From: Eric Sandeen <sandeen@xxxxxxxxxx>
We only call ->is_partially_uptodate to look for an uptodate range
within a not-uptodate page.
If the range covers all blocks in the page, there is no point to checking
each block individually - if the whole range (i.e. the whole page) were
uptodate, the page would be uptodate as well. Hence in this case, we
can return early and skip the loop.
This is similar to what is done in block_is_partially_uptodate().
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxxx>
---
fs/iomap.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/iomap.c b/fs/iomap.c
index ce837d9..7d7d985 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -515,6 +515,10 @@ struct iomap_readpage_ctx {
first = from >> inode->i_blkbits;
last = (from + len - 1) >> inode->i_blkbits;
+ /* If page wasn't uptodate and range covers all blocks: no partial */
+ if (first == 0 && last == (PAGE_SIZE - 1) >> inode->i_blkbits)
+ return 0;
+
if (iop) {
for (i = first; i <= last; i++)
if (!test_bit(i, iop->uptodate))
--
1.8.3.1
