mm: make snapshotting pages for stable writes a per-bio operation
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: Darrick 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: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds
parent
106c992a5e
commit
7136851117
@ -2949,7 +2949,7 @@ static void guard_bh_eod(int rw, struct bio *bio, struct buffer_head *bh)
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}
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}
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int submit_bh(int rw, struct buffer_head * bh)
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int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
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{
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struct bio *bio;
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int ret = 0;
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@ -2984,6 +2984,7 @@ int submit_bh(int rw, struct buffer_head * bh)
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bio->bi_end_io = end_bio_bh_io_sync;
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bio->bi_private = bh;
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bio->bi_flags |= bio_flags;
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/* Take care of bh's that straddle the end of the device */
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guard_bh_eod(rw, bio, bh);
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@ -2997,6 +2998,12 @@ int submit_bh(int rw, struct buffer_head * bh)
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bio_put(bio);
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return ret;
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}
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EXPORT_SYMBOL_GPL(_submit_bh);
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int submit_bh(int rw, struct buffer_head *bh)
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{
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return _submit_bh(rw, bh, 0);
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}
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EXPORT_SYMBOL(submit_bh);
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/**
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