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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>
This commit is contained in:
Yan, Zheng 2011-01-18 13:34:40 +08:00 committed by Chris Mason
parent 8e4eef7a60
commit 3a90983dbd

View File

@ -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)