kernel.git/fs/overlayfs/util.c, branch linux-4.13.y

ovl: fix missing unlock_rename() in ovl_do_copy_up()

2017-10-12T09:56:15Z

commit 5820dc0888d302ac05f8b91ffdf7e4e53b4fbf53 upstream. Use the ovl_lock_rename_workdir() helper which requires unlock_rename() only on lock success. Fixes: ("fd210b7d67ee ovl: move copy up lock out") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix dput() of ERR_PTR in ovl_cleanup_index()

2017-10-12T09:56:15Z

commit 9f4ec904dbd4eb1a2db10d5e7dc16eae386fe64d upstream. Fixes: caf70cb2ba5d ("ovl: cleanup orphan index entries") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix xattr get and set with selinux

2017-07-20T09:08:21Z

inode_doinit_with_dentry() in SELinux wants to read the upper inode's xattr to get security label, and ovl_xattr_get() calls ovl_dentry_real(), which depends on dentry->d_inode, but d_inode is null and not initialized yet at this point resulting in an Oops. Fix by getting the upperdentry info from the inode directly in this case. Reported-by: Eryu Guan Fixes: 09d8b586731b ("ovl: move __upperdentry to ovl_inode") Signed-off-by: Miklos Szeredi

ovl: cleanup orphan index entries

2017-07-04T20:03:19Z

index entry should live only as long as there are upper or lower hardlinks. Cleanup orphan index entries on mount and when dropping the last overlay inode nlink. When about to cleanup or link up to orphan index and the index inode nlink > 1, admit that something went wrong and adjust overlay nlink to index inode nlink - 1 to prevent it from dropping below zero. This could happen when adding lower hardlinks underneath a mounted overlay and then trying to unlink them. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: persistent overlay inode nlink for indexed inodes

2017-07-04T20:03:19Z

With inodes index enabled, an overlay inode nlink counts the union of upper and non-covered lower hardlinks. During the lifetime of a non-pure upper inode, the following nlink modifying operations can happen: 1. Lower hardlink copy up 2. Upper hardlink created, unlinked or renamed over 3. Lower hardlink whiteout or renamed over For the first, copy up case, the union nlink does not change, whether the operation succeeds or fails, but the upper inode nlink may change. Therefore, before copy up, we store the union nlink value relative to the lower inode nlink in the index inode xattr trusted.overlay.nlink. For the second, upper hardlink case, the union nlink should be incremented or decremented IFF the operation succeeds, aligned with nlink change of the upper inode. Therefore, before link/unlink/rename, we store the union nlink value relative to the upper inode nlink in the index inode. For the last, lower cover up case, we simplify things by preceding the whiteout or cover up with copy up. This makes sure that there is an index upper inode where the nlink xattr can be stored before the copied up upper entry is unlink. Return the overlay inode nlinks for indexed upper inodes on stat(2). Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: implement index dir copy up

2017-07-04T20:03:19Z

Implement a copy up method for non-dir objects using index dir to prevent breaking lower hardlinks on copy up. This method requires that the inodes index dir feature was enabled and that all underlying fs support file handle encoding/decoding. On the first lower hardlink copy up, upper file is created in index dir, named after the hex representation of the lower origin inode file handle. On the second lower hardlink copy up, upper file is found in index dir, by the same lower handle key. On either case, the upper indexed inode is then linked to the copy up upper path. The index entry remains linked for future lower hardlink copy up and for lower to upper inode map, that is needed for exporting overlayfs to NFS. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: add flag for upper in ovl_entry

2017-07-04T20:03:18Z

For rename, we need to ensure that an upper alias exists for hard links before attempting the operation. Introduce a flag in ovl_entry to track the state of the upper alias. Signed-off-by: Miklos Szeredi

ovl: defer upper dir lock to tempfile link

2017-07-04T20:03:18Z

On copy up of regular file using an O_TMPFILE, lock upper dir only before linking the tempfile in place. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: hash overlay non-dir inodes by copy up origin

2017-07-04T20:03:17Z

Signed-off-by: Miklos Szeredi

ovl: introduce the inodes index dir feature

2017-07-04T20:03:17Z

Create the index dir on mount. The index dir will contain hardlinks to upper inodes, named after the hex representation of their origin lower inodes. The index dir is going to be used to prevent breaking lower hardlinks on copy up and to implement overlayfs NFS export. Because the feature is not fully backward compat, enabling the feature is opt-in by config/module/mount option. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi