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![Vladimir Zapolskiy](/assets/img/avatar_default.png)
The kthread_run() function returns either a valid task_struct or ERR_PTR() value, check for NULL is invalid. This change fixes potential for oops, e.g. in OOM situation. Signed-off-by: Vladimir Zapolskiy <vz@mleia.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
813 lines
20 KiB
C
813 lines
20 KiB
C
/*
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* Copyright (C) 2014 Facebook. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#include <linux/device-mapper.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/blkdev.h>
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#include <linux/bio.h>
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#include <linux/slab.h>
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#include <linux/kthread.h>
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#include <linux/freezer.h>
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#define DM_MSG_PREFIX "log-writes"
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/*
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* This target will sequentially log all writes to the target device onto the
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* log device. This is helpful for replaying writes to check for fs consistency
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* at all times. This target provides a mechanism to mark specific events to
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* check data at a later time. So for example you would:
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*
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* write data
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* fsync
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* dmsetup message /dev/whatever mark mymark
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* unmount /mnt/test
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*
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* Then replay the log up to mymark and check the contents of the replay to
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* verify it matches what was written.
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*
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* We log writes only after they have been flushed, this makes the log describe
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* close to the order in which the data hits the actual disk, not its cache. So
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* for example the following sequence (W means write, C means complete)
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*
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* Wa,Wb,Wc,Cc,Ca,FLUSH,FUAd,Cb,CFLUSH,CFUAd
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*
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* Would result in the log looking like this:
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*
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* c,a,flush,fuad,b,<other writes>,<next flush>
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*
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* This is meant to help expose problems where file systems do not properly wait
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* on data being written before invoking a FLUSH. FUA bypasses cache so once it
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* completes it is added to the log as it should be on disk.
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*
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* We treat DISCARDs as if they don't bypass cache so that they are logged in
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* order of completion along with the normal writes. If we didn't do it this
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* way we would process all the discards first and then write all the data, when
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* in fact we want to do the data and the discard in the order that they
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* completed.
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*/
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#define LOG_FLUSH_FLAG (1 << 0)
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#define LOG_FUA_FLAG (1 << 1)
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#define LOG_DISCARD_FLAG (1 << 2)
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#define LOG_MARK_FLAG (1 << 3)
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#define WRITE_LOG_VERSION 1ULL
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#define WRITE_LOG_MAGIC 0x6a736677736872ULL
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/*
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* The disk format for this is braindead simple.
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*
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* At byte 0 we have our super, followed by the following sequence for
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* nr_entries:
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*
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* [ 1 sector ][ entry->nr_sectors ]
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* [log_write_entry][ data written ]
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*
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* The log_write_entry takes up a full sector so we can have arbitrary length
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* marks and it leaves us room for extra content in the future.
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*/
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/*
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* Basic info about the log for userspace.
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*/
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struct log_write_super {
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__le64 magic;
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__le64 version;
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__le64 nr_entries;
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__le32 sectorsize;
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};
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/*
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* sector - the sector we wrote.
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* nr_sectors - the number of sectors we wrote.
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* flags - flags for this log entry.
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* data_len - the size of the data in this log entry, this is for private log
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* entry stuff, the MARK data provided by userspace for example.
