kernel/linux.git/mm/truncate.c, branch v6.1.174

mm/truncate: unmap large folio on split failure

2025-12-06T21:12:40+00:00

commit fa04f5b60fda62c98a53a60de3a1e763f11feb41 upstream. Accesses within VMA, but beyond i_size rounded up to PAGE_SIZE are supposed to generate SIGBUS. This behavior might not be respected on truncation. During truncation, the kernel splits a large folio in order to reclaim memory. As a side effect, it unmaps the folio and destroys PMD mappings of the folio. The folio will be refaulted as PTEs and SIGBUS semantics are preserved. However, if the split fails, PMD mappings are preserved and the user will not receive SIGBUS on any accesses within the PMD. Unmap the folio on split failure. It will lead to refault as PTEs and preserve SIGBUS semantics. Make an exception for shmem/tmpfs that for long time intentionally mapped with PMDs across i_size. Link: https://lkml.kernel.org/r/20251027115636.82382-3-kirill@shutemov.name Fixes: b9a8a4195c7d ("truncate,shmem: Handle truncates that split large folios") Signed-off-by: Kiryl Shutsemau Cc: Al Viro Cc: Baolin Wang Cc: Christian Brauner Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: David Hildenbrand Cc: Hugh Dickins Cc: Johannes Weiner Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Rik van Riel Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Kiryl Shutsemau Signed-off-by: Greg Kroah-Hartman

mm: Fix missing folio invalidation calls during truncation

2024-09-04T11:25:00+00:00

[ Upstream commit 0aa2e1b2fb7a75aa4b5b4347055ccfea6f091769 ] When AS_RELEASE_ALWAYS is set on a mapping, the ->release_folio() and ->invalidate_folio() calls should be invoked even if PG_private and PG_private_2 aren't set. This is used by netfslib to keep track of the point above which reads can be skipped in favour of just zeroing pagecache locally. There are a couple of places in truncation in which invalidation is only called when folio_has_private() is true. Fix these to check folio_needs_release() instead. Without this, the generic/075 and generic/112 xfstests (both fsx-based tests) fail with minimum folio size patches applied[1]. Fixes: b4fa966f03b7 ("mm, netfs, fscache: stop read optimisation when folio removed from pagecache") Signed-off-by: David Howells Link: https://lore.kernel.org/r/20240815090849.972355-1-kernel@pankajraghav.com/ [1] Link: https://lore.kernel.org/r/20240823200819.532106-2-dhowells@redhat.com Reviewed-by: Matthew Wilcox (Oracle) cc: Matthew Wilcox (Oracle) cc: Pankaj Raghav cc: Jeff Layton cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

mm: merge folio_has_private()/filemap_release_folio() call pairs

2024-01-10T16:10:31+00:00

[ Upstream commit 0201ebf274a306a6ebb95e5dc2d6a0a27c737cac ] Patch series "mm, netfs, fscache: Stop read optimisation when folio removed from pagecache", v7. This fixes an optimisation in fscache whereby we don't read from the cache for a particular file until we know that there's data there that we don't have in the pagecache. The problem is that I'm no longer using PG_fscache (aka PG_private_2) to indicate that the page is cached and so I don't get a notification when a cached page is dropped from the pagecache. The first patch merges some folio_has_private() and filemap_release_folio() pairs and introduces a helper, folio_needs_release(), to indicate if a release is required. The second patch is the actual fix. Following Willy's suggestions[1], it adds an AS_RELEASE_ALWAYS flag to an address_space that will make filemap_release_folio() always call ->release_folio(), even if PG_private/PG_private_2 aren't set. folio_needs_release() is altered to add a check for this. This patch (of 2): Make filemap_release_folio() check folio_has_private(). Then, in most cases, where a call to folio_has_private() is immediately followed by a call to filemap_release_folio(), we can get rid of the test in the pair. There are a couple of sites in mm/vscan.c that this can't so easily be done. In shrink_folio_list(), there are actually three cases (something different is done for incompletely invalidated buffers), but filemap_release_folio() elides two of them. In shrink_active_list(), we don't have have the folio lock yet, so the check allows us to avoid locking the page unnecessarily. A wrapper function to check if a folio needs release is provided for those places that still need to do it in the mm/ directory. This will acquire additional parts to the condition in a future patch. After this, the only remaining caller of folio_has_private() outside of mm/ is a check in fuse. Link: https://lkml.kernel.org/r/20230628104852.3391651-1-dhowells@redhat.com Link: https://lkml.kernel.org/r/20230628104852.3391651-2-dhowells@redhat.com Reported-by: Rohith Surabattula Suggested-by: Matthew Wilcox Signed-off-by: David Howells Cc: Matthew Wilcox Cc: Linus Torvalds Cc: Steve French Cc: Shyam Prasad N Cc: Rohith Surabattula Cc: Dave Wysochanski Cc: Dominique Martinet Cc: Ilya Dryomov Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Xiubo Li Cc: Jingbo Xu Signed-off-by: Andrew Morton Stable-dep-of: 1898efcdbed3 ("block: update the stable_writes flag in bdev_add") Signed-off-by: Sasha Levin

