kernel.git/fs/afs/write.c, branch linux-6.4.y

afs: Fix accidental truncation when storing data

2023-07-19T14:36:48Z

[ Upstream commit 03275585cabd0240944f19f33d7584a1b099a3a8 ] When an AFS FS.StoreData RPC call is made, amongst other things it is given the resultant file size to be. On the server, this is processed by truncating the file to new size and then writing the data. Now, kafs has a lock (vnode->io_lock) that serves to serialise operations against a specific vnode (ie. inode), but the parameters for the op are set before the lock is taken. This allows two writebacks (say sync and kswapd) to race - and if writes are ongoing the writeback for a later write could occur before the writeback for an earlier one if the latter gets interrupted. Note that afs_writepages() cannot take i_mutex and only takes a shared lock on vnode->validate_lock. Also note that the server does the truncation and the write inside a lock, so there's no problem at that end. Fix this by moving the calculation for the proposed new i_size inside the vnode->io_lock. Also reset the iterator (which we might have read from) and update the mtime setting there. Fixes: bd80d8a80e12 ("afs: Use ITER_XARRAY for writing") Reported-by: Marc Dionne Signed-off-by: David Howells Reviewed-by: Jeffrey Altman Reviewed-by: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/3526895.1687960024@warthog.procyon.org.uk/ Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

afs: Fix waiting for writeback then skipping folio

2023-06-19T13:30:58Z

Commit acc8d8588cb7 converted afs_writepages_region() to write back a folio batch. The function waits for writeback to a folio, but then proceeds to the rest of the batch without trying to write that folio again. This patch fixes has it attempt to write the folio again. [DH: Also remove an 'else' that adding a goto makes redundant] Fixes: acc8d8588cb7 ("afs: convert afs_writepages_region() to use filemap_get_folios_tag()") Signed-off-by: Vishal Moola (Oracle) Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20230607204120.89416-2-vishal.moola@gmail.com/

afs: Fix dangling folio ref counts in writeback

2023-06-19T13:30:48Z

Commit acc8d8588cb7 converted afs_writepages_region() to write back a folio batch. If writeback needs rescheduling, the function exits without dropping the references to the folios in fbatch. This patch fixes that. [DH: Moved the added line before the _leave()] Fixes: acc8d8588cb7 ("afs: convert afs_writepages_region() to use filemap_get_folios_tag()") Signed-off-by: Vishal Moola (Oracle) Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20230607204120.89416-1-vishal.moola@gmail.com/

mm: return an ERR_PTR from __filemap_get_folio

2023-04-06T02:42:42Z

Instead of returning NULL for all errors, distinguish between: - no entry found and not asked to allocated (-ENOENT) - failed to allocate memory (-ENOMEM) - would block (-EAGAIN) so that callers don't have to guess the error based on the passed in flags. Also pass through the error through the direct callers: filemap_get_folio, filemap_lock_folio filemap_grab_folio and filemap_get_incore_folio. [hch@lst.de: fix null-pointer deref] Link: https://lkml.kernel.org/r/20230310070023.GA13563@lst.de Link: https://lkml.kernel.org/r/20230310043137.GA1624890@u2004 Link: https://lkml.kernel.org/r/20230307143410.28031-8-hch@lst.de Signed-off-by: Christoph Hellwig Acked-by: Ryusuke Konishi [nilfs2] Cc: Andreas Gruenbacher Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Naoya Horiguchi Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-02-24T01:09:35Z