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*/
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struct log_write_entry {
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__le64 sector;
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__le64 nr_sectors;
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__le64 flags;
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__le64 data_len;
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};
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struct log_writes_c {
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struct dm_dev *dev;
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struct dm_dev *logdev;
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u64 logged_entries;
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u32 sectorsize;
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atomic_t io_blocks;
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atomic_t pending_blocks;
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sector_t next_sector;
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sector_t end_sector;
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bool logging_enabled;
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bool device_supports_discard;
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spinlock_t blocks_lock;
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struct list_head unflushed_blocks;
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struct list_head logging_blocks;
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wait_queue_head_t wait;
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struct task_struct *log_kthread;
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};
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struct pending_block {
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int vec_cnt;
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u64 flags;
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sector_t sector;
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sector_t nr_sectors;
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char *data;
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u32 datalen;
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struct list_head list;
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struct bio_vec vecs[0];
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};
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struct per_bio_data {
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struct pending_block *block;
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};
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static void put_pending_block(struct log_writes_c *lc)
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{
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if (atomic_dec_and_test(&lc->pending_blocks)) {
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smp_mb__after_atomic();
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if (waitqueue_active(&lc->wait))
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wake_up(&lc->wait);
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}
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}
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static void put_io_block(struct log_writes_c *lc)
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{
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if (atomic_dec_and_test(&lc->io_blocks)) {
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smp_mb__after_atomic();
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if (waitqueue_active(&lc->wait))
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wake_up(&lc->wait);
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}
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}
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static void log_end_io(struct bio *bio)
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{
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struct log_writes_c *lc = bio->bi_private;
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struct bio_vec *bvec;
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int i;
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if (bio->bi_error) {
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unsigned long flags;
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DMERR("Error writing log block, error=%d", bio->bi_error);
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spin_lock_irqsave(&lc->blocks_lock, flags);
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lc->logging_enabled = false;
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spin_unlock_irqrestore(&lc->blocks_lock, flags);
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}
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bio_for_each_segment_all(bvec, bio, i)
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__free_page(bvec->bv_page);
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put_io_block(lc);
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bio_put(bio);
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}
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/*
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* Meant to be called if there is an error, it will free all the pages
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* associated with the block.
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*/
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static void free_pending_block(struct log_writes_c *lc,
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struct pending_block *block)
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{
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int i;
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for (i = 0; i < block->vec_cnt; i++) {
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if (block->vecs[i].bv_page)
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__free_page(block->vecs[i].bv_page);
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}
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kfree(block->data);
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kfree(block);
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put_pending_block(lc);
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}
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static int write_metadata(struct log_writes_c *lc, void *entry,
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size_t entrylen, void *data, size_t datalen,
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sector_t sector)
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{
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struct bio *bio;
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struct page *page;
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void *ptr;
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size_t ret;
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bio = bio_alloc(GFP_KERNEL, 1);
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if (!bio) {
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DMERR("Couldn't alloc log bio");
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goto error;
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}
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bio->bi_iter.bi_size = 0;
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bio->bi_iter.bi_sector = sector;
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bio->bi_bdev = lc->logdev->bdev;
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bio->bi_end_io = log_end_io;
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bio->bi_private = lc;
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bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
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page = alloc_page(GFP_KERNEL);
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if (!page) {
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DMERR("Couldn't alloc log page");
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bio_put(bio);
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goto error;
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}
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ptr = kmap_atomic(page);
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memcpy(ptr, entry, entrylen);
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if (datalen)
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memcpy(ptr + entrylen, data, datalen);
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memset(ptr + entrylen + datalen, 0,
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lc->sectorsize - entrylen - datalen);
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kunmap_atomic(ptr);
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ret = bio_add_page(bio, page, lc->sectorsize, 0);
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if (ret != lc->sectorsize) {
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DMERR("Couldn't add page to the log block");
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goto error_bio;
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}
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submit_bio(bio);
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return 0;
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error_bio:
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bio_put(bio);
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__free_page(page);
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error:
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put_io_block(lc);
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return -1;
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}
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static int log_one_block(struct log_writes_c *lc,
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struct pending_block *block, sector_t sector)
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{
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struct bio *bio;
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struct log_write_entry entry;
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size_t ret;
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int i;
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entry.sector = cpu_to_le64(block->sector);
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entry.nr_sectors = cpu_to_le64(block->nr_sectors);
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entry.flags = cpu_to_le64(block->flags);
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entry.data_len = cpu_to_le64(block->datalen);
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if (write_metadata(lc, &entry, sizeof(entry), block->data,
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block->datalen, sector)) {
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free_pending_block(lc, block);
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return -1;
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}
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if (!block->vec_cnt)
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goto out;
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sector++;
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atomic_inc(&lc->io_blocks);
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bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt, BIO_MAX_PAGES));
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if (!bio) {
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DMERR("Couldn't alloc log bio");
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goto error;
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}
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bio->bi_iter.bi_size = 0;
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bio->bi_iter.bi_sector = sector;
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bio->bi_bdev = lc->logdev->bdev;
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bio->bi_end_io = log_end_io;
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bio->bi_private = lc;
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bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
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for (i = 0; i < block->vec_cnt; i++) {
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/*
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* The page offset is always 0 because we allocate a new page
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* for every bvec in the original bio for simplicity sake.
