Btrfs: seperate out btrfs_block_rsv_check out into 2 different functions

Currently btrfs_block_rsv_check does 2 things, it will either refill a block
reserve like in the truncate or refill case, or it will check to see if there is
enough space in the global reserve and possibly refill it.  However because of
overcommit we could be well overcommitting ourselves just to try and refill the
global reserve, when really we should just be committing the transaction.  So
breack this out into btrfs_block_rsv_refill and btrfs_block_rsv_check.  Refill
will try to reserve more metadata if it can and btrfs_block_rsv_check will not,
it will only tell you if the factor of the total space is still reserved.
Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>

1 files changed, 27 insertions, 14 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index eb4fe56b08bb..a5f1421eeee9 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3422,7 +3422,6 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
  * @block_rsv - the block_rsv we're allocating for
  * @orig_bytes - the number of bytes we want
  * @flush - wether or not we can flush to make our reservation
- * @check - wether this is just to check if we have enough space or not
  *
  * This will reserve orgi_bytes number of bytes from the space info associated
  * with the block_rsv.  If there is not enough space it will make an attempt to
@@ -3433,7 +3432,7 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
  */
 static int reserve_metadata_bytes(struct btrfs_root *root,
                                   struct btrfs_block_rsv *block_rsv,
-                                  u64 orig_bytes, int flush, int check)
+                                  u64 orig_bytes, int flush)
 {
         struct btrfs_space_info *space_info = block_rsv->space_info;
         struct btrfs_trans_handle *trans;
@@ -3507,7 +3506,7 @@ again:
                         (orig_bytes * (retries + 1));
         }
 
-        if (ret && !check) {
+        if (ret) {
                 u64 profile = btrfs_get_alloc_profile(root, 0);
                 u64 avail;
 
@@ -3742,7 +3741,7 @@ int btrfs_block_rsv_add(struct btrfs_root *root,
         if (num_bytes == 0)
                 return 0;
 
-        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, 1, 0);
+        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, 1);
         if (!ret) {
                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
                 return 0;
@@ -3752,8 +3751,7 @@ int btrfs_block_rsv_add(struct btrfs_root *root,
 }
 
 int btrfs_block_rsv_check(struct btrfs_root *root,
-                          struct btrfs_block_rsv *block_rsv,
-                          u64 min_reserved, int min_factor, int flush)
+                          struct btrfs_block_rsv *block_rsv, int min_factor)
 {
         u64 num_bytes = 0;
         int ret = -ENOSPC;
@@ -3762,11 +3760,26 @@ int btrfs_block_rsv_check(struct btrfs_root *root,
                 return 0;
 
         spin_lock(&block_rsv->lock);
-        if (min_factor > 0)
-                num_bytes = div_factor(block_rsv->size, min_factor);
-        if (min_reserved > num_bytes)
-                num_bytes = min_reserved;
+        num_bytes = div_factor(block_rsv->size, min_factor);
+        if (block_rsv->reserved >= num_bytes)
+                ret = 0;
+        spin_unlock(&block_rsv->lock);
 
+        return ret;
+}
+
+int btrfs_block_rsv_refill(struct btrfs_root *root,
+                          struct btrfs_block_rsv *block_rsv,
+                          u64 min_reserved)
+{
+        u64 num_bytes = 0;
+        int ret = -ENOSPC;
+
+        if (!block_rsv)
+                return 0;
+
+        spin_lock(&block_rsv->lock);
+        num_bytes = min_reserved;
         if (block_rsv->reserved >= num_bytes)
                 ret = 0;
         else
@@ -3776,7 +3789,7 @@ int btrfs_block_rsv_check(struct btrfs_root *root,
         if (!ret)
                 return 0;
 
-        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush, !flush);
+        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, 1);
         if (!ret) {
                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
                 return 0;
@@ -4073,7 +4086,7 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
         spin_unlock(&BTRFS_I(inode)->lock);
 
-        ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush, 0);
+        ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
         if (ret) {
                 u64 to_free = 0;
                 unsigned dropped;
@@ -5728,7 +5741,7 @@ use_block_rsv(struct btrfs_trans_handle *trans,
         block_rsv = get_block_rsv(trans, root);
 
         if (block_rsv->size == 0) {
-                ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0, 0);
+                ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
                 /*
                  * If we couldn't reserve metadata bytes try and use some from
                  * the global reserve.
@@ -5749,7 +5762,7 @@ use_block_rsv(struct btrfs_trans_handle *trans,
                 return block_rsv;
         if (ret) {
                 WARN_ON(1);
-                ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0, 0);
+                ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
                 if (!ret) {
                         return block_rsv;
                 } else if (ret && block_rsv != global_rsv) {