| Message ID | 20210107023051.119063-1-xiubli@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] ceph: defer flushing the capsnap if the Fb is used | expand |
On Thu, 2021-01-07 at 10:30 +0800, xiubli@redhat.com wrote: > From: Xiubo Li <xiubli@redhat.com> > > If the Fb cap is used it means the client is flushing the dirty > data to OSD, just defer flushing the capsnap. > > URL: https://tracker.ceph.com/issues/48679 > URL: https://tracker.ceph.com/issues/48640 > Signed-off-by: Xiubo Li <xiubli@redhat.com> > --- > > V2: > - Fix inode reference leak bug > > fs/ceph/caps.c | 32 +++++++++++++++++++------------- > fs/ceph/snap.c | 6 +++--- > 2 files changed, 22 insertions(+), 16 deletions(-) > > diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c > index abbf48fc6230..2f2451d563bd 100644 > --- a/fs/ceph/caps.c > +++ b/fs/ceph/caps.c > @@ -3047,6 +3047,7 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, > { > struct inode *inode = &ci->vfs_inode; > int last = 0, put = 0, flushsnaps = 0, wake = 0; > + bool check_flushsnaps = false; > > > > > spin_lock(&ci->i_ceph_lock); > if (had & CEPH_CAP_PIN) > @@ -3064,25 +3065,15 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, > if (--ci->i_wb_ref == 0) { > last++; > put++; > + check_flushsnaps = true; > } > dout("put_cap_refs %p wb %d -> %d (?)\n", > inode, ci->i_wb_ref+1, ci->i_wb_ref); > } > - if (had & CEPH_CAP_FILE_WR) > + if (had & CEPH_CAP_FILE_WR) { > if (--ci->i_wr_ref == 0) { > last++; > - if (__ceph_have_pending_cap_snap(ci)) { > - struct ceph_cap_snap *capsnap = > - list_last_entry(&ci->i_cap_snaps, > - struct ceph_cap_snap, > - ci_item); > - capsnap->writing = 0; > - if (ceph_try_drop_cap_snap(ci, capsnap)) > - put++; > - else if (__ceph_finish_cap_snap(ci, capsnap)) > - flushsnaps = 1; > - wake = 1; > - } > + check_flushsnaps = true; > if (ci->i_wrbuffer_ref_head == 0 && > ci->i_dirty_caps == 0 && > ci->i_flushing_caps == 0) { > @@ -3094,6 +3085,21 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, > if (!__ceph_is_any_real_caps(ci) && ci->i_snap_realm) > drop_inode_snap_realm(ci); > } > + } > + if (check_flushsnaps) { > + if (__ceph_have_pending_cap_snap(ci)) { > + struct ceph_cap_snap *capsnap = > + list_last_entry(&ci->i_cap_snaps, > + struct ceph_cap_snap, > + ci_item); > + capsnap->writing = 0; > + if (ceph_try_drop_cap_snap(ci, capsnap)) > + put++; > + else if (__ceph_finish_cap_snap(ci, capsnap)) > + flushsnaps = 1; > + wake = 1; > + } > + } Ok, so let's assume you're putting Fb. You increment put and set check_flushsnaps to true. Later, you get down to here and call ceph_try_drop_cap_snap and it returns true and now you've incremented "put" twice. Is that right? Do Fb caps hold two inode references? Either way, I think this function needs some better documentation/comments, particularly since you're making a significant change to how it works. > spin_unlock(&ci->i_ceph_lock); > > > > > dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had), > diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c > index b611f829cb61..639fb91cc9db 100644 > --- a/fs/ceph/snap.c > +++ b/fs/ceph/snap.c > @@ -561,10 +561,10 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci) > capsnap->context = old_snapc; > list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps); > > > > > - if (used & CEPH_CAP_FILE_WR) { > + if (used & (CEPH_CAP_FILE_WR | CEPH_CAP_FILE_BUFFER)) { > dout("queue_cap_snap %p cap_snap %p snapc %p" > - " seq %llu used WR, now pending\n", inode, > - capsnap, old_snapc, old_snapc->seq); > + " seq %llu used WR | BUFFFER, now pending\n", > + inode, capsnap, old_snapc, old_snapc->seq); > capsnap->writing = 1; > } else { > /* note mtime, size NOW. */ -- Jeff Layton <jlayton@kernel.org>
