iomap/gfs2: Unlock and put folio in page_done handler

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When an iomap defines a ->page_done() handler in its page_ops, delegate
unlocking the folio and putting the folio reference to that handler.

This allows to fix a race between journaled data writes and folio
writeback in gfs2: before this change, gfs2_iomap_page_done() was called
after unlocking the folio, so writeback could start writing back the
folio's buffers before they could be marked for writing to the journal.
Also, try_to_free_buffers() could free the buffers before
gfs2_iomap_page_done() was done adding the buffers to the current
current transaction.  With this change, gfs2_iomap_page_done() adds the
buffers to the current transaction while the folio is still locked, so
the problems described above can no longer occur.

The only current user of ->page_done() is gfs2, so other filesystems are
not affected.  To catch out any out-of-tree users, switch from a page to
a folio in ->page_done().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

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This commit is contained in:

Andreas Gruenbacher 2023-01-15 08:45:51 -08:00 • committed by Darrick J. Wong

parent 7a70a5085e

commit 80baab88bb

3 changed files with 20 additions and 10 deletions

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15

fs/gfs2/bmap.c

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8

fs/iomap/buffered-io.c

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7

include/linux/iomap.h

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