kernel-packages team mailing list archive

[Colin Ian King <1434183@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

SRU Justification:  (Trusty, Utopic)

[Impact]
Remounting from compress-force to compress could not clear compress-force option. The problem is there is no way for users to clear compress-force option separately. 

[Fix]
upstream commit 4027e0f4c4b2df28d564560a3c65c179bebae4c8
"Btrfs: clear compress-force when remounting with compress option"

this is a simple one-liner, risk is low to zero.

[Testcase]
See attached hacked up bash script.btrfs: Without the fix I can reproduce the oops every time. With the fix, it works perfectly.

echo "MNT=$MNT"
echo "TMP=$TMP"

TMPIMG=$TMP/test.img
DEV=/dev/loop0

truncate --size 1500m $TMPIMG
losetup $DEV $TMPIMG
mkfs.btrfs -f $DEV
mount $DEV $MNT -o compress-force=lzo
mount $DEV $MNT -o remount,compress=zlib
n=$(cat /proc/mounts | grep $DEV | grep "compress-force=zlib" | wc -l)
umount $DEV
losetup -d $DEV
rm $TMPIMG

if [ $n -eq 0 ]; then
        echo "compress-force=zlib cleared in remount"
        exit 0
else
        echo "compress-force=zlib NOT cleared in remount"
        exit 1
fi

** Affects: linux (Ubuntu)
     Importance: Low
     Assignee: Colin Ian King (colin-king)
         Status: In Progress

** Changed in: linux (Ubuntu)
       Status: New => In Progress

** Changed in: linux (Ubuntu)
   Importance: Undecided => Low

** Changed in: linux (Ubuntu)
     Assignee: (unassigned) => Colin Ian King (colin-king)

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https://bugs.launchpad.net/bugs/1434183

Title:
  btrfs: ccompress-force needs clearing when remounting with compress
  option

Status in linux package in Ubuntu:
  In Progress

Bug description:
  SRU Justification:  (Trusty, Utopic)

  [Impact]
  Remounting from compress-force to compress could not clear compress-force option. The problem is there is no way for users to clear compress-force option separately. 

  [Fix]
  upstream commit 4027e0f4c4b2df28d564560a3c65c179bebae4c8
  "Btrfs: clear compress-force when remounting with compress option"

  this is a simple one-liner, risk is low to zero.

  [Testcase]
  See attached hacked up bash script.btrfs: Without the fix I can reproduce the oops every time. With the fix, it works perfectly.

  echo "MNT=$MNT"
  echo "TMP=$TMP"

  TMPIMG=$TMP/test.img
  DEV=/dev/loop0

  truncate --size 1500m $TMPIMG
  losetup $DEV $TMPIMG
  mkfs.btrfs -f $DEV
  mount $DEV $MNT -o compress-force=lzo
  mount $DEV $MNT -o remount,compress=zlib
  n=$(cat /proc/mounts | grep $DEV | grep "compress-force=zlib" | wc -l)
  umount $DEV
  losetup -d $DEV
  rm $TMPIMG

  if [ $n -eq 0 ]; then
          echo "compress-force=zlib cleared in remount"
          exit 0
  else
          echo "compress-force=zlib NOT cleared in remount"
          exit 1
  fi

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