ceph: track pending caps flushing accurately
Previously we do not trace accurate TID for flushing caps. when
MDS failovers, we have no choice but to re-send all flushing caps
with a new TID. This can cause problem because MDS can has already
flushed some caps and has issued the same caps to other client.
The re-sent cap flush has a new TID, which makes MDS unable to
detect if it has already processed the cap flush.
This patch adds code to track pending caps flushing accurately.
When re-sending cap flush is needed, we use its original flush
TID.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index dc98833..9a25f8d 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1097,7 +1097,8 @@
* caller should hold snap_rwsem (read), s_mutex.
*/
static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
- int op, int used, int want, int retain, int flushing)
+ int op, int used, int want, int retain, int flushing,
+ u64 flush_tid)
__releases(cap->ci->i_ceph_lock)
{
struct ceph_inode_info *ci = cap->ci;
@@ -1115,8 +1116,6 @@
u64 xattr_version = 0;
struct ceph_buffer *xattr_blob = NULL;
int delayed = 0;
- u64 flush_tid = 0;
- int i;
int ret;
bool inline_data;
@@ -1160,24 +1159,7 @@
cap->implemented &= cap->issued | used;
cap->mds_wanted = want;
- if (flushing) {
- /*
- * assign a tid for flush operations so we can avoid
- * flush1 -> dirty1 -> flush2 -> flushack1 -> mark
- * clean type races. track latest tid for every bit
- * so we can handle flush AxFw, flush Fw, and have the
- * first ack clean Ax.
- */
- flush_tid = ++ci->i_cap_flush_last_tid;
- dout(" cap_flush_tid %d\n", (int)flush_tid);
- for (i = 0; i < CEPH_CAP_BITS; i++)
- if (flushing & (1 << i))
- ci->i_cap_flush_tid[i] = flush_tid;
-
- follows = ci->i_head_snapc->seq;
- } else {
- follows = 0;
- }
+ follows = flushing ? ci->i_head_snapc->seq : 0;
keep = cap->implemented;
seq = cap->seq;
@@ -1311,7 +1293,10 @@
goto retry;
}
- capsnap->flush_tid = ++ci->i_cap_flush_last_tid;
+ spin_lock(&mdsc->cap_dirty_lock);
+ capsnap->flush_tid = ++mdsc->last_cap_flush_tid;
+ spin_unlock(&mdsc->cap_dirty_lock);
+
atomic_inc(&capsnap->nref);
if (list_empty(&capsnap->flushing_item))
list_add_tail(&capsnap->flushing_item,
@@ -1407,6 +1392,29 @@
return dirty;
}
+static void __add_cap_flushing_to_inode(struct ceph_inode_info *ci,
+ struct ceph_cap_flush *cf)
+{
+ struct rb_node **p = &ci->i_cap_flush_tree.rb_node;
+ struct rb_node *parent = NULL;
+ struct ceph_cap_flush *other = NULL;
+
+ while (*p) {
+ parent = *p;
+ other = rb_entry(parent, struct ceph_cap_flush, i_node);
+
+ if (cf->tid < other->tid)
+ p = &(*p)->rb_left;
+ else if (cf->tid > other->tid)
+ p = &(*p)->rb_right;
+ else
+ BUG();
+ }
+
+ rb_link_node(&cf->i_node, parent, p);
+ rb_insert_color(&cf->i_node, &ci->i_cap_flush_tree);
+}
+
/*
* Add dirty inode to the flushing list. Assigned a seq number so we
* can wait for caps to flush without starving.
@@ -1414,10 +1422,12 @@
* Called under i_ceph_lock.
