path: root/fs/splice.c
diff options
authorAbhi Das <adas@redhat.com>2015-12-18 14:11:36 -0600
committerAl Viro <viro@zeniv.linux.org.uk>2016-01-09 02:55:35 -0500
commit90330e689c32e5105265c461c54af6ecec3373fa (patch)
tree0dcb8a77f49ecc2f5c24fbb74327ccd4323b20d4 /fs/splice.c
parentfs: xattr: Use kvfree() (diff)
fs: __generic_file_splice_read retry lookup on AOP_TRUNCATED_PAGE
During testing, I discovered that __generic_file_splice_read() returns 0 (EOF) when aops->readpage fails with AOP_TRUNCATED_PAGE on the first page of a single/multi-page splice read operation. This EOF return code causes the userspace test to (correctly) report a zero-length read error when it was expecting otherwise. The current strategy of returning a partial non-zero read when ->readpage returns AOP_TRUNCATED_PAGE works only when the failed page is not the first of the lot being processed. This patch attempts to retry lookup and call ->readpage again on pages that had previously failed with AOP_TRUNCATED_PAGE. With this patch, my tests pass and I haven't noticed any unwanted side effects. This version removes the thrice-retry loop and instead indefinitely retries lookups on AOP_TRUNCATED_PAGE errors from ->readpage. This behavior is now similar to do_generic_file_read(). Signed-off-by: Abhi Das <adas@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Bob Peterson <rpeterso@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/splice.c')
1 files changed, 3 insertions, 5 deletions
diff --git a/fs/splice.c b/fs/splice.c
index 4cf700d50b40..82bc0d64fc38 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -415,6 +415,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
if (!page->mapping) {
page = find_or_create_page(mapping, index,
@@ -439,13 +440,10 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
error = mapping->a_ops->readpage(in, page);
if (unlikely(error)) {
- * We really should re-lookup the page here,
- * but it complicates things a lot. Instead
- * lets just do what we already stored, and
- * we'll get it the next time we are called.
+ * Re-lookup the page
if (error == AOP_TRUNCATED_PAGE)
- error = 0;
+ goto retry_lookup;