dm: add log writes target
Introduce a new target that is meant for file system developers to test file system integrity at particular points in the life of a file system. We capture all write requests and associated data and log them to a separate device for later replay. There is a userspace utility to do this replay. The idea behind this is to give file system developers a tool to verify that the file system is always consistent. Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Zach Brown <zab@zabbo.net> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Josef Bacik
Mike Snitzer
parent
7f61f5a022
commit
0e9cebe724
|
|
@ -0,0 +1,140 @@
|
||||||
|
dm-log-writes
|
||||||
|
=============
|
||||||
|
|
||||||
|
This target takes 2 devices, one to pass all IO to normally, and one to log all
|
||||||
|
of the write operations to. This is intended for file system developers wishing
|
||||||
|
to verify the integrity of metadata or data as the file system is written to.
|
||||||
|
There is a log_write_entry written for every WRITE request and the target is
|
||||||
|
able to take arbitrary data from userspace to insert into the log. The data
|
||||||
|
that is in the WRITE requests is copied into the log to make the replay happen
|
||||||
|
exactly as it happened originally.
|
||||||
|
|
||||||
|
Log Ordering
|
||||||
|
============
|
||||||
|
|
||||||
|
We log things in order of completion once we are sure the write is no longer in
|
||||||
|
cache. This means that normal WRITE requests are not actually logged until the
|
||||||
|
next REQ_FLUSH request. This is to make it easier for userspace to replay the
|
||||||
|
log in a way that correlates to what is on disk and not what is in cache, to
|
||||||
|
make it easier to detect improper waiting/flushing.
|
||||||
|
|
||||||
|
This works by attaching all WRITE requests to a list once the write completes.
|
||||||
|
Once we see a REQ_FLUSH request we splice this list onto the request and once
|
||||||
|
the FLUSH request completes we log all of the WRITEs and then the FLUSH. Only
|
||||||
|
completed WRITEs, at the time the REQ_FLUSH is issued, are added in order to
|
||||||
|
simulate the worst case scenario with regard to power failures. Consider the
|
||||||
|
following example (W means write, C means complete):
|
||||||
|
|
||||||
|
W1,W2,W3,C3,C2,Wflush,C1,Cflush
|
||||||
|
|
||||||
|
The log would show the following
|
||||||
|
|
||||||
|
W3,W2,flush,W1....
|
||||||
|
|
||||||
|
Again this is to simulate what is actually on disk, this allows us to detect
|
||||||
|
cases where a power failure at a particular point in time would create an
|
||||||
|
inconsistent file system.
|
||||||
|
|
||||||
|
Any REQ_FUA requests bypass this flushing mechanism and are logged as soon as
|
||||||
|
they complete as those requests will obviously bypass the device cache.
|
||||||
|
|
||||||
|
Any REQ_DISCARD requests are treated like WRITE requests. Otherwise we would
|
||||||
|
have all the DISCARD requests, and then the WRITE requests and then the FLUSH
|
||||||
|
request. Consider the following example:
|
||||||
|
|
||||||
|
WRITE block 1, DISCARD block 1, FLUSH
|
||||||
|
|
||||||
|
If we logged DISCARD when it completed, the replay would look like this
|
||||||
|
|
||||||
|
DISCARD 1, WRITE 1, FLUSH
|
||||||
|
|
||||||
|
which isn't quite what happened and wouldn't be caught during the log replay.
|
||||||
|
|
||||||
|
Target interface
|
||||||
|
================
|
||||||
|
|
||||||
|
i) Constructor
|
||||||
|
|
||||||
|
log-writes <dev_path> <log_dev_path>
|
||||||
|
|
||||||
|
dev_path : Device that all of the IO will go to normally.
|
||||||
|
log_dev_path : Device where the log entries are written to.
|
||||||
|
|
||||||
|
ii) Status
|
||||||
|
|
||||||
|
<#logged entries> <highest allocated sector>
|
||||||
|
|
||||||
|
#logged entries : Number of logged entries
|
||||||
|
highest allocated sector : Highest allocated sector
|
||||||
|
|
||||||
|
iii) Messages
|
||||||
|
|
||||||
|
mark <description>
|
||||||
|
|
||||||
|
You can use a dmsetup message to set an arbitrary mark in a log.
|
||||||
|
For example say you want to fsck a file system after every
|
||||||
|
write, but first you need to replay up to the mkfs to make sure
|
||||||
|
we're fsck'ing something reasonable, you would do something like
|
||||||
|
this:
|
||||||
|
|
||||||
|
mkfs.btrfs -f /dev/mapper/log
|
||||||
|
dmsetup message log 0 mark mkfs
|
||||||
|
<run test>
|
||||||
|
|
||||||
|
This would allow you to replay the log up to the mkfs mark and
|
||||||
|
then replay from that point on doing the fsck check in the
|
||||||
|
interval that you want.
|
||||||
|
|
||||||
|
Every log has a mark at the end labeled "dm-log-writes-end".
|
||||||
|
|
||||||
|
Userspace component
|
||||||
|
===================
|
||||||
|
|
||||||
|
There is a userspace tool that will replay the log for you in various ways.
