mirror of https://github.com/hak5/openwrt-owl.git
110 lines
3.2 KiB
Diff
110 lines
3.2 KiB
Diff
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[linux-unionfs added to Cc]
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On Tue, May 19, 2015 at 09:51:20AM +0200, Bastian Bittorf wrote:
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> Hi Miklos,
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>
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> sorry for writing directly to you, feel free to forward
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> this to the appropriate mailinglist.
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>
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> we have a problem with mainline overlay filesystem on kernel 3.18:
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> https://dev.openwrt.org/ticket/19564
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>
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> 2 things are odd:
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> when the working filesystem is full, overlays fails with:
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>
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> overlayfs: failed to create directory /overlay/work/work
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>
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> what is strange, that we call it with:
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>
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> mount(overlay, "/mnt", "overlay", MS_NOATIME, lowerdir)
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>
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> see here:
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> http://nbd.name/gitweb.cgi?p=fstools.git;a=blob;f=libfstools/mount.c;h=81176ce399b4cd8e2d347c0008c13dec92407f55;hb=e6004000ff15d7bd32cf5663e8690fc94d7ec747#l125
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>
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> do you have an idea whats wrong?
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> 1) is it really needed, that we need space for creating dir "/overlay/work"?
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> 2) why does overlay need "/overlay/work/work"?
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The work directory is needed for atomic copy-up and similar. It is not actually
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necessary to mount a read-only overlay. Post 4.0 it is possible to mount the
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overlay without workdir (but even then it won't happen automatically in case the
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upper fs is full, so this should be fixed in the latest kernel too).
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Could you please try the following patch? If the workdir can't be created it
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will fall back to mounting the overlay read-only.
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Thanks,
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Miklos
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---
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fs/overlayfs/copy_up.c | 3 +++
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fs/overlayfs/dir.c | 9 +++++++++
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fs/overlayfs/super.c | 12 +++++++++---
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3 files changed, 21 insertions(+), 3 deletions(-)
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--- a/fs/overlayfs/copy_up.c
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+++ b/fs/overlayfs/copy_up.c
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@@ -300,6 +300,9 @@ int ovl_copy_up_one(struct dentry *paren
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struct cred *override_cred;
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char *link = NULL;
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+ if (WARN_ON(!workdir))
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+ return -EROFS;
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+
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ovl_path_upper(parent, &parentpath);
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upperdir = parentpath.dentry;
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--- a/fs/overlayfs/dir.c
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+++ b/fs/overlayfs/dir.c
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@@ -222,6 +222,9 @@ static struct dentry *ovl_clear_empty(st
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struct kstat stat;
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int err;
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+ if (WARN_ON(!workdir))
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+ return ERR_PTR(-EROFS);
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+
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err = ovl_lock_rename_workdir(workdir, upperdir);
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if (err)
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goto out;
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@@ -322,6 +325,9 @@ static int ovl_create_over_whiteout(stru
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struct dentry *newdentry;
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int err;
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+ if (WARN_ON(!workdir))
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+ return -EROFS;
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+
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err = ovl_lock_rename_workdir(workdir, upperdir);
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if (err)
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goto out;
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@@ -506,6 +512,9 @@ static int ovl_remove_and_whiteout(struc
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struct dentry *opaquedir = NULL;
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int err;
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+ if (WARN_ON(!workdir))
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+ return -EROFS;
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+
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if (is_dir) {
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opaquedir = ovl_check_empty_and_clear(dentry);
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err = PTR_ERR(opaquedir);
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--- a/fs/overlayfs/super.c
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+++ b/fs/overlayfs/super.c
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@@ -740,9 +740,15 @@ static int ovl_fill_super(struct super_b
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ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
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err = PTR_ERR(ufs->workdir);
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if (IS_ERR(ufs->workdir)) {
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- pr_err("overlayfs: failed to create directory %s/%s\n",
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- ufs->config.workdir, OVL_WORKDIR_NAME);
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- goto out_put_lower_mnt;
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+ if (err == -ENOSPC || err == -EROFS) {
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+ pr_warning("overlayfs: failed to create work directory (%s), mounting read-only\n", err == ENOSPC ? "ENOSPC" : "EROFS");
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+ sb->s_flags |= MS_RDONLY;
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+ ufs->workdir = NULL;
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+ } else {
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+ pr_err("overlayfs: failed to create directory %s/%s\n",
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+ ufs->config.workdir, OVL_WORKDIR_NAME);
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+ goto out_put_lower_mnt;
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+ }
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}
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/*
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