On 2021/1/9 2:24, Jeff Layton wrote: > On Thu, 2021-01-07 at 10:30 +0800, xiubli@redhat.com wrote: >> From: Xiubo Li <xiubli@redhat.com> >> >> If the Fb cap is used it means the client is flushing the dirty >> data to OSD, just defer flushing the capsnap. >> >> URL: https://tracker.ceph.com/issues/48679 >> URL: https://tracker.ceph.com/issues/48640 >> Signed-off-by: Xiubo Li <xiubli@redhat.com> >> --- >> >> V2: >> - Fix inode reference leak bug >> >> fs/ceph/caps.c | 32 +++++++++++++++++++------------- >> fs/ceph/snap.c | 6 +++--- >> 2 files changed, 22 insertions(+), 16 deletions(-) >> >> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c >> index abbf48fc6230..2f2451d563bd 100644 >> --- a/fs/ceph/caps.c >> +++ b/fs/ceph/caps.c >> @@ -3047,6 +3047,7 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, >> { >> struct inode *inode = &ci->vfs_inode; >> int last = 0, put = 0, flushsnaps = 0, wake = 0; >> + bool check_flushsnaps = false; >> >> >> >> >> spin_lock(&ci->i_ceph_lock); >> if (had & CEPH_CAP_PIN) >> @@ -3064,25 +3065,15 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, >> if (--ci->i_wb_ref == 0) { >> last++; >> put++; >> + check_flushsnaps = true; >> } >> dout("put_cap_refs %p wb %d -> %d (?)\n", >> inode, ci->i_wb_ref+1, ci->i_wb_ref); >> } >> - if (had & CEPH_CAP_FILE_WR) >> + if (had & CEPH_CAP_FILE_WR) { >> if (--ci->i_wr_ref == 0) { >> last++; >> - if (__ceph_have_pending_cap_snap(ci)) { >> - struct ceph_cap_snap *capsnap = >> - list_last_entry(&ci->i_cap_snaps, >> - struct ceph_cap_snap, >> - ci_item); >> - capsnap->writing = 0; >> - if (ceph_try_drop_cap_snap(ci, capsnap)) >> - put++; >> - else if (__ceph_finish_cap_snap(ci, capsnap)) >> - flushsnaps = 1; >> - wake = 1; >> - } >> + check_flushsnaps = true; >> if (ci->i_wrbuffer_ref_head == 0 && >> ci->i_dirty_caps == 0 && >> ci->i_flushing_caps == 0) { >> @@ -3094,6 +3085,21 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, >> if (!__ceph_is_any_real_caps(ci) && ci->i_snap_realm) >> drop_inode_snap_realm(ci); >> } >> + } >> + if (check_flushsnaps) { >> + if (__ceph_have_pending_cap_snap(ci)) { >> + struct ceph_cap_snap *capsnap = >> + list_last_entry(&ci->i_cap_snaps, >> + struct ceph_cap_snap, >> + ci_item); >> + capsnap->writing = 0; >> + if (ceph_try_drop_cap_snap(ci, capsnap)) >> + put++; >> + else if (__ceph_finish_cap_snap(ci, capsnap)) >> + flushsnaps = 1; >> + wake = 1; >> + } >> + } > > Ok, so let's assume you're putting Fb. You increment put and set > check_flushsnaps to true. Later, you get down to here and call > ceph_try_drop_cap_snap and it returns true and now you've incremented > "put" twice. > > Is that right? Do Fb caps hold two inode references? Yeah, one in ceph_take_cap_refs(). Another one is in ceph_queue_cap_snap() and when `used & (Fb | Fw)` is true, the flush capsnap will be delayed by holding the inode ref, so we need to put the inode ref here or in __ceph_finish_cap_snap(). > Either way, I think this function needs some better > documentation/comments, particularly since you're