|
||||||
|
It can be found here: https://github.com/josefbacik/log-writes
|
||||||
|
|
||||||
|
Example usage
|
||||||
|
=============
|
||||||
|
|
||||||
|
Say you want to test fsync on your file system. You would do something like
|
||||||
|
this:
|
||||||
|
|
||||||
|
TABLE="0 $(blockdev --getsz /dev/sdb) log-writes /dev/sdb /dev/sdc"
|
||||||
|
dmsetup create log --table "$TABLE"
|
||||||
|
mkfs.btrfs -f /dev/mapper/log
|
||||||
|
dmsetup message log 0 mark mkfs
|
||||||
|
|
||||||
|
mount /dev/mapper/log /mnt/btrfs-test
|
||||||
|
<some test that does fsync at the end>
|
||||||
|
dmsetup message log 0 mark fsync
|
||||||
|
md5sum /mnt/btrfs-test/foo
|
||||||
|
umount /mnt/btrfs-test
|
||||||
|
|
||||||
|
dmsetup remove log
|
||||||
|
replay-log --log /dev/sdc --replay /dev/sdb --end-mark fsync
|
||||||
|
mount /dev/sdb /mnt/btrfs-test
|
||||||
|
md5sum /mnt/btrfs-test/foo
|
||||||
|
<verify md5sum's are correct>
|
||||||
|
|
||||||
|
Another option is to do a complicated file system operation and verify the file
|
||||||
|
system is consistent during the entire operation. You could do this with:
|
||||||
|
|
||||||
|
TABLE="0 $(blockdev --getsz /dev/sdb) log-writes /dev/sdb /dev/sdc"
|
||||||
|
dmsetup create log --table "$TABLE"
|
||||||
|
mkfs.btrfs -f /dev/mapper/log
|
||||||
|
dmsetup message log 0 mark mkfs
|
||||||
|
|
||||||
|
mount /dev/mapper/log /mnt/btrfs-test
|
||||||
|
<fsstress to dirty the fs>
|
||||||
|
btrfs filesystem balance /mnt/btrfs-test
|
||||||
|
umount /mnt/btrfs-test
|
||||||
|
dmsetup remove log
|
||||||
|
|
||||||
|
replay-log --log /dev/sdc --replay /dev/sdb --end-mark mkfs
|
||||||
|
btrfsck /dev/sdb
|
||||||
|
replay-log --log /dev/sdc --replay /dev/sdb --start-mark mkfs \
|
||||||
|
--fsck "btrfsck /dev/sdb" --check fua
|
||||||
|
|
||||||
|
And that will replay the log until it sees a FUA request, run the fsck command
|
||||||
|
and if the fsck passes it will replay to the next FUA, until it is completed or
|
||||||
|
the fsck command exists abnormally.
|
||||||
|
|
@ -443,4 +443,20 @@ config DM_SWITCH
|
||||||
|
|
||||||
If unsure, say N.
|
If unsure, say N.
|
||||||
|
|
||||||
|
config DM_LOG_WRITES
|
||||||
|
tristate "Log writes target support"
|
||||||
|
depends on BLK_DEV_DM
|
||||||
|
---help---
|
||||||
|
This device-mapper target takes two devices, one device to use
|
||||||
|
normally, one to log all write operations done to the first device.
|
||||||
|
This is for use by file system developers wishing to verify that
|
||||||
|
their fs is writing a consitent file system at all times by allowing
|
||||||
|
them to replay the log in a variety of ways and to check the
|
||||||
|
contents.
|
||||||
|
|
||||||
|
To compile this code as a module, choose M here: the module will
|
||||||
|
be called dm-log-writes.
|
||||||
|
|
||||||
|
If unsure, say N.
|
||||||
|
|
||||||
endif # MD
|
endif # MD
|
||||||
|
|
|
||||||
|
|
@ -55,6 +55,7 @@ obj-$(CONFIG_DM_CACHE) += dm-cache.o
|
||||||
obj-$(CONFIG_DM_CACHE_MQ) += dm-cache-mq.o
|
obj-$(CONFIG_DM_CACHE_MQ) += dm-cache-mq.o
|
||||||
obj-$(CONFIG_DM_CACHE_CLEANER) += dm-cache-cleaner.o
|
obj-$(CONFIG_DM_CACHE_CLEANER) += dm-cache-cleaner.o
|
||||||
obj-$(CONFIG_DM_ERA) += dm-era.o
|
obj-$(CONFIG_DM_ERA) += dm-era.o
|
||||||
|
obj-$(CONFIG_DM_LOG_WRITES) += dm-log-writes.o
|
||||||
|
|
||||||
ifeq ($(CONFIG_DM_UEVENT),y)
|
ifeq ($(CONFIG_DM_UEVENT),y)
|
||||||
dm-mod-objs += dm-uevent.o
|
dm-mod-objs += dm-uevent.o
|
||||||
|
|
|
||||||
|
|
@ -0,0 +1,825 @@
|
||||||
|
/*
|
||||||
|
* Copyright (C) 2014 Facebook. All rights reserved.
|
||||||
|
*
|
||||||
|
* This file is released under the GPL.
|
||||||
|
*/
|
||||||
|
|
||||||
|
#include <linux/device-mapper.h>
|
||||||
|
|
||||||
|
#include <linux/module.h>
|
||||||
|
#include <linux/init.h>
|
||||||
|
#include <linux/blkdev.h>
|
||||||
|
#include <linux/bio.h>
|
||||||
|
#include <linux/slab.h>
|
||||||
|
#include <linux/kthread.h>
|
||||||
|
#include <linux/freezer.h>
|
||||||
|
|
||||||
|
#define DM_MSG_PREFIX "log-writes"
|
||||||
|
|
||||||
|
/*
|
||||||
|
* This target will sequentially log all writes to the target device onto the
|
||||||
|
* log device. This is helpful for replaying writes to check for fs consistency
|
||||||
|
* at all times. This target provides a mechanism to mark specific events to
|
||||||
|
* check data at a later time. So for example you would:
|
||||||
|
*
|
||||||
|
* write data
|
||||||
|
* fsync
|
||||||
|
* dmsetup message /dev/whatever mark mymark
|
||||||
|
* unmount /mnt/test
|
||||||
|
*
|
||||||
|
* Then replay the log up to mymark and check the contents of the replay to
|
||||||
|
* verify it matches what was written.
