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Commit 28e21170 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Felix Blyakher
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xfs: fix getbmap vs mmap deadlock



xfs_getbmap (or rather the formatters called by it) copy out the getbmap
structures under the ilock, which can deadlock against mmap.  This has
been reported via bugzilla a while ago (#717) and has recently also
shown up via lockdep.

So allocate a temporary buffer to format the kernel getbmap structures
into and then copy them out after dropping the locks.

A little problem with this is that we limit the number of extents we
can copy out by the maximum allocation size, but I see no real way
around that.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarEric Sandeen <sandeen@sandeen.net>
Reviewed-by: default avatarFelix Blyakher <felixb@sgi.com>
Signed-off-by: default avatarFelix Blyakher <felixb@sgi.com>
parent 5f79ed68
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