openwrt/upstream - upstream openwrt

	Commit message (Expand)	Author	Age	Files	Lines
*	mac80211: update to version based on 4.19-rc4	Hauke Mehrtens	2018-09-26	1	-1/+1
*	mac80211: rebase ontop of v4.18.5	John Crispin	2018-09-26	1	-0/+11

From eea2fb4851e9dcbab6b991aaf47e2e024f1f55a0 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi <mszeredi@redhat.com> Date: Thu, 1 Sep 2016 11:11:59 +0200 Subject: [PATCH] ovl: proper cleanup of workdir When mounting overlayfs it needs a clean "work" directory under the supplied workdir. Previously the mount code removed this directory if it already existed and created a new one. If the removal failed (e.g. directory was not empty) then it fell back to a read-only mount not using the workdir. While this has never been reported, it is possible to get a non-empty "work" dir from a previous mount of overlayfs in case of crash in the middle of an operation using the work directory. In this case the left over state should be discarded and the overlay filesystem will be consistent, guaranteed by the atomicity of operations on moving to/from the workdir to the upper layer. This patch implements cleaning out any files left in workdir. It is implemented using real recursion for simplicity, but the depth is limited to 2, because the worst case is that of a directory containing whiteouts under "work". Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> --- fs/overlayfs/overlayfs.h | 2 ++ fs/overlayfs/readdir.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++- fs/overlayfs/super.c | 2 +- 3 files changed, 65 insertions(+), 2 deletions(-) --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -164,6 +164,8 @@ extern const struct file_operations ovl_ int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); void ovl_cache_free(struct list_head *list); +void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, + struct dentry *dentry, int level); /* inode.c */ int ovl_setattr(struct dentry *dentry, struct iattr *attr); --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -247,7 +247,7 @@ static inline int ovl_dir_read(struct pa err = rdd->err; } while (!err && rdd->count); - if (!err && rdd->first_maybe_whiteout) + if (!err && rdd->first_maybe_whiteout && rdd->dentry) err = ovl_check_whiteouts(realpath->dentry, rdd); fput(realfile); @@ -573,3 +573,64 @@ void ovl_cleanup_whiteouts(struct dentry } mutex_unlock(&upper->d_inode->i_mutex); } + +static void ovl_workdir_cleanup_recurse(struct path *path, int level) +{ + int err; + struct inode *dir = path->dentry->d_inode; + LIST_HEAD(list); + struct ovl_cache_entry *p; + struct ovl_readdir_data rdd = { + .ctx.actor = ovl_fill_merge, + .dentry = NULL, + .list = &list, + .root = RB_ROOT, + .is_lowest = false, + }; + + err = ovl_dir_read(path, &rdd); + if (err) + goto out; + + mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); + list_for_each_entry(p, &list, l_node) { + struct dentry *dentry; + + if (p->name[0] == '.') { + if (p->len == 1) + continue; + if (p->len == 2 && p->name[1] == '.') + continue; + } + dentry = lookup_one_len(p->name, path->dentry, p->len); + if (IS_ERR(dentry)) + continue; + if (dentry->d_inode) + ovl_workdir_cleanup(dir, path->mnt, dentry, level); + dput(dentry); + } + mutex_unlock(&dir->i_mutex); +out: + ovl_cache_free(&list); +} + +void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, + struct dentry *dentry, int level) +{ + int err; + + if (!d_is_dir(dentry) || level > 1) { + ovl_cleanup(dir, dentry); + return; + } + + err = ovl_do_rmdir(dir, dentry); + if (err) { + struct path path = { .mnt = mnt, .dentry = dentry }; + + mutex_unlock(&dir->i_mutex); + ovl_workdir_cleanup_recurse(&path, level + 1); + mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); + ovl_cleanup(dir, dentry); + } +} --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -784,7 +784,7 @@ retry: goto out_dput; retried = true; - ovl_cleanup(dir, work); + ovl_workdir_cleanup(dir, mnt, work, 0); dput(work); goto retry; }