From 2cd698be9a3d3a0f8f3c66814eac34144c31954c Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Fri, 18 Apr 2014 13:20:27 +0800 Subject: ceph: handle cap import atomically cap import messages are processed by both handle_cap_import() and handle_cap_grant(). These two functions are not executed in the same atomic context, so they can races with cap release. The fix is make handle_cap_import() not release the i_ceph_lock when it returns. Let handle_cap_grant() release the lock after it finishes its job. Signed-off-by: Yan, Zheng diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 73a42f5..9f2c99c 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -2379,23 +2379,20 @@ static void invalidate_aliases(struct inode *inode) * actually be a revocation if it specifies a smaller cap set.) * * caller holds s_mutex and i_ceph_lock, we drop both. - * - * return value: - * 0 - ok - * 1 - check_caps on auth cap only (writeback) - * 2 - check_caps (ack revoke) */ -static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant, +static void handle_cap_grant(struct ceph_mds_client *mdsc, + struct inode *inode, struct ceph_mds_caps *grant, + void *snaptrace, int snaptrace_len, + struct ceph_buffer *xattr_buf, struct ceph_mds_session *session, - struct ceph_cap *cap, - struct ceph_buffer *xattr_buf) - __releases(ci->i_ceph_lock) + struct ceph_cap *cap, int issued) + __releases(ci->i_ceph_lock) { struct ceph_inode_info *ci = ceph_inode(inode); int mds = session->s_mds; int seq = le32_to_cpu(grant->seq); int newcaps = le32_to_cpu(grant->caps); - int issued, implemented, used, wanted, dirty; + int used, wanted, dirty; u64 size = le64_to_cpu(grant->size); u64 max_size = le64_to_cpu(grant->max_size); struct timespec mtime, atime, ctime; @@ -2449,10 +2446,6 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant, } /* side effects now are allowed */ - - issued = __ceph_caps_issued(ci, &implemented); - issued |= implemented | __ceph_caps_dirty(ci); - cap->cap_gen = session->s_cap_gen; cap->seq = seq; @@ -2585,6 +2578,17 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant, spin_unlock(&ci->i_ceph_lock); + if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) { + down_write(&mdsc->snap_rwsem); + ceph_update_snap_trace(mdsc, snaptrace, + snaptrace + snaptrace_len, false); + downgrade_write(&mdsc->snap_rwsem); + kick_flushing_inode_caps(mdsc, session, inode); + up_read(&mdsc->snap_rwsem); + if (newcaps & ~issued) + wake = 1; + } + if (queue_trunc) { ceph_queue_vmtruncate(inode); ceph_queue_revalidate(inode); @@ -2886,21 +2890,22 @@ out_unlock: } /* - * Handle cap IMPORT. If there are temp bits from an older EXPORT, - * clean them up. + * Handle cap IMPORT. * - * caller holds s_mutex. + * caller holds s_mutex. acquires i_ceph_lock */ static void handle_cap_import(struct ceph_mds_client *mdsc, struct inode *inode, struct ceph_mds_caps *im, struct ceph_mds_cap_peer *ph, struct ceph_mds_session *session, - void *snaptrace, int snaptrace_len) + struct ceph_cap **target_cap, int *old_issued) + __acquires(ci->i_ceph_lock) { struct ceph_inode_info *ci = ceph_inode(inode); - struct ceph_cap *cap, *new_cap = NULL; + struct ceph_cap *cap, *ocap, *new_cap = NULL; int mds = session->s_mds; - unsigned issued = le32_to_cpu(im->caps); + int issued; + unsigned caps = le32_to_cpu(im->caps); unsigned wanted = le32_to_cpu(im->wanted); unsigned seq = le32_to_cpu(im->seq); unsigned mseq = le32_to_cpu(im->migrate_seq); @@ -2929,44 +2934,43 @@ retry: new_cap = ceph_get_cap(mdsc, NULL); goto retry; } + cap = new_cap; + } else { + if (new_cap) { + ceph_put_cap(mdsc, new_cap); + new_cap = NULL; + } } - ceph_add_cap(inode, session, cap_id, -1, issued, wanted, seq, mseq, + __ceph_caps_issued(ci, &issued); + issued |= __ceph_caps_dirty(ci); + + ceph_add_cap(inode, session, cap_id, -1, caps, wanted, seq, mseq, realmino, CEPH_CAP_FLAG_AUTH, &new_cap); - cap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL; - if (cap && cap->cap_id == p_cap_id) { + ocap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL; + if (ocap && ocap->cap_id == p_cap_id) { dout(" remove export cap %p mds%d flags %d\n", - cap, peer, ph->flags); + ocap, peer, ph->flags); if ((ph->flags & CEPH_CAP_FLAG_AUTH) && - (cap->seq != le32_to_cpu(ph->seq) || - cap->mseq != le32_to_cpu(ph->mseq))) { + (ocap->seq != le32_to_cpu(ph->seq) || + ocap->mseq != le32_to_cpu(ph->mseq))) { pr_err("handle_cap_import: mismatched seq/mseq: " "ino (%llx.%llx) mds%d seq %d mseq %d " "importer mds%d has peer seq %d mseq %d\n", - ceph_vinop(inode), peer, cap->seq, - cap->mseq, mds, le32_to_cpu(ph->seq), + ceph_vinop(inode), peer, ocap->seq, + ocap->mseq, mds, le32_to_cpu(ph->seq), le32_to_cpu(ph->mseq)); } - __ceph_remove_cap(cap, (ph->flags & CEPH_CAP_FLAG_RELEASE)); + __ceph_remove_cap(ocap, (ph->flags & CEPH_CAP_FLAG_RELEASE)); } /* make sure we re-request max_size, if necessary */ ci->i_wanted_max_size = 0; ci->i_requested_max_size = 0; - spin_unlock(&ci->i_ceph_lock); - - wake_up_all(&ci->i_cap_wq); - down_write(&mdsc->snap_rwsem); - ceph_update_snap_trace(mdsc, snaptrace, snaptrace+snaptrace_len, - false); - downgrade_write(&mdsc->snap_rwsem); - kick_flushing_inode_caps(mdsc, session, inode); - up_read(&mdsc->snap_rwsem); - - if (new_cap) - ceph_put_cap(mdsc, new_cap); + *old_issued = issued; + *target_cap = cap; } /* @@ -2986,7 +2990,7 @@ void ceph_handle_caps(struct ceph_mds_session *session, struct ceph_mds_caps *h; struct ceph_mds_cap_peer *peer = NULL; int mds = session->s_mds; - int op; + int op, issued; u32 seq, mseq; struct ceph_vino vino; u64 cap_id; @@ -3078,7 +3082,10 @@ void ceph_handle_caps(struct ceph_mds_session *session, case CEPH_CAP_OP_IMPORT: handle_cap_import(mdsc, inode, h, peer, session, - snaptrace, snaptrace_len); + &cap, &issued); + handle_cap_grant(mdsc, inode, h, snaptrace, snaptrace_len, + msg->middle, session, cap, issued); + goto done_unlocked; } /* the rest require a cap */ @@ -3095,8 +3102,10 @@ void ceph_handle_caps(struct ceph_mds_session *session, switch (op) { case CEPH_CAP_OP_REVOKE: case CEPH_CAP_OP_GRANT: - case CEPH_CAP_OP_IMPORT: - handle_cap_grant(inode, h, session, cap, msg->middle); + __ceph_caps_issued(ci, &issued); + issued |= __ceph_caps_dirty(ci); + handle_cap_grant(mdsc, inode, h, NULL, 0, msg->middle, + session, cap, issued); goto done_unlocked; case CEPH_CAP_OP_FLUSH_ACK: -- cgit v0.10.2