From: Jeff Layton <jlayton@kernel.org>
Date: Tue, 17 Mar 2020 08:47:31 -0400
Subject: ceph: reorganize __send_cap for less spinlock abuse
Git-commit: 0a454bdd501ad1aa30bb72e9581efa338ad6ce5c
Patch-mainline: v5.8-rc1
References: bsc#1172940
Get rid of the __releases annotation by breaking it up into two
functions: __prep_cap which is done under the spinlock and __send_cap
that is done outside it. Add new fields to cap_msg_args for the wake
boolean and old_xattr_buf pointer.
Nothing checks the return value from __send_cap, so make it void
return.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
fs/ceph/caps.c | 165 ++++++++++++++++++++++++++++++---------------------------
1 file changed, 86 insertions(+), 79 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 82914866affc..8b17f4b4ef7c 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1181,6 +1181,7 @@ struct cap_msg_args {
u64 xattr_version;
u64 change_attr;
struct ceph_buffer *xattr_buf;
+ struct ceph_buffer *old_xattr_buf;
struct timespec64 atime, mtime, ctime, btime;
int op, caps, wanted, dirty;
u32 seq, issue_seq, mseq, time_warp_seq;
@@ -1189,6 +1190,7 @@ struct cap_msg_args {
kgid_t gid;
umode_t mode;
bool inline_data;
+ bool wake;
};
/*
@@ -1318,44 +1320,29 @@ void __ceph_remove_caps(struct ceph_inode_info *ci)
}
/*
- * Send a cap msg on the given inode. Update our caps state, then
- * drop i_ceph_lock and send the message.
+ * Prepare to send a cap message to an MDS. Update the cap state, and populate
+ * the arg struct with the parameters that will need to be sent. This should
+ * be done under the i_ceph_lock to guard against changes to cap state.
*
* Make note of max_size reported/requested from mds, revoked caps
* that have now been implemented.
- *
- * Return non-zero if delayed release, or we experienced an error
- * such that the caller should requeue + retry later.
- *
- * called with i_ceph_lock, then drops it.
- * caller should hold snap_rwsem (read), s_mutex.
*/
-static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
- int op, int flags, int used, int want, int retain,
- int flushing, u64 flush_tid, u64 oldest_flush_tid)
- __releases(cap->ci->i_ceph_lock)
+static void __prep_cap(struct cap_msg_args *arg, struct ceph_cap *cap,
+ int op, int flags, int used, int want, int retain,
+ int flushing, u64 flush_tid, u64 oldest_flush_tid)
{
struct ceph_inode_info *ci = cap->ci;
struct inode *inode = &ci->vfs_inode;
- struct ceph_buffer *old_blob = NULL;
- struct cap_msg_args arg;
int held, revoking;
- int wake = 0;
- int ret;
- /* Don't send anything if it's still being created. Return delayed */
- if (ci->i_ceph_flags & CEPH_I_ASYNC_CREATE) {
- spin_unlock(&ci->i_ceph_lock);
- dout("%s async create in flight for %p\n", __func__, inode);
- return 1;
- }
+ lockdep_assert_held(&ci->i_ceph_lock);
held = cap->issued | cap->implemented;
revoking = cap->implemented & ~cap->issued;
retain &= ~revoking;
- dout("__send_cap %p cap %p session %p %s -> %s (revoking %s)\n",
- inode, cap, cap->session,
+ dout("%s %p cap %p session %p %s -> %s (revoking %s)\n",
+ __func__, inode, cap, cap->session,
ceph_cap_string(held), ceph_cap_string(held & retain),
ceph_cap_string(revoking));
BUG_ON((retain & CEPH_CAP_PIN) == 0);
@@ -1363,60 +1350,58 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
ci->i_ceph_flags &= ~CEPH_I_FLUSH;
cap->issued &= retain; /* drop bits we don't want */
- if (cap->implemented & ~cap->issued) {
- /*
- * Wake up any waiters on wanted -> needed transition.
- * This is due to the weird transition from buffered
- * to sync IO... we need to flush dirty pages _before_
- * allowing sync writes to avoid reordering.
- */
- wake = 1;
- }
+ /*
+ * Wake up any waiters on wanted -> needed transition. This is due to
+ * the weird transition from buffered to sync IO... we need to flush
+ * dirty pages _before_ allowing sync writes to avoid reordering.