*/
static int __mark_caps_flushing(struct inode *inode,
- struct ceph_mds_session *session)
+ struct ceph_mds_session *session,
+ u64 *flush_tid)
{
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_cap_flush *cf;
int flushing;
BUG_ON(ci->i_dirty_caps == 0);
@@ -1432,9 +1442,14 @@
ci->i_dirty_caps = 0;
dout(" inode %p now !dirty\n", inode);
+ cf = kmalloc(sizeof(*cf), GFP_ATOMIC);
+ cf->caps = flushing;
+
spin_lock(&mdsc->cap_dirty_lock);
list_del_init(&ci->i_dirty_item);
+ cf->tid = ++mdsc->last_cap_flush_tid;
+
if (list_empty(&ci->i_flushing_item)) {
ci->i_cap_flush_seq = ++mdsc->cap_flush_seq;
list_add_tail(&ci->i_flushing_item, &session->s_cap_flushing);
@@ -1448,6 +1463,9 @@
}
spin_unlock(&mdsc->cap_dirty_lock);
+ __add_cap_flushing_to_inode(ci, cf);
+
+ *flush_tid = cf->tid;
return flushing;
}
@@ -1493,6 +1511,7 @@
struct ceph_mds_client *mdsc = fsc->mdsc;
struct inode *inode = &ci->vfs_inode;
struct ceph_cap *cap;
+ u64 flush_tid;
int file_wanted, used, cap_used;
int took_snap_rwsem = 0; /* true if mdsc->snap_rwsem held */
int issued, implemented, want, retain, revoking, flushing = 0;
@@ -1711,17 +1730,20 @@
took_snap_rwsem = 1;
}
- if (cap == ci->i_auth_cap && ci->i_dirty_caps)
- flushing = __mark_caps_flushing(inode, session);
- else
+ if (cap == ci->i_auth_cap && ci->i_dirty_caps) {
+ flushing = __mark_caps_flushing(inode, session,
+ &flush_tid);
+ } else {
flushing = 0;
+ flush_tid = 0;
+ }
mds = cap->mds; /* remember mds, so we don't repeat */
sent++;
/* __send_cap drops i_ceph_lock */
delayed += __send_cap(mdsc, cap, CEPH_CAP_OP_UPDATE, cap_used,
- want, retain, flushing);
+ want, retain, flushing, flush_tid);
goto retry; /* retake i_ceph_lock and restart our cap scan. */
}
@@ -1750,12 +1772,13 @@
/*
* Try to flush dirty caps back to the auth mds.
*/
-static int try_flush_caps(struct inode *inode, u16 flush_tid[])
+static int try_flush_caps(struct inode *inode, u64 *ptid)
{
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_session *session = NULL;
int flushing = 0;
+ u64 flush_tid = 0;
retry:
spin_lock(&ci->i_ceph_lock);
@@ -1780,46 +1803,52 @@
if (cap->session->s_state < CEPH_MDS_SESSION_OPEN)
goto out;
- flushing = __mark_caps_flushing(inode, session);
+ flushing = __mark_caps_flushing(inode, session, &flush_tid);
/* __send_cap drops i_ceph_lock */
delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, used, want,
- cap->issued | cap->implemented, flushing);
+ (cap->issued | cap->implemented),
+ flushing, flush_tid);
- spin_lock(&ci->i_ceph_lock);
- if (delayed)
+ if (delayed) {
+ spin_lock(&ci->i_ceph_lock);
__cap_delay_requeue(mdsc, ci);
+ spin_unlock(&ci->i_ceph_lock);
+ }
+ } else {
+ struct rb_node *n = rb_last(&ci->i_cap_flush_tree);
+ if (n) {
+ struct ceph_cap_flush *cf =
+ rb_entry(n, struct ceph_cap_flush, i_node);
+ flush_tid = cf->tid;
+ }
+ flushing = ci->i_flushing_caps;
+ spin_unlock(&ci->i_ceph_lock);
}
-
- flushing = ci->i_flushing_caps;
- if (flushing)
- memcpy(flush_tid, ci->i_cap_flush_tid,
- sizeof(ci->i_cap_flush_tid));
out:
- spin_unlock(&ci->i_ceph_lock);
if (session)
mutex_unlock(&session->s_mutex);
+
+ *ptid = flush_tid;
return flushing;
}
/*
* Return true if we've flushed caps through the given flush_tid.
