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    mm: make snapshotting pages for stable writes a per-bio operation · 71368511
    Darrick J. Wong 提交于
    Walking a bio's page mappings has proved problematic, so create a new
    bio flag to indicate that a bio's data needs to be snapshotted in order
    to guarantee stable pages during writeback.  Next, for the one user
    (ext3/jbd) of snapshotting, hook all the places where writes can be
    initiated without PG_writeback set, and set BIO_SNAP_STABLE there.
    
    We must also flag journal "metadata" bios for stable writeout, since
    file data can be written through the journal.  Finally, the
    MS_SNAP_STABLE mount flag (only used by ext3) is now superfluous, so get
    rid of it.
    
    [akpm@linux-foundation.org: rename _submit_bh()'s `flags' to `bio_flags', delobotomize the _submit_bh declaration]
    [akpm@linux-foundation.org: teeny cleanup]
    Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Artem Bityutskiy <dedekind1@gmail.com>
    Reviewed-by: NJan Kara <jack@suse.cz>
    Cc: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    71368511
page-writeback.c 69.9 KB