tree fa26840c5e85eeed63575615c140f2913e6d9189
parent b5a20aa2657063cbf3b47fc700603180de4bb554
author Christoph Hellwig <hch@infradead.org> 1227842611 +1100
committer Niv Sardi <xaiki@sgi.com> 1228090004 +1100

[XFS] fix NULL pointer dereference in xfs_log_force_umount

xfs_log_force_umount may be called very early during log recovery where

If we fail a buffer read in xlog_recover_do_inode_trans we abort the mount.
But at that point log recovery has started delayed writeback of inode
buffers.   As part of the aborted mount we try to flush out all delwri
buffers, but at that point we have already freed the superblock, and set
mp->m_sb_bp to NULL, and xfs_log_force_umount which gets called after
the inode buffer writeback trips over it.

Make xfs_log_force_umount a little more careful when accessing mp->m_sb_bp
to avoid this.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Niv Sardi <xaiki@sgi.com>