+ */
+ arg->wake = cap->implemented & ~cap->issued;
cap->implemented &= cap->issued | used;
cap->mds_wanted = want;
- arg.session = cap->session;
- arg.ino = ceph_vino(inode).ino;
- arg.cid = cap->cap_id;
- arg.follows = flushing ? ci->i_head_snapc->seq : 0;
- arg.flush_tid = flush_tid;
- arg.oldest_flush_tid = oldest_flush_tid;
+ arg->session = cap->session;
+ arg->ino = ceph_vino(inode).ino;
+ arg->cid = cap->cap_id;
+ arg->follows = flushing ? ci->i_head_snapc->seq : 0;
+ arg->flush_tid = flush_tid;
+ arg->oldest_flush_tid = oldest_flush_tid;
- arg.size = inode->i_size;
- ci->i_reported_size = arg.size;
- arg.max_size = ci->i_wanted_max_size;
+ arg->size = inode->i_size;
+ ci->i_reported_size = arg->size;
+ arg->max_size = ci->i_wanted_max_size;
if (cap == ci->i_auth_cap)
- ci->i_requested_max_size = arg.max_size;
+ ci->i_requested_max_size = arg->max_size;
if (flushing & CEPH_CAP_XATTR_EXCL) {
- old_blob = __ceph_build_xattrs_blob(ci);
- arg.xattr_version = ci->i_xattrs.version;
- arg.xattr_buf = ci->i_xattrs.blob;
+ arg->old_xattr_buf = __ceph_build_xattrs_blob(ci);
+ arg->xattr_version = ci->i_xattrs.version;
+ arg->xattr_buf = ci->i_xattrs.blob;
} else {
- arg.xattr_buf = NULL;
+ arg->xattr_buf = NULL;
+ arg->old_xattr_buf = NULL;
}
- arg.mtime = inode->i_mtime;
- arg.atime = inode->i_atime;
- arg.ctime = inode->i_ctime;
- arg.btime = ci->i_btime;
- arg.change_attr = inode_peek_iversion_raw(inode);
+ arg->mtime = inode->i_mtime;
+ arg->atime = inode->i_atime;
+ arg->ctime = inode->i_ctime;
+ arg->btime = ci->i_btime;
+ arg->change_attr = inode_peek_iversion_raw(inode);
- arg.op = op;
- arg.caps = cap->implemented;
- arg.wanted = want;
- arg.dirty = flushing;
+ arg->op = op;
+ arg->caps = cap->implemented;
+ arg->wanted = want;
+ arg->dirty = flushing;
- arg.seq = cap->seq;
- arg.issue_seq = cap->issue_seq;
- arg.mseq = cap->mseq;
- arg.time_warp_seq = ci->i_time_warp_seq;
+ arg->seq = cap->seq;
+ arg->issue_seq = cap->issue_seq;
+ arg->mseq = cap->mseq;
+ arg->time_warp_seq = ci->i_time_warp_seq;
- arg.uid = inode->i_uid;
- arg.gid = inode->i_gid;
- arg.mode = inode->i_mode;
+ arg->uid = inode->i_uid;
+ arg->gid = inode->i_gid;
+ arg->mode = inode->i_mode;
- arg.inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
+ arg->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
if (!(flags & CEPH_CLIENT_CAPS_PENDING_CAPSNAP) &&
!list_empty(&ci->i_cap_snaps)) {
struct ceph_cap_snap *capsnap;
@@ -1429,27 +1414,35 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
}
}
}
- arg.flags = flags;
-
- spin_unlock(&ci->i_ceph_lock);
+ arg->flags = flags;
+}
- ceph_buffer_put(old_blob);
+/*
+ * Send a cap msg on the given inode.
+ *
+ * Caller should hold snap_rwsem (read), s_mutex.
