diff options
Diffstat (limited to 'fs/ceph/snap.c')
-rw-r--r-- | fs/ceph/snap.c | 49 |
1 files changed, 37 insertions, 12 deletions
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index 5bfdab9a..ba70801 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -436,6 +436,14 @@ static int dup_array(u64 **dst, __le64 *src, u32 num) return 0; } +static bool has_new_snaps(struct ceph_snap_context *o, + struct ceph_snap_context *n) +{ + if (n->num_snaps == 0) + return false; + /* snaps are in descending order */ + return n->snaps[0] > o->seq; +} /* * When a snapshot is applied, the size/mtime inode metadata is queued @@ -455,7 +463,7 @@ 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; + struct ceph_snap_context *old_snapc, *new_snapc; int used, dirty; capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS); @@ -469,6 +477,7 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci) dirty = __ceph_caps_dirty(ci); old_snapc = ci->i_head_snapc; + new_snapc = ci->i_snap_realm->cached_context; /* * If there is a write in progress, treat that as a dirty Fw, @@ -486,20 +495,37 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci) dout("queue_cap_snap %p already pending\n", inode); goto update_snapc; } - if (ci->i_snap_realm->cached_context == ceph_empty_snapc) { - dout("queue_cap_snap %p empty snapc\n", inode); - goto update_snapc; - } - if (!(dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL| - CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR))) { + if (ci->i_wrbuffer_ref_head == 0 && + !(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) { dout("queue_cap_snap %p nothing dirty|writing\n", inode); goto update_snapc; } BUG_ON(!old_snapc); - dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n", - inode, capsnap, old_snapc, ceph_cap_string(dirty)); + /* + * There is no need to send FLUSHSNAP message to MDS if there is + * no new snapshot. But when there is dirty pages or on-going + * writes, we still need to create cap_snap. cap_snap is needed + * by the write path and page writeback path. + * + * also see ceph_try_drop_cap_snap() + */ + if (has_new_snaps(old_snapc, new_snapc)) { + if (dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR)) + capsnap->need_flush = true; + } else { + if (!(used & CEPH_CAP_FILE_WR) && + ci->i_wrbuffer_ref_head == 0) { + dout("queue_cap_snap %p " + "no new_snap|dirty_page|writing\n", inode); + goto update_snapc; + } + } + + dout("queue_cap_snap %p cap_snap %p queuing under %p %s %s\n", + inode, capsnap, old_snapc, ceph_cap_string(dirty), + capsnap->need_flush ? "" : "no_flush"); ihold(inode); atomic_set(&capsnap->nref, 1); @@ -549,9 +575,8 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci) 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); + ci->i_head_snapc = ceph_get_snap_context(new_snapc); + dout(" new snapc is %p\n", new_snapc); } spin_unlock(&ci->i_ceph_lock); |