Add a per-inode lock around btrfs_drop_extents
btrfs_drop_extents is always called with a range lock held on the inode.
But, it may operate on extents outside that range as it drops and splits
them.
This patch adds a per-inode mutex that is held while calling
btrfs_drop_extents and while inserting new extents into the tree. It
prevents races from two procs working against adjacent ranges in the tree.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 293355c..0d1e2ba 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -516,6 +516,8 @@
trans->transid, inode->i_ino,
ordered_extent->file_offset, &ins);
BUG_ON(ret);
+
+ mutex_lock(&BTRFS_I(inode)->extent_mutex);
ret = btrfs_drop_extents(trans, root, inode,
ordered_extent->file_offset,
ordered_extent->file_offset +
@@ -531,6 +533,8 @@
btrfs_drop_extent_cache(inode, ordered_extent->file_offset,
ordered_extent->file_offset +
ordered_extent->len - 1);
+ mutex_unlock(&BTRFS_I(inode)->extent_mutex);
+
inode->i_blocks += ordered_extent->len >> 9;
unlock_extent(io_tree, ordered_extent->file_offset,
ordered_extent->file_offset + ordered_extent->len - 1,
@@ -1399,6 +1403,7 @@
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
+ mutex_lock(&BTRFS_I(inode)->extent_mutex);
err = btrfs_drop_extents(trans, root, inode,
hole_start, block_end, hole_start,
&alloc_hint);
@@ -1412,6 +1417,7 @@
(u64)-1);
btrfs_check_file(root, inode);
}
+ mutex_unlock(&BTRFS_I(inode)->extent_mutex);
btrfs_end_transaction(trans, root);
unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
if (err)
@@ -1578,6 +1584,7 @@
inode->i_mapping, GFP_NOFS);
btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);
mutex_init(&BTRFS_I(inode)->csum_mutex);
+ mutex_init(&BTRFS_I(inode)->extent_mutex);
return 0;
}
@@ -1880,6 +1887,7 @@
inode->i_mapping, GFP_NOFS);
btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);
mutex_init(&BTRFS_I(inode)->csum_mutex);
+ mutex_init(&BTRFS_I(inode)->extent_mutex);
BTRFS_I(inode)->delalloc_bytes = 0;
BTRFS_I(inode)->disk_i_size = 0;
BTRFS_I(inode)->root = root;
@@ -2105,6 +2113,7 @@
extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
inode->i_mapping, GFP_NOFS);
mutex_init(&BTRFS_I(inode)->csum_mutex);
+ mutex_init(&BTRFS_I(inode)->extent_mutex);
BTRFS_I(inode)->delalloc_bytes = 0;
BTRFS_I(inode)->disk_i_size = 0;
BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
@@ -3079,6 +3088,7 @@
extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
inode->i_mapping, GFP_NOFS);
mutex_init(&BTRFS_I(inode)->csum_mutex);
+ mutex_init(&BTRFS_I(inode)->extent_mutex);
BTRFS_I(inode)->delalloc_bytes = 0;
BTRFS_I(inode)->disk_i_size = 0;
BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;