+ */
+static void __send_cap(struct ceph_mds_client *mdsc, struct cap_msg_args *arg,
+ struct ceph_inode_info *ci)
+{
+ struct inode *inode = &ci->vfs_inode;
+ int ret;
- ret = send_cap_msg(&arg);
+ ret = send_cap_msg(arg);
if (ret < 0) {
pr_err("error sending cap msg, ino (%llx.%llx) "
"flushing %s tid %llu, requeue\n",
- ceph_vinop(inode), ceph_cap_string(flushing),
- flush_tid);
+ ceph_vinop(inode), ceph_cap_string(arg->dirty),
+ arg->flush_tid);
spin_lock(&ci->i_ceph_lock);
__cap_delay_requeue(mdsc, ci);
spin_unlock(&ci->i_ceph_lock);
}
- if (wake)
- wake_up_all(&ci->i_cap_wq);
+ ceph_buffer_put(arg->old_xattr_buf);
- return ret;
+ if (arg->wake)
+ wake_up_all(&ci->i_cap_wq);
}
static inline int __send_flush_snap(struct inode *inode,
@@ -1470,6 +1463,7 @@ static inline int __send_flush_snap(struct inode *inode,
arg.max_size = 0;
arg.xattr_version = capsnap->xattr_version;
arg.xattr_buf = capsnap->xattr_blob;
+ arg.old_xattr_buf = NULL;
arg.atime = capsnap->atime;
arg.mtime = capsnap->mtime;
@@ -1493,6 +1487,7 @@ static inline int __send_flush_snap(struct inode *inode,
arg.inline_data = capsnap->inline_data;
arg.flags = 0;
+ arg.wake = false;
return send_cap_msg(&arg);
}
@@ -1967,6 +1962,8 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
}
for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+ struct cap_msg_args arg;
+
cap = rb_entry(p, struct ceph_cap, ci_node);
/* avoid looping forever */
@@ -2094,9 +2091,12 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
mds = cap->mds; /* remember mds, so we don't repeat */
- /* __send_cap drops i_ceph_lock */
- __send_cap(mdsc, cap, CEPH_CAP_OP_UPDATE, 0, cap_used, want,
+ __prep_cap(&arg, cap, CEPH_CAP_OP_UPDATE, 0, cap_used, want,
retain, flushing, flush_tid, oldest_flush_tid);
+ spin_unlock(&ci->i_ceph_lock);
+
+ __send_cap(mdsc, &arg, ci);
+
goto retry; /* retake i_ceph_lock and restart our cap scan. */
}
@@ -2135,6 +2135,7 @@ static int try_flush_caps(struct inode *inode, u64 *ptid)
retry_locked:
if (ci->i_dirty_caps && ci->i_auth_cap) {
struct ceph_cap *cap = ci->i_auth_cap;
+ struct cap_msg_args arg;
if (session != cap->session) {
spin_unlock(&ci->i_ceph_lock);
@@ -2162,11 +2163,13 @@ static int try_flush_caps(struct inode *inode, u64 *ptid)
flush_tid = __mark_caps_flushing(inode, session, true,
&oldest_flush_tid);
- /* __send_cap drops i_ceph_lock */
- __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, CEPH_CLIENT_CAPS_SYNC,
+ __prep_cap(&arg, cap, CEPH_CAP_OP_FLUSH, CEPH_CLIENT_CAPS_SYNC,
__ceph_caps_used(ci), __ceph_caps_wanted(ci),
(cap->issued | cap->implemented),
flushing, flush_tid, oldest_flush_tid);
+ spin_unlock(&ci->i_ceph_lock);
+
+ __send_cap(mdsc, &arg, ci);
} else {
if (!list_empty(&ci->i_cap_flush_list)) {
struct ceph_cap_flush *cf =
@@ -2368,15 +2371,19 @@ static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
first_tid = cf->tid + 1;
if (cf->caps) {
+ struct cap_msg_args arg;
+
dout("kick_flushing_caps %p cap %p tid %llu %s\n",
inode, cap, cf->tid, ceph_cap_string(cf->caps));
- __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
+ __prep_cap(&arg, cap, CEPH_CAP_OP_FLUSH,
(cf->tid < last_snap_flush ?
CEPH_CLIENT_CAPS_PENDING_CAPSNAP : 0),
__ceph_caps_used(ci),
__ceph_caps_wanted(ci),
(cap->issued | cap->implemented),
cf->caps, cf->tid, oldest_flush_tid);
+ spin_unlock(&ci->i_ceph_lock);
+ __send_cap(mdsc, &arg, ci);
} else {
struct ceph_cap_snap *capsnap =
container_of(cf, struct ceph_cap_snap,