|
||||||
|
*
|
||||||
|
* We log writes only after they have been flushed, this makes the log describe
|
||||||
|
* close to the order in which the data hits the actual disk, not its cache. So
|
||||||
|
* for example the following sequence (W means write, C means complete)
|
||||||
|
*
|
||||||
|
* Wa,Wb,Wc,Cc,Ca,FLUSH,FUAd,Cb,CFLUSH,CFUAd
|
||||||
|
*
|
||||||
|
* Would result in the log looking like this:
|
||||||
|
*
|
||||||
|
* c,a,flush,fuad,b,<other writes>,<next flush>
|
||||||
|
*
|
||||||
|
* This is meant to help expose problems where file systems do not properly wait
|
||||||
|
* on data being written before invoking a FLUSH. FUA bypasses cache so once it
|
||||||
|
* completes it is added to the log as it should be on disk.
|
||||||
|
*
|
||||||
|
* We treat DISCARDs as if they don't bypass cache so that they are logged in
|
||||||
|
* order of completion along with the normal writes. If we didn't do it this
|
||||||
|
* way we would process all the discards first and then write all the data, when
|
||||||
|
* in fact we want to do the data and the discard in the order that they
|
||||||
|
* completed.
|
||||||
|
*/
|
||||||
|
#define LOG_FLUSH_FLAG (1 << 0)
|
||||||
|
#define LOG_FUA_FLAG (1 << 1)
|
||||||
|
#define LOG_DISCARD_FLAG (1 << 2)
|
||||||
|
#define LOG_MARK_FLAG (1 << 3)
|
||||||
|
|
||||||
|
#define WRITE_LOG_VERSION 1
|
||||||
|
#define WRITE_LOG_MAGIC 0x6a736677736872
|
||||||
|
|
||||||
|
/*
|
||||||
|
* The disk format for this is braindead simple.
|
||||||
|
*
|
||||||
|
* At byte 0 we have our super, followed by the following sequence for
|
||||||
|
* nr_entries:
|
||||||
|
*
|
||||||
|
* [ 1 sector ][ entry->nr_sectors ]
|
||||||
|
* [log_write_entry][ data written ]
|
||||||
|
*
|
||||||
|
* The log_write_entry takes up a full sector so we can have arbitrary length
|
||||||
|
* marks and it leaves us room for extra content in the future.
|
||||||
|
*/
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Basic info about the log for userspace.
|
||||||
|
*/
|
||||||
|
struct log_write_super {
|
||||||
|
__le64 magic;
|
||||||
|
__le64 version;
|
||||||
|
__le64 nr_entries;
|
||||||
|
__le32 sectorsize;
|
||||||
|
};
|
||||||
|
|
||||||
|
/*
|
||||||
|
* sector - the sector we wrote.
|
||||||
|
* nr_sectors - the number of sectors we wrote.
|
||||||
|
* flags - flags for this log entry.
|
||||||
|
* data_len - the size of the data in this log entry, this is for private log
|
||||||
|
* entry stuff, the MARK data provided by userspace for example.
|
||||||
|
*/
|
||||||
|
struct log_write_entry {
|
||||||
|
__le64 sector;
|
||||||
|
__le64 nr_sectors;
|
||||||
|
__le64 flags;
|
||||||
|
__le64 data_len;
|
||||||
|
};
|
||||||
|
|
||||||
|
struct log_writes_c {
|
||||||
|
struct dm_dev *dev;
|
||||||
|
struct dm_dev *logdev;
|
||||||
|
u64 logged_entries;
|
||||||
|
u32 sectorsize;
|
||||||
|
atomic_t io_blocks;
|
||||||
|
atomic_t pending_blocks;
|
||||||
|
sector_t next_sector;
|
||||||
|
sector_t end_sector;
|
||||||
|
bool logging_enabled;
|
||||||
|
bool device_supports_discard;
|
||||||
|
spinlock_t blocks_lock;
|
||||||
|
struct list_head unflushed_blocks;
|
||||||
|
struct list_head logging_blocks;
|
||||||
|
wait_queue_head_t wait;
|
||||||
|
struct task_struct *log_kthread;
|
||||||
|
};
|
||||||
|
|
||||||
|
struct pending_block {
|
||||||
|
int vec_cnt;
|
||||||
|
u64 flags;
|
||||||
|
sector_t sector;
|
||||||
|
sector_t nr_sectors;
|
||||||
|
char *data;
|
||||||
|
u32 datalen;
|
||||||
|
struct list_head list;
|
||||||
|
struct bio_vec vecs[0];
|
||||||
|
};
|
||||||
|
|
||||||
|
struct per_bio_data {
|
||||||
|
struct pending_block *block;
|
||||||
|
};
|
||||||
|
|
||||||
|
static void put_pending_block(struct log_writes_c *lc)
|
||||||
|
{
|
||||||
|
if (atomic_dec_and_test(&lc->pending_blocks)) {
|
||||||
|
smp_mb__after_atomic();
|
||||||
|
if (waitqueue_active(&lc->wait))
|
||||||
|
wake_up(&lc->wait);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
static void put_io_block(struct log_writes_c *lc)
|
||||||
|
{
|
||||||
|
if (atomic_dec_and_test(&lc->io_blocks)) {
|
||||||
|
smp_mb__after_atomic();
|
||||||
|
if (waitqueue_active(&lc->wait))
|
||||||
|
wake_up(&lc->wait);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
static void log_end_io(struct bio *bio, int err)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = bio->bi_private;
|
||||||
|
struct bio_vec *bvec;
|
||||||
|
int i;
|
||||||
|
|
||||||
|
if (err) {
|
||||||
|
unsigned long flags;
|
||||||
|
|
||||||
|
DMERR("Error writing log block, error=%d", err);
|
||||||
|
spin_lock_irqsave(&lc->blocks_lock, flags);
|
||||||
|
lc->logging_enabled = false;
|
||||||
|
spin_unlock_irqrestore(&lc->blocks_lock, flags);
|
||||||
|
}
|
||||||
|
|
||||||
|
bio_for_each_segment_all(bvec, bio, i)
|
||||||
|
__free_page(bvec->bv_page);
|
||||||
|
|
||||||
|
put_io_block(lc);
|
||||||
|
bio_put(bio);
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Meant to be called if there is an error, it will free all the pages
|
||||||
|
* associated with the block.
