diff options
| author | Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> | 2016-09-02 10:58:46 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2016-09-06 16:31:43 +0200 |
| commit | ce129655c9d9aaa7b3bcc46529db1b36693575ed (patch) | |
| tree | 3e653a3c55e2393f04ebc881712921f35cf3eb2b /fs | |
| parent | ed7a6948394305b810d0c6203268648715e5006f (diff) | |
btrfs: introduce tickets_id to determine whether asynchronous metadata reclaim work makes progress
In btrfs_async_reclaim_metadata_space(), we use ticket's address to
determine whether asynchronous metadata reclaim work is making progress.
ticket = list_first_entry(&space_info->tickets,
struct reserve_ticket, list);
if (last_ticket == ticket) {
flush_state++;
} else {
last_ticket = ticket;
flush_state = FLUSH_DELAYED_ITEMS_NR;
if (commit_cycles)
commit_cycles--;
}
But indeed it's wrong, we should not rely on local variable's address to
do this check, because addresses may be same. In my test environment, I
dd one 168MB file in a 256MB fs, found that for this file, every time
wait_reserve_ticket() called, local variable ticket's address is same,
For above codes, assume a previous ticket's address is addrA, last_ticket
is addrA. Btrfs_async_reclaim_metadata_space() finished this ticket and
wake up it, then another ticket is added, but with the same address addrA,
now last_ticket will be same to current ticket, then current ticket's flush
work will start from current flush_state, not initial FLUSH_DELAYED_ITEMS_NR,
which may result in some enospc issues(I have seen this in my test machine).
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/ctree.h | 1 | ||||
| -rw-r--r-- | fs/btrfs/extent-tree.c | 11 |
2 files changed, 7 insertions, 5 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index ec4154faab61..146d1c7078ed 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -427,6 +427,7 @@ struct btrfs_space_info { struct list_head ro_bgs; struct list_head priority_tickets; struct list_head tickets; + u64 tickets_id; struct rw_semaphore groups_sem; /* for block groups in our same type */ diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 4483487ef021..d09cf7aa083b 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4966,12 +4966,12 @@ static void wake_all_tickets(struct list_head *head) */ static void btrfs_async_reclaim_metadata_space(struct work_struct *work) { - struct reserve_ticket *last_ticket = NULL; struct btrfs_fs_info *fs_info; struct btrfs_space_info *space_info; u64 to_reclaim; int flush_state; int commit_cycles = 0; + u64 last_tickets_id; fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work); space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA); @@ -4984,8 +4984,7 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work) spin_unlock(&space_info->lock); return; } - last_ticket = list_first_entry(&space_info->tickets, - struct reserve_ticket, list); + last_tickets_id = space_info->tickets_id; spin_unlock(&space_info->lock); flush_state = FLUSH_DELAYED_ITEMS_NR; @@ -5005,10 +5004,10 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work) space_info); ticket = list_first_entry(&space_info->tickets, struct reserve_ticket, list); - if (last_ticket == ticket) { + if (last_tickets_id == space_info->tickets_id) { flush_state++; } else { - last_ticket = ticket; + last_tickets_id = space_info->tickets_id; flush_state = FLUSH_DELAYED_ITEMS_NR; if (commit_cycles) commit_cycles--; @@ -5384,6 +5383,7 @@ again: list_del_init(&ticket->list); num_bytes -= ticket->bytes; ticket->bytes = 0; + space_info->tickets_id++; wake_up(&ticket->wait); } else { ticket->bytes -= num_bytes; @@ -5426,6 +5426,7 @@ again: num_bytes -= ticket->bytes; space_info->bytes_may_use += ticket->bytes; ticket->bytes = 0; + space_info->tickets_id++; wake_up(&ticket->wait); } else { trace_btrfs_space_reservation(fs_info, "space_info", |