diff options
| -rw-r--r-- | target/linux/ar71xx/patches-3.18/910-overlayfs-fallback-to-readonly-when-full.patch | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/target/linux/ar71xx/patches-3.18/910-overlayfs-fallback-to-readonly-when-full.patch b/target/linux/ar71xx/patches-3.18/910-overlayfs-fallback-to-readonly-when-full.patch new file mode 100644 index 0000000000..53d9e516fc --- /dev/null +++ b/target/linux/ar71xx/patches-3.18/910-overlayfs-fallback-to-readonly-when-full.patch @@ -0,0 +1,109 @@ +[linux-unionfs added to Cc] + +On Tue, May 19, 2015 at 09:51:20AM +0200, Bastian Bittorf wrote: +> Hi Miklos, +> +> sorry for writing directly to you, feel free to forward +> this to the appropriate mailinglist. +> +> we have a problem with mainline overlay filesystem on kernel 3.18: +> https://dev.openwrt.org/ticket/19564 +> +> 2 things are odd: +> when the working filesystem is full, overlays fails with: +> +> overlayfs: failed to create directory /overlay/work/work +> +> what is strange, that we call it with: +> +> mount(overlay, "/mnt", "overlay", MS_NOATIME, lowerdir) +> +> see here: +> http://nbd.name/gitweb.cgi?p=fstools.git;a=blob;f=libfstools/mount.c;h=81176ce399b4cd8e2d347c0008c13dec92407f55;hb=e6004000ff15d7bd32cf5663e8690fc94d7ec747#l125 +> +> do you have an idea whats wrong? +> 1) is it really needed, that we need space for creating dir "/overlay/work"? +> 2) why does overlay need "/overlay/work/work"? + +The work directory is needed for atomic copy-up and similar. It is not actually +necessary to mount a read-only overlay. Post 4.0 it is possible to mount the +overlay without workdir (but even then it won't happen automatically in case the +upper fs is full, so this should be fixed in the latest kernel too). + +Could you please try the following patch? If the workdir can't be created it +will fall back to mounting the overlay read-only. + +Thanks, +Miklos + +--- + fs/overlayfs/copy_up.c | 3 +++ + fs/overlayfs/dir.c | 9 +++++++++ + fs/overlayfs/super.c | 12 +++++++++--- + 3 files changed, 21 insertions(+), 3 deletions(-) + +--- a/fs/overlayfs/copy_up.c ++++ b/fs/overlayfs/copy_up.c +@@ -300,6 +300,9 @@ int ovl_copy_up_one(struct dentry *paren + struct cred *override_cred; + char *link = NULL; + ++ if (WARN_ON(!workdir)) ++ return -EROFS; ++ + ovl_path_upper(parent, &parentpath); + upperdir = parentpath.dentry; + +--- a/fs/overlayfs/dir.c ++++ b/fs/overlayfs/dir.c +@@ -222,6 +222,9 @@ static struct dentry *ovl_clear_empty(st + struct kstat stat; + int err; + ++ if (WARN_ON(!workdir)) ++ return ERR_PTR(-EROFS); ++ + err = ovl_lock_rename_workdir(workdir, upperdir); + if (err) + goto out; +@@ -322,6 +325,9 @@ static int ovl_create_over_whiteout(stru + struct dentry *newdentry; + int err; + ++ if (WARN_ON(!workdir)) ++ return -EROFS; ++ + err = ovl_lock_rename_workdir(workdir, upperdir); + if (err) + goto out; +@@ -506,6 +512,9 @@ static int ovl_remove_and_whiteout(struc + struct dentry *opaquedir = NULL; + int err; + ++ if (WARN_ON(!workdir)) ++ return -EROFS; ++ + if (is_dir) { + opaquedir = ovl_check_empty_and_clear(dentry); + err = PTR_ERR(opaquedir); +--- a/fs/overlayfs/super.c ++++ b/fs/overlayfs/super.c +@@ -740,9 +740,15 @@ static int ovl_fill_super(struct super_b + ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry); + err = PTR_ERR(ufs->workdir); + if (IS_ERR(ufs->workdir)) { +- pr_err("overlayfs: failed to create directory %s/%s\n", +- ufs->config.workdir, OVL_WORKDIR_NAME); +- goto out_put_lower_mnt; ++ if (err == -ENOSPC || err == -EROFS) { ++ pr_warning("overlayfs: failed to create work directory (%s), mounting read-only\n", err == ENOSPC ? "ENOSPC" : "EROFS"); ++ sb->s_flags |= MS_RDONLY; ++ ufs->workdir = NULL; ++ } else { ++ pr_err("overlayfs: failed to create directory %s/%s\n", ++ ufs->config.workdir, OVL_WORKDIR_NAME); ++ goto out_put_lower_mnt; ++ } + } + + /* |