|
||||||
|
*/
|
||||||
|
static void free_pending_block(struct log_writes_c *lc,
|
||||||
|
struct pending_block *block)
|
||||||
|
{
|
||||||
|
int i;
|
||||||
|
|
||||||
|
for (i = 0; i < block->vec_cnt; i++) {
|
||||||
|
if (block->vecs[i].bv_page)
|
||||||
|
__free_page(block->vecs[i].bv_page);
|
||||||
|
}
|
||||||
|
kfree(block->data);
|
||||||
|
kfree(block);
|
||||||
|
put_pending_block(lc);
|
||||||
|
}
|
||||||
|
|
||||||
|
static int write_metadata(struct log_writes_c *lc, void *entry,
|
||||||
|
size_t entrylen, void *data, size_t datalen,
|
||||||
|
sector_t sector)
|
||||||
|
{
|
||||||
|
struct bio *bio;
|
||||||
|
struct page *page;
|
||||||
|
void *ptr;
|
||||||
|
size_t ret;
|
||||||
|
|
||||||
|
bio = bio_alloc(GFP_KERNEL, 1);
|
||||||
|
if (!bio) {
|
||||||
|
DMERR("Couldn't alloc log bio");
|
||||||
|
goto error;
|
||||||
|
}
|
||||||
|
bio->bi_iter.bi_size = 0;
|
||||||
|
bio->bi_iter.bi_sector = sector;
|
||||||
|
bio->bi_bdev = lc->logdev->bdev;
|
||||||
|
bio->bi_end_io = log_end_io;
|
||||||
|
bio->bi_private = lc;
|
||||||
|
set_bit(BIO_UPTODATE, &bio->bi_flags);
|
||||||
|
|
||||||
|
page = alloc_page(GFP_KERNEL);
|
||||||
|
if (!page) {
|
||||||
|
DMERR("Couldn't alloc log page");
|
||||||
|
bio_put(bio);
|
||||||
|
goto error;
|
||||||
|
}
|
||||||
|
|
||||||
|
ptr = kmap_atomic(page);
|
||||||
|
memcpy(ptr, entry, entrylen);
|
||||||
|
if (datalen)
|
||||||
|
memcpy(ptr + entrylen, data, datalen);
|
||||||
|
memset(ptr + entrylen + datalen, 0,
|
||||||
|
lc->sectorsize - entrylen - datalen);
|
||||||
|
kunmap_atomic(ptr);
|
||||||
|
|
||||||
|
ret = bio_add_page(bio, page, lc->sectorsize, 0);
|
||||||
|
if (ret != lc->sectorsize) {
|
||||||
|
DMERR("Couldn't add page to the log block");
|
||||||
|
goto error_bio;
|
||||||
|
}
|
||||||
|
submit_bio(WRITE, bio);
|
||||||
|
return 0;
|
||||||
|
error_bio:
|
||||||
|
bio_put(bio);
|
||||||
|
__free_page(page);
|
||||||
|
error:
|
||||||
|
put_io_block(lc);
|
||||||
|
return -1;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_one_block(struct log_writes_c *lc,
|
||||||
|
struct pending_block *block, sector_t sector)
|
||||||
|
{
|
||||||
|
struct bio *bio;
|
||||||
|
struct log_write_entry entry;
|
||||||
|
size_t ret;
|
||||||
|
int i;
|
||||||
|
|
||||||
|
entry.sector = cpu_to_le64(block->sector);
|
||||||
|
entry.nr_sectors = cpu_to_le64(block->nr_sectors);
|
||||||
|
entry.flags = cpu_to_le64(block->flags);
|
||||||
|
entry.data_len = cpu_to_le64(block->datalen);
|
||||||
|
if (write_metadata(lc, &entry, sizeof(entry), block->data,
|
||||||
|
block->datalen, sector)) {
|
||||||
|
free_pending_block(lc, block);
|
||||||
|
return -1;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (!block->vec_cnt)
|
||||||
|
goto out;
|
||||||
|
sector++;
|
||||||
|
|
||||||
|
bio = bio_alloc(GFP_KERNEL, block->vec_cnt);
|
||||||
|
if (!bio) {
|
||||||
|
DMERR("Couldn't alloc log bio");
|
||||||
|
goto error;
|
||||||
|
}
|
||||||
|
atomic_inc(&lc->io_blocks);
|
||||||
|
bio->bi_iter.bi_size = 0;
|
||||||
|
bio->bi_iter.bi_sector = sector;
|
||||||
|
bio->bi_bdev = lc->logdev->bdev;
|
||||||
|
bio->bi_end_io = log_end_io;
|
||||||
|
bio->bi_private = lc;
|
||||||
|
set_bit(BIO_UPTODATE, &bio->bi_flags);
|
||||||
|
|
||||||
|
for (i = 0; i < block->vec_cnt; i++) {
|
||||||
|
/*
|
||||||
|
* The page offset is always 0 because we allocate a new page
|
||||||
|
* for every bvec in the original bio for simplicity sake.
