From e1518c7c0a67a75727f7285780dbef0ca7121cc9 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Thu, 13 May 2010 11:19:06 -0700 Subject: [PATCH] ceph: clean up mds reply, error handling We would occasionally BUG out in the reply handler because r_reply was nonzero, due to a race with ceph_mdsc_do_request temporarily setting r_reply to an ERR_PTR value. This is unnecessary, messy, and also wrong in the EIO case. Clean up by consistently using r_err for errors and r_reply for messages. Also fix the abort logic to trigger consistently for all errors that return to the caller early (e.g., EIO from timeout case). If an abort races with a reply, use the result from the reply. Also fix locking for r_err, r_reply update in the reply handler. Signed-off-by: Sage Weil --- fs/ceph/mds_client.c | 111 +++++++++++++++++++++---------------------- fs/ceph/mds_client.h | 2 +- 2 files changed, 55 insertions(+), 58 deletions(-) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 24561a557e01..b3b19f05b821 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -1517,7 +1517,7 @@ static int __prepare_send_request(struct ceph_mds_client *mdsc, } msg = create_request_message(mdsc, req, mds); if (IS_ERR(msg)) { - req->r_reply = ERR_PTR(PTR_ERR(msg)); + req->r_err = PTR_ERR(msg); complete_request(mdsc, req); return -PTR_ERR(msg); } @@ -1552,7 +1552,7 @@ static int __do_request(struct ceph_mds_client *mdsc, int mds = -1; int err = -EAGAIN; - if (req->r_reply) + if (req->r_err || req->r_got_result) goto out; if (req->r_timeout && @@ -1609,7 +1609,7 @@ out: return err; finish: - req->r_reply = ERR_PTR(err); + req->r_err = err; complete_request(mdsc, req); goto out; } @@ -1689,59 +1689,53 @@ int ceph_mdsc_do_request(struct ceph_mds_client *mdsc, __register_request(mdsc, req, dir); __do_request(mdsc, req); - /* wait */ - if (!req->r_reply) { - mutex_unlock(&mdsc->mutex); - if (req->r_timeout) { - err = (long)wait_for_completion_interruptible_timeout( - &req->r_completion, req->r_timeout); - if (err == 0) - req->r_reply = ERR_PTR(-EIO); - else if (err < 0) - req->r_reply = ERR_PTR(err); - } else { - err = wait_for_completion_interruptible( - &req->r_completion); - if (err) - req->r_reply = ERR_PTR(err); - } - mutex_lock(&mdsc->mutex); + if (req->r_err) { + err = req->r_err; + __unregister_request(mdsc, req); + dout("do_request early error %d\n", err); + goto out; } - if (IS_ERR(req->r_reply)) { - err = PTR_ERR(req->r_reply); - req->r_reply = NULL; - - if (err == -ERESTARTSYS) { - /* aborted */ - req->r_aborted = true; + /* wait */ + mutex_unlock(&mdsc->mutex); + dout("do_request waiting\n"); + if (req->r_timeout) { + err = (long)wait_for_completion_interruptible_timeout( + &req->r_completion, req->r_timeout); + if (err == 0) + err = -EIO; + } else { + err = wait_for_completion_interruptible(&req->r_completion); + } + dout("do_request waited, got %d\n", err); + mutex_lock(&mdsc->mutex); - if (req->r_locked_dir && - (req->r_op & CEPH_MDS_OP_WRITE)) { - struct ceph_inode_info *ci = - ceph_inode(req->r_locked_dir); + /* only abort if we didn't race with a real reply */ + if (req->r_got_result) { + err = le32_to_cpu(req->r_reply_info.head->result); + } else if (err < 0) { + dout("aborted request %lld with %d\n", req->r_tid, err); + req->r_err = err; + req->r_aborted = true; - dout("aborted, clearing I_COMPLETE on %p\n", - req->r_locked_dir); - spin_lock(&req->r_locked_dir->i_lock); - ci->i_ceph_flags &= ~CEPH_I_COMPLETE; - ci->i_release_count++; - spin_unlock(&req->r_locked_dir->i_lock); - } - } else { - /* clean up this request */ - __unregister_request(mdsc, req); - if (!list_empty(&req->r_unsafe_item)) - list_del_init(&req->r_unsafe_item); - complete(&req->r_safe_completion); + if (req->r_locked_dir && + (req->r_op & CEPH_MDS_OP_WRITE)) { + struct ceph_inode_info *ci = + ceph_inode(req->r_locked_dir); + + dout("aborted, clearing I_COMPLETE on %p\n", + req->r_locked_dir); + spin_lock(&req->r_locked_dir->i_lock); + ci->i_ceph_flags &= ~CEPH_I_COMPLETE; + ci->i_release_count++; + spin_unlock(&req->r_locked_dir->i_lock); } - } else if (req->r_err) { - err = req->r_err; } else { - err = le32_to_cpu(req->r_reply_info.head->result); + err = req->r_err; } - mutex_unlock(&mdsc->mutex); +out: + mutex_unlock(&mdsc->mutex); dout("do_request %p done, result %d\n", req, err); return err; } @@ -1838,11 +1832,7 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg) mutex_unlock(&mdsc->mutex); goto out; } - } - - BUG_ON(req->r_reply); - - if (!head->safe) { + } else { req->r_got_unsafe = true; list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe); } @@ -1880,12 +1870,19 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg) up_read(&mdsc->snap_rwsem); out_err: - if (err) { - req->r_err = err; + mutex_lock(&mdsc->mutex); + if (!req->r_aborted) { + if (err) { + req->r_err = err; + } else { + req->r_reply = msg; + ceph_msg_get(msg); + req->r_got_result = true; + } } else { - req->r_reply = msg; - ceph_msg_get(msg); + dout("reply arrived after request %lld was aborted\n", tid); } + mutex_unlock(&mdsc->mutex); add_cap_releases(mdsc, req->r_session, -1); mutex_unlock(&session->s_mutex); diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h index 961cc6f65878..0b1dd10be39a 100644 --- a/fs/ceph/mds_client.h +++ b/fs/ceph/mds_client.h @@ -213,7 +213,7 @@ struct ceph_mds_request { struct completion r_safe_completion; ceph_mds_request_callback_t r_callback; struct list_head r_unsafe_item; /* per-session unsafe list item */ - bool r_got_unsafe, r_got_safe; + bool r_got_unsafe, r_got_safe, r_got_result; bool r_did_prepopulate; u32 r_readdir_offset; -- 2.20.1