ceph: avoid block operation when !TASK_RUNNING (ceph_get_caps)

we should not do block operation in wait_event_interruptible()'s condition
check function, but reading inline data can block. so move the read inline
data code to ceph_get_caps()

Signed-off-by: Yan, Zheng <zyan@redhat.com>

1 files changed, 42 insertions, 44 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 844b57cb52bd..8172775428a0 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2072,17 +2072,16 @@ static void __take_cap_refs(struct ceph_inode_info *ci, int got)
  * requested from the MDS.
  */
 static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
-                            loff_t endoff, int *got, struct page **pinned_page,
-                            int *check_max, int *err)
+                            loff_t endoff, int *got, int *check_max, int *err)
 {
         struct inode *inode = &ci->vfs_inode;
         int ret = 0;
-        int have, implemented, _got = 0;
+        int have, implemented;
         int file_wanted;
 
         dout("get_cap_refs %p need %s want %s\n", inode,
              ceph_cap_string(need), ceph_cap_string(want));
-again:
+
         spin_lock(&ci->i_ceph_lock);
 
         /* make sure file is actually open */
@@ -2137,8 +2136,8 @@ again:
                      inode, ceph_cap_string(have), ceph_cap_string(not),
                      ceph_cap_string(revoking));
                 if ((revoking & not) == 0) {
-                        _got = need | (have & want);
-                        __take_cap_refs(ci, _got);
+                        *got = need | (have & want);
+                        __take_cap_refs(ci, *got);
                         ret = 1;
                 }
         } else {
@@ -2163,39 +2162,8 @@ again:
 out_unlock:
         spin_unlock(&ci->i_ceph_lock);
 
-        if (ci->i_inline_version != CEPH_INLINE_NONE &&
-            (_got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
-            i_size_read(inode) > 0) {
-                int ret1;
-                struct page *page = find_get_page(inode->i_mapping, 0);
-                if (page) {
-                        if (PageUptodate(page)) {
-                                *pinned_page = page;
-                                goto out;
-                        }
-                        page_cache_release(page);
-                }
-                /*
-                 * drop cap refs first because getattr while holding
-                 * caps refs can cause deadlock.
-                 */
-                ceph_put_cap_refs(ci, _got);
-                _got = 0;
-
-                /* getattr request will bring inline data into page cache */
-                ret1 = __ceph_do_getattr(inode, NULL,
-                                         CEPH_STAT_CAP_INLINE_DATA, true);
-                if (ret1 >= 0) {
-                        ret = 0;
-                        goto again;
-                }
-                *err = ret1;
-                ret = 1;
-        }
-out:
         dout("get_cap_refs %p ret %d got %s\n", inode,
-             ret, ceph_cap_string(_got));
-        *got = _got;
+             ret, ceph_cap_string(*got));
         return ret;
 }
 
@@ -2235,22 +2203,52 @@ static void check_max_size(struct inode *inode, loff_t endoff)
 int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
                   loff_t endoff, int *got, struct page **pinned_page)
 {
-        int check_max, ret, err;
+        int _got, check_max, ret, err = 0;
 
 retry:
         if (endoff > 0)
                 check_max_size(&ci->vfs_inode, endoff);
+        _got = 0;
         check_max = 0;
-        err = 0;
         ret = wait_event_interruptible(ci->i_cap_wq,
-                                       try_get_cap_refs(ci, need, want, endoff,
-                                                        got, pinned_page,
-                                                        &check_max, &err));
+                                try_get_cap_refs(ci, need, want, endoff,
+                                                 &_got, &check_max, &err));
         if (err)
                 ret = err;
+        if (ret < 0)
+                return ret;
+
         if (check_max)
                 goto retry;
-        return ret;
+
+        if (ci->i_inline_version != CEPH_INLINE_NONE &&
+            (_got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
+            i_size_read(&ci->vfs_inode) > 0) {
+                struct page *page = find_get_page(ci->vfs_inode.i_mapping, 0);
+                if (page) {
+                        if (PageUptodate(page)) {
+                                *pinned_page = page;
+                                goto out;
+                        }
+                        page_cache_release(page);
+                }
+                /*
+                 * drop cap refs first because getattr while holding
+                 * caps refs can cause deadlock.
+                 */
+                ceph_put_cap_refs(ci, _got);
+                _got = 0;
+
+                /* getattr request will bring inline data into page cache */
+                ret = __ceph_do_getattr(&ci->vfs_inode, NULL,
+                                        CEPH_STAT_CAP_INLINE_DATA, true);
+                if (ret < 0)
+                        return ret;
+                goto retry;
+        }
+out:
+        *got = _got;
+        return 0;
 }
 
 /*