automake distdir.test fails because of an EPERM error

This was a hard one to track down but an easy one to fix. The make distcheck command was having difficulty with this:

find "distdir-1.0" -type d ! -perm -200 -exec chmod u+w {} ';' && rm -rf "distdir-1.0"

That find command fixes up directory permissions to make sure that they're writeable before trying to recursively delete the directory tree. I discovered that the chmod wasn't happening because when the find program stat'ed the directories, they showed up as writable. But then, strangely, the `rm -rf` failed with a permissions error.

After a lot of debugging to discover that the upper and lower inode's i_mode were getting out of sync somewhere, I then discovered that it was during a setxattr() call on the "system.posix_acl_access" extended attribute. If the lower filesystem modified the inode's i_mode because of a new POSIX ACL being created, eCryptfs was not mirroring those changes back up to the eCryptfs inode.

So, a subsequent stat on the eCryptfs inode could end up lying about the write permissions, causing find to never chmod the inode. But the lack of write permissions was, of course, enforced by the lower filesystem, resulting in the failed `rm -rf`.

Proposed fix posted here:

http://article.gmane.org/gmane.comp.file-systems.ecryptfs.general/139

Test case pushed here:

http://bazaar.launchpad.net/~ecryptfs/ecryptfs/trunk/revision/640

Since it is a trivial fix, I went ahead and pushed it to the eCryptfs -next branch and I plan on getting into Linus' tree soon.

Released upstream in 3.3-rc4: http://git.kernel.org/linus/545d680938be1e86a6c5250701ce9abaf360c495

I've gone ahead and cherry-picked this for Precise and applied to master-next. Fix should be available in the first upload after Beta-1. Thanks.

Oneiric SRU justification:

Impact:

After passing through a ->setxattr() call, eCryptfs needs to copy the
inode attributes from the lower inode to the eCryptfs inode, as they
may have changed in the lower filesystem's ->setxattr() path.

One example is if an extended attribute containing a POSIX Access
Control List is being set. The new ACL may cause the lower filesystem to
modify the mode of the lower inode and the eCryptfs inode would need to
be updated to reflect the new mode.

Fix:

Upstream commit 545d680938be1e86a6c5250701ce9abaf360c495

Testcase:

http://bazaar.launchpad.net/~ecryptfs/ecryptfs/trunk/revision/640

This bug is awaiting verification that the kernel for Oneiric in -proposed solves the problem ( 3.0.0-17.30). Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-oneiric' to 'verification-done-oneiric'.

If verification is not done by one week from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

Verified with ecryptfs lower on ext2, ext3, ext4, xfs and btrfs for Oneiric -proposed.

Verified on Oneiric.

I had this issue when copying a directory into eCryptfs using 'cp -Rp' command. '-p' option was causing the issue of the permissions.
I tested the oneiric-proposed kernel and it is working fine, permissions are copied correctly.

Released in 3.2.0-18.28. I verified the failure no longer occurs.

This bug was fixed in the package linux - 3.0.0-17.30

---------------
linux (3.0.0-17.30) oneiric-proposed; urgency=low

  [Luis Henriques]

  * Release Tracking Bug
    - LP: #949882

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  * [Config] restore build-% shortcut

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  * (config) Fix virtual flavour inclusion of xen-kbdfront
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  [ Upstream Kernel Changes ]

  * readahead: fix pipeline break caused by block plug
    - LP: #931719
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    - LP: #924320, #931719
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    outputs
    - LP: #931719
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    - LP: #931719
  * ARM: OMAP2+: GPMC: fix device size setup
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  * IB/mlx4: pass SMP vendor-specific attribute MADs to firmware
    - LP: #931719
  * kprobes: fix a memory leak in function pre_handler_kretprobe()
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  * at_hdmac: bugfix for enabling channel irq
    - LP: #931719
  * mm/filemap_xip.c: fix race condition in xip_file_fault()
    - LP: #931719
  * mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGES
    block during isolation for migration
    - LP: #931719
  * drm/radeon: Set DESKTOP_HEIGHT register to the framebuffer (not mode)
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    - LP: #931719
  * drm/nouveau/gem: fix fence_sync race / oops
    - LP: #931719
  * drm/radeon/kms: disable output polling when suspended
    - LP: #931719
  * sched/rt: Fix task stack corruption under
    __ARCH_WANT_INTERRUPTS_ON_CTXSW
    - LP: #931719
  * ASoC: Ensure we generate a driver name
    - LP: #931719
  * udf: Mark LVID buffer as uptodate before marking it dirty
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  * drm/i915: HDMI hot remove notification to audio driver
    - LP: #931719
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  * drm/i915: check ACTHD of all rings
    - LP: #931719
  * drm/i915: Fix TV Out refresh rate.
    - LP: #931719
  * drm/i915: handle 3rd pipe
    - LP: #931719
  * eCryptfs: Infinite loop due to overflow in ecryptfs_write()
    - LP: #931719
  * cifs: Fix oops in session setup code for null user mounts
    - LP: #931719
  * atmel_lcdfb: fix usage of CONTRAST_CTR in suspend/resume
    - LP: #931719
  * lockdep, bug: Exclude TAINT_FIRMWARE_WORKAROUND from disabling lockdep
    - LP: #931719
  * hwmon: (w83627ehf) Fix number of fans for NCT6776F
    - LP: #931719
  * ASoC: wm_hubs: Fix routing of input PGAs to li...