linux-toradex.git/mm/filemap.c, branch v5.12

mm/filemap: fix mapping_seek_hole_data on THP & 32-bit

2021-04-23T21:42:39+00:00

No problem on 64-bit, or without huge pages, but xfstests generic/285
and other SEEK_HOLE/SEEK_DATA tests have regressed on huge tmpfs, and on
32-bit architectures, with the new mapping_seek_hole_data().  Several
different bugs turned out to need fixing.

u64 cast to stop losing bits when converting unsigned long to loff_t
(and let's use shifts throughout, rather than mixed with * and /).

Use round_up() when advancing pos, to stop assuming that pos was already
THP-aligned when advancing it by THP-size.  (This use of round_up()
assumes that any THP has THP-aligned index: true at present and true
going forward, but could be recoded to avoid the assumption.)

Use xas_set() when iterating away from a THP, so that xa_index stays in
synch with start, instead of drifting away to return bogus offset.

Check start against end to avoid wrapping 32-bit xa_index to 0 (and to
handle these additional cases, seek_data or not, it's easier to break
the loop than goto: so rearrange exit from the function).

[hughd@google.com: remove unneeded u64 casts, per Matthew]
  Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104221347240.1170@eggly.anvils

Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104211737410.3299@eggly.anvils
Fixes: 41139aa4c3a3 ("mm/filemap: add mapping_seek_hole_data")
Signed-off-by: Hugh Dickins 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Jan Kara 
Cc: Johannes Weiner 
Cc: "Kirill A. Shutemov" 
Cc: Matthew Wilcox 
Cc: William Kucharski 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/filemap: fix find_lock_entries hang on 32-bit THP

2021-04-23T21:42:39+00:00

No problem on 64-bit, or without huge pages, but xfstests generic/308
hung uninterruptibly on 32-bit huge tmpfs.

Since commit 0cc3b0ec23ce ("Clarify (and fix) in 4.13 MAX_LFS_FILESIZE
macros"), MAX_LFS_FILESIZE is only a PAGE_SIZE away from wrapping 32-bit
xa_index to 0, so the new find_lock_entries() has to be extra careful
when handling a THP.

Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104211735430.3299@eggly.anvils
Fixes: 5c211ba29deb ("mm: add and use find_lock_entries")
Signed-off-by: Hugh Dickins 
Cc: Matthew Wilcox 
Cc: William Kucharski 
Cc: Christoph Hellwig 
Cc: Jan Kara 
Cc: Dave Chinner 
Cc: Johannes Weiner 
Cc: "Kirill A. Shutemov" 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: pass pvec directly to find_get_entries

2021-02-26T17:40:59+00:00

All callers of find_get_entries() use a pvec, so pass it directly instead
of manipulating it in the caller.

Link: https://lkml.kernel.org/r/20201112212641.27837-14-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Jan Kara 
Reviewed-by: William Kucharski 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add an 'end' parameter to find_get_entries

2021-02-26T17:40:59+00:00

This simplifies the callers and leads to a more efficient implementation
since the XArray has this functionality already.

Link: https://lkml.kernel.org/r/20201112212641.27837-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Jan Kara 
Reviewed-by: William Kucharski 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add and use find_lock_entries

2021-02-26T17:40:59+00:00

We have three functions (shmem_undo_range(), truncate_inode_pages_range()
and invalidate_mapping_pages()) which want exactly this function, so add
it to filemap.c.  Before this patch, shmem_undo_range() would split any
compound page which overlaps either end of the range being punched in both
the first and second loops through the address space.  After this patch,
that functionality is left for the second loop, which is arguably more
appropriate since the first loop is supposed to run through all the pages
quickly, and splitting a page can sleep.

[willy@infradead.org: add assertion]
  Link: https://lkml.kernel.org/r/20201124041507.28996-3-willy@infradead.org

Link: https://lkml.kernel.org/r/20201112212641.27837-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Jan Kara 
Reviewed-by: William Kucharski 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

iomap: use mapping_seek_hole_data

2021-02-26T17:40:59+00:00

Enhance mapping_seek_hole_data() to handle partially uptodate pages and
convert the iomap seek code to call it.

Link: https://lkml.kernel.org/r/20201112212641.27837-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Jan Kara 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: William Kucharski 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/filemap: add mapping_seek_hole_data

2021-02-26T17:40:59+00:00

Rewrite shmem_seek_hole_data() and move it to filemap.c.

[willy@infradead.org: don't put an xa_is_value() page]
  Link: https://lkml.kernel.org/r/20201124041507.28996-4-willy@infradead.org

Link: https://lkml.kernel.org/r/20201112212641.27837-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: William Kucharski 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Jan Kara 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/filemap: add helper for finding pages

2021-02-26T17:40:59+00:00

There is a lot of common code in find_get_entries(),
find_get_pages_range() and find_get_pages_range_tag().  Factor out
find_get_entry() which simplifies all three functions.

[willy@infradead.org: remove VM_BUG_ON_PAGE()]
  Link: https://lkml.kernel.org/r/20201124041507.28996-2-willy@infradead.orgLink: https://lkml.kernel.org/r/20201112212641.27837-7-willy@infradead.org

Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Jan Kara 
Reviewed-by: William Kucharski 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/filemap: rename find_get_entry to mapping_get_entry

2021-02-26T17:40:59+00:00

find_get_entry doesn't "find" anything.  It returns the entry at a
particular index.

Link: https://lkml.kernel.org/r/20201112212641.27837-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Jan Kara 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: William Kucharski 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add FGP_ENTRY

2021-02-26T17:40:59+00:00

The functionality of find_lock_entry() and find_get_entry() can be
provided by pagecache_get_page(), which lets us delete find_lock_entry()
and make find_get_entry() static.

Link: https://lkml.kernel.org/r/20201112212641.27837-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Jan Kara 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: William Kucharski 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds