ceph: use empty snap context for uninline_data and get_pool_perm
Cached_context in ceph_snap_realm is directly accessed by
uninline_data() and get_pool_perm(). This is racy in theory.
both uninline_data() and get_pool_perm() do not modify existing
object, they only create new object. So we can pass the empty
snap context to them. Unlike cached_context in ceph_snap_realm,
we do not need to protect the empty snap context.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index b960277..ccc4325 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1510,8 +1510,7 @@
ceph_vino(inode), 0, &len, 0, 1,
CEPH_OSD_OP_CREATE,
CEPH_OSD_FLAG_ONDISK | CEPH_OSD_FLAG_WRITE,
- ci->i_snap_realm->cached_context,
- 0, 0, false);
+ ceph_empty_snapc, 0, 0, false);
if (IS_ERR(req)) {
err = PTR_ERR(req);
goto out;
@@ -1529,7 +1528,7 @@
ceph_vino(inode), 0, &len, 1, 3,
CEPH_OSD_OP_WRITE,
CEPH_OSD_FLAG_ONDISK | CEPH_OSD_FLAG_WRITE,
- ci->i_snap_realm->cached_context,
+ ceph_empty_snapc,
ci->i_truncate_seq, ci->i_truncate_size,
false);
if (IS_ERR(req)) {
@@ -1653,7 +1652,7 @@
}
rd_req = ceph_osdc_alloc_request(&fsc->client->osdc,
- ci->i_snap_realm->cached_context,
+ ceph_empty_snapc,
1, false, GFP_NOFS);
if (!rd_req) {
err = -ENOMEM;
@@ -1668,7 +1667,7 @@
rd_req->r_base_oid.name_len = strlen(rd_req->r_base_oid.name);
wr_req = ceph_osdc_alloc_request(&fsc->client->osdc,
- ci->i_snap_realm->cached_context,
+ ceph_empty_snapc,
1, false, GFP_NOFS);
if (!wr_req) {
err = -ENOMEM;
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index a97e39f..b2a9453 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -296,7 +296,7 @@
}
-static struct ceph_snap_context *empty_snapc;
+struct ceph_snap_context *ceph_empty_snapc;
/*
* build the snap context for a given realm.
@@ -338,9 +338,9 @@
return 0;
}
- if (num == 0 && realm->seq == empty_snapc->seq) {
- ceph_get_snap_context(empty_snapc);
- snapc = empty_snapc;
+ if (num == 0 && realm->seq == ceph_empty_snapc->seq) {
+ ceph_get_snap_context(ceph_empty_snapc);
+ snapc = ceph_empty_snapc;
goto done;
}
@@ -482,7 +482,7 @@
cap_snap. lucky us. */
dout("queue_cap_snap %p already pending\n", inode);
kfree(capsnap);
- } else if (ci->i_snap_realm->cached_context == empty_snapc) {
+ } else if (ci->i_snap_realm->cached_context == ceph_empty_snapc) {
dout("queue_cap_snap %p empty snapc\n", inode);
kfree(capsnap);
} else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
@@ -964,14 +964,14 @@
int __init ceph_snap_init(void)
{
- empty_snapc = ceph_create_snap_context(0, GFP_NOFS);
- if (!empty_snapc)
+ ceph_empty_snapc = ceph_create_snap_context(0, GFP_NOFS);
+ if (!ceph_empty_snapc)
return -ENOMEM;
- empty_snapc->seq = 1;
+ ceph_empty_snapc->seq = 1;
return 0;
}
void ceph_snap_exit(void)
{
- ceph_put_snap_context(empty_snapc);
+ ceph_put_snap_context(ceph_empty_snapc);
}
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 18b917c..b182fd7 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -692,6 +692,7 @@
/* snap.c */
+extern struct ceph_snap_context *ceph_empty_snapc;
struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
u64 ino);
extern void ceph_get_snap_realm(struct ceph_mds_client *mdsc,