On Wed, Oct 23, 2019 at 06:51:02PM +0200, David Sterba wrote:
On Fri, Oct 11, 2019 at 09:03:54AM -0400, Josef Bacik wrote:
--- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -474,6 +474,7 @@ static noinline int compress_file_range(struct async_chunk *async_chunk) u64 start = async_chunk->start; u64 end = async_chunk->end; u64 actual_end;
- loff_t i_size = i_size_read(inode); int ret = 0; struct page **pages = NULL; unsigned long nr_pages;
@@ -488,7 +489,13 @@ static noinline int compress_file_range(struct async_chunk *async_chunk) inode_should_defrag(BTRFS_I(inode), start, end, end - start + 1, SZ_16K);
- actual_end = min_t(u64, i_size_read(inode), end + 1);
- /*
* We need to save i_size before now because it could change in between* us evaluating the size and assigning it. This is because we lock and* unlock the page in truncate and fallocate, and then modify the i_size* later on.*/- actual_end = min_t(u64, i_size, end + 1);
Ping. This is not a future proof fix, please update the changelog and code according to the reply I sent.
The vfs i_size_read patch is being ignored so I guess we're on our own. I have postponed last weeks pull request so I'll add this patch on top and send in a day or two. The READ_ONCE will be simulated by barrier()s, I've verified the assembly and actually that's alwo what read once does among other things.