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 <zheng.z.yan@intel.com>
This commit is contained in:
Yan, Zheng
parent
d9df278350
commit
2cd698be9a
@ -2379,23 +2379,20 @@ static void invalidate_aliases(struct inode *inode)
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* actually be a revocation if it specifies a smaller cap set.)
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*
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* caller holds s_mutex and i_ceph_lock, we drop both.
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*
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* return value:
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* 0 - ok
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* 1 - check_caps on auth cap only (writeback)
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* 2 - check_caps (ack revoke)
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*/
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static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
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static void handle_cap_grant(struct ceph_mds_client *mdsc,
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struct inode *inode, struct ceph_mds_caps *grant,
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void *snaptrace, int snaptrace_len,
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struct ceph_buffer *xattr_buf,
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struct ceph_mds_session *session,
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struct ceph_cap *cap,
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struct ceph_buffer *xattr_buf)
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__releases(ci->i_ceph_lock)
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struct ceph_cap *cap, int issued)
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__releases(ci->i_ceph_lock)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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int mds = session->s_mds;
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int seq = le32_to_cpu(grant->seq);
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int newcaps = le32_to_cpu(grant->caps);
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int issued, implemented, used, wanted, dirty;
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int used, wanted, dirty;
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u64 size = le64_to_cpu(grant->size);
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u64 max_size = le64_to_cpu(grant->max_size);
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struct timespec mtime, atime, ctime;
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@ -2449,10 +2446,6 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
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}
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/* side effects now are allowed */
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issued = __ceph_caps_issued(ci, &implemented);
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issued |= implemented | __ceph_caps_dirty(ci);
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cap->cap_gen = session->s_cap_gen;
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cap->seq = seq;
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@ -2585,6 +2578,17 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
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spin_unlock(&ci->i_ceph_lock);
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if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
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down_write(&mdsc->snap_rwsem);
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ceph_update_snap_trace(mdsc, snaptrace,
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snaptrace + snaptrace_len, false);
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downgrade_write(&mdsc->snap_rwsem);
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kick_flushing_inode_caps(mdsc, session, inode);
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up_read(&mdsc->snap_rwsem);
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if (newcaps & ~issued)
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wake = 1;
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}
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if (queue_trunc) {
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ceph_queue_vmtruncate(inode);
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ceph_queue_revalidate(inode);
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@ -2886,21 +2890,22 @@ out_unlock:
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}
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/*
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* Handle cap IMPORT. If there are temp bits from an older EXPORT,
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* clean them up.
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* Handle cap IMPORT.
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*
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* caller holds s_mutex.
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* caller holds s_mutex. acquires i_ceph_lock
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*/
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static void handle_cap_import(struct ceph_mds_client *mdsc,
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struct inode *inode, struct ceph_mds_caps *im,
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struct ceph_mds_cap_peer *ph,
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struct ceph_mds_session *session,
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void *snaptrace, int snaptrace_len)
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struct ceph_cap **target_cap, int *old_issued)
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__acquires(ci->i_ceph_lock)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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struct ceph_cap *cap, *new_cap = NULL;
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struct ceph_cap *cap, *ocap, *new_cap = NULL;
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int mds = session->s_mds;
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unsigned issued = le32_to_cpu(im->caps);
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int issued;
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unsigned caps = le32_to_cpu(im->caps);
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unsigned wanted = le32_to_cpu(im->wanted);
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unsigned seq = le32_to_cpu(im->seq);
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unsigned mseq = le32_to_cpu(im->migrate_seq);
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@ -2929,44 +2934,43 @@ retry:
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new_cap = ceph_get_cap(mdsc, NULL);
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goto retry;
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}
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cap = new_cap;
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} else {
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if (new_cap) {
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ceph_put_cap(mdsc, new_cap);
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new_cap = NULL;
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}
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}
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ceph_add_cap(inode, session, cap_id, -1, issued, wanted, seq, mseq,
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__ceph_caps_issued(ci, &issued);
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issued |= __ceph_caps_dirty(ci);
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ceph_add_cap(inode, session, cap_id, -1, caps, wanted, seq, mseq,
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realmino, CEPH_CAP_FLAG_AUTH, &new_cap);
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cap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL;
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if (cap && cap->cap_id == p_cap_id) {
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ocap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL;
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if (ocap && ocap->cap_id == p_cap_id) {
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dout(" remove export cap %p mds%d flags %d\n",
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cap, peer, ph->flags);
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ocap, peer, ph->flags);
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if ((ph->flags & CEPH_CAP_FLAG_AUTH) &&
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(cap->seq != le32_to_cpu(ph->seq) ||
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cap->mseq != le32_to_cpu(ph->mseq))) {
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(ocap->seq != le32_to_cpu(ph->seq) ||
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ocap->mseq != le32_to_cpu(ph->mseq))) {
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pr_err("handle_cap_import: mismatched seq/mseq: "
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"ino (%llx.%llx) mds%d seq %d mseq %d "
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"importer mds%d has peer seq %d mseq %d\n",
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ceph_vinop(inode), peer, cap->seq,
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cap->mseq, mds, le32_to_cpu(ph->seq),
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ceph_vinop(inode), peer, ocap->seq,
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ocap->mseq, mds, le32_to_cpu(ph->seq),
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le32_to_cpu(ph->mseq));
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}
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__ceph_remove_cap(cap, (ph->flags & CEPH_CAP_FLAG_RELEASE));
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__ceph_remove_cap(ocap, (ph->flags & CEPH_CAP_FLAG_RELEASE));
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}
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/* make sure we re-request max_size, if necessary */
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ci->i_wanted_max_size = 0;
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ci->i_requested_max_size = 0;
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spin_unlock(&ci->i_ceph_lock);
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wake_up_all(&ci->i_cap_wq);
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down_write(&mdsc->snap_rwsem);
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ceph_update_snap_trace(mdsc, snaptrace, snaptrace+snaptrace_len,
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false);
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downgrade_write(&mdsc->snap_rwsem);
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kick_flushing_inode_caps(mdsc, session, inode);
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up_read(&mdsc->snap_rwsem);
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if (new_cap)
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ceph_put_cap(mdsc, new_cap);
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*old_issued = issued;
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*target_cap = cap;
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}
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/*
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@ -2986,7 +2990,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
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struct ceph_mds_caps *h;
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struct ceph_mds_cap_peer *peer = NULL;
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int mds = session->s_mds;
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int op;
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int op, issued;
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u32 seq, mseq;
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struct ceph_vino vino;
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u64 cap_id;
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@ -3078,7 +3082,10 @@ void ceph_handle_caps(struct ceph_mds_session *session,
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case CEPH_CAP_OP_IMPORT:
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handle_cap_import(mdsc, inode, h, peer, session,
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snaptrace, snaptrace_len);
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&cap, &issued);
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handle_cap_grant(mdsc, inode, h, snaptrace, snaptrace_len,
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msg->middle, session, cap, issued);
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goto done_unlocked;
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}
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/* the rest require a cap */
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@ -3095,8 +3102,10 @@ void ceph_handle_caps(struct ceph_mds_session *session,
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switch (op) {
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case CEPH_CAP_OP_REVOKE:
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case CEPH_CAP_OP_GRANT:
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case CEPH_CAP_OP_IMPORT:
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handle_cap_grant(inode, h, session, cap, msg->middle);
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__ceph_caps_issued(ci, &issued);
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issued |= __ceph_caps_dirty(ci);
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handle_cap_grant(mdsc, inode, h, NULL, 0, msg->middle,
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session, cap, issued);
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goto done_unlocked;
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case CEPH_CAP_OP_FLUSH_ACK:
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