]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
xfs: fix getbmap vs mmap deadlock
authorChristoph Hellwig <hch@infradead.org>
Tue, 24 Feb 2009 13:39:02 +0000 (08:39 -0500)
committerFelix Blyakher <felixb@sgi.com>
Wed, 29 Apr 2009 18:25:29 +0000 (13:25 -0500)
commit6321e3ed2acf3ee9643cdd403e1c88605d7944ba
tree42ccd5dd1082d291089fec1aa6e8b6a84866bb0c
parent4be4a00fb55879ef44b5914c189aecffa828deb4
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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
fs/xfs/xfs_bmap.c