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*/
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ret = bio_add_page(bio, block->vecs[i].bv_page,
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block->vecs[i].bv_len, 0);
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if (ret != block->vecs[i].bv_len) {
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atomic_inc(&lc->io_blocks);
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submit_bio(bio);
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bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt - i, BIO_MAX_PAGES));
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if (!bio) {
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DMERR("Couldn't alloc log bio");
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goto error;
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}
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bio->bi_iter.bi_size = 0;
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bio->bi_iter.bi_sector = sector;
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bio->bi_bdev = lc->logdev->bdev;
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bio->bi_end_io = log_end_io;
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bio->bi_private = lc;
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bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
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ret = bio_add_page(bio, block->vecs[i].bv_page,
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block->vecs[i].bv_len, 0);
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if (ret != block->vecs[i].bv_len) {
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DMERR("Couldn't add page on new bio?");
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bio_put(bio);
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goto error;
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}
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}
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sector += block->vecs[i].bv_len >> SECTOR_SHIFT;
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}
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submit_bio(bio);
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out:
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kfree(block->data);
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kfree(block);
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put_pending_block(lc);
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return 0;
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error:
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free_pending_block(lc, block);
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put_io_block(lc);
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return -1;
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}
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static int log_super(struct log_writes_c *lc)
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{
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struct log_write_super super;
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super.magic = cpu_to_le64(WRITE_LOG_MAGIC);
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super.version = cpu_to_le64(WRITE_LOG_VERSION);
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super.nr_entries = cpu_to_le64(lc->logged_entries);
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super.sectorsize = cpu_to_le32(lc->sectorsize);
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if (write_metadata(lc, &super, sizeof(super), NULL, 0, 0)) {
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DMERR("Couldn't write super");
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return -1;
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}
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return 0;
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}
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static inline sector_t logdev_last_sector(struct log_writes_c *lc)
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{
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return i_size_read(lc->logdev->bdev->bd_inode) >> SECTOR_SHIFT;
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}
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static int log_writes_kthread(void *arg)
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{
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struct log_writes_c *lc = (struct log_writes_c *)arg;
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sector_t sector = 0;
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while (!kthread_should_stop()) {
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bool super = false;
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bool logging_enabled;
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struct pending_block *block = NULL;
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int ret;
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spin_lock_irq(&lc->blocks_lock);
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if (!list_empty(&lc->logging_blocks)) {
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block = list_first_entry(&lc->logging_blocks,
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struct pending_block, list);
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list_del_init(&block->list);
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if (!lc->logging_enabled)
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goto next;
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sector = lc->next_sector;
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if (block->flags & LOG_DISCARD_FLAG)
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lc->next_sector++;
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else
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lc->next_sector += block->nr_sectors + 1;
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/*
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* Apparently the size of the device may not be known
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* right away, so handle this properly.
