From 6a92b08fdad22ae3558faaef561587ebfcb8b901 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 4 Jun 2021 11:01:25 -0400 Subject: ceph: don't take s_mutex or snap_rwsem in ceph_check_caps These locks appear to be completely unnecessary. Almost all of this function is done under the inode->i_ceph_lock, aside from the actual sending of the message. Don't take either lock in this function. Signed-off-by: Jeff Layton Reviewed-by: Luis Henriques Signed-off-by: Ilya Dryomov --- fs/ceph/caps.c | 72 +++++++++------------------------------------------------- 1 file changed, 11 insertions(+), 61 deletions(-) (limited to 'fs/ceph') diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 919eada97a1f..95f56b377312 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -1912,7 +1912,6 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags, struct ceph_cap *cap; u64 flush_tid, oldest_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; int mds = -1; /* keep track of how far we've gone through i_caps list to avoid an infinite loop on retry */ @@ -1920,14 +1919,13 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags, bool queue_invalidate = false; bool tried_invalidate = false; + if (session) + ceph_get_mds_session(session); + spin_lock(&ci->i_ceph_lock); if (ci->i_ceph_flags & CEPH_I_FLUSH) flags |= CHECK_CAPS_FLUSH; - - goto retry_locked; retry: - spin_lock(&ci->i_ceph_lock); -retry_locked: /* Caps wanted by virtue of active open files. */ file_wanted = __ceph_caps_file_wanted(ci); @@ -2007,7 +2005,7 @@ retry_locked: ci->i_rdcache_revoking = ci->i_rdcache_gen; } tried_invalidate = true; - goto retry_locked; + goto retry; } for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) { @@ -2021,8 +2019,6 @@ retry_locked: ((flags & CHECK_CAPS_AUTHONLY) && cap != ci->i_auth_cap)) continue; - /* NOTE: no side-effects allowed, until we take s_mutex */ - /* * If we have an auth cap, we don't need to consider any * overlapping caps as used. @@ -2085,37 +2081,8 @@ retry_locked: continue; /* nope, all good */ ack: - if (session && session != cap->session) { - dout("oops, wrong session %p mutex\n", session); - mutex_unlock(&session->s_mutex); - session = NULL; - } - if (!session) { - session = cap->session; - if (mutex_trylock(&session->s_mutex) == 0) { - dout("inverting session/ino locks on %p\n", - session); - session = ceph_get_mds_session(session); - spin_unlock(&ci->i_ceph_lock); - if (took_snap_rwsem) { - up_read(&mdsc->snap_rwsem); - took_snap_rwsem = 0; - } - if (session) { - mutex_lock(&session->s_mutex); - ceph_put_mds_session(session); - } else { - /* - * Because we take the reference while - * holding the i_ceph_lock, it should - * never be NULL. Throw a warning if it - * ever is. - */ - WARN_ON_ONCE(true); - } - goto retry; - } - } + ceph_put_mds_session(session); + session = ceph_get_mds_session(cap->session); /* kick flushing and flush snaps before sending normal * cap message */ @@ -2127,20 +2094,7 @@ ack: if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS) __ceph_flush_snaps(ci, session); - goto retry_locked; - } - - /* take snap_rwsem after session mutex */ - if (!took_snap_rwsem) { - if (down_read_trylock(&mdsc->snap_rwsem) == 0) { - dout("inverting snap/in locks on %p\n", - inode); - spin_unlock(&ci->i_ceph_lock); - down_read(&mdsc->snap_rwsem); - took_snap_rwsem = 1; - goto retry; - } - took_snap_rwsem = 1; + goto retry; } if (cap == ci->i_auth_cap && ci->i_dirty_caps) { @@ -2162,9 +2116,10 @@ ack: __prep_cap(&arg, cap, CEPH_CAP_OP_UPDATE, mflags, cap_used, want, retain, flushing, flush_tid, oldest_flush_tid); - spin_unlock(&ci->i_ceph_lock); + spin_unlock(&ci->i_ceph_lock); __send_cap(&arg, ci); + spin_lock(&ci->i_ceph_lock); goto retry; /* retake i_ceph_lock and restart our cap scan. */ } @@ -2179,13 +2134,9 @@ ack: spin_unlock(&ci->i_ceph_lock); + ceph_put_mds_session(session); if (queue_invalidate) ceph_queue_invalidate(inode); - - if (session) - mutex_unlock(&session->s_mutex); - if (took_snap_rwsem) - up_read(&mdsc->snap_rwsem); } /* @@ -3550,13 +3501,12 @@ static void handle_cap_grant(struct inode *inode, if (wake) wake_up_all(&ci->i_cap_wq); + mutex_unlock(&session->s_mutex); if (check_caps == 1) ceph_check_caps(ci, CHECK_CAPS_AUTHONLY | CHECK_CAPS_NOINVAL, session); else if (check_caps == 2) ceph_check_caps(ci, CHECK_CAPS_NOINVAL, session); - else - mutex_unlock(&session->s_mutex); } /* -- cgit v1.2.3