mm: add split_folio()

2022-10-03T21:02:45+00:00

This wrapper removes a need to use split_huge_page(&folio->page). Convert two callers. Link: https://lkml.kernel.org/r/20220902194653.1739778-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm: Remove __delete_from_page_cache()

2022-06-29T12:51:05+00:00

This wrapper is no longer used. Remove it and all references to it. Signed-off-by: Matthew Wilcox (Oracle)

Merge tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache

2022-03-23T01:26:56+00:00

Pull filesystem folio updates from Matthew Wilcox: "Primarily this series converts some of the address_space operations to take a folio instead of a page. Notably: - a_ops->is_partially_uptodate() takes a folio instead of a page and changes the type of the 'from' and 'count' arguments to make it obvious they're bytes. - a_ops->invalidatepage() becomes ->invalidate_folio() and has a similar type change. - a_ops->launder_page() becomes ->launder_folio() - a_ops->set_page_dirty() becomes ->dirty_folio() and adds the address_space as an argument. There are a couple of other misc changes up front that weren't worth separating into their own pull request" * tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache: (53 commits) fs: Remove aops ->set_page_dirty fb_defio: Use noop_dirty_folio() fs: Convert __set_page_dirty_no_writeback to noop_dirty_folio fs: Convert __set_page_dirty_buffers to block_dirty_folio nilfs: Convert nilfs_set_page_dirty() to nilfs_dirty_folio() mm: Convert swap_set_page_dirty() to swap_dirty_folio() ubifs: Convert ubifs_set_page_dirty to ubifs_dirty_folio f2fs: Convert f2fs_set_node_page_dirty to f2fs_dirty_node_folio f2fs: Convert f2fs_set_data_page_dirty to f2fs_dirty_data_folio f2fs: Convert f2fs_set_meta_page_dirty to f2fs_dirty_meta_folio afs: Convert afs_dir_set_page_dirty() to afs_dir_dirty_folio() btrfs: Convert extent_range_redirty_for_io() to use folios fs: Convert trivial uses of __set_page_dirty_nobuffers to filemap_dirty_folio btrfs: Convert from set_page_dirty to dirty_folio fscache: Convert fscache_set_page_dirty() to fscache_dirty_folio() fs: Add aops->dirty_folio fs: Remove aops->launder_page orangefs: Convert launder_page to launder_folio nfs: Convert from launder_page to launder_folio fuse: Convert from launder_page to launder_folio ...

mm/truncate: Combine invalidate_mapping_pagevec() and __invalidate_mapping_pages()

2022-03-21T16:59:02+00:00

We can save a function call by combining these two functions, which are identical except for the return value. Also move the prototype to mm/internal.h. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: Miaohe Lin

mm: Turn deactivate_file_page() into deactivate_file_folio()

2022-03-21T16:59:02+00:00

This function has one caller which already has a reference to the page, so we don't need to use get_page_unless_zero(). Also move the prototype to mm/internal.h. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: Miaohe Lin

mm/truncate: Convert __invalidate_mapping_pages() to use a folio

2022-03-21T16:59:02+00:00

Now we can call mapping_evict_folio() instead of invalidate_inode_page() and save a few calls to compound_head(). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: Miaohe Lin

mm/truncate: Split invalidate_inode_page() into mapping_evict_folio()

2022-03-21T16:59:02+00:00

Some of the callers already have the address_space and can avoid calling folio_mapping() and checking if the folio was already truncated. Also add kernel-doc and fix the return type (in case we ever support folios larger than 4TB). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: Miaohe Lin