making a significant > change to how it works. Okay, I will post the V3 after my back later to add more comments about this. Thanks > >> spin_unlock(&ci->i_ceph_lock); >> >> >> >> >> dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had), >> diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c >> index b611f829cb61..639fb91cc9db 100644 >> --- a/fs/ceph/snap.c >> +++ b/fs/ceph/snap.c >> @@ -561,10 +561,10 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci) >> capsnap->context = old_snapc; >> list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps); >> >> >> >> >> - if (used & CEPH_CAP_FILE_WR) { >> + if (used & (CEPH_CAP_FILE_WR | CEPH_CAP_FILE_BUFFER)) { >> dout("queue_cap_snap %p cap_snap %p snapc %p" >> - " seq %llu used WR, now pending\n", inode, >> - capsnap, old_snapc, old_snapc->seq); >> + " seq %llu used WR | BUFFFER, now pending\n", >> + inode, capsnap, old_snapc, old_snapc->seq); >> capsnap->writing = 1; >> } else { >> /* note mtime, size NOW. */
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index abbf48fc6230..2f2451d563bd 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -3047,6 +3047,7 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, { struct inode *inode = &ci->vfs_inode; int last = 0, put = 0, flushsnaps = 0, wake = 0; + bool check_flushsnaps = false; spin_lock(&ci->i_ceph_lock); if (had & CEPH_CAP_PIN) @@ -3064,25 +3065,15 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, if (--ci->i_wb_ref == 0) { last++; put++; + check_flushsnaps = true; } dout("put_cap_refs %p wb %d -> %d (?)\n", inode, ci->i_wb_ref+1, ci->i_wb_ref); } - if (had & CEPH_CAP_FILE_WR) + if (had & CEPH_CAP_FILE_WR) { if (--ci->i_wr_ref == 0) { last++; - if (__ceph_have_pending_cap_snap(ci)) { - struct ceph_cap_snap *capsnap = - list_last_entry(&ci->i_cap_snaps, - struct ceph_cap_snap, - ci_item); - capsnap->writing = 0; - if (ceph_try_drop_cap_snap(ci, capsnap)) - put++; - else if (__ceph_finish_cap_snap(ci, capsnap)) - flushsnaps = 1; - wake = 1; - } + check_flushsnaps = true; if (ci->i_wrbuffer_ref_head == 0 && ci->i_dirty_caps == 0 && ci->i_flushing_caps == 0) { @@ -3094,6 +3085,21 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, if (!__ceph_is_any_real_caps(ci) && ci->i_snap_realm) drop_inode_snap_realm(ci); } + } + if (check_flushsnaps) { + if (__ceph_have_pending_cap_snap(ci)) { + struct ceph_cap_snap *capsnap = + list_last_entry(&ci->i_cap_snaps, + struct ceph_cap_snap, + ci_item); + capsnap->writing = 0; + if (ceph_try_drop_cap_snap(ci, capsnap)) + put++; + else if (__ceph_finish_cap_snap(ci, capsnap)) + flushsnaps = 1; + wake = 1; + } + } spin_unlock(&ci->i_ceph_lock); dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had), diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index b611f829cb61..639fb91cc9db 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -561,10 +561,10 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci) capsnap->context = old_snapc; list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps); - if (used & CEPH_CAP_FILE_WR) { + if (used & (CEPH_CAP_FILE_WR | CEPH_CAP_FILE_BUFFER)) { dout("queue_cap_snap %p cap_snap %p snapc %p" - " seq %llu used WR, now pending\n", inode, - capsnap, old_snapc, old_snapc->seq); + " seq %llu used WR | BUFFFER, now pending\n", + inode, capsnap, old_snapc, old_snapc->seq); capsnap->writing = 1; } else { /* note mtime, size NOW. */