linux/include
JP Abgrall cc14b9e149 ANDROID: ext4: Add support for FIDTRIM, a best-effort ioctl for deep discard trim
* What
This provides an interface for issuing an FITRIM which uses the
secure discard instead of just a discard.
Only the eMMC command is "secure", and not how the FS uses it:
due to the fact that the FS might reassign a region somewhere else,
the original deleted data will not be affected by the "trim" which only
handles un-used regions.
So we'll just call it "deep discard", and note that this is a
"best effort" cleanup.

* Why
Once in a while, We want to be able to cleanup most of the unused blocks
after erasing a bunch of files.
We don't want to constantly secure-discard via a mount option.

From an eMMC spec perspective, it tells the device to really get rid of
all the data for the specified blocks and not just put them back into the
pool of free ones (unlike the normal TRIM). The eMMC spec says the
secure trim handling must make sure the data (and metadata) is not available
anymore. A simple TRIM doesn't clear the data, it just puts blocks in the
free pool.
JEDEC Standard No. 84-A441
  7.6.9 Secure Erase
  7.6.10 Secure Trim

From an FS perspective, it is acceptable to leave some data behind.
 - directory entries related to deleted files
 - databases entries related to deleted files
 - small-file data stored in inode extents
 - blocks held by the FS waiting to be re-used (mitigated by sync).
 - blocks reassigned by the FS prior to FIDTRIM.

Change-Id: I676a1404a80130d93930c84898360f2e6fb2f81e
Signed-off-by: Geremy Condra <gcondra@google.com>
Signed-off-by: JP Abgrall <jpa@google.com>
2017-01-27 13:52:25 -08:00
..
acpi Merge branches 'acpica-fixes', 'acpi-cppc-fixes' and 'acpi-tools-fixes' 2016-11-18 21:34:42 +01:00
asm-generic Revert "default exported asm symbols to zero" 2016-12-07 08:39:00 -08:00
clocksource
crypto crypto: drbg - prevent invalid SG mappings 2016-11-30 19:46:44 +08:00
drm drm: Don't force all planes to be added to the state due to zpos 2016-10-26 18:48:05 +02:00
dt-bindings Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2016-10-12 11:05:23 -07:00
keys
kvm
linux ANDROID: hardlockup: detect hard lockups without NMIs using secondary cpus 2017-01-27 13:52:24 -08:00
math-emu
media Linux 4.8 2016-10-05 16:43:53 -03:00
memory
misc
net ANDROID: tcp: add a sysctl to config the tcp_default_init_rwnd 2017-01-19 13:32:34 -08:00
pcmcia
ras
rdma Merge of primary rdma-core code for 4.9 2016-10-09 17:04:33 -07:00
rxrpc
scsi
soc powerpc updates for 4.9 #2 2016-10-14 11:07:42 -07:00
sound ASoC: Updates for v4.9 2016-09-30 18:40:40 +02:00
target target: Make EXTENDED_COPY 0xe4 failure return COPY TARGET DEVICE NOT REACHABLE 2016-10-19 21:22:32 -07:00
trace ANDROID: trace: power: add trace_clock_set_parent 2017-01-27 13:51:43 -08:00
uapi ANDROID: ext4: Add support for FIDTRIM, a best-effort ioctl for deep discard trim 2017-01-27 13:52:25 -08:00
video fbdev changes for 4.9 2016-10-12 11:01:37 -07:00
xen xen: features and fixes for 4.9-rc0 2016-10-06 11:19:10 -07:00
Kbuild