*/
-static int caps_are_flushed(struct inode *inode, u16 flush_tid[])
+static int caps_are_flushed(struct inode *inode, u64 flush_tid)
{
struct ceph_inode_info *ci = ceph_inode(inode);
- int i, ret = 1;
+ struct ceph_cap_flush *cf;
+ struct rb_node *n;
+ int ret = 1;
spin_lock(&ci->i_ceph_lock);
- for (i = 0; i < CEPH_CAP_BITS; i++) {
- if (!(ci->i_flushing_caps & (1 << i)))
- continue;
- // tid only has 16 bits. we need to handle wrapping
- if ((s16)(ci->i_cap_flush_tid[i] - flush_tid[i]) <= 0) {
- /* still flushing this bit */
+ n = rb_first(&ci->i_cap_flush_tree);
+ if (n) {
+ cf = rb_entry(n, struct ceph_cap_flush, i_node);
+ if (cf->tid <= flush_tid)
ret = 0;
- break;
- }
}
spin_unlock(&ci->i_ceph_lock);
return ret;
@@ -1922,7 +1951,7 @@
{
struct inode *inode = file->f_mapping->host;
struct ceph_inode_info *ci = ceph_inode(inode);
- u16 flush_tid[CEPH_CAP_BITS];
+ u64 flush_tid;
int ret;
int dirty;
@@ -1938,7 +1967,7 @@
mutex_lock(&inode->i_mutex);
- dirty = try_flush_caps(inode, flush_tid);
+ dirty = try_flush_caps(inode, &flush_tid);
dout("fsync dirty caps are %s\n", ceph_cap_string(dirty));
ret = unsafe_dirop_wait(inode);
@@ -1967,14 +1996,14 @@
int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)
{
struct ceph_inode_info *ci = ceph_inode(inode);
- u16 flush_tid[CEPH_CAP_BITS];
+ u64 flush_tid;
int err = 0;
int dirty;
int wait = wbc->sync_mode == WB_SYNC_ALL;
dout("write_inode %p wait=%d\n", inode, wait);
if (wait) {
- dirty = try_flush_caps(inode, flush_tid);
+ dirty = try_flush_caps(inode, &flush_tid);
if (dirty)
err = wait_event_interruptible(ci->i_cap_wq,
caps_are_flushed(inode, flush_tid));
@@ -2022,6 +2051,51 @@
}
}
+static int __kick_flushing_caps(struct ceph_mds_client *mdsc,
+ struct ceph_mds_session *session,
+ struct ceph_inode_info *ci)
+{
+ struct inode *inode = &ci->vfs_inode;
+ struct ceph_cap *cap;
+ struct ceph_cap_flush *cf;
+ struct rb_node *n;
+ int delayed = 0;
+ u64 first_tid = 0;
+
+ while (true) {
+ spin_lock(&ci->i_ceph_lock);
+ cap = ci->i_auth_cap;
+ if (!(cap && cap->session == session)) {
+ pr_err("%p auth cap %p not mds%d ???\n", inode,
+ cap, session->s_mds);
+ spin_unlock(&ci->i_ceph_lock);
+ break;
+ }
+
+ for (n = rb_first(&ci->i_cap_flush_tree); n; n = rb_next(n)) {
+ cf = rb_entry(n, struct ceph_cap_flush, i_node);
+ if (cf->tid >= first_tid)
+ break;
+ }
+ if (!n) {
+ spin_unlock(&ci->i_ceph_lock);
+ break;
+ }
+
+ cf = rb_entry(n, struct ceph_cap_flush, i_node);
+ first_tid = cf->tid + 1;
+
+ dout("kick_flushing_caps %p cap %p tid %llu %s\n", inode,
+ cap, cf->tid, ceph_cap_string(cf->caps));
+ delayed |= __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
+ __ceph_caps_used(ci),
+ __ceph_caps_wanted(ci),
+ cap->issued | cap->implemented,
+ cf->caps, cf->tid);
+ }
+ return delayed;
+}
+
