linux.git/fs/overlayfs, branch v4.14

ovl: do not cleanup unsupported index entries

2017-10-24T14:06:17+00:00

With index=on, ovl_indexdir_cleanup() tries to cleanup invalid index
entries (e.g. bad index name). This behavior could result in cleaning of
entries created by newer kernels and is therefore undesirable.
Instead, abort mount if such entries are encountered. We still cleanup
'stale' entries and 'orphan' entries, both those cases can be a result
of offline changes to lower and upper dirs.

When encoutering an index entry of type directory or whiteout, kernel
was supposed to fallback to read-only mount, but the fill_super()
operation returns EROFS in this case instead of returning success with
read-only mount flag, so mount fails when encoutering directory or
whiteout index entries. Bless this behavior by returning -EINVAL on
directory and whiteout index entries as we do for all unsupported index
entries.

Fixes: 61b674710cd9 ("ovl: do not cleanup directory and whiteout index..")
Cc:  # v4.13
Signed-off-by: Amir Goldstein

ovl: handle ENOENT on index lookup

2017-10-24T14:06:17+00:00

Treat ENOENT from index entry lookup the same way as treating a returned
negative dentry. Apparently, either could be returned if file is not
found, depending on the underlying file system.

Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin")
Cc:  # v4.13
Signed-off-by: Amir Goldstein

ovl: fix EIO from lookup of non-indexed upper

2017-10-24T14:06:16+00:00

Commit fbaf94ee3cd5 ("ovl: don't set origin on broken lower hardlink")
attempt to avoid the condition of non-indexed upper inode with lower
hardlink as origin. If this condition is found, lookup returns EIO.

The protection of commit mentioned above does not cover the case of lower
that is not a hardlink when it is copied up (with either index=off/on)
and then lower is hardlinked while overlay is offline.

Changes to lower layer while overlayfs is offline should not result in
unexpected behavior, so a permanent EIO error after creating a link in
lower layer should not be considered as correct behavior.

This fix replaces EIO error with success in cases where upper has origin
but no index is found, or index is found that does not match upper
inode. In those cases, lookup will not fail and the returned overlay inode
will be hashed by upper inode instead of by lower origin inode.

Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin")
Cc:  # v4.13
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: Return -ENOMEM if an allocation fails ovl_lookup()

2017-10-19T14:19:52+00:00

The error code is missing here so it means we return ERR_PTR(0) or NULL.
The other error paths all return an error code so this probably should
as well.

Fixes: 02b69b284cd7 ("ovl: lookup redirects")
Signed-off-by: Dan Carpenter 
Reviewed-by: Chandan Rajendra 
Signed-off-by: Miklos Szeredi

ovl: add NULL check in ovl_alloc_inode

2017-10-19T14:19:51+00:00

This was detected by fault injection test

Signed-off-by: Hirofumi Nakagawa 
Fixes: 13cf199d0088 ("ovl: allocate an ovl_inode struct")
Cc:  # v4.13

ovl: fix regression caused by exclusive upper/work dir protection

2017-10-05T13:53:18+00:00

Enforcing exclusive ownership on upper/work dirs caused a docker
regression: https://github.com/moby/moby/issues/34672.

Euan spotted the regression and pointed to the offending commit.
Vivek has brought the regression to my attention and provided this
reproducer:

Terminal 1:

  mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
        merged/

Terminal 2:

  unshare -m

Terminal 1:

  umount merged
  mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
        merged/
  mount: /root/overlay-testing/merged: none already mounted or mount point
         busy

To fix the regression, I replaced the error with an alarming warning.
With index feature enabled, mount does fail, but logs a suggestion to
override exclusive dir protection by disabling index.
Note that index=off mount does take the inuse locks, so a concurrent
index=off will issue the warning and a concurrent index=on mount will fail.

Documentation was updated to reflect this change.

Fixes: 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs")
Cc:  # v4.13
Reported-by: Euan Kemp 
Reported-by: Vivek Goyal 
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: fix missing unlock_rename() in ovl_do_copy_up()

2017-10-05T13:53:18+00:00

Use the ovl_lock_rename_workdir() helper which requires
unlock_rename() only on lock success.

Fixes: ("fd210b7d67ee ovl: move copy up lock out")
Cc:  # v4.13
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: fix dentry leak in ovl_indexdir_cleanup()

2017-10-05T13:53:18+00:00

index dentry was not released when breaking out of the loop
due to index verification error.

Fixes: 415543d5c64f ("ovl: cleanup bad and stale index entries on mount")
Cc:  # v4.13
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

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

2017-10-05T13:53:18+00:00

Fixes: caf70cb2ba5d ("ovl: cleanup orphan index entries")
Cc:  # v4.13
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: fix error value printed in ovl_lookup_index()

2017-10-05T13:53:18+00:00

Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin")
Cc:  # v4.13
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi