Re: [OpenWrt-Devel] [PATCH] [kernel] upstream fix: mount overlayfs r/o if workdir cannot be created
Am 19.05.2015 um 16:17 schrieb Bastian Bittorf: +diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c +index 5f0d199..bf8537c 100644 +--- a/fs/overlayfs/super.c b/fs/overlayfs/super.c +@@ -529,7 +529,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data) this function was added with linux 4.0, so your patch for 3.18 does not apply. Can you give me a hint to make it work with 3.18? Best Christian ___ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
Re: [OpenWrt-Devel] [PATCH] [kernel] upstream fix: mount overlayfs r/o if workdir cannot be created
* Christian Mehlis christ...@m3hlis.de [21.05.2015 12:49]: +--- a/fs/overlayfs/super.c b/fs/overlayfs/super.c +@@ -529,7 +529,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data) this function was added with linux 4.0, so your patch for 3.18 does not apply. Can you give me a hint to make it work with 3.18? i will investigate - it applied locally here with 3.18 - will check why... bye, bastian ___ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
Re: [OpenWrt-Devel] [PATCH] [kernel] upstream fix: mount overlayfs r/o if workdir cannot be created
* Christian Mehlis christ...@m3hlis.de [21.05.2015 12:49]:
Can you give me a hint to make it work with 3.18?
can you please try to apply the appended patch with
git am $file
make target/linux/clean
make
bye, bastian
From f5d917da8665f1a3c79e5beb34acea7daf019ff5 Mon Sep 17 00:00:00 2001
From: Bastian Bittorf bitt...@bluebottle.com
Date: Thu, 21 May 2015 13:55:00 +0200
Subject: [PATCH] [kernel] upstream fix: mount overlayfs r/o if workdir cannot be created
see: https://www.mail-archive.com/linux-unionfs@vger.kernel.org/msg00246.html
runtime tested on ar71xx with kernel 3.18.11 and r45705
this paritially fixes #19564
Signed-off-by: Bastian Bittorf bitt...@bluebottle.com
---
...-overlayfs-fallback-to-readonly-when-full.patch | 109
1 file changed, 109 insertions(+)
create mode 100644 target/linux/ar71xx/patches-3.18/910-overlayfs-fallback-to-readonly-when-full.patch
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 000..3433cbc
--- /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 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;
++ }
+ }
+
+ /*
--
1.7.10.4
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[OpenWrt-Devel] [PATCH] [kernel] upstream fix: mount overlayfs r/o if workdir cannot be created
runtime tested on ar71xx with kernel 3.18.11
this paritially fixes #19564
Signed-off-by: Bastian Bittorf bitt...@bluebottle.com
---
...unt-read-only-if-workdir-can-t-be-created.patch | 114
1 file changed, 114 insertions(+)
create mode 100644
target/linux/ar71xx/patches-3.18/910-overlayfs-mount-read-only-if-workdir-can-t-be-created.patch
diff --git
a/target/linux/ar71xx/patches-3.18/910-overlayfs-mount-read-only-if-workdir-can-t-be-created.patch
b/target/linux/ar71xx/patches-3.18/910-overlayfs-mount-read-only-if-workdir-can-t-be-created.patch
new file mode 100644
index 000..e563398
--- /dev/null
+++
b/target/linux/ar71xx/patches-3.18/910-overlayfs-mount-read-only-if-workdir-can-t-be-created.patch
@@ -0,0 +1,114 @@
+From cc6f67bcafcb62d1be1603dcd95125a52800 Mon Sep 17 00:00:00 2001
+From: Miklos Szeredi mszer...@suse.cz
+Date: Tue, 19 May 2015 14:30:12 +0200
+Subject: [PATCH] ovl: mount read-only if workdir can't be created
+
+OpenWRT folks reported that overlayfs fails to mount if upper fs is full,
+because workdir can't be created. Wordir creation can fail for various
+other reasons too.
+
+There's no reason that the mount itself should fail, overlayfs can work
+fine without a workdir, as long as the overlay isn't modified.
+
+So mount it read-only and don't allow remounting read-write.
+
+Add a couple of WARN_ON()s for the impossible case of workdir being used
+despite being read-only.
+
+Reported-by: Bastian Bittorf bitt...@bluebottle.com
+Signed-off-by: Miklos Szeredi mszer...@suse.cz
+Cc: sta...@vger.kernel.org # v3.18+
+Signed-off-by: Bastian Bittorf bitt...@bluebottle.com
+
+---
+ fs/overlayfs/copy_up.c |3 +++
+ fs/overlayfs/dir.c |9 +
+ fs/overlayfs/super.c | 10 +-
+ 3 files changed, 17 insertions(+), 5 deletions(-)
+
+diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
+index 24f6404..84d693d 100644
+--- a/fs/overlayfs/copy_up.c
b/fs/overlayfs/copy_up.c
+@@ -299,6 +299,9 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry
*dentry,
+ struct cred *override_cred;
+ char *link = NULL;
+
++ if (WARN_ON(!workdir))
++ return -EROFS;
++
+ ovl_path_upper(parent, parentpath);
+ upperdir = parentpath.dentry;
+
+diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
+index 2578a0c..692ceda 100644
+--- a/fs/overlayfs/dir.c
b/fs/overlayfs/dir.c
+@@ -222,6 +222,9 @@ static struct dentry *ovl_clear_empty(struct dentry
*dentry,
+ 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(struct dentry *dentry,
struct inode *inode,
+ 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(struct dentry *dentry,
bool is_dir)
+ struct dentry *opaquedir = NULL;
+ int err;
+
++ if (WARN_ON(!workdir))
++ return -EROFS;
++
+ if (is_dir) {
+ if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
+ opaquedir = ovl_check_empty_and_clear(dentry);
+diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
+index 5f0d199..bf8537c 100644
+--- a/fs/overlayfs/super.c
b/fs/overlayfs/super.c
+@@ -529,7 +529,7 @@ static int ovl_remount(struct super_block *sb, int *flags,
char *data)
+ {
+ struct ovl_fs *ufs = sb-s_fs_info;
+
+- if (!(*flags MS_RDONLY) !ufs-upper_mnt)
++ if (!(*flags MS_RDONLY) (!ufs-upper_mnt || !ufs-workdir))
+ return -EROFS;
+
+ return 0;
+@@ -925,9 +925,10 @@ static int ovl_fill_super(struct super_block *sb, void
*data, int silent)
+ 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_upper_mnt;
++ pr_warn(overlayfs: failed to create directory %s/%s
(errno: %i); mounting read-only\n,
++ ufs-config.workdir, OVL_WORKDIR_NAME, -err);
++ sb-s_flags |= MS_RDONLY;
++ ufs-workdir = NULL;
+ }
+ }
+
+@@ -997,7 +998,6 @@ out_put_lower_mnt:
+ kfree(ufs-lower_mnt);
+ out_put_workdir:
+ dput(ufs-workdir);
+-out_put_upper_mnt:
+ mntput(ufs-upper_mnt);
+ out_put_lowerpath:
+ for (i = 0; i numlower; i++)
+--
+1.7.10.4
+
--
1.7.10.4
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