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

[Colin Ian King]

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

[Andy Whitcroft (apw)]

This was upstream as of v3.18-rc4, therefore vivid is already released; marking same.

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-trusty' to 'verification-done-trusty'.

If verification is not done by 5 working days 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!

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-utopic' to 'verification-done-utopic'.

If verification is not done by 5 working days 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!

[Colin Ian King (colin-king)]

Fix tested on utopic, $ uname -a
Linux ubuntu 3.16.0-34-generic #45-Ubuntu SMP Mon Mar 23 17:21:27 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Works fine with the proposed kernel.

[Colin Ian King (colin-king)]

Fix tested on trusty, $ uname -a
Linux ubuntu 3.16.0-34-generic #45~14.04.1-Ubuntu SMP Tue Mar 24 11:14:29 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Works fine with the -proposed kernel

[Colin Ian King (colin-king)]

Fix tested on trusty,
Linux ubuntu 3.13.0-49-generic #81-Ubuntu SMP Tue Mar 24 19:29:48 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Works fine with the -proposed kernel

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.13.0-49.81

---------------
linux (3.13.0-49.81) trusty; urgency=low

  [ Kamal Mostafa ]

  * Release Tracking Bug
    - LP: #1436016

  [ Alex Hung ]

  * SAUCE: ACPI / blacklist: blacklist Win8 OSI for HP Pavilion dv6
    - LP: #1416940

  [ Andy Whitcroft ]

  * [Packaging] generate live watchdog blacklists
    - LP: #1432837

  [ Ben Widawsky ]

  * SAUCE: i915_bdw: drm/i915/bdw: enable eDRAM.
    - LP: #1430855

  [ Chris J Arges ]

  * [Config] Add ibmvfc to d-i
    - LP: #1416001

  [ Seth Forshee ]

  * [Config] updateconfigs - enable X86_UP_APIC_MSI

  [ Upstream Kernel Changes ]

  * net: add sysfs helpers for netdev_adjacent logic
    - LP: #1410852
  * net: Mark functions as static in core/dev.c
    - LP: #1410852
  * net: rename sysfs symlinks on device name change
    - LP: #1410852
  * btrfs: fix null pointer dereference in clone_fs_devices when name is
    null
    - LP: #1429804
  * cdc-acm: add sanity checks
    - LP: #1413992
  * x86: thinkpad_acpi.c: fixed spacing coding style issue
    - LP: #1417915
  * thinkpad_acpi: support new BIOS version string pattern
    - LP: #1417915
  * net: sctp: fix slab corruption from use after free on INIT collisions
    - LP: #1416506
    - CVE-2015-1421
  * ipv4: try to cache dst_entries which would cause a redirect
    - LP: #1420027
    - CVE-2015-1465
  * x86, mm/ASLR: Fix stack randomization on 64-bit systems
    - LP: #1423757
    - CVE-2015-1593
  * net: llc: use correct size for sysctl timeout entries
    - LP: #1425271
    - CVE-2015-2041
  * net: rds: use correct size for max unacked packets and bytes
    - LP: #1425274
    - CVE-2015-2042
  * Btrfs: clear compress-force when remounting with compress option
    - LP: #1434183
  * ext4: merge uninitialized extents
    - LP: #1430184
  * btrfs: filter invalid arg for btrfs resize
    - LP: #1435441
  * Bluetooth: Add firmware update for Atheros 0cf3:311f
  * Bluetooth: btusb: Add IMC Networks (Broadcom based)
  * Bluetooth: sort the list of IDs in the source code
  * Bluetooth: append new supported device to the list [0b05:17d0]
  * Bluetooth: Add support for Intel bootloader devices
  * Bluetooth: Ignore isochronous endpoints for Intel USB bootloader
  * Bluetooth: Add support for Acer [13D3:3432]
  * Bluetooth: Add support for Broadcom device of Asus Z97-DELUXE
    motherboard
  * Add a new PID/VID 0227/0930 for AR3012.
  * Bluetooth: Add support for Acer [0489:e078]
  * Bluetooth: Add USB device 04ca:3010 as Atheros AR3012
  * x86: mm: move mmap_sem unlock from mm_fault_error() to caller
  * vm: add VM_FAULT_SIGSEGV handling support
  * vm: make stack guard page errors return VM_FAULT_SIGSEGV rather than
    SIGBUS
  * spi/pxa2xx: Clear cur_chip pointer before starting next message
  * spi: dw: Fix detecting FIFO depth
  * spi: dw-mid: fix FIFO size
  * ASoC: wm8960: Fix capture sample rate from 11250 to 11025
  * regulator: core: fix race condition in regulator_put()
  * ASoC: omap-mcbsp: Correct CBM_CFS dai format configuration
  * can: c_can: end pending transmission on network stop (ifdown)
  * nfs: fix dio deadlock when O_DIRECT flag is flipped
  * NFSv4.1: Fix an Oops in nfs41_...