|
||||||
|
*/
|
||||||
|
ret = bio_add_page(bio, block->vecs[i].bv_page,
|
||||||
|
block->vecs[i].bv_len, 0);
|
||||||
|
if (ret != block->vecs[i].bv_len) {
|
||||||
|
atomic_inc(&lc->io_blocks);
|
||||||
|
submit_bio(WRITE, bio);
|
||||||
|
bio = bio_alloc(GFP_KERNEL, block->vec_cnt - i);
|
||||||
|
if (!bio) {
|
||||||
|
DMERR("Couldn't alloc log bio");
|
||||||
|
goto error;
|
||||||
|
}
|
||||||
|
bio->bi_iter.bi_size = 0;
|
||||||
|
bio->bi_iter.bi_sector = sector;
|
||||||
|
bio->bi_bdev = lc->logdev->bdev;
|
||||||
|
bio->bi_end_io = log_end_io;
|
||||||
|
bio->bi_private = lc;
|
||||||
|
set_bit(BIO_UPTODATE, &bio->bi_flags);
|
||||||
|
|
||||||
|
ret = bio_add_page(bio, block->vecs[i].bv_page,
|
||||||
|
block->vecs[i].bv_len, 0);
|
||||||
|
if (ret != block->vecs[i].bv_len) {
|
||||||
|
DMERR("Couldn't add page on new bio?");
|
||||||
|
bio_put(bio);
|
||||||
|
goto error;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
sector += block->vecs[i].bv_len >> SECTOR_SHIFT;
|
||||||
|
}
|
||||||
|
submit_bio(WRITE, bio);
|
||||||
|
out:
|
||||||
|
kfree(block->data);
|
||||||
|
kfree(block);
|
||||||
|
put_pending_block(lc);
|
||||||
|
return 0;
|
||||||
|
error:
|
||||||
|
free_pending_block(lc, block);
|
||||||
|
put_io_block(lc);
|
||||||
|
return -1;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_super(struct log_writes_c *lc)
|
||||||
|
{
|
||||||
|
struct log_write_super super;
|
||||||
|
|
||||||
|
super.magic = cpu_to_le64(WRITE_LOG_MAGIC);
|
||||||
|
super.version = cpu_to_le64(WRITE_LOG_VERSION);
|
||||||
|
super.nr_entries = cpu_to_le64(lc->logged_entries);
|
||||||
|
super.sectorsize = cpu_to_le32(lc->sectorsize);
|
||||||
|
|
||||||
|
if (write_metadata(lc, &super, sizeof(super), NULL, 0, 0)) {
|
||||||
|
DMERR("Couldn't write super");
|
||||||
|
return -1;
|
||||||
|
}
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static inline sector_t logdev_last_sector(struct log_writes_c *lc)
|
||||||
|
{
|
||||||
|
return i_size_read(lc->logdev->bdev->bd_inode) >> SECTOR_SHIFT;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_writes_kthread(void *arg)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = (struct log_writes_c *)arg;
|
||||||
|
sector_t sector = 0;
|
||||||
|
|
||||||
|
while (!kthread_should_stop()) {
|
||||||
|
bool super = false;
|
||||||
|
bool logging_enabled;
|
||||||
|
struct pending_block *block = NULL;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
if (!list_empty(&lc->logging_blocks)) {
|
||||||
|
block = list_first_entry(&lc->logging_blocks,
|
||||||
|
struct pending_block, list);
|
||||||
|
list_del_init(&block->list);
|
||||||
|
if (!lc->logging_enabled)
|
||||||
|
goto next;
|
||||||
|
|
||||||
|
sector = lc->next_sector;
|
||||||
|
if (block->flags & LOG_DISCARD_FLAG)
|
||||||
|
lc->next_sector++;
|
||||||
|
else
|
||||||
|
lc->next_sector += block->nr_sectors + 1;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Apparently the size of the device may not be known
|
||||||
|
* right away, so handle this properly.
