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Commit 0444d76a authored by Dave Chinner's avatar Dave Chinner Committed by Linus Torvalds
Browse files

fs: don't use igrab() while holding i_lock 



Fix the incorrect use of igrab() inside the i_lock in NFS and Ceph‥

If we are already holding the i_lock, we have a reference to the
inode so we can safely use ihold() to gain an extra reference. This
avoids hangs due to lock recursion on the i_lock now that the
inode_lock is gone and igrab() uses the i_lock itself.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cb1817b3

fs/ceph/addr.c

+1 −1
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ static int ceph_set_page_dirty(struct page *page) 
		ci->i_head_snapc = ceph_get_snap_context(snapc);

	++ci->i_wrbuffer_ref_head;

	if (ci->i_wrbuffer_ref == 0)

		igrab(inode);

		ihold(inode);

	++ci->i_wrbuffer_ref;

	dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "

	     "snapc %p seq %lld (%d snaps)\n",

fs/ceph/snap.c

+2 −2
Original line number Diff line number Diff line
@@ -463,7 +463,7 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci) 


		dout("queue_cap_snap %p cap_snap %p queuing under %p\n", inode,

		     capsnap, snapc);

		igrab(inode);

		ihold(inode);



		atomic_set(&capsnap->nref, 1);

		capsnap->ci = ci;

fs/nfs/nfs4state.c

+2 −1
Original line number Diff line number Diff line
@@ -590,7 +590,8 @@ nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner) 
		state->owner = owner;

		atomic_inc(&owner->so_count);

		list_add(&state->inode_states, &nfsi->open_states);

		state->inode = igrab(inode);

		ihold(inode);

		state->inode = inode;

		spin_unlock(&inode->i_lock);

		/* Note: The reclaim code dictates that we add stateless

		 * and read-only stateids to the end of the list */