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Commit 972f0d3a authored by Yehuda Sadeh's avatar Yehuda Sadeh Committed by Sage Weil
Browse files

ceph: fix short synchronous reads 



Zeroing of holes was not done correctly: page_off was miscalculated and
zeroing the tail didn't not adjust the 'read' value to include the zeroed
portion.

Signed-off-by: default avatarYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent 02f90c61

fs/ceph/file.c

+9 −9
Original line number Diff line number Diff line
@@ -395,23 +395,22 @@ static void zero_page_vector_range(int off, int len, struct page **pages) 
{

	int i = off >> PAGE_CACHE_SHIFT;



	off &= ~PAGE_CACHE_MASK;



	dout("zero_page_vector_page %u~%u\n", off, len);

	BUG_ON(len < PAGE_CACHE_SIZE);



	/* leading partial page? */

	if (off & ~PAGE_CACHE_MASK) {

	if (off) {

		int end = min((int)PAGE_CACHE_SIZE, off + len);

		dout("zeroing %d %p head from %d\n", i, pages[i],

		     (int)(off & ~PAGE_CACHE_MASK));

		zero_user_segment(pages[i], off & ~PAGE_CACHE_MASK,

				  PAGE_CACHE_SIZE);

		off += PAGE_CACHE_SIZE;

		off &= PAGE_CACHE_MASK;

		     (int)off);

		zero_user_segment(pages[i], off, end);

		len -= (end - off);

		i++;

	}

	while (len >= PAGE_CACHE_SIZE) {

		dout("zeroing %d %p\n", i, pages[i]);

		zero_user_segment(pages[i], 0, PAGE_CACHE_SIZE);

		off += PAGE_CACHE_SIZE;

		len -= PAGE_CACHE_SIZE;

		i++;

	}
@@ -437,7 +436,7 @@ static int striped_read(struct inode *inode, 
	struct ceph_client *client = ceph_inode_to_client(inode);

	struct ceph_inode_info *ci = ceph_inode(inode);

	u64 pos, this_len;

	int page_off = off & ~PAGE_CACHE_SIZE; /* first byte's offset in page */

	int page_off = off & ~PAGE_CACHE_MASK; /* first byte's offset in page */

	int left, pages_left;

	int read;

	struct page **page_pos;
@@ -493,6 +492,7 @@ more: 
			dout("zero tail\n");

			zero_page_vector_range(page_off + read, len - read,

					       pages);

			read = len;

			goto out;

		}