|
||||||
|
*/
|
||||||
|
if (!lc->end_sector)
|
||||||
|
lc->end_sector = logdev_last_sector(lc);
|
||||||
|
if (lc->end_sector &&
|
||||||
|
lc->next_sector >= lc->end_sector) {
|
||||||
|
DMERR("Ran out of space on the logdev");
|
||||||
|
lc->logging_enabled = false;
|
||||||
|
goto next;
|
||||||
|
}
|
||||||
|
lc->logged_entries++;
|
||||||
|
atomic_inc(&lc->io_blocks);
|
||||||
|
|
||||||
|
super = (block->flags & (LOG_FUA_FLAG | LOG_MARK_FLAG));
|
||||||
|
if (super)
|
||||||
|
atomic_inc(&lc->io_blocks);
|
||||||
|
}
|
||||||
|
next:
|
||||||
|
logging_enabled = lc->logging_enabled;
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
if (block) {
|
||||||
|
if (logging_enabled) {
|
||||||
|
ret = log_one_block(lc, block, sector);
|
||||||
|
if (!ret && super)
|
||||||
|
ret = log_super(lc);
|
||||||
|
if (ret) {
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
lc->logging_enabled = false;
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
}
|
||||||
|
} else
|
||||||
|
free_pending_block(lc, block);
|
||||||
|
continue;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (!try_to_freeze()) {
|
||||||
|
set_current_state(TASK_INTERRUPTIBLE);
|
||||||
|
if (!kthread_should_stop() &&
|
||||||
|
!atomic_read(&lc->pending_blocks))
|
||||||
|
schedule();
|
||||||
|
__set_current_state(TASK_RUNNING);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Construct a log-writes mapping:
|
||||||
|
* log-writes <dev_path> <log_dev_path>
|
||||||
|
*/
|
||||||
|
static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc;
|
||||||
|
struct dm_arg_set as;
|
||||||
|
const char *devname, *logdevname;
|
||||||
|
|
||||||
|
as.argc = argc;
|
||||||
|
as.argv = argv;
|
||||||
|
|
||||||
|
if (argc < 2) {
|
||||||
|
ti->error = "Invalid argument count";
|
||||||
|
return -EINVAL;
|
||||||
|
}
|
||||||
|
|
||||||
|
lc = kzalloc(sizeof(struct log_writes_c), GFP_KERNEL);
|
||||||
|
if (!lc) {
|
||||||
|
ti->error = "Cannot allocate context";
|
||||||
|
return -ENOMEM;
|
||||||
|
}
|
||||||
|
spin_lock_init(&lc->blocks_lock);
|
||||||
|
INIT_LIST_HEAD(&lc->unflushed_blocks);
|
||||||
|
INIT_LIST_HEAD(&lc->logging_blocks);
|
||||||
|
init_waitqueue_head(&lc->wait);
|
||||||
|
lc->sectorsize = 1 << SECTOR_SHIFT;
|
||||||
|
atomic_set(&lc->io_blocks, 0);
|
||||||
|
atomic_set(&lc->pending_blocks, 0);
|
||||||
|
|
||||||
|
devname = dm_shift_arg(&as);
|
||||||
|
if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &lc->dev)) {
|
||||||
|
ti->error = "Device lookup failed";
|
||||||
|
goto bad;
|
||||||
|
}
|
||||||
|
|
||||||
|
logdevname = dm_shift_arg(&as);
|
||||||
|
if (dm_get_device(ti, logdevname, dm_table_get_mode(ti->table), &lc->logdev)) {
|
||||||
|
ti->error = "Log device lookup failed";
|
||||||
|
dm_put_device(ti, lc->dev);
|
||||||
|
goto bad;
|
||||||
|
}
|
||||||
|
|
||||||
|
lc->log_kthread = kthread_run(log_writes_kthread, lc, "log-write");
|
||||||
|
if (!lc->log_kthread) {
|
||||||
|
ti->error = "Couldn't alloc kthread";
|
||||||
|
dm_put_device(ti, lc->dev);
|
||||||
|
dm_put_device(ti, lc->logdev);
|
||||||
|
goto bad;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* We put the super at sector 0, start logging at sector 1 */
|
||||||
|
lc->next_sector = 1;
|
||||||
|
lc->logging_enabled = true;
|
||||||
|
lc->end_sector = logdev_last_sector(lc);
|
||||||
|
lc->device_supports_discard = true;
|
||||||
|
|
||||||
|
ti->num_flush_bios = 1;
|
||||||
|
ti->flush_supported = true;
|
||||||
|
ti->num_discard_bios = 1;
|
||||||
|
ti->discards_supported = true;
|
||||||
|
ti->per_bio_data_size = sizeof(struct per_bio_data);
|
||||||
|
ti->private = lc;
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
bad:
|
||||||
|
kfree(lc);
|
||||||
|
return -EINVAL;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_mark(struct log_writes_c *lc, char *data)
|
||||||
|
{
|
||||||
|
struct pending_block *block;
|
||||||
|
size_t maxsize = lc->sectorsize - sizeof(struct log_write_entry);
|
||||||
|
|
||||||
|
block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
|
||||||
|
if (!block) {
|
||||||
|
DMERR("Error allocating pending block");
|
||||||
|
return -ENOMEM;
|
||||||
|
}
|
||||||
|
|
||||||
|
block->data = kstrndup(data, maxsize, GFP_KERNEL);
|
||||||
|
if (!block->data) {
|
||||||
|
DMERR("Error copying mark data");
|
||||||
|
kfree(block);
|
||||||
|
return -ENOMEM;
|
||||||
|
}
|
||||||
|
atomic_inc(&lc->pending_blocks);
|
||||||
|
block->datalen = strlen(block->data);
|
||||||
|
block->flags |= LOG_MARK_FLAG;
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
list_add_tail(&block->list, &lc->logging_blocks);
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
wake_up_process(lc->log_kthread);
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static void log_writes_dtr(struct dm_target *ti)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
list_splice_init(&lc->unflushed_blocks, &lc->logging_blocks);
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* This is just nice to have since it'll update the super to include the
|
||||||
|
* unflushed blocks, if it fails we don't really care.
|
||||||
|
*/
|
||||||
|
log_mark(lc, "dm-log-writes-end");
|
||||||
|
wake_up_process(lc->log_kthread);
|
||||||
|
wait_event(lc->wait, !atomic_read(&lc->io_blocks) &&
|
||||||
|
!atomic_read(&lc->pending_blocks));
|
||||||
|
kthread_stop(lc->log_kthread);
|
||||||
|
|
||||||
|
WARN_ON(!list_empty(&lc->logging_blocks));
|
||||||
|
WARN_ON(!list_empty(&lc->unflushed_blocks));
|
||||||
|
dm_put_device(ti, lc->dev);
|
||||||
|
dm_put_device(ti, lc->logdev);
|
||||||
|
kfree(lc);
|
||||||
|
}
|
||||||
|
|
||||||
|
static void normal_map_bio(struct dm_target *ti, struct bio *bio)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
|
||||||
|
bio->bi_bdev = lc->dev->bdev;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_writes_map(struct dm_target *ti, struct bio *bio)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
|
||||||
|
struct pending_block *block;
|
||||||
|
struct bvec_iter iter;
|
||||||
|
struct bio_vec bv;
|
||||||
|
size_t alloc_size;
|
||||||
|
int i = 0;
|
||||||
|
bool flush_bio = (bio->bi_rw & REQ_FLUSH);
|
||||||
|
bool fua_bio = (bio->bi_rw & REQ_FUA);
|
||||||
|
bool discard_bio = (bio->bi_rw & REQ_DISCARD);
|
||||||
|
|
||||||
|
pb->block = NULL;
|
||||||
|
|
||||||
|
/* Don't bother doing anything if logging has been disabled */
|
||||||
|
if (!lc->logging_enabled)
|
||||||
|
goto map_bio;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Map reads as normal.
