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authorJosef Bacik <josef@toxicpanda.com>2018-11-21 22:03:13 +0300
committerDavid Sterba <dsterba@suse.com>2019-02-25 16:13:35 +0300
commit260e77025ffa8779a7dc4bc21f3890273c93f9d4 (patch)
tree830325be528cb9efbffaa2ad7fb6b5d536c0e15f /fs/btrfs
parent8a1bbe1d5cba415c771fe5ff68b83b93701c1d7f (diff)
downloadlinux-260e77025ffa8779a7dc4bc21f3890273c93f9d4.tar.xz
btrfs: reserve extra space during evict
We could generate a lot of delayed refs in evict but never have any left over space from our block rsv to make up for that fact. So reserve some extra space and give it to the transaction so it can be used to refill the delayed refs rsv every loop through the truncate path. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/inode.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a443645cf815..3f180b857e20 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5293,13 +5293,15 @@ static struct btrfs_trans_handle *evict_refill_and_join(struct btrfs_root *root,
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+ u64 delayed_refs_extra = btrfs_calc_trans_metadata_size(fs_info, 1);
int failures = 0;
for (;;) {
struct btrfs_trans_handle *trans;
int ret;
- ret = btrfs_block_rsv_refill(root, rsv, rsv->size,
+ ret = btrfs_block_rsv_refill(root, rsv,
+ rsv->size + delayed_refs_extra,
BTRFS_RESERVE_FLUSH_LIMIT);
if (ret && ++failures > 2) {
@@ -5308,9 +5310,28 @@ static struct btrfs_trans_handle *evict_refill_and_join(struct btrfs_root *root,
return ERR_PTR(-ENOSPC);
}
+ /*
+ * Evict can generate a large amount of delayed refs without
+ * having a way to add space back since we exhaust our temporary
+ * block rsv. We aren't allowed to do FLUSH_ALL in this case
+ * because we could deadlock with so many things in the flushing
+ * code, so we have to try and hold some extra space to
+ * compensate for our delayed ref generation. If we can't get
+ * that space then we need see if we can steal our minimum from
+ * the global reserve. We will be ratelimited by the amount of
+ * space we have for the delayed refs rsv, so we'll end up
+ * committing and trying again.
+ */
trans = btrfs_join_transaction(root);
- if (IS_ERR(trans) || !ret)
+ if (IS_ERR(trans) || !ret) {
+ if (!IS_ERR(trans)) {
+ trans->block_rsv = &fs_info->trans_block_rsv;
+ trans->bytes_reserved = delayed_refs_extra;
+ btrfs_block_rsv_migrate(rsv, trans->block_rsv,
+ delayed_refs_extra, 1);
+ }
return trans;
+ }
/*
* Try to steal from the global reserve if there is space for