Pull MM updates from Andrew Morton: - Daniel Verkamp has contributed a memfd series ("mm/memfd: add F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". * tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits) include/linux/migrate.h: remove unneeded externs mm/memory_hotplug: cleanup return value handing in do_migrate_range() mm/uffd: fix comment in handling pte markers mm: change to return bool for isolate_movable_page() mm: hugetlb: change to return bool for isolate_hugetlb() mm: change to return bool for isolate_lru_page() mm: change to return bool for folio_isolate_lru() objtool: add UACCESS exceptions for __tsan_volatile_read/write kmsan: disable ftrace in kmsan core code kasan: mark addr_has_metadata __always_inline mm: memcontrol: rename memcg_kmem_enabled() sh: initialize max_mapnr m68k/nommu: add missing definition of ARCH_PFN_OFFSET mm: percpu: fix incorrect size in pcpu_obj_full_size() maple_tree: reduce stack usage with gcc-9 and earlier mm: page_alloc: call panic() when memoryless node allocation fails mm: multi-gen LRU: avoid futile retries migrate_pages: move THP/hugetlb migration support check to simplify code migrate_pages: batch flushing TLB migrate_pages: share more code between _unmap and _move ...

afs: use bvec_set_folio to initialize a bvec

2023-02-03T15:20:55Z

Use the bvec_set_folio helper to initialize a bvec. Signed-off-by: Christoph Hellwig Acked-by: David Howells Link: https://lore.kernel.org/r/20230203150634.3199647-12-hch@lst.de Signed-off-by: Jens Axboe

afs: convert afs_writepages_region() to use filemap_get_folios_tag()

2023-02-03T06:33:14Z

Convert to use folios throughout. This function is in preparation to remove find_get_pages_range_tag(). Also modify this function to write the whole batch one at a time, rather than calling for a new set every single write. Link: https://lkml.kernel.org/r/20230104211448.4804-6-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Tested-by: David Howells Signed-off-by: Andrew Morton

afs: Stop implementing ->writepage()

2022-12-22T11:40:35Z

We're trying to get rid of the ->writepage() hook[1]. Stop afs from using it by unlocking the page and calling afs_writepages_region() rather than folio_write_one(). A flag is passed to afs_writepages_region() to indicate that it should only write a single region so that we don't flush the entire file in ->write_begin(), but do add other dirty data to the region being written to try and reduce the number of RPC ops. This requires ->migrate_folio() to be implemented, so point that at filemap_migrate_folio() for files and also for symlinks and directories. This can be tested by turning on the afs_folio_dirty tracepoint and then doing something like: xfs_io -c "w 2223 7000" -c "w 15000 22222" -c "w 23 7" /afs/my/test/foo and then looking in the trace to see if the write at position 15000 gets stored before page 0 gets dirtied for the write at position 23. Signed-off-by: David Howells cc: Marc Dionne cc: Christoph Hellwig cc: Matthew Wilcox cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20221113162902.883850-1-hch@lst.de/ [1] Link: https://lore.kernel.org/r/166876785552.222254.4403222906022558715.stgit@warthog.procyon.org.uk/ # v1

use less confusing names for iov_iter direction initializers

2022-11-25T18:01:55Z

READ/WRITE proved to be actively confusing - the meanings are "data destination, as used with read(2)" and "data source, as used with write(2)", but people keep interpreting those as "we read data from it" and "we write data to it", i.e. exactly the wrong way. Call them ITER_DEST and ITER_SOURCE - at least that is harder to misinterpret... Signed-off-by: Al Viro

afs: Enable multipage folio support

2022-08-14T00:20:51Z

Enable multipage folio support for the afs filesystem. Support has already been implemented in netfslib, fscache and cachefiles and in most of afs, but I've waited for Matthew Wilcox's latest folio changes. Note that it does require a change to afs_write_begin() to return the correct subpage. This is a "temporary" change as we're working on getting rid of the need for ->write_begin() and ->write_end() completely, at least as far as network filesystems are concerned - but it doesn't prevent afs from making use of the capability. Signed-off-by: David Howells Acked-by: Matthew Wilcox (Oracle) Tested-by: kafs-testing@auristor.com Cc: Marc Dionne Cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/lkml/2274528.1645833226@warthog.procyon.org.uk/ Signed-off-by: Linus Torvalds