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Btrfs: wrap repeated code into scrub_blocked_if_needed()

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Just wrap same code into one function scrub_blocked_if_needed().

This make a change that we will move waiting (@workers_pending = 0)
before we can wake up commiting transaction(atomic_inc(@scrub_paused)),
we must take carefully to not deadlock here.

Thread 1			Thread 2
				|->btrfs_commit_transaction()
					|->set trans type(COMMIT_DOING)
					|->btrfs_scrub_paused()(blocked)
|->join_transaction(blocked)

Move btrfs_scrub_paused() before setting trans type which means we can
still join a transaction when commiting_transaction is blocked.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Suggested-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Wang Shilong 2013-12-04 21:16:53 +08:00 committed by Chris Mason
parent 3cb0929ad2
commit cb7ab02156
2 changed files with 19 additions and 27 deletions
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43
fs/btrfs/scrub.c
View file

@ -256,6 +256,7 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
int mirror_num, u64 physical_for_dev_replace);
static void copy_nocow_pages_worker(struct btrfs_work *work);
static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
@ -270,7 +271,7 @@ static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
wake_up(&sctx->list_wait);
}
static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
{
while (atomic_read(&fs_info->scrub_pause_req)) {
mutex_unlock(&fs_info->scrub_lock);
@ -280,6 +281,19 @@ static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
}
}
static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
{
atomic_inc(&fs_info->scrubs_paused);
wake_up(&fs_info->scrub_pause_wait);
mutex_lock(&fs_info->scrub_lock);
__scrub_blocked_if_needed(fs_info);
atomic_dec(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
wake_up(&fs_info->scrub_pause_wait);
}
/*
* used for workers that require transaction commits (i.e., for the
* NOCOW case)
@ -2295,8 +2309,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
wait_event(sctx->list_wait,
atomic_read(&sctx->bios_in_flight) == 0);
atomic_inc(&fs_info->scrubs_paused);
wake_up(&fs_info->scrub_pause_wait);
scrub_blocked_if_needed(fs_info);
/* FIXME it might be better to start readahead at commit root */
key_start.objectid = logical;
@ -2320,12 +2333,6 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
if (!IS_ERR(reada2))
btrfs_reada_wait(reada2);
mutex_lock(&fs_info->scrub_lock);
scrub_blocked_if_needed(fs_info);
atomic_dec(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
wake_up(&fs_info->scrub_pause_wait);
/*
* collect all data csums for the stripe to avoid seeking during
@ -2362,15 +2369,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
wait_event(sctx->list_wait,
atomic_read(&sctx->bios_in_flight) == 0);
atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
atomic_inc(&fs_info->scrubs_paused);
wake_up(&fs_info->scrub_pause_wait);
mutex_lock(&fs_info->scrub_lock);
scrub_blocked_if_needed(fs_info);
atomic_dec(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
wake_up(&fs_info->scrub_pause_wait);
}
key.objectid = logical;
@ -2685,17 +2684,9 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
wait_event(sctx->list_wait,
atomic_read(&sctx->bios_in_flight) == 0);
atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
atomic_inc(&fs_info->scrubs_paused);
wake_up(&fs_info->scrub_pause_wait);
wait_event(sctx->list_wait,
atomic_read(&sctx->workers_pending) == 0);
mutex_lock(&fs_info->scrub_lock);
scrub_blocked_if_needed(fs_info);
atomic_dec(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
wake_up(&fs_info->scrub_pause_wait);
btrfs_put_block_group(cache);
if (ret)
@ -2912,7 +2903,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
* checking @scrub_pause_req here, we can avoid
* race between committing transaction and scrubbing.
*/
scrub_blocked_if_needed(fs_info);
__scrub_blocked_if_needed(fs_info);
atomic_inc(&fs_info->scrubs_running);
mutex_unlock(&fs_info->scrub_lock);

3
fs/btrfs/transaction.c
View file

@ -1748,6 +1748,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
goto cleanup_transaction;
btrfs_wait_delalloc_flush(root->fs_info);
btrfs_scrub_pause(root);
/*
* Ok now we need to make sure to block out any other joins while we
* commit the transaction. We could have started a join before setting
@ -1812,7 +1814,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
WARN_ON(cur_trans != trans->transaction);
btrfs_scrub_pause(root);
/* btrfs_commit_tree_roots is responsible for getting the
* various roots consistent with each other. Every pointer
* in the tree of tree roots has to point to the most up to date