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- [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
- @@ -313,6 +313,9 @@ 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;
- @@ -507,6 +513,9 @@ static int ovl_remove_and_whiteout(struc
- int err;
- int flags = 0;
-
- + 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
- @@ -760,9 +760,15 @@ 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;
- + }
- }
-
- /*
|