void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session)
{
@@ -2031,28 +2105,10 @@
dout("kick_flushing_caps mds%d\n", session->s_mds);
list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
- struct inode *inode = &ci->vfs_inode;
- struct ceph_cap *cap;
- int delayed = 0;
-
- spin_lock(&ci->i_ceph_lock);
- cap = ci->i_auth_cap;
- if (cap && cap->session == session) {
- dout("kick_flushing_caps %p cap %p %s\n", inode,
- cap, ceph_cap_string(ci->i_flushing_caps));
- delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
- __ceph_caps_used(ci),
- __ceph_caps_wanted(ci),
- cap->issued | cap->implemented,
- ci->i_flushing_caps);
- if (delayed) {
- spin_lock(&ci->i_ceph_lock);
- __cap_delay_requeue(mdsc, ci);
- spin_unlock(&ci->i_ceph_lock);
- }
- } else {
- pr_err("%p auth cap %p not mds%d ???\n", inode,
- cap, session->s_mds);
+ int delayed = __kick_flushing_caps(mdsc, session, ci);
+ if (delayed) {
+ spin_lock(&ci->i_ceph_lock);
+ __cap_delay_requeue(mdsc, ci);
spin_unlock(&ci->i_ceph_lock);
}
}
@@ -2064,7 +2120,6 @@
{
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_cap *cap;
- int delayed = 0;
spin_lock(&ci->i_ceph_lock);
cap = ci->i_auth_cap;
@@ -2074,16 +2129,16 @@
__ceph_flush_snaps(ci, &session, 1);
if (ci->i_flushing_caps) {
+ int delayed;
+
spin_lock(&mdsc->cap_dirty_lock);
list_move_tail(&ci->i_flushing_item,
&cap->session->s_cap_flushing);
spin_unlock(&mdsc->cap_dirty_lock);
- delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
- __ceph_caps_used(ci),
- __ceph_caps_wanted(ci),
- cap->issued | cap->implemented,
- ci->i_flushing_caps);
+ spin_unlock(&ci->i_ceph_lock);
+
+ delayed = __kick_flushing_caps(mdsc, session, ci);
if (delayed) {
spin_lock(&ci->i_ceph_lock);
__cap_delay_requeue(mdsc, ci);
@@ -2836,16 +2891,29 @@
{
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+ struct ceph_cap_flush *cf;
+ struct rb_node *n;
+ LIST_HEAD(to_remove);
unsigned seq = le32_to_cpu(m->seq);
int dirty = le32_to_cpu(m->dirty);
int cleaned = 0;
int drop = 0;
- int i;
- for (i = 0; i < CEPH_CAP_BITS; i++)
- if ((dirty & (1 << i)) &&
- (u16)flush_tid == ci->i_cap_flush_tid[i])
- cleaned |= 1 << i;
+ n = rb_first(&ci->i_cap_flush_tree);
+ while (n) {
+ cf = rb_entry(n, struct ceph_cap_flush, i_node);
+ n = rb_next(&cf->i_node);
+ if (cf->tid == flush_tid)
+ cleaned = cf->caps;
+ if (cf->tid <= flush_tid) {
+ rb_erase(&cf->i_node, &ci->i_cap_flush_tree);
+ list_add_tail(&cf->list, &to_remove);
+ } else {
+ cleaned &= ~cf->caps;
+ if (!cleaned)
+ break;
+ }
+ }
dout("handle_cap_flush_ack inode %p mds%d seq %d on %s cleaned %s,"
" flushing %s -> %s\n",
@@ -2890,6 +2958,13 @@
out:
spin_unlock(&ci->i_ceph_lock);
+
+ while (!list_empty(&to_remove)) {
+ cf = list_first_entry(&to_remove,
+ struct ceph_cap_flush, list);
+ list_del(&cf->list);
+ kfree(cf);
+ }
if (drop)
iput(inode);
}