Btrfs: Replace the big fs_mutex with a collection of other locks

Extent alloctions are still protected by a large alloc_mutex.
Objectid allocations are covered by a objectid mutex
Other btree operations are protected by a lock on individual btree nodes

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 73c6d085bd90..18bbe108a0e6 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -252,7 +252,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
         end_of_last_block = start_pos + num_bytes - 1;
 
         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         if (!trans) {
                 err = -ENOMEM;
@@ -341,7 +340,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 failed:
         err = btrfs_end_transaction(trans, root);
 out_unlock:
-        mutex_unlock(&root->fs_info->fs_mutex);
         unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
         return err;
 }
@@ -905,9 +903,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 WARN_ON(num_pages > nrptrs);
                 memset(pages, 0, sizeof(pages));
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 ret = btrfs_check_free_space(root, write_bytes, 0);
-                mutex_unlock(&root->fs_info->fs_mutex);
                 if (ret)
                         goto out;
 
@@ -998,9 +994,9 @@ static int btrfs_sync_file(struct file *file,
          * check the transaction that last modified this inode
          * and see if its already been committed
          */
-        mutex_lock(&root->fs_info->fs_mutex);
         if (!BTRFS_I(inode)->last_trans)
                 goto out;
+
         mutex_lock(&root->fs_info->trans_mutex);
         if (BTRFS_I(inode)->last_trans <=
             root->fs_info->last_trans_committed) {
@@ -1023,7 +1019,6 @@ static int btrfs_sync_file(struct file *file,
         }
         ret = btrfs_commit_transaction(trans, root);
 out:
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret > 0 ? EIO : ret;
 }