler1-5/+4
dax_clear_blocks() needs a valid struct block_device and previously it was using inode->i_sb->s_bdev in all cases. This is correct for normal inodes on mounted ext2, ext4 and XFS filesystems, but is incorrect for DAX raw block devices and for XFS real-time devices. Instead, rename dax_clear_blocks() to dax_clear_sectors(), and change its arguments to take a bdev and a sector instead of an inode and a block. This better reflects what the function does, and it allows the filesystem and raw block device code to pass in an appropriate struct block_device. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Suggested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@fb.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> 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>
2016-02-08direct-io: always call ->end_io if non-NULLChristoph Hellwig1-2/+7
This way we can pass back errors to the file system, and allow for cleanup required for all direct I/O invocations. Also allow the ->end_io handlers to return errors on their own, so that I/O completion errors can be passed on to the callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-05dax: dirty inode only if requiredDmitry Monakhov1-1/+2
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ross Zwisler <ross.zwisler@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>
2016-01-30block: use DAX for partition table readsDan Williams1-0/+20
Avoid populating pagecache when the block device is in DAX mode. Otherwise these page cache entries collide with the fsync/msync implementation and break data durability guarantees. Cc: Jan Kara <jack@suse.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Andrew Morton <akpm@linux-foundation.org> Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com> Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-01-23Merge branch 'for-linus' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull final vfs updates from Al Viro: - The ->i_mutex wrappers (with small prereq in lustre) - a fix for too early freeing of symlink bodies on shmem (they need to be RCU-delayed) (-stable fodder) - followup to dedupe stuff merged this cycle * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: abort dedupe loop if fatal signals are pending make sure that freeing shmem fast symlinks is RCU-delayed wrappers for ->i_mutex access lustre: remove unused declaration
2016-01-22dax: never rely on bh.b_dev being set by get_block()Ross Zwisler1-0/+3
Previously in DAX we assumed that calls to get_block() would set bh.b_bdev, and we would then use that value even in error cases for debugging. This caused a NULL pointer dereference in __dax_dbg() which was fixed by a previous commit, but that commit only changed the one place where we were hitting an error. Instead, update dax.c so that we always initialize bh.b_bdev as best we can based on the information that DAX has. get_block() may or may not update to a new value, but this at least lets us get something helpful from bh.b_bdev for error messages and not have to worry about whether it was set by get_block() or not. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-22dax: add support for fsync/syncRoss Zwisler1-16/+258
To properly handle fsync/msync in an efficient way DAX needs to track dirty pages so it is able to flush them durably to media on demand. The tracking of dirty pages is done via the radix tree in struct address_space. This radix tree is already used by the page writeback infrastructure for tracking dirty pages associated with an open file, and it already has support for exceptional (non struct page*) entries. We build upon these features to add exceptional entries to the radix tree for DAX dirty PMD or PTE pages at fault time. [dan.j.williams@intel.com: fix dax_pmd_dbg build warning] Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Dave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.com> Cc: Jeff Layton <jlayton@poochiereds.net> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-22dax: fix conversion of holes to PMDsRoss Zwisler1-10/+10
When we get a DAX PMD fault for a write it is possible that there could be some number of 4k zero pages already present for the same range that were inserted to service reads from a hole. These 4k zero pages need to be unmapped from the VMAs and removed from the struct address_space radix tree before the real DAX PMD entry can be inserted. For PTE faults this same use case also exists and is handled by a combination of unmap_mapping_range() to unmap the VMAs and delete_from_page_cache() to remove the page from the address_space radix tree. For PMD faults we do have a call to unmap_mapping_range() (protected by a buffer_new() check), but nothing clears out the radix tree entry. The buffer_new() check is also incorrect as the current ext4 and XFS filesystem code will never return a buffer_head with BH_New set, even when allocating new blocks over a hole. Instead the filesystem will zero the blocks manually and return a buffer_head with only BH_Mapped set. Fix this situation by removing the buffer_new() check and adding a call to truncate_inode_pages_range() to clear out the radix tree entries before we insert the DAX PMD. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Dave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeff Layton <jlayton@poochiereds.net> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-22dax: fix NULL pointer dereference in __dax_dbg()Ross Zwisler1-0/+1
In __dax_pmd_fault() we currently assume that get_block() will always set bh.b_bdev and we unconditionally dereference it in __dax_dbg(). This assumption isn't always true - when called for reads of holes ext4_dax_mmap_get_block() returns a buffer head where bh->b_bdev is never set. I hit this BUG while testing the DAX PMD fault path. Instead, initialize bh.b_bdev before passing bh into get_block(). It is possible that the filesystem's get_block() will update bh.b_bdev, and this is fine - we just want to initialize bh.b_bdev to something reasonable so that the calls to __dax_dbg() work and print something useful. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: Dan Williams <dan.j.williams@intel.com> Cc: Jan Kara <jack@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-22wrappers for ->i_mutex accessAl Viro1-3/+3
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-15dax: re-enable dax pmd mappingsDan Williams1-6/+2
Now that the get_user_pages() path knows how to handle dax-pmd mappings, remove the protections that disabled dax-pmd support. Tests available from github.com/pmem/ndctl: make TESTS="lib/test-dax.sh lib/test-mmap.sh" check Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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