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-rw-r--r--fs/ceph/caps.c69
-rw-r--r--fs/ceph/snap.c49
-rw-r--r--fs/ceph/super.h5
3 files changed, 78 insertions, 45 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index feb8ec92f1b4..f1dbcae7c75c 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1297,11 +1297,8 @@ retry:
if (capsnap->dirty_pages || capsnap->writing)
break;
- /*
- * if cap writeback already occurred, we should have dropped
- * the capsnap in ceph_put_wrbuffer_cap_refs.
- */
- BUG_ON(capsnap->dirty == 0);
+ /* should be removed by ceph_try_drop_cap_snap() */
+ BUG_ON(!capsnap->need_flush);
/* pick mds, take s_mutex */
if (ci->i_auth_cap == NULL) {
@@ -2347,6 +2344,27 @@ void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps)
spin_unlock(&ci->i_ceph_lock);
}
+
+/*
+ * drop cap_snap that is not associated with any snapshot.
+ * we don't need to send FLUSHSNAP message for it.
+ */
+static int ceph_try_drop_cap_snap(struct ceph_cap_snap *capsnap)
+{
+ if (!capsnap->need_flush &&
+ !capsnap->writing && !capsnap->dirty_pages) {
+
+ dout("dropping cap_snap %p follows %llu\n",
+ capsnap, capsnap->follows);
+ ceph_put_snap_context(capsnap->context);
+ list_del(&capsnap->ci_item);
+ list_del(&capsnap->flushing_item);
+ ceph_put_cap_snap(capsnap);
+ return 1;
+ }
+ return 0;
+}
+
/*
* Release cap refs.
*
@@ -2360,7 +2378,6 @@ void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
{
struct inode *inode = &ci->vfs_inode;
int last = 0, put = 0, flushsnaps = 0, wake = 0;
- struct ceph_cap_snap *capsnap;
spin_lock(&ci->i_ceph_lock);
if (had & CEPH_CAP_PIN)
@@ -2382,17 +2399,17 @@ void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
if (had & CEPH_CAP_FILE_WR)
if (--ci->i_wr_ref == 0) {
last++;
- if (!list_empty(&ci->i_cap_snaps)) {
- capsnap = list_first_entry(&ci->i_cap_snaps,
- struct ceph_cap_snap,
- ci_item);
- if (capsnap->writing) {
- capsnap->writing = 0;
- flushsnaps =
- __ceph_finish_cap_snap(ci,
- capsnap);
- wake = 1;
- }
+ if (__ceph_have_pending_cap_snap(ci)) {
+ struct ceph_cap_snap *capsnap =
+ list_last_entry(&ci->i_cap_snaps,
+ struct ceph_cap_snap,
+ ci_item);
+ capsnap->writing = 0;
+ if (ceph_try_drop_cap_snap(capsnap))
+ put++;
+ else if (__ceph_finish_cap_snap(ci, capsnap))
+ flushsnaps = 1;
+ wake = 1;
}
if (ci->i_wrbuffer_ref_head == 0 &&
ci->i_dirty_caps == 0 &&
@@ -2416,7 +2433,7 @@ void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
ceph_flush_snaps(ci);
if (wake)
wake_up_all(&ci->i_cap_wq);
- if (put)
+ while (put-- > 0)
iput(inode);
}
@@ -2467,25 +2484,15 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
capsnap->dirty_pages -= nr;
if (capsnap->dirty_pages == 0) {
complete_capsnap = 1;
- if (capsnap->dirty == 0)
- /* cap writeback completed before we created
- * the cap_snap; no FLUSHSNAP is needed */
- drop_capsnap = 1;
+ drop_capsnap = ceph_try_drop_cap_snap(capsnap);
}
dout("put_wrbuffer_cap_refs on %p cap_snap %p "
- " snap %lld %d/%d -> %d/%d %s%s%s\n",
+ " snap %lld %d/%d -> %d/%d %s%s\n",
inode, capsnap, capsnap->context->seq,
ci->i_wrbuffer_ref+nr, capsnap->dirty_pages + nr,
ci->i_wrbuffer_ref, capsnap->dirty_pages,
last ? " (wrbuffer last)" : "",
- complete_capsnap ? " (complete capsnap)" : "",
- drop_capsnap ? " (drop capsnap)" : "");
- if (drop_capsnap) {
- ceph_put_snap_context(capsnap->context);
- list_del(&capsnap->ci_item);
- list_del(&capsnap->flushing_item);
- ceph_put_cap_snap(capsnap);
- }
+ complete_capsnap ? " (complete capsnap)" : "");
}
spin_unlock(&ci->i_ceph_lock);
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 5bfdab9a465e..ba708017d60b 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);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index b182fd7499d9..4ef1ae92c2a6 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -164,6 +164,7 @@ struct ceph_cap_snap {
int writing; /* a sync write is still in progress */
int dirty_pages; /* dirty pages awaiting writeback */
bool inline_data;
+ bool need_flush;
};
static inline void ceph_put_cap_snap(struct ceph_cap_snap *capsnap)
@@ -719,8 +720,8 @@ extern void ceph_snap_exit(void);
static inline bool __ceph_have_pending_cap_snap(struct ceph_inode_info *ci)
{
return !list_empty(&ci->i_cap_snaps) &&
- list_entry(ci->i_cap_snaps.prev, struct ceph_cap_snap,
- ci_item)->writing;
+ list_last_entry(&ci->i_cap_snaps, struct ceph_cap_snap,
+ ci_item)->writing;
}
/* inode.c */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 01:44:13 +0000