ceph: revert commit 22cddde104

commit 22cddde104 breaks the atomicity of write operation, it also
introduces a deadlock between write and truncate.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>

Conflicts:
	fs/ceph/addr.c

3 files changed, 48 insertions, 77 deletions

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index a60ea977af6f..2a571fb4803b 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1067,51 +1067,23 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
                             struct page **pagep, void **fsdata)
 {
         struct inode *inode = file_inode(file);
-        struct ceph_inode_info *ci = ceph_inode(inode);
-        struct ceph_file_info *fi = file->private_data;
         struct page *page;
         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
-        int r, want, got = 0;
-
-        if (fi->fmode & CEPH_FILE_MODE_LAZY)
-                want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
-        else
-                want = CEPH_CAP_FILE_BUFFER;
-
-        dout("write_begin %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
-             inode, ceph_vinop(inode), pos, len, inode->i_size);
-        r = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos+len);
-        if (r < 0)
-                return r;
-        dout("write_begin %p %llx.%llx %llu~%u  got cap refs on %s\n",
-             inode, ceph_vinop(inode), pos, len, ceph_cap_string(got));
-        if (!(got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO))) {
-                ceph_put_cap_refs(ci, got);
-                return -EAGAIN;
-        }
+        int r;
 
         do {
                 /* get a page */
                 page = grab_cache_page_write_begin(mapping, index, 0);
-                if (!page) {
-                        r = -ENOMEM;
-                        break;
-                }
+                if (!page)
+                        return -ENOMEM;
+                *pagep = page;
 
                 dout("write_begin file %p inode %p page %p %d~%d\n", file,
                      inode, page, (int)pos, (int)len);
 
                 r = ceph_update_writeable_page(file, pos, len, page);
-                if (r)
-                        page_cache_release(page);
         } while (r == -EAGAIN);
 
-        if (r) {
-                ceph_put_cap_refs(ci, got);
-        } else {
-                *pagep = page;
-                *(int *)fsdata = got;
-        }
         return r;
 }
 
@@ -1125,12 +1097,10 @@ static int ceph_write_end(struct file *file, struct address_space *mapping,
                           struct page *page, void *fsdata)
 {
         struct inode *inode = file_inode(file);
-        struct ceph_inode_info *ci = ceph_inode(inode);
         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
         struct ceph_mds_client *mdsc = fsc->mdsc;
         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
         int check_cap = 0;
-        int got = (unsigned long)fsdata;
 
         dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
              inode, page, (int)pos, (int)copied, (int)len);
@@ -1153,19 +1123,6 @@ static int ceph_write_end(struct file *file, struct address_space *mapping,
         up_read(&mdsc->snap_rwsem);
         page_cache_release(page);
 
-        if (copied > 0) {
-                int dirty;
-                spin_lock(&ci->i_ceph_lock);
-                dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
-                spin_unlock(&ci->i_ceph_lock);
-                if (dirty)
-                        __mark_inode_dirty(inode, dirty);
-        }
-
-        dout("write_end %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
-             inode, ceph_vinop(inode), pos, len, ceph_cap_string(got));
-        ceph_put_cap_refs(ci, got);
-
         if (check_cap)
                 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
 
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index bf338d9b67e3..b86d2a0eb145 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -718,53 +718,63 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
         struct ceph_osd_client *osdc =
                 &ceph_sb_to_client(inode->i_sb)->client->osdc;
         loff_t endoff = pos + iov->iov_len;
-        int got = 0;
-        int ret, err, written;
+        int want, got = 0;
+        int ret, err;
 
         if (ceph_snap(inode) != CEPH_NOSNAP)
                 return -EROFS;
 
 retry_snap:
-        written = 0;
         if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
                 return -ENOSPC;
         __ceph_do_pending_vmtruncate(inode);
+        dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
+             inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+             inode->i_size);
+        if (fi->fmode & CEPH_FILE_MODE_LAZY)
+                want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
+        else
+                want = CEPH_CAP_FILE_BUFFER;
+        ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
+        if (ret < 0)
+                goto out_put;
 
-        /*
-         * try to do a buffered write.  if we don't have sufficient
-         * caps, we'll get -EAGAIN from generic_file_aio_write, or a
-         * short write if we only get caps for some pages.
-         */
-        if (!(iocb->ki_filp->f_flags & O_DIRECT) &&
-            !(inode->i_sb->s_flags & MS_SYNCHRONOUS) &&
-            !(fi->flags & CEPH_F_SYNC)) {
-                ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
-                if (ret >= 0)
-                        written = ret;
+        dout("aio_write %p %llx.%llx %llu~%u  got cap refs on %s\n",
+             inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+             ceph_cap_string(got));
+
+        if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
+            (iocb->ki_filp->f_flags & O_DIRECT) ||
+            (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
+            (fi->flags & CEPH_F_SYNC)) {
+                ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
+                        &iocb->ki_pos);
+        } else {
+                /*
+                 * buffered write; drop Fw early to avoid slow
+                 * revocation if we get stuck on balance_dirty_pages
+                 */
+                int dirty;
 
+                spin_lock(&ci->i_ceph_lock);
+                dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
+                spin_unlock(&ci->i_ceph_lock);
+                ceph_put_cap_refs(ci, got);
+
+                ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
                 if ((ret >= 0 || ret == -EIOCBQUEUED) &&
                     ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)
                      || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
-                        err = vfs_fsync_range(file, pos, pos + written - 1, 1);
+                        err = vfs_fsync_range(file, pos, pos + ret - 1, 1);
                         if (err < 0)
                                 ret = err;
                 }
-                if ((ret < 0 && ret != -EAGAIN) || pos + written >= endoff)
-                        goto out;
-        }
 
-        dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
-             inode, ceph_vinop(inode), pos + written,
-             (unsigned)iov->iov_len - written, inode->i_size);
-        ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, 0, &got, endoff);
-        if (ret < 0)
+                if (dirty)
+                        __mark_inode_dirty(inode, dirty);
                 goto out;
+        }
 
-        dout("aio_write %p %llx.%llx %llu~%u  got cap refs on %s\n",
-             inode, ceph_vinop(inode), pos + written,
-             (unsigned)iov->iov_len - written, ceph_cap_string(got));
-        ret = ceph_sync_write(file, iov->iov_base + written,
-                              iov->iov_len - written, &iocb->ki_pos);
         if (ret >= 0) {
                 int dirty;
                 spin_lock(&ci->i_ceph_lock);
@@ -773,10 +783,13 @@ retry_snap:
                 if (dirty)
                         __mark_inode_dirty(inode, dirty);
         }
+
+out_put:
         dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
-             inode, ceph_vinop(inode), pos + written,
-             (unsigned)iov->iov_len - written, ceph_cap_string(got));
+             inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+             ceph_cap_string(got));
         ceph_put_cap_refs(ci, got);
+
 out:
         if (ret == -EOLDSNAPC) {
                 dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 56da380878c5..9811caae7be4 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1916,6 +1916,7 @@ static void __wake_requests(struct ceph_mds_client *mdsc,
                 req = list_entry(tmp_list.next,
                                  struct ceph_mds_request, r_wait);
                 list_del_init(&req->r_wait);
+                dout(" wake request %p tid %llu\n", req, req->r_tid);
                 __do_request(mdsc, req);
         }
 }