From: Yan, Zheng Date: Tue, 18 Jan 2011 05:34:40 +0000 (+0800) Subject: Btrfs: Fix page count calculation X-Git-Tag: firefly_0821_release~7613^2~2263^2~19 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3a90983dbdcb2f4f48c0d771d8e5b4d88f27fae6;p=firefly-linux-kernel-4.4.55.git Btrfs: Fix page count calculation take offset of start position into account when calculating page count. Signed-off-by: Yan, Zheng Signed-off-by: Chris Mason --- 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)