|
||||||
|
*/
|
||||||
|
if (bio_data_dir(bio) == READ)
|
||||||
|
goto map_bio;
|
||||||
|
|
||||||
|
/* No sectors and not a flush? Don't care */
|
||||||
|
if (!bio_sectors(bio) && !flush_bio)
|
||||||
|
goto map_bio;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Discards will have bi_size set but there's no actual data, so just
|
||||||
|
* allocate the size of the pending block.
|
||||||
|
*/
|
||||||
|
if (discard_bio)
|
||||||
|
alloc_size = sizeof(struct pending_block);
|
||||||
|
else
|
||||||
|
alloc_size = sizeof(struct pending_block) + sizeof(struct bio_vec) * bio_segments(bio);
|
||||||
|
|
||||||
|
block = kzalloc(alloc_size, GFP_NOIO);
|
||||||
|
if (!block) {
|
||||||
|
DMERR("Error allocating pending block");
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
lc->logging_enabled = false;
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
return -ENOMEM;
|
||||||
|
}
|
||||||
|
INIT_LIST_HEAD(&block->list);
|
||||||
|
pb->block = block;
|
||||||
|
atomic_inc(&lc->pending_blocks);
|
||||||
|
|
||||||
|
if (flush_bio)
|
||||||
|
block->flags |= LOG_FLUSH_FLAG;
|
||||||
|
if (fua_bio)
|
||||||
|
block->flags |= LOG_FUA_FLAG;
|
||||||
|
if (discard_bio)
|
||||||
|
block->flags |= LOG_DISCARD_FLAG;
|
||||||
|
|
||||||
|
block->sector = bio->bi_iter.bi_sector;
|
||||||
|
block->nr_sectors = bio_sectors(bio);
|
||||||
|
|
||||||
|
/* We don't need the data, just submit */
|
||||||
|
if (discard_bio) {
|
||||||
|
WARN_ON(flush_bio || fua_bio);
|
||||||
|
if (lc->device_supports_discard)
|
||||||
|
goto map_bio;
|
||||||
|
bio_endio(bio, 0);
|
||||||
|
return DM_MAPIO_SUBMITTED;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Flush bio, splice the unflushed blocks onto this list and submit */
|
||||||
|
if (flush_bio && !bio_sectors(bio)) {
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
list_splice_init(&lc->unflushed_blocks, &block->list);
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
goto map_bio;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* We will write this bio somewhere else way later so we need to copy
|
||||||
|
* the actual contents into new pages so we know the data will always be
|
||||||
|
* there.
|
||||||
|
*
|
||||||
|
* We do this because this could be a bio from O_DIRECT in which case we
|
||||||
|
* can't just hold onto the page until some later point, we have to
|
||||||
|
* manually copy the contents.
|
||||||
|
*/
|
||||||
|
bio_for_each_segment(bv, bio, iter) {
|
||||||
|
struct page *page;
|
||||||
|
void *src, *dst;
|
||||||
|
|
||||||
|
page = alloc_page(GFP_NOIO);
|
||||||
|
if (!page) {
|
||||||
|
DMERR("Error allocing page");
|
||||||
|
free_pending_block(lc, block);
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
lc->logging_enabled = false;
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
return -ENOMEM;
|
||||||
|
}
|
||||||
|
|
||||||
|
src = kmap_atomic(bv.bv_page);
|
||||||
|
dst = kmap_atomic(page);
|
||||||
|
memcpy(dst, src + bv.bv_offset, bv.bv_len);
|
||||||
|
kunmap_atomic(dst);
|
||||||
|
kunmap_atomic(src);
|
||||||
|
block->vecs[i].bv_page = page;
|
||||||
|
block->vecs[i].bv_len = bv.bv_len;
|
||||||
|
block->vec_cnt++;
|
||||||
|
i++;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Had a flush with data in it, weird */
|
||||||
|
if (flush_bio) {
|
||||||
|
spin_lock_irq(&lc->blocks_lock);
|
||||||
|
list_splice_init(&lc->unflushed_blocks, &block->list);
|
||||||
|
spin_unlock_irq(&lc->blocks_lock);
|
||||||
|
}
|
||||||
|
map_bio:
|
||||||
|
normal_map_bio(ti, bio);
|
||||||
|
return DM_MAPIO_REMAPPED;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int normal_end_io(struct dm_target *ti, struct bio *bio, int error)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
|
||||||
|
|
||||||
|
if (bio_data_dir(bio) == WRITE && pb->block) {
|
||||||
|
struct pending_block *block = pb->block;
|
||||||
|
unsigned long flags;
|
||||||
|
|
||||||
|
spin_lock_irqsave(&lc->blocks_lock, flags);
|
||||||
|
if (block->flags & LOG_FLUSH_FLAG) {
|
||||||
|
list_splice_tail_init(&block->list, &lc->logging_blocks);
|
||||||
|
list_add_tail(&block->list, &lc->logging_blocks);
|
||||||
|
wake_up_process(lc->log_kthread);
|
||||||
|
} else if (block->flags & LOG_FUA_FLAG) {
|
||||||
|
list_add_tail(&block->list, &lc->logging_blocks);
|
||||||
|
wake_up_process(lc->log_kthread);
|
||||||
|
} else
|
||||||
|
list_add_tail(&block->list, &lc->unflushed_blocks);
|
||||||
|
spin_unlock_irqrestore(&lc->blocks_lock, flags);
|
||||||
|
}
|
||||||
|
|
||||||
|
return error;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* INFO format: <logged entries> <highest allocated sector>
|
||||||
|
*/
|
||||||
|
static void log_writes_status(struct dm_target *ti, status_type_t type,
|
||||||
|
unsigned status_flags, char *result,
|
||||||
|
unsigned maxlen)
|
||||||
|
{
|
||||||
|
unsigned sz = 0;
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
|
||||||
|
switch (type) {
|
||||||
|
case STATUSTYPE_INFO:
|
||||||
|
DMEMIT("%llu %llu", lc->logged_entries,
|
||||||
|
(unsigned long long)lc->next_sector - 1);
|
||||||
|
if (!lc->logging_enabled)
|
||||||
|
DMEMIT(" logging_disabled");
|
||||||
|
break;
|
||||||
|
|
||||||
|
case STATUSTYPE_TABLE:
|
||||||
|
DMEMIT("%s %s", lc->dev->name, lc->logdev->name);
|
||||||
|
break;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_writes_ioctl(struct dm_target *ti, unsigned int cmd,
|
||||||
|
unsigned long arg)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
struct dm_dev *dev = lc->dev;
|
||||||
|
int r = 0;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Only pass ioctls through if the device sizes match exactly.
