From: Josef Bacik Date: Mon, 23 Apr 2012 18:41:09 +0000 (-0400) Subject: Btrfs: remove useless waiting and extra filemap work X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=551ebb2d34304ee2abfe6b00d39ec65d5e4e8266;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git Btrfs: remove useless waiting and extra filemap work In btrfs_wait_ordered_range we have been calling filemap_fdata_write() twice because compression does strange things and then waiting. Then we look up ordered extents and if we find any we will always schedule_timeout(); once and then loop back around and do it all again. We will even check to see if there is delalloc pages on this range and loop again. So this patch gets rid of the multipe fdata_write() calls and just does filemap_write_and_wait(). In the case of compression we will still find the ordered extents and start those individually if we need to so that is ok, but in the normal buffered case we avoid all this weird overhead. Then in the case of the schedule_timeout(1), we don't need it. All callers either 1) don't care, they just want to make sure what they just wrote maeks it to disk or 2) are doing the lock()->lookup ordered->unlock->flush thing in which case it will lock and check for ordered extents _anyway_ so get back to them as quickly as possible. The delaloc check is simply not needed, this only catches the case where we write to the file again since doing the filemap_write_and_wait() and if the caller truly cares about that it will take care of everything itself. Thanks, Signed-off-by: Josef Bacik --- diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index bbf6d0d9aebe..9807750c6255 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -621,19 +621,11 @@ void btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len) if (orig_end > INT_LIMIT(loff_t)) orig_end = INT_LIMIT(loff_t); } -again: + /* start IO across the range first to instantiate any delalloc * extents */ - filemap_fdatawrite_range(inode->i_mapping, start, orig_end); - - /* The compression code will leave pages locked but return from - * writepage without setting the page writeback. Starting again - * with WB_SYNC_ALL will end up waiting for the IO to actually start. - */ - filemap_fdatawrite_range(inode->i_mapping, start, orig_end); - - filemap_fdatawait_range(inode->i_mapping, start, orig_end); + filemap_write_and_wait_range(inode->i_mapping, start, orig_end); end = orig_end; found = 0; @@ -657,11 +649,6 @@ again: break; end--; } - if (found || test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end, - EXTENT_DELALLOC, 0, NULL)) { - schedule_timeout(1); - goto again; - } } /*