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.16.0-34.45

---------------
linux (3.16.0-34.45) utopic; urgency=low

  [ Luis Henriques ]

  * Release Tracking Bug
    - LP: #1435400

  [ Andy Whitcroft ]

  * [Packaging] generate live watchdog blacklists
    - LP: #1432837

  [ Chris J Arges ]

  * [Config] Add ibmvfc to d-i
    - LP: #1416001

  [ John Johansen ]

  * SAUCE: (no-up): apparmor: fix mediation of fs unix sockets
    - LP: #1408833

  [ Seth Forshee ]

  * [Config] updateconfigs - enable X86_UP_APIC_MSI

  [ Upstream Kernel Changes ]

  * cdc-acm: add sanity checks
    - LP: #1413992
  * x86: thinkpad_acpi.c: fixed spacing coding style issue
    - LP: #1417915
  * thinkpad_acpi: support new BIOS version string pattern
    - LP: #1417915
  * powernv: Use _GLOBAL_TOC for opal wrappers
    - LP: #1431196
  * Btrfs: clear compress-force when remounting with compress option
    - LP: #1434183
  * Btrfs: send, don't delay dir move if there's a new parent inode
    - LP: #1434223
  * [media] em28xx: fix em28xx-input removal
    - LP: #1434595
  * [media] em28xx: ensure "closing" messages terminate with a newline
    - LP: #1434595
  * [media] em28xx-input: fix missing newlines
    - LP: #1434595
  * [media] em28xx-core: fix missing newlines
    - LP: #1434595
  * [media] em28xx-audio: fix missing newlines
    - LP: #1434595
  * [media] em28xx-audio: fix missing newlines
    - LP: #1434595
  * [media] em28xx-dvb: fix missing newlines
    - LP: #1434595
  * [media] em28xx-video: fix missing newlines
    - LP: #1434595
  * ARM: pxa: add regulator_has_full_constraints to corgi board file
    - LP: #1434595
  * ARM: pxa: add regulator_has_full_constraints to poodle board file
    - LP: #1434595
  * ARM: pxa: add regulator_has_full_constraints to spitz board file
    - LP: #1434595
  * hx4700: regulator: declare full constraints
    - LP: #1434595
  * HID: input: fix confusion on conflicting mappings
    - LP: #1434595
  * HID: fixup the conflicting keyboard mappings quirk
    - LP: #1434595
  * ARM: dts: tegra20: fix GR3D, DSI unit and reg base addresses
    - LP: #1434595
  * megaraid_sas: disable interrupt_mask before enabling hardware
    interrupts
    - LP: #1434595
  * PCI: Generate uppercase hex for modalias var in uevent
    - LP: #1434595
  * usb: core: buffer: smallest buffer should start at ARCH_DMA_MINALIGN
    - LP: #1434595
  * tty/serial: at91: enable peripheral clock before accessing I/O
    registers
    - LP: #1434595
  * tty/serial: at91: fix error handling in atmel_serial_probe()
    - LP: #1434595
  * axonram: Fix bug in direct_access
    - LP: #1434595
  * btrfs: fix leak of path in btrfs_find_item
    - LP: #1434595
  * ksoftirqd: Enable IRQs and call cond_resched() before poking RCU
    - LP: #1434595
  * TPM: Add new TPMs to the tail of the list to prevent inadvertent change
    of dev
    - LP: #1434595
  * char: tpm: Add missing error check for devm_kzalloc
    - LP: #1434595
  * tpm_tis: verify interrupt during init
    - LP: #1434595
  * tpm: Fix NULL return in tpm_ibmvtpm_get_desired_dma
    - LP: #1434595
  * tpm/tpm_i2c_stm_st33: Fix potential bug in tpm_stm_i2c_send
    - LP: #1434595
  * tpm/tpm_i2c_stm_st33:...