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*/
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if (!lc->end_sector)
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lc->end_sector = logdev_last_sector(lc);
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if (lc->end_sector &&
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lc->next_sector >= lc->end_sector) {
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DMERR("Ran out of space on the logdev");
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lc->logging_enabled = false;
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goto next;
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}
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lc->logged_entries++;
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atomic_inc(&lc->io_blocks);
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super = (block->flags & (LOG_FUA_FLAG | LOG_MARK_FLAG));
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if (super)
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atomic_inc(&lc->io_blocks);
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}
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next:
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logging_enabled = lc->logging_enabled;
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spin_unlock_irq(&lc->blocks_lock);
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if (block) {
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if (logging_enabled) {
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ret = log_one_block(lc, block, sector);
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if (!ret && super)
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ret = log_super(lc);
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if (ret) {
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spin_lock_irq(&lc->blocks_lock);
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lc->logging_enabled = false;
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spin_unlock_irq(&lc->blocks_lock);
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}
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} else
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free_pending_block(lc, block);
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continue;
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}
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if (!try_to_freeze()) {
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set_current_state(TASK_INTERRUPTIBLE);
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if (!kthread_should_stop() &&
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!atomic_read(&lc->pending_blocks))
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schedule();
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__set_current_state(TASK_RUNNING);
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}
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}
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return 0;
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}
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/*
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* Construct a log-writes mapping:
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* log-writes <dev_path> <log_dev_path>
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*/
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static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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{
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struct log_writes_c *lc;
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struct dm_arg_set as;
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const char *devname, *logdevname;
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int ret;
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as.argc = argc;
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as.argv = argv;
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if (argc < 2) {
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ti->error = "Invalid argument count";
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return -EINVAL;
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}
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lc = kzalloc(sizeof(struct log_writes_c), GFP_KERNEL);
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if (!lc) {
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ti->error = "Cannot allocate context";
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return -ENOMEM;
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}
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spin_lock_init(&lc->blocks_lock);
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INIT_LIST_HEAD(&lc->unflushed_blocks);
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INIT_LIST_HEAD(&lc->logging_blocks);
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init_waitqueue_head(&lc->wait);
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lc->sectorsize = 1 << SECTOR_SHIFT;
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atomic_set(&lc->io_blocks, 0);
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atomic_set(&lc->pending_blocks, 0);
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devname = dm_shift_arg(&as);
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ret = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &lc->dev);
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if (ret) {
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ti->error = "Device lookup failed";
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goto bad;
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}
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logdevname = dm_shift_arg(&as);
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ret = dm_get_device(ti, logdevname, dm_table_get_mode(ti->table),
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&lc->logdev);
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if (ret) {
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ti->error = "Log device lookup failed";
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dm_put_device(ti, lc->dev);
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goto bad;
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}
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lc->log_kthread = kthread_run(log_writes_kthread, lc, "log-write");
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if (IS_ERR(lc->log_kthread)) {
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ret = PTR_ERR(lc->log_kthread);
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ti->error = "Couldn't alloc kthread";
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dm_put_device(ti, lc->dev);
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dm_put_device(ti, lc->logdev);
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goto bad;
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}
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/* We put the super at sector 0, start logging at sector 1 */
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lc->next_sector = 1;
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lc->logging_enabled = true;
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lc->end_sector = logdev_last_sector(lc);
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lc->device_supports_discard = true;
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ti->num_flush_bios = 1;
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ti->flush_supported = true;
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ti->num_discard_bios = 1;
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ti->discards_supported = true;
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ti->per_io_data_size = sizeof(struct per_bio_data);
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ti->private = lc;
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return 0;
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bad:
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kfree(lc);
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return ret;
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}
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static int log_mark(struct log_writes_c *lc, char *data)
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{
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struct pending_block *block;
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size_t maxsize = lc->sectorsize - sizeof(struct log_write_entry);
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block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
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if (!block) {
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DMERR("Error allocating pending block");
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return -ENOMEM;
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}
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block->data = kstrndup(data, maxsize, GFP_KERNEL);
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if (!block->data) {
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DMERR("Error copying mark data");
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kfree(block);
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return -ENOMEM;
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}
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atomic_inc(&lc->pending_blocks);
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block->datalen = strlen(block->data);
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block->flags |= LOG_MARK_FLAG;
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spin_lock_irq(&lc->blocks_lock);
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list_add_tail(&block->list, &lc->logging_blocks);
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spin_unlock_irq(&lc->blocks_lock);
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|
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_opf & REQ_PREFLUSH);
|
|
bool fua_bio = (bio->bi_opf & REQ_FUA);
|
|
bool discard_bio = (bio_op(bio) == REQ_OP_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);
|
|
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_prepare_ioctl(struct dm_target *ti,
|
|
struct block_device **bdev, fmode_t *mode)
|
|
{
|
|
struct log_writes_c *lc = ti->private;
|
|
struct dm_dev *dev = lc->dev;
|
|
|
|
*bdev = dev->bdev;
|
|
/*
|
|
* Only pass ioctls through if the device sizes match exactly.
|
|
*/
|
|
if (ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
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,
|
|
.prepare_ioctl = log_writes_prepare_ioctl,
|
|
.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");
|