Eric Lee / smarc-fsl-linux-kernel

12 Apr, 2018

1 commit

24 Jan, 2018

3 commits

  • a01f64b5c   ovl: document NFS export ... Browse Code »

    Document NFS export design.
    Followup patches will implement this design.

    Signed-off-by: Amir Goldstein
    Signed-off-by: Miklos Szeredi

    Amir Goldstein
     
  • f168f1098   ovl: add support for "nfs_export" configuration ... Browse Code »

    Introduce the "nfs_export" config, module and mount options.

    The NFS export feature depends on the "index" feature and enables two
    implicit overlayfs features: "index_all" and "verify_lower".
    The "index_all" feature creates an index on copy up of every file and
    directory. The "verify_lower" feature uses the full index to detect
    overlay filesystems inconsistencies on lookup, like redirect from
    multiple upper dirs to the same lower dir.

    NFS export can be enabled for non-upper mount with no index. However,
    because lower layer redirects cannot be verified with the index, enabling
    NFS export support on an overlay with no upper layer requires turning off
    redirect follow (e.g. "redirect_dir=nofollow").

    The full index may incur some overhead on mount time, especially when
    verifying that lower directory file handles are not stale.

    NFS export support, full index and consistency verification will be
    implemented by following patches.

    Signed-off-by: Amir Goldstein
    Signed-off-by: Miklos Szeredi

    Amir Goldstein
     
  • 60b866420   ovl: update documentation of inodes index feature ... Browse Code »

    Document that inode index feature solves breaking hard links on
    copy up.

    Simplify Kconfig backward compatibility disclaimer.

    Signed-off-by: Amir Goldstein
    Signed-off-by: Miklos Szeredi

    Amir Goldstein
     

11 Dec, 2017

1 commit

  • 438c84c2f   ovl: don't follow redirects if redirect_dir=off ... Browse Code »

    Overlayfs is following redirects even when redirects are disabled. If this
    is unintentional (probably the majority of cases) then this can be a
    problem. E.g. upper layer comes from untrusted USB drive, and attacker
    crafts a redirect to enable read access to otherwise unreadable
    directories.

    If "redirect_dir=off", then turn off following as well as creation of
    redirects. If "redirect_dir=follow", then turn on following, but turn off
    creation of redirects (which is what "redirect_dir=off" does now).

    This is a backward incompatible change, so make it dependent on a config
    option.

    Reported-by: David Howells
    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     

05 Oct, 2017

1 commit

  • 85fdee1ee   ovl: fix regression caused by exclusive upper/work dir protection ... Browse Code »

    Enforcing exclusive ownership on upper/work dirs caused a docker
    regression: https://github.com/moby/moby/issues/34672.

    Euan spotted the regression and pointed to the offending commit.
    Vivek has brought the regression to my attention and provided this
    reproducer:

    Terminal 1:

    mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
    merged/

    Terminal 2:

    unshare -m

    Terminal 1:

    umount merged
    mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
    merged/
    mount: /root/overlay-testing/merged: none already mounted or mount point
    busy

    To fix the regression, I replaced the error with an alarming warning.
    With index feature enabled, mount does fail, but logs a suggestion to
    override exclusive dir protection by disabling index.
    Note that index=off mount does take the inuse locks, so a concurrent
    index=off will issue the warning and a concurrent index=on mount will fail.

    Documentation was updated to reflect this change.

    Fixes: 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs")
    Cc: # v4.13
    Reported-by: Euan Kemp
    Reported-by: Vivek Goyal
    Signed-off-by: Amir Goldstein
    Signed-off-by: Miklos Szeredi

    Amir Goldstein
     

05 Jul, 2017

1 commit

  • 9412812ef   ovl: document copying layers restrictions with inodes index ... Browse Code »

    The inodes index feature introduces a behavior change - on mount,
    upper root origin file handle is verified to match the lower root dir.
    This implies that copied layers cannot be mounted with the inodes index
    feature enabled, without explicitly removing the upper dir origin xattr
    and the index dir.

    The inodes index feature is required to support:
    - Prevent breaking hardlinks on copy up
    - NFS export support (upcoming)
    - Overlayfs snapshots (POC)

    Signed-off-by: Amir Goldstein
    Signed-off-by: Miklos Szeredi

    Amir Goldstein
     

05 May, 2017

1 commit

16 Dec, 2016

3 commits

  • c3c869966   ovl: fix reStructuredText syntax errors in documentation ... Browse Code »

    - Fix broken long line block quote
    - Fix missing newline before bullets list
    - Use correct numbered list syntax

    Signed-off-by: Amir Goldstein
    Signed-off-by: Miklos Szeredi

    Amir Goldstein
     
  • a6c606551   ovl: redirect on rename-dir ... Browse Code »

    Current code returns EXDEV when a directory would need to be copied up to
    move. We could copy up the directory tree in this case, but there's
    another, simpler solution: point to old lower directory from moved upper
    directory.

    This is achieved with a "trusted.overlay.redirect" xattr storing the path
    relative to the root of the overlay. After such attribute has been set,
    the directory can be moved without further actions required.

    This is a backward incompatible feature, old kernels won't be able to
    correctly mount an overlay containing redirected directories.

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     
  • 2d8f2908e   ovl: update doc ... Browse Code »

    The quirk for file locks and leases no longer applies.

    Add missing info about renaming directory residing on lower layer.

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     

01 Sep, 2016

1 commit

27 May, 2016

1 commit

12 Nov, 2015

1 commit

08 Jan, 2015

1 commit

13 Dec, 2014

2 commits

20 Nov, 2014

1 commit

  • ef94b1864   ovl: rename filesystem type to "overlay" ... Browse Code »

    Some distributions carry an "old" format of overlayfs while mainline has a
    "new" format.

    The distros will possibly want to keep the old overlayfs alongside the new
    for compatibility reasons.

    To make it possible to differentiate the two versions change the name of
    the new one from "overlayfs" to "overlay".

    Signed-off-by: Miklos Szeredi
    Reported-by: Serge Hallyn
    Cc: Andy Whitcroft

    Miklos Szeredi
     

24 Oct, 2014

1 commit