From f30bed83426c5cb9fce6cabb3f7cc5a9d5428fcc Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Fri, 13 Nov 2020 11:24:17 +0000 Subject: [PATCH] btrfs: remove unnecessary attempt to drop extent maps after adding inline extent At inode.c:cow_file_range_inline(), after we insert the inline extent in the fs/subvolume btree, we call btrfs_drop_extent_cache() to drop all extent maps in the file range, however that is not necessary because we have already done it in the call to btrfs_drop_extents(), which calls btrfs_drop_extent_cache() for us, and since at this point we have the file range locked in the inode's iotree (we are in the writeback path), we know no other task can come in and read stale file extent items or find none and therefore create either stale extent maps or an extent map that represents a hole. So just remove that unnecessary call to btrfs_drop_extent_cache(), as it's doing nothing and only wasting time. This call has been around since 2008, introduced in commit c8b978188c9a ("Btrfs: Add zlib compression support"), but even back then it seems it was not necessary, since we had the range locked in the inode's iotree and the call to btrfs_drop_extents() already used to always call btrfs_drop_extent_cache(). Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/inode.c | 1 - 1 file changed, 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 5b9815b..abc0fd1 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -392,7 +392,6 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start, } set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags); - btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0); out: /* * Don't forget to free the reserved space, as for inlined extent -- 2.7.4