diff options
Diffstat (limited to 'target/linux/generic/pending-4.4/051-0005-ovl-proper-cleanup-of-workdir.patch')
| -rw-r--r-- | target/linux/generic/pending-4.4/051-0005-ovl-proper-cleanup-of-workdir.patch | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/target/linux/generic/pending-4.4/051-0005-ovl-proper-cleanup-of-workdir.patch b/target/linux/generic/pending-4.4/051-0005-ovl-proper-cleanup-of-workdir.patch new file mode 100644 index 0000000000..eb095b7a2e --- /dev/null +++ b/target/linux/generic/pending-4.4/051-0005-ovl-proper-cleanup-of-workdir.patch @@ -0,0 +1,131 @@ +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); +@@ -569,3 +569,64 @@ 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; + } |