From 6643558db29006825dbb10012b3f8890aca4bcd5 Mon Sep 17 00:00:00 2001 From: Yan Zheng Date: Thu, 30 Oct 2008 14:19:50 -0400 Subject: Btrfs: Fix bookend extent race v2 When dropping middle part of an extent, btrfs_drop_extents truncates the extent at first, then inserts a bookend extent. Since truncation and insertion can't be done atomically, there is a small period that the bookend extent isn't in the tree. This causes problem for functions that search the tree for file extent item. The way to fix this is lock the range of the bookend extent before truncation. Signed-off-by: Yan Zheng --- fs/btrfs/inode.c | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'fs/btrfs/inode.c') diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 8254d6f..e8511d1 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -246,7 +246,6 @@ static int cow_file_range_inline(struct btrfs_trans_handle *trans, return 1; } - mutex_lock(&BTRFS_I(inode)->extent_mutex); ret = btrfs_drop_extents(trans, root, inode, start, aligned_end, aligned_end, &hint_byte); BUG_ON(ret); @@ -258,7 +257,6 @@ static int cow_file_range_inline(struct btrfs_trans_handle *trans, compressed_pages); BUG_ON(ret); btrfs_drop_extent_cache(inode, start, aligned_end, 0); - mutex_unlock(&BTRFS_I(inode)->extent_mutex); return 0; } @@ -437,9 +435,7 @@ again: BUG_ON(disk_num_bytes > btrfs_super_total_bytes(&root->fs_info->super_copy)); - mutex_lock(&BTRFS_I(inode)->extent_mutex); btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0); - mutex_unlock(&BTRFS_I(inode)->extent_mutex); while(disk_num_bytes > 0) { unsigned long min_bytes; @@ -477,8 +473,6 @@ again: em->block_start = ins.objectid; em->block_len = ins.offset; em->bdev = root->fs_info->fs_devices->latest_bdev; - - mutex_lock(&BTRFS_I(inode)->extent_mutex); set_bit(EXTENT_FLAG_PINNED, &em->flags); if (will_compress) @@ -495,7 +489,6 @@ again: btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0); } - mutex_unlock(&BTRFS_I(inode)->extent_mutex); cur_alloc_size = ins.offset; ret = btrfs_add_ordered_extent(inode, start, ins.objectid, @@ -1016,8 +1009,6 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end) INIT_LIST_HEAD(&list); - mutex_lock(&BTRFS_I(inode)->extent_mutex); - ret = btrfs_drop_extents(trans, root, inode, ordered_extent->file_offset, ordered_extent->file_offset + @@ -1059,7 +1050,6 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end) btrfs_drop_extent_cache(inode, ordered_extent->file_offset, ordered_extent->file_offset + ordered_extent->len - 1, 0); - mutex_unlock(&BTRFS_I(inode)->extent_mutex); ins.objectid = ordered_extent->start; ins.offset = ordered_extent->disk_len; -- cgit v1.1