kernel/git/stable/linux.git/fs/overlayfs/util.c, branch linux-5.9.y

ovl: add accessor for ofs->upper_mnt

2020-06-04T08:48:19+00:00

Next patch will remove ofs->upper_mnt, so add an accessor function for this field. Signed-off-by: Miklos Szeredi

ovl: verify permissions in ovl_path_open()

2020-06-02T20:20:26+00:00

Check permission before opening a real file. ovl_path_open() is used by readdir and copy-up routines. ovl_permission() theoretically already checked copy up permissions, but it doesn't hurt to re-do these checks during the actual copy-up. For directory reading ovl_permission() only checks access to topmost underlying layer. Readdir on a merged directory accesses layers below the topmost one as well. Permission wasn't checked for these layers. Note: modifying ovl_permission() to perform this check would be far more complex and hence more bug prone. The result is less precise permissions returned in access(2). If this turns out to be an issue, we can revisit this bug. Signed-off-by: Miklos Szeredi

ovl: whiteout inode sharing

2020-05-13T09:11:24+00:00

Share inode with different whiteout files for saving inode and speeding up delete operation. If EMLINK is encountered when linking a shared whiteout, create a new one. In case of any other error, disable sharing for this super block. Note: ofs->whiteout is protected by inode lock on workdir. Signed-off-by: Chengguang Xu Reviewed-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: allow remote upper

2020-03-17T14:04:22+00:00

No reason to prevent upper layer being a remote filesystem. Do the revalidation in that case, just as we already do for lower layers. This lets virtiofs be used as upper layer, which appears to be a real use case. Signed-off-by: Miklos Szeredi

ovl: decide if revalidate needed on a per-dentry basis

2020-03-17T14:04:22+00:00

Allow completely skipping ->revalidate() on a per-dentry basis, in case the underlying layers used for a dentry do not themselves have ->revalidate(). E.g. negative overlay dentry has no underlying layers, hence revalidate is unnecessary. Or if lower layer is remote but overlay dentry is pure-upper, then can skip revalidate. The following places need to update whether the dentry needs revalidate or not: - fill-super (root dentry) - lookup - create - fh_to_dentry Signed-off-by: Miklos Szeredi

ovl: separate detection of remote upper layer from stacked overlay

2020-03-17T14:04:22+00:00

Following patch will allow remote as upper layer, but not overlay stacked on upper layer. Separate the two concepts. This patch is doesn't change behavior. Signed-off-by: Miklos Szeredi

ovl: simplify i_ino initialization

2020-03-17T14:04:22+00:00

Move i_ino initialization to ovl_inode_init() to avoid the dance of setting i_ino in ovl_fill_inode() sometimes on the first call and sometimes on the seconds call. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: fix out of date comment and unreachable code

2020-03-17T14:04:21+00:00

ovl_inode_update() is no longer called from create object code path. Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly...") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: fix lock in ovl_llseek()

2020-03-12T15:38:10+00:00

ovl_inode_lock() is interruptible. When inode_lock() in ovl_llseek() was replaced with ovl_inode_lock(), we did not add a check for error. Fix this by making ovl_inode_lock() uninterruptible and change the existing call sites to use an _interruptible variant. Reported-by: syzbot+66a9752fa927f745385e@syzkaller.appspotmail.com Fixes: b1f9d3858f72 ("ovl: use ovl_inode_lock in ovl_llseek()") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: layer is const

2020-01-24T08:46:45+00:00

The ovl_layer struct is never modified except at initialization. Signed-off-by: Miklos Szeredi