ceph: set i_head_snapc when getting CEPH_CAP_FILE_WR reference

[firefly-linux-kernel-4.4.55.git] / fs / ceph / snap.c

diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index b2a945345d2b97633d1c0ec78adb48c68fdcb21b..5bfdab9a465ed13dd8612a9bec41ebf6976ecd0b 100644 (file)
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -455,6 +455,7 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
 {
        struct inode *inode = &ci->vfs_inode;
        struct ceph_cap_snap *capsnap;
+       struct ceph_snap_context *old_snapc;
        int used, dirty;
 
        capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
@@ -467,6 +468,8 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
        used = __ceph_caps_used(ci);
        dirty = __ceph_caps_dirty(ci);
 
+       old_snapc = ci->i_head_snapc;
+
        /*
         * If there is a write in progress, treat that as a dirty Fw,
         * even though it hasn't completed yet; by the time we finish
@@ -481,76 +484,79 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
                   writes in progress now were started before the previous
                   cap_snap.  lucky us. */
                dout("queue_cap_snap %p already pending\n", inode);
-               kfree(capsnap);
-       } else if (ci->i_snap_realm->cached_context == ceph_empty_snapc) {
+               goto update_snapc;
+       }
+       if (ci->i_snap_realm->cached_context == ceph_empty_snapc) {
                dout("queue_cap_snap %p empty snapc\n", inode);
-               kfree(capsnap);
-       } else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
-                           CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) {
-               struct ceph_snap_context *snapc = ci->i_head_snapc;
+               goto update_snapc;
+       }
+       if (!(dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
+                      CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR))) {
+               dout("queue_cap_snap %p nothing dirty|writing\n", inode);
+               goto update_snapc;
+       }
 
-               /*
-                * if we are a sync write, we may need to go to the snaprealm
-                * to get the current snapc.
-                */
-               if (!snapc)
-                       snapc = ci->i_snap_realm->cached_context;
+       BUG_ON(!old_snapc);
 
-               dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n",
-                    inode, capsnap, snapc, ceph_cap_string(dirty));
-               ihold(inode);
+       dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n",
+            inode, capsnap, old_snapc, ceph_cap_string(dirty));
+       ihold(inode);
 
-               atomic_set(&capsnap->nref, 1);
-               capsnap->ci = ci;
-               INIT_LIST_HEAD(&capsnap->ci_item);
-               INIT_LIST_HEAD(&capsnap->flushing_item);
-
-               capsnap->follows = snapc->seq;
-               capsnap->issued = __ceph_caps_issued(ci, NULL);
-               capsnap->dirty = dirty;
-
-               capsnap->mode = inode->i_mode;
-               capsnap->uid = inode->i_uid;
-               capsnap->gid = inode->i_gid;
-
-               if (dirty & CEPH_CAP_XATTR_EXCL) {
-                       __ceph_build_xattrs_blob(ci);
-                       capsnap->xattr_blob =
-                               ceph_buffer_get(ci->i_xattrs.blob);
-                       capsnap->xattr_version = ci->i_xattrs.version;
-               } else {
-                       capsnap->xattr_blob = NULL;
-                       capsnap->xattr_version = 0;
-               }
+       atomic_set(&capsnap->nref, 1);
+       capsnap->ci = ci;
+       INIT_LIST_HEAD(&capsnap->ci_item);
+       INIT_LIST_HEAD(&capsnap->flushing_item);
 
-               capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
+       capsnap->follows = old_snapc->seq;
+       capsnap->issued = __ceph_caps_issued(ci, NULL);
+       capsnap->dirty = dirty;
 
-               /* dirty page count moved from _head to this cap_snap;
-                  all subsequent writes page dirties occur _after_ this
-                  snapshot. */
-               capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
-               ci->i_wrbuffer_ref_head = 0;
-               capsnap->context = snapc;
-               ci->i_head_snapc =
-                       ceph_get_snap_context(ci->i_snap_realm->cached_context);
-               dout(" new snapc is %p\n", ci->i_head_snapc);
-               list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
-
-               if (used & CEPH_CAP_FILE_WR) {
-                       dout("queue_cap_snap %p cap_snap %p snapc %p"
-                            " seq %llu used WR, now pending\n", inode,
-                            capsnap, snapc, snapc->seq);
-                       capsnap->writing = 1;
-               } else {
-                       /* note mtime, size NOW. */
-                       __ceph_finish_cap_snap(ci, capsnap);
-               }
+       capsnap->mode = inode->i_mode;
+       capsnap->uid = inode->i_uid;
+       capsnap->gid = inode->i_gid;
+
+       if (dirty & CEPH_CAP_XATTR_EXCL) {
+               __ceph_build_xattrs_blob(ci);
+               capsnap->xattr_blob =
+                       ceph_buffer_get(ci->i_xattrs.blob);
+               capsnap->xattr_version = ci->i_xattrs.version;
        } else {
-               dout("queue_cap_snap %p nothing dirty|writing\n", inode);
-               kfree(capsnap);
+               capsnap->xattr_blob = NULL;
+               capsnap->xattr_version = 0;
        }
 
+       capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
+
+       /* dirty page count moved from _head to this cap_snap;
+          all subsequent writes page dirties occur _after_ this
+          snapshot. */
+       capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
+       ci->i_wrbuffer_ref_head = 0;
+       capsnap->context = old_snapc;
+       list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
+       old_snapc = NULL;
+
+       if (used & CEPH_CAP_FILE_WR) {
+               dout("queue_cap_snap %p cap_snap %p snapc %p"
+                    " seq %llu used WR, now pending\n", inode,
+                    capsnap, old_snapc, old_snapc->seq);
+               capsnap->writing = 1;
+       } else {
+               /* note mtime, size NOW. */
+               __ceph_finish_cap_snap(ci, capsnap);
+       }
+       capsnap = NULL;
+
+update_snapc:
+       if (ci->i_head_snapc) {
+               ci->i_head_snapc = ceph_get_snap_context(
+                               ci->i_snap_realm->cached_context);
+               dout(" new snapc is %p\n", ci->i_head_snapc);
+       }
        spin_unlock(&ci->i_ceph_lock);
+
+       kfree(capsnap);
+       ceph_put_snap_context(old_snapc);
 }
 
 /*