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authorAndreas Gruenbacher <agruenba@redhat.com>2016-06-14 12:22:27 -0500
committerBob Peterson <rpeterso@redhat.com>2016-06-27 09:47:07 -0500
commit3ce37b2cb4917674fa5b776e857dcea94c0e0835 (patch)
tree76adc95997a6e5ba7668630597c0872dde734a45 /fs/gfs2/inode.h
parentgfs2: Initialize iopen glock holder for new inodes (diff)
downloadlinux-dev-3ce37b2cb4917674fa5b776e857dcea94c0e0835.tar.xz
linux-dev-3ce37b2cb4917674fa5b776e857dcea94c0e0835.zip
gfs2: Fix gfs2_lookup_by_inum lock inversion
The current gfs2_lookup_by_inum takes the glock of a presumed inode identified by block number, verifies that the block is indeed an inode, and then instantiates and reads the new inode via gfs2_inode_lookup. However, instantiating a new inode may block on freeing a previous instance of that inode (__wait_on_freeing_inode), and freeing an inode requires to take the glock already held, leading to lock inversion and deadlock. Fix this by first instantiating the new inode, then verifying that the block is an inode (if required), and then reading in the new inode, all in gfs2_inode_lookup. If the block we are looking for is not an inode, we discard the new inode via iget_failed, which marks inodes as bad and unhashes them. Other tasks waiting on that inode will get back a bad inode back from ilookup or iget_locked; in that case, retry the lookup. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Diffstat (limited to 'fs/gfs2/inode.h')
-rw-r--r--fs/gfs2/inode.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index e1af0d4aa308..443b46cfb8f2 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -94,7 +94,8 @@ err:
}
extern struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type,
- u64 no_addr, u64 no_formal_ino);
+ u64 no_addr, u64 no_formal_ino,
+ unsigned int blktype);
extern struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
u64 *no_formal_ino,
unsigned int blktype);