ceph: fix readpage from fscache
ceph_readpage() unlocks page prematurely prematurely in the case
that page is reading from fscache. Caller of readpage expects that
page is uptodate when it get unlocked. So page shoule get locked
by completion callback of fscache_read_or_alloc_pages()
Cc: stable@vger.kernel.org # 4.1+, needs backporting for < 4.7
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 5083628..1bc709f 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -189,7 +189,7 @@
/*
* read a single page, without unlocking it.
*/
-static int readpage_nounlock(struct file *filp, struct page *page)
+static int ceph_do_readpage(struct file *filp, struct page *page)
{
struct inode *inode = file_inode(filp);
struct ceph_inode_info *ci = ceph_inode(inode);
@@ -219,7 +219,7 @@
err = ceph_readpage_from_fscache(inode, page);
if (err == 0)
- goto out;
+ return -EINPROGRESS;
dout("readpage inode %p file %p page %p index %lu\n",
inode, filp, page, page->index);
@@ -249,8 +249,11 @@
static int ceph_readpage(struct file *filp, struct page *page)
{
- int r = readpage_nounlock(filp, page);
- unlock_page(page);
+ int r = ceph_do_readpage(filp, page);
+ if (r != -EINPROGRESS)
+ unlock_page(page);
+ else
+ r = 0;
return r;
}
@@ -1237,7 +1240,7 @@
goto retry_locked;
r = writepage_nounlock(page, NULL);
if (r < 0)
- goto fail_nosnap;
+ goto fail_unlock;
goto retry_locked;
}
@@ -1265,11 +1268,14 @@
}
/* we need to read it. */
- r = readpage_nounlock(file, page);
- if (r < 0)
- goto fail_nosnap;
+ r = ceph_do_readpage(file, page);
+ if (r < 0) {
+ if (r == -EINPROGRESS)
+ return -EAGAIN;
+ goto fail_unlock;
+ }
goto retry_locked;
-fail_nosnap:
+fail_unlock:
unlock_page(page);
return r;
}
diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c
index fd11728..337f886 100644
--- a/fs/ceph/cache.c
+++ b/fs/ceph/cache.c
@@ -297,13 +297,7 @@
}
}
-static void ceph_vfs_readpage_complete(struct page *page, void *data, int error)
-{
- if (!error)
- SetPageUptodate(page);
-}
-
-static void ceph_vfs_readpage_complete_unlock(struct page *page, void *data, int error)
+static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
{
if (!error)
SetPageUptodate(page);
@@ -331,7 +325,7 @@
return -ENOBUFS;
ret = fscache_read_or_alloc_page(ci->fscache, page,
- ceph_vfs_readpage_complete, NULL,
+ ceph_readpage_from_fscache_complete, NULL,
GFP_KERNEL);
switch (ret) {
@@ -360,7 +354,7 @@
return -ENOBUFS;
ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
- ceph_vfs_readpage_complete_unlock,
+ ceph_readpage_from_fscache_complete,
NULL, mapping_gfp_mask(mapping));
switch (ret) {