|
||||||
|
*/
|
||||||
|
if (ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
|
||||||
|
r = scsi_verify_blk_ioctl(NULL, cmd);
|
||||||
|
|
||||||
|
return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_writes_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
|
||||||
|
struct bio_vec *biovec, int max_size)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
struct request_queue *q = bdev_get_queue(lc->dev->bdev);
|
||||||
|
|
||||||
|
if (!q->merge_bvec_fn)
|
||||||
|
return max_size;
|
||||||
|
|
||||||
|
bvm->bi_bdev = lc->dev->bdev;
|
||||||
|
bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
|
||||||
|
|
||||||
|
return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
|
||||||
|
}
|
||||||
|
|
||||||
|
static int log_writes_iterate_devices(struct dm_target *ti,
|
||||||
|
iterate_devices_callout_fn fn,
|
||||||
|
void *data)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
|
||||||
|
return fn(ti, lc->dev, 0, ti->len, data);
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Messages supported:
|
||||||
|
* mark <mark data> - specify the marked data.
|
||||||
|
*/
|
||||||
|
static int log_writes_message(struct dm_target *ti, unsigned argc, char **argv)
|
||||||
|
{
|
||||||
|
int r = -EINVAL;
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
|
||||||
|
if (argc != 2) {
|
||||||
|
DMWARN("Invalid log-writes message arguments, expect 2 arguments, got %d", argc);
|
||||||
|
return r;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (!strcasecmp(argv[0], "mark"))
|
||||||
|
r = log_mark(lc, argv[1]);
|
||||||
|
else
|
||||||
|
DMWARN("Unrecognised log writes target message received: %s", argv[0]);
|
||||||
|
|
||||||
|
return r;
|
||||||
|
}
|
||||||
|
|
||||||
|
static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limits)
|
||||||
|
{
|
||||||
|
struct log_writes_c *lc = ti->private;
|
||||||
|
struct request_queue *q = bdev_get_queue(lc->dev->bdev);
|
||||||
|
|
||||||
|
if (!q || !blk_queue_discard(q)) {
|
||||||
|
lc->device_supports_discard = false;
|
||||||
|
limits->discard_granularity = 1 << SECTOR_SHIFT;
|
||||||
|
limits->max_discard_sectors = (UINT_MAX >> SECTOR_SHIFT);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
static struct target_type log_writes_target = {
|
||||||
|
.name = "log-writes",
|
||||||
|
.version = {1, 0, 0},
|
||||||
|
.module = THIS_MODULE,
|
||||||
|
.ctr = log_writes_ctr,
|
||||||
|
.dtr = log_writes_dtr,
|
||||||
|
.map = log_writes_map,
|
||||||
|
.end_io = normal_end_io,
|
||||||
|
.status = log_writes_status,
|
||||||
|
.ioctl = log_writes_ioctl,
|
||||||
|
.merge = log_writes_merge,
|
||||||
|
.message = log_writes_message,
|
||||||
|
.iterate_devices = log_writes_iterate_devices,
|
||||||
|
.io_hints = log_writes_io_hints,
|
||||||
|
};
|
||||||
|
|
||||||
|
static int __init dm_log_writes_init(void)
|
||||||
|
{
|
||||||
|
int r = dm_register_target(&log_writes_target);
|
||||||
|
|
||||||
|
if (r < 0)
|
||||||
|
DMERR("register failed %d", r);
|
||||||
|
|
||||||
|
return r;
|
||||||
|
}
|
||||||
|
|
||||||
|
static void __exit dm_log_writes_exit(void)
|
||||||
|
{
|
||||||
|
dm_unregister_target(&log_writes_target);
|
||||||
|
}
|
||||||
|
|
||||||
|
module_init(dm_log_writes_init);
|
||||||
|
module_exit(dm_log_writes_exit);
|
||||||
|
|
||||||
|
MODULE_DESCRIPTION(DM_NAME " log writes target");
|
||||||
|
MODULE_AUTHOR("Josef Bacik <jbacik@fb.com>");
|
||||||
|
MODULE_LICENSE("GPL");
|
||||||
Loading…
Reference in New Issue