Btrfs: set truncate block rsv's size

While debugging a different issue I noticed that we were always reserving space
when we tried to use our truncate block rsv's.  This is because they didn't have
a ->size value, so use_block_rsv just assumes there is nothing reserved and it
does a reserve_metadata_bytes.  This is because btrfs_check_block_rsv() doesn't
actually add to the size of the block rsv.  That seems to be the right thing to
do so set ->size to the minimum truncate size we need, since we will always only
refill to that size anyway, and this way everything works out correctly.

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

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e40b9239660d6ad6d63f9e1d4a12bca54e2f7c53..06ae5b173fd78659525f1c132f549d0ce3713487 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3561,6 +3561,7 @@ void btrfs_evict_inode(struct inode *inode)
                btrfs_orphan_del(NULL, inode);
                goto no_delete;
        }
+       rsv->size = min_size;
 
        btrfs_i_size_write(inode, 0);
 
@@ -6530,6 +6531,7 @@ static int btrfs_truncate(struct inode *inode)
        rsv = btrfs_alloc_block_rsv(root);
        if (!rsv)
                return -ENOMEM;
+       rsv->size = min_size;
 
        /*
         * 1 for the truncate slack space