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ceph: track pending caps flushing accurately

Browse source 
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>
This commit is contained in:
Yan, Zheng 2015-06-09 15:48:57 +08:00 committed by Ilya Dryomov
parent 6c13a6bb55
commit 553adfd941
5 changed files with 192 additions and 88 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

245
fs/ceph/caps.c
View file

@ -1097,7 +1097,8 @@ void ceph_queue_caps_release(struct inode *inode)
* 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 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
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 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
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 @@ void __ceph_flush_snaps(struct ceph_inode_info *ci,
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 @@ int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask)
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 @@ int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask)
* 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 @@ static int __mark_caps_flushing(struct inode *inode,
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 @@ static int __mark_caps_flushing(struct inode *inode,
}
spin_unlock(&mdsc->cap_dirty_lock);
__add_cap_flushing_to_inode(ci, cf);
*flush_tid = cf->tid;
return flushing;
}
@ -1493,6 +1511,7 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
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 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
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 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
/*
* 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 @@ static int try_flush_caps(struct inode *inode, u16 flush_tid[])
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 @@ int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
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 @@ int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync)
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_fsync(struct file *file, loff_t start, loff_t end, int datasync)
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 void kick_flushing_capsnaps(struct ceph_mds_client *mdsc,
}
}
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 @@ void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
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 @@ static void kick_flushing_inode_caps(struct ceph_mds_client *mdsc,
{
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 @@ static void kick_flushing_inode_caps(struct ceph_mds_client *mdsc,
__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 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
{
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 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
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);
}

3
fs/ceph/inode.c
View file

@ -417,8 +417,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
INIT_LIST_HEAD(&ci->i_dirty_item);
INIT_LIST_HEAD(&ci->i_flushing_item);
ci->i_cap_flush_seq = 0;
ci->i_cap_flush_last_tid = 0;
memset(&ci->i_cap_flush_tid, 0, sizeof(ci->i_cap_flush_tid));
ci->i_cap_flush_tree = RB_ROOT;
init_waitqueue_head(&ci->i_cap_wq);
ci->i_hold_caps_min = 0;
ci->i_hold_caps_max = 0;

20
fs/ceph/mds_client.c
View file

@ -1142,6 +1142,7 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
void *arg)
{
struct ceph_inode_info *ci = ceph_inode(inode);
LIST_HEAD(to_remove);
int drop = 0;
dout("removing cap %p, ci is %p, inode is %p\n",
@ -1149,9 +1150,19 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
spin_lock(&ci->i_ceph_lock);
__ceph_remove_cap(cap, false);
if (!ci->i_auth_cap) {
struct ceph_cap_flush *cf;
struct ceph_mds_client *mdsc =
ceph_sb_to_client(inode->i_sb)->mdsc;
while (true) {
struct rb_node *n = rb_first(&ci->i_cap_flush_tree);
if (!n)
break;
cf = rb_entry(n, struct ceph_cap_flush, i_node);
rb_erase(&cf->i_node, &ci->i_cap_flush_tree);
list_add(&cf->list, &to_remove);
}
spin_lock(&mdsc->cap_dirty_lock);
if (!list_empty(&ci->i_dirty_item)) {
pr_warn_ratelimited(
@ -1173,8 +1184,16 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
drop = 1;
}
spin_unlock(&mdsc->cap_dirty_lock);
}
spin_unlock(&ci->i_ceph_lock);
while (!list_empty(&to_remove)) {
struct ceph_cap_flush *cf;
cf = list_first_entry(&to_remove,
struct ceph_cap_flush, list);
list_del(&cf->list);
kfree(cf);
}
while (drop--)
iput(inode);
return 0;
@ -3408,6 +3427,7 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
INIT_LIST_HEAD(&mdsc->snap_flush_list);
spin_lock_init(&mdsc->snap_flush_lock);
mdsc->cap_flush_seq = 0;
mdsc->last_cap_flush_tid = 1;
INIT_LIST_HEAD(&mdsc->cap_dirty);
INIT_LIST_HEAD(&mdsc->cap_dirty_migrating);
mdsc->num_cap_flushing = 0;

1
fs/ceph/mds_client.h
View file

@ -307,6 +307,7 @@ struct ceph_mds_client {
spinlock_t snap_flush_lock;
u64 cap_flush_seq;
u64 last_cap_flush_tid;
struct list_head cap_dirty; /* inodes with dirty caps */
struct list_head cap_dirty_migrating; /* ...that are migration... */
int num_cap_flushing; /* # caps we are flushing */

11
fs/ceph/super.h
View file

@ -186,6 +186,15 @@ static inline void ceph_put_cap_snap(struct ceph_cap_snap *capsnap)
}
}
struct ceph_cap_flush {
u64 tid;
int caps;
union {
struct rb_node i_node;
struct list_head list;
};
};
/*
* The frag tree describes how a directory is fragmented, potentially across
* multiple metadata servers. It is also used to indicate points where
@ -299,7 +308,7 @@ struct ceph_inode_info {
/* we need to track cap writeback on a per-cap-bit basis, to allow
* overlapping, pipelined cap flushes to the mds. we can probably
* reduce the tid to 8 bits if we're concerned about inode size. */
u16 i_cap_flush_last_tid, i_cap_flush_tid[CEPH_CAP_BITS];
struct rb_root i_cap_flush_tree;
wait_queue_head_t i_cap_wq; /* threads waiting on a capability */
unsigned long i_hold_caps_min; /* jiffies */
unsigned long i_hold_caps_max; /* jiffies */