* Re: linux / overlay / OpenWrt / problems with full working dir
[not found] <20150519075120.GL28644@medion.lan>
@ 2015-05-19 9:03 ` Miklos Szeredi
2015-05-19 9:55 ` hujianyang
2015-05-19 12:00 ` Bastian Bittorf
0 siblings, 2 replies; 4+ messages in thread
From: Miklos Szeredi @ 2015-05-19 9:03 UTC (permalink / raw)
To: Bastian Bittorf; +Cc: linux-unionfs
[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 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;
+ }
}
/*
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: linux / overlay / OpenWrt / problems with full working dir
2015-05-19 9:03 ` linux / overlay / OpenWrt / problems with full working dir Miklos Szeredi
@ 2015-05-19 9:55 ` hujianyang
2015-05-19 12:00 ` Bastian Bittorf
1 sibling, 0 replies; 4+ messages in thread
From: hujianyang @ 2015-05-19 9:55 UTC (permalink / raw)
To: Miklos Szeredi; +Cc: Bastian Bittorf, linux-unionfs
Hi Miklos,
On 2015/5/19 17:03, Miklos Szeredi wrote:
>
> ---
> 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;
> +
When will this condition occur?
> 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) {
Since upper fs should not be R/O after commit 71cbad7e694ee81,
could the return value here be -EROFS?
> + pr_warning("overlayfs: failed to 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;
> + }
> }
>
> /*
> --
> To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> .
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: linux / overlay / OpenWrt / problems with full working dir
2015-05-19 9:03 ` linux / overlay / OpenWrt / problems with full working dir Miklos Szeredi
2015-05-19 9:55 ` hujianyang
@ 2015-05-19 12:00 ` Bastian Bittorf
2015-05-19 12:35 ` Miklos Szeredi
1 sibling, 1 reply; 4+ messages in thread
From: Bastian Bittorf @ 2015-05-19 12:00 UTC (permalink / raw)
To: Miklos Szeredi; +Cc: openwrt-devel, linux-unionfs
* Miklos Szeredi <miklos@szeredi.hu> [19.05.2015 11:19]:
> 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.
Thank you!
I applied it on top of 3.18 and it works.
Here some output with full 'work-dir'/jffs2:
...
[ 8.800000] jffs2: notice: (323) jffs2_build_xattr_subsystem: complete building xattr subsystem, 2 of xdatum (2 unc hecked, 0 orphan) and 2 of xref (0 dead, 0 orphan) found.
[ 8.820000] mount_root: switching to jffs2 overlay
[ 9.030000] overlayfs: failed to work directory (EROFS), mounting read-only
...
root@box:~ df -h
Filesystem Size Used Available Use% Mounted on
rootfs 576.0K 532.0K 44.0K 92% /
/dev/root 2.3M 2.3M 0 100% /rom
tmpfs 14.0M 1.2M 12.8M 8% /tmp
/dev/mtdblock3 576.0K 532.0K 44.0K 92% /overlay
overlayfs:/overlay 576.0K 532.0K 44.0K 92% /
tmpfs 512.0K 0 512.0K 0% /dev
root@box:~ mount
rootfs on / type rootfs (rw)
/dev/root on /rom type squashfs (ro,relatime)
proc on /proc type proc (rw,noatime)
sysfs on /sys type sysfs (rw,noatime)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noatime)
/dev/mtdblock3 on /overlay type jffs2 (rw,noatime)
overlayfs:/overlay on / type overlay (ro,noatime,lowerdir=/,upperdir=/overlay/upper,workdir=/overlay/work)
tmpfs on /dev type tmpfs (rw,relatime,size=512k,mode=755)
devpts on /dev/pts type devpts (rw,relatime,mode=600)
debugfs on /sys/kernel/debug type debugfs (rw,noatime)
please apply it on your git, and we will cherrypick/backport it for OpenWrt.
(and close ticket https://dev.openwrt.org/ticket/19564)
bye, bastian
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: linux / overlay / OpenWrt / problems with full working dir
2015-05-19 12:00 ` Bastian Bittorf
@ 2015-05-19 12:35 ` Miklos Szeredi
0 siblings, 0 replies; 4+ messages in thread
From: Miklos Szeredi @ 2015-05-19 12:35 UTC (permalink / raw)
To: Miklos Szeredi, linux-unionfs, openwrt-devel
On Tue, May 19, 2015 at 2:00 PM, Bastian Bittorf <bittorf@bluebottle.com> wrote:
> please apply it on your git, and we will cherrypick/backport it for OpenWrt.
> (and close ticket https://dev.openwrt.org/ticket/19564)
Pushed to:
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git
overlayfs-current
Thanks,
Miklos
^ permalink raw reply [flat|nested] 4+ messages in thread
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[not found] <20150519075120.GL28644@medion.lan>
2015-05-19 9:03 ` linux / overlay / OpenWrt / problems with full working dir Miklos Szeredi
2015-05-19 9:55 ` hujianyang
2015-05-19 12:00 ` Bastian Bittorf
2015-05-19 12:35 ` Miklos Szeredi
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