xfs: reserve enough blocks to handle btree splits when remapping

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commit fe0be23e68 upstream.

In xfs_reflink_end_cow, we erroneously reserve only enough blocks to
handle adding 1 extent.  This is problematic if we fragment free space,
have to do CoW, and then have to perform multiple bmap btree expansions.
Furthermore, the BUI recovery routine doesn't reserve /any/ blocks to
handle btree splits, so log recovery fails after our first error causes
the filesystem to go down.

Therefore, refactor the transaction block reservation macros until we
have a macro that works for our deferred (re)mapping activities, and fix
both problems by using that macro.

With 1k blocks we can hit this fairly often in g/187 if the scratch fs
is big enough.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Darrick J. Wong 2017-04-12 12:26:07 -07:00 • committed by Greg Kroah-Hartman

parent 0ba833fe73

commit d457f82281

3 changed files with 37 additions and 9 deletions

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23

fs/xfs/libxfs/xfs_trans_space.h

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5

fs/xfs/xfs_bmap_item.c

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18

fs/xfs/xfs_reflink.c

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