From: Eric W. Biederman <ebiederm@xmission.com>
Date: Sat, 15 Aug 2015 18:36:41 +0000 (-0500)
Subject: dcache: Reduce the scope of i_lock in d_splice_alias
X-Git-Tag: omap-for-v4.3/fixes-rc1~80^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a03e283bf5c3d4851b4998122196ce9f849e6dfb;p=pandora-kernel.git

dcache: Reduce the scope of i_lock in d_splice_alias

i_lock is only needed until __d_find_any_alias calls dget on the alias
dentry.  After that the reference to new ensures that dentry_kill and
d_delete will not remove the inode from the dentry, and remove the
dentry from the inode->d_entry list.

The inode i_lock came to be held over the the __d_move calls in
d_splice_alias through a series of introduction of locks with
increasing smaller scope.  First it was the dcache_lock, then
it was the dcache_inode_lock, and finally inode->i_lock.

Furthermore inode->i_lock is not held over any other calls
to d_move or __d_move so it can not provide any meaningful
rename protection.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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