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Commit af17e1fc authored by Al Viro's avatar Al Viro Committed by Greg Kroah-Hartman
Browse files

exportfs_decode_fh(): negative pinned may become positive without the parent locked 



[ Upstream commit a2ece088882666e1dc7113744ac912eb161e3f87 ]

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent dadd71d1

fs/exportfs/expfs.c

+19 −12
Original line number Diff line number Diff line
@@ -517,26 +517,33 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, 
		 * inode is actually connected to the parent.

		 */

		err = exportfs_get_name(mnt, target_dir, nbuf, result);

		if (!err) {

		if (err) {

			dput(target_dir);

			goto err_result;

		}



		inode_lock(target_dir->d_inode);

			nresult = lookup_one_len(nbuf, target_dir,

						 strlen(nbuf));

			inode_unlock(target_dir->d_inode);

		nresult = lookup_one_len(nbuf, target_dir, strlen(nbuf));

		if (!IS_ERR(nresult)) {

				if (nresult->d_inode) {

					dput(result);

					result = nresult;

				} else

			if (unlikely(nresult->d_inode != result->d_inode)) {

				dput(nresult);

				nresult = ERR_PTR(-ESTALE);

			}

		}



		inode_unlock(target_dir->d_inode);

		/*

		 * At this point we are done with the parent, but it's pinned

		 * by the child dentry anyway.

		 */

		dput(target_dir);



		if (IS_ERR(nresult)) {

			err = PTR_ERR(nresult);

			goto err_result;

		}

		dput(result);

		result = nresult;



		/*

		 * And finally make sure the dentry is actually acceptable

		 * to NFSD.