On Wed, May 16, 2018 at 04:28:54PM +0800, Ethan Lien wrote: > In nocow path, we check if the extent is snapshotted in > btrfs_cross_ref_exist(). We can do the similar check earlier and avoid > unnecessary search into extent tree. > > Signed-off-by: Ethan Lien <ethanlien@xxxxxxxxxxxx> > --- > fs/btrfs/inode.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index d241285a0d2a..96927f2ccd4b 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -1373,6 +1373,9 @@ static noinline int run_delalloc_nocow(struct inode *inode, > btrfs_file_extent_encryption(leaf, fi) || > btrfs_file_extent_other_encoding(leaf, fi)) > goto out_check; > + if (btrfs_file_extent_generation(leaf, fi) <= > + btrfs_root_last_snapshot(&root->root_item)) > + goto out_check; > if (extent_type == BTRFS_FILE_EXTENT_REG && !force) > goto out_check; > if (btrfs_extent_readonly(fs_info, disk_bytenr)) > @@ -7368,6 +7371,10 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len, > btrfs_file_extent_other_encoding(leaf, fi)) > goto out; > > + if (btrfs_file_extent_generation(leaf, fi) <= > + btrfs_root_last_snapshot(&root->root_item)) > + goto out; Please add some brief comment why we're taking a shortcut here, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
