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| author | Hugh Dickins <hughd@google.com> | 2022-04-14 19:13:27 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-04-15 14:49:54 -0700 |
| commit | 1bdec44b1eee32e311b44b5b06144bb7d9b33938 (patch) | |
| tree | 67349dd5de85a8db47093ac128cea601f2b628eb /mm/filemap.c | |
| parent | 7fbd166a8f2d697c3e2b4c8432d33253f00266b3 (diff) | |
| download | linux-1bdec44b1eee32e311b44b5b06144bb7d9b33938.tar.bz2 | |
tmpfs: fix regressions from wider use of ZERO_PAGE
Chuck Lever reported fsx-based xfstests generic 075 091 112 127 failing
when 5.18-rc1 NFS server exports tmpfs: bisected to recent tmpfs change.
Whilst nfsd_splice_action() does contain some questionable handling of
repeated pages, and Chuck was able to work around there, history from
Mark Hemment makes clear that there might be similar dangers elsewhere:
it was not a good idea for me to pass ZERO_PAGE down to unknown actors.
Revert shmem_file_read_iter() to using ZERO_PAGE for holes only when
iter_is_iovec(); in other cases, use the more natural iov_iter_zero()
instead of copy_page_to_iter().
We would use iov_iter_zero() throughout, but the x86 clear_user() is not
nearly so well optimized as copy to user (dd of 1T sparse tmpfs file
takes 57 seconds rather than 44 seconds).
And now pagecache_init() does not need to SetPageUptodate(ZERO_PAGE(0)):
which had caused boot failure on arm noMMU STM32F7 and STM32H7 boards
Link: https://lkml.kernel.org/r/9a978571-8648-e830-5735-1f4748ce2e30@google.com
Fixes: 56a8c8eb1eaf ("tmpfs: do not allocate pages on read")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Patrice CHOTARD <patrice.chotard@foss.st.com>
Reported-by: Chuck Lever III <chuck.lever@oracle.com>
Tested-by: Chuck Lever III <chuck.lever@oracle.com>
Cc: Mark Hemment <markhemm@googlemail.com>
Cc: Patrice CHOTARD <patrice.chotard@foss.st.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Lukas Czerner <lczerner@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Darrick J. Wong" <djwong@kernel.org>
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 | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 3a5ffb5587cd..9a1eef6c5d35 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1063,12 +1063,6 @@ void __init pagecache_init(void) init_waitqueue_head(&folio_wait_table[i]); page_writeback_init(); - - /* - * tmpfs uses the ZERO_PAGE for reading holes: it is up-to-date, - * and splice's page_cache_pipe_buf_confirm() needs to see that. - */ - SetPageUptodate(ZERO_PAGE(0)); } /* |