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authorYan, Zheng <zyan@redhat.com>2018-03-16 11:22:29 +0800
committerIlya Dryomov <idryomov@gmail.com>2018-03-30 11:17:48 +0200
commit85784f9395987a422fa04263e7c0fb13da11eb5c (patch)
treef8f998acb306c25992468d0a52e9082616b37ea5
parent3eb2ce825ea1ad89d20f7a3b5780df850e4be274 (diff)
downloadlinux-sh-85784f9395987a422fa04263e7c0fb13da11eb5c.tar.gz
ceph: only dirty ITER_IOVEC pages for direct read
If a page is already locked, attempting to dirty it leads to a deadlock in lock_page(). This is what currently happens to ITER_BVEC pages when a dio-enabled loop device is backed by ceph: $ losetup --direct-io /dev/loop0 /mnt/cephfs/img $ xfs_io -c 'pread 0 4k' /dev/loop0 Follow other file systems and only dirty ITER_IOVEC pages. Cc: stable@kernel.org Signed-off-by: "Yan, Zheng" <zyan@redhat.com> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
-rw-r--r--fs/ceph/file.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 6639926eed4e..b67eec3532a1 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -640,7 +640,8 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
struct ceph_aio_request {
struct kiocb *iocb;
size_t total_len;
- int write;
+ bool write;
+ bool should_dirty;
int error;
struct list_head osd_reqs;
unsigned num_reqs;
@@ -750,7 +751,7 @@ static void ceph_aio_complete_req(struct ceph_osd_request *req)
}
}
- ceph_put_page_vector(osd_data->pages, num_pages, !aio_req->write);
+ ceph_put_page_vector(osd_data->pages, num_pages, aio_req->should_dirty);
ceph_osdc_put_request(req);
if (rc < 0)
@@ -847,6 +848,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
size_t count = iov_iter_count(iter);
loff_t pos = iocb->ki_pos;
bool write = iov_iter_rw(iter) == WRITE;
+ bool should_dirty = !write && iter_is_iovec(iter);
if (write && ceph_snap(file_inode(file)) != CEPH_NOSNAP)
return -EROFS;
@@ -914,6 +916,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
if (aio_req) {
aio_req->iocb = iocb;
aio_req->write = write;
+ aio_req->should_dirty = should_dirty;
INIT_LIST_HEAD(&aio_req->osd_reqs);
if (write) {
aio_req->mtime = mtime;
@@ -971,7 +974,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
len = ret;
}
- ceph_put_page_vector(pages, num_pages, !write);
+ ceph_put_page_vector(pages, num_pages, should_dirty);
ceph_osdc_put_request(req);
if (ret < 0)