From 3a90983dbdcb2f4f48c0d771d8e5b4d88f27fae6 Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zheng.z.yan@linux.intel.com>
Date: Tue, 18 Jan 2011 13:34:40 +0800
Subject: [PATCH] Btrfs: Fix page count calculation
take offset of start position into account when calculating page count.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
fs/btrfs/file.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9e097fbfc78d..b0ff34b96607 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -991,8 +991,8 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
size_t write_bytes = min(iov_iter_count(&i),
nrptrs * (size_t)PAGE_CACHE_SIZE -
offset);
- size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
+ size_t num_pages = (write_bytes + offset +
+ PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
WARN_ON(num_pages > nrptrs);
memset(pages, 0, sizeof(struct page *) * nrptrs);
@@ -1022,8 +1022,8 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
copied = btrfs_copy_from_user(pos, num_pages,
write_bytes, pages, &i);
- dirty_pages = (copied + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
+ dirty_pages = (copied + offset + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT;
if (num_pages > dirty_pages) {
if (copied > 0)
--
2.34.1