ceph: do not use i_wrbuffer_ref as refcount for Fb cap
We increments i_wrbuffer_ref when taking the Fb cap. This breaks
the dirty page accounting and causes looping in
__ceph_do_pending_vmtruncate, and ceph client hangs.
This bug can be reproduced occasionally by running blogbench.
Add a new field i_wb_ref to inode and dedicate it to Fb reference
counting.
Signed-off-by: Henry C Chang <henry.cy.chang@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 9fa0866..2a5404c 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -819,7 +819,7 @@
used |= CEPH_CAP_FILE_CACHE;
if (ci->i_wr_ref)
used |= CEPH_CAP_FILE_WR;
- if (ci->i_wrbuffer_ref)
+ if (ci->i_wb_ref || ci->i_wrbuffer_ref)
used |= CEPH_CAP_FILE_BUFFER;
return used;
}
@@ -1990,11 +1990,11 @@
if (got & CEPH_CAP_FILE_WR)
ci->i_wr_ref++;
if (got & CEPH_CAP_FILE_BUFFER) {
- if (ci->i_wrbuffer_ref == 0)
+ if (ci->i_wb_ref == 0)
ihold(&ci->vfs_inode);
- ci->i_wrbuffer_ref++;
- dout("__take_cap_refs %p wrbuffer %d -> %d (?)\n",
- &ci->vfs_inode, ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref);
+ ci->i_wb_ref++;
+ dout("__take_cap_refs %p wb %d -> %d (?)\n",
+ &ci->vfs_inode, ci->i_wb_ref-1, ci->i_wb_ref);
}
}
@@ -2169,12 +2169,12 @@
if (--ci->i_rdcache_ref == 0)
last++;
if (had & CEPH_CAP_FILE_BUFFER) {
- if (--ci->i_wrbuffer_ref == 0) {
+ if (--ci->i_wb_ref == 0) {
last++;
put++;
}
- dout("put_cap_refs %p wrbuffer %d -> %d (?)\n",
- inode, ci->i_wrbuffer_ref+1, ci->i_wrbuffer_ref);
+ 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 (--ci->i_wr_ref == 0) {
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 03d6daf..70b6a48 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -355,6 +355,7 @@
ci->i_rd_ref = 0;
ci->i_rdcache_ref = 0;
ci->i_wr_ref = 0;
+ ci->i_wb_ref = 0;
ci->i_wrbuffer_ref = 0;
ci->i_wrbuffer_ref_head = 0;
ci->i_shared_gen = 0;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index b1f1b8b..f5cabef 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -293,7 +293,7 @@
/* held references to caps */
int i_pin_ref;
- int i_rd_ref, i_rdcache_ref, i_wr_ref;
+ int i_rd_ref, i_rdcache_ref, i_wr_ref, i_wb_ref;
int i_wrbuffer_ref, i_wrbuffer_ref_head;
u32 i_shared_gen; /* increment each time we get FILE_SHARED */
u32 i_rdcache_gen; /* incremented each time we get FILE_CACHE. */