[RFC PATCH V11 15/21] Btrfs: subpagesize-blocksize: Revert commit fc4adbff823f76577ece26dcb88bf6f8392dbd43.

[Chandan Rajendra <chandan@linux.vnet.ibm.com>]

In subpagesize-blocksize, we have multiple blocks in a page. Checking for
existence of a page in the page cache isn't a sufficient check, since we
could be truncating a subset of the blocks mapped by the page.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
 fs/btrfs/btrfs_inode.h | 2 --
 fs/btrfs/file.c        | 4 +++-
 fs/btrfs/inode.c       | 3 ++-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 0ef5cc1..2bf8043 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -323,6 +323,4 @@ static inline void btrfs_inode_resume_unlocked_dio(struct inode *inode)
 		  &BTRFS_I(inode)->runtime_flags);
 }
 
-bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end);
-
 #endif
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9600410a..cc9feed 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2419,7 +2419,9 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 		if ((!ordered ||
 		    (ordered->file_offset + ordered->len <= lockstart ||
 		     ordered->file_offset > lockend)) &&
-		     !btrfs_page_exists_in_range(inode, lockstart, lockend)) {
+		     !test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
+				     lockend, EXTENT_UPTODATE, 0,
+				     cached_state)) {
 			if (ordered)
 				btrfs_put_ordered_extent(ordered);
 			break;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index bfffc62..03faff0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7281,7 +7281,8 @@ out:
 	return ret;
 }
 
-bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
+static bool btrfs_page_exists_in_range(struct inode *inode, loff_t start,
+				loff_t end)
 {
 	struct radix_tree_root *root = &inode->i_mapping->page_tree;
 	int found = false;
-- 
2.1.0