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| author |   Hugh Dickins <hughd@google.com> | 2022-03-24 18:13:59 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-24 19:06:51 -0700 |
| commit | 566d3362885aab04d6b0f885f12db3176ca3a032 (patch) | |
| tree | 25ac4e4fd25635a26587151d6b54a90a9e86888d /mm/filemap.c | |
| parent | mm/huge_memory: remove stale locking logic from __split_huge_pmd() (diff) | |
| download | linux-dev-566d3362885aab04d6b0f885f12db3176ca3a032.tar.xz linux-dev-566d3362885aab04d6b0f885f12db3176ca3a032.zip | |
mm: warn on deleting redirtied only if accounted
filemap_unaccount_folio() has a WARN_ON_ONCE(folio_test_dirty(folio)). It
is good to warn of late dirtying on a persistent filesystem, but late
dirtying on tmpfs can only lose data which is expected to be thrown away;
and it's a pity if that warning comes ONCE on tmpfs, then hides others
which really matter. Make it conditional on mapping_cap_writeback().
Cleanup: then folio_account_cleaned() no longer needs to check that for
itself, and so no longer needs to know the mapping.
Link: https://lkml.kernel.org/r/b5a1106c-7226-a5c6-ad41-ad4832cae1f@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index c5c169c16bae..8426434042f4 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -193,16 +193,20 @@ static void filemap_unaccount_folio(struct address_space *mapping, /* * At this point folio must be either written or cleaned by * truncate. Dirty folio here signals a bug and loss of - * unwritten data. + * unwritten data - on ordinary filesystems. * - * This fixes dirty accounting after removing the folio entirely + * But it's harmless on in-memory filesystems like tmpfs; and can + * occur when a driver which did get_user_pages() sets page dirty + * before putting it, while the inode is being finally evicted. + * + * Below fixes dirty accounting after removing the folio entirely * but leaves the dirty flag set: it has no effect for truncated * folio and anyway will be cleared before returning folio to * buddy allocator. */ - if (WARN_ON_ONCE(folio_test_dirty(folio))) - folio_account_cleaned(folio, mapping, - inode_to_wb(mapping->host)); + if (WARN_ON_ONCE(folio_test_dirty(folio) && + mapping_can_writeback(mapping))) + folio_account_cleaned(folio, inode_to_wb(mapping->host)); } /* |