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Subject[PATCH 4.9 31/78] xfs: Move handling of missing page into one place in xfs_find_get_desired_pgoff()
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@suse.cz>

commit a54fba8f5a0dc36161cacdf2aa90f007f702ec1a upstream.

Currently several places in xfs_find_get_desired_pgoff() handle the case
of a missing page. Make them all handled in one place after the loop has
terminated.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/xfs/xfs_file.c | 38 ++++++++------------------------------
1 file changed, 8 insertions(+), 30 deletions(-)

--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1139,29 +1139,8 @@ xfs_find_get_desired_pgoff(
want = min_t(pgoff_t, end - index, PAGEVEC_SIZE - 1) + 1;
nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
want);
- /*
- * No page mapped into given range. If we are searching holes
- * and if this is the first time we got into the loop, it means
- * that the given offset is landed in a hole, return it.
- *
- * If we have already stepped through some block buffers to find
- * holes but they all contains data. In this case, the last
- * offset is already updated and pointed to the end of the last
- * mapped page, if it does not reach the endpoint to search,
- * that means there should be a hole between them.
- */
- if (nr_pages == 0) {
- /* Data search found nothing */
- if (type == DATA_OFF)
- break;
-
- ASSERT(type == HOLE_OFF);
- if (lastoff == startoff || lastoff < endoff) {
- found = true;
- *offset = lastoff;
- }
+ if (nr_pages == 0)
break;
- }

for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
@@ -1227,21 +1206,20 @@ xfs_find_get_desired_pgoff(

/*
* The number of returned pages less than our desired, search
- * done. In this case, nothing was found for searching data,
- * but we found a hole behind the last offset.
+ * done.
*/
- if (nr_pages < want) {
- if (type == HOLE_OFF) {
- *offset = lastoff;
- found = true;
- }
+ if (nr_pages < want)
break;
- }

index = pvec.pages[i - 1]->index + 1;
pagevec_release(&pvec);
} while (index <= end);

+ /* No page at lastoff and we are not done - we found a hole. */
+ if (type == HOLE_OFF && lastoff < endoff) {
+ *offset = lastoff;
+ found = true;
+ }
out:
pagevec_release(&pvec);
return found;

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