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ceph: queue cap snap writeback for realm children on snap update

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When a realm is updated, we need to queue writeback on inodes in that
realm _and_ its children.  Otherwise, if the inode gets cowed on the
server, we can get a hang later due to out-of-sync cap/snap state.

Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil
2010-08-16 13:37:31 -07:00
parent 4a625be472
commit ed32604448
1 changed files with 37 additions and 23 deletions
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60
fs/ceph/snap.c
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@@ -548,6 +548,41 @@ int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
return 1; /* caller may want to ceph_flush_snaps */ return 1; /* caller may want to ceph_flush_snaps */
} }
/*
* Queue cap_snaps for snap writeback for this realm and its children.
* Called under snap_rwsem, so realm topology won't change.
*/
static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
{
struct ceph_inode_info *ci;
struct inode *lastinode = NULL;
struct ceph_snap_realm *child;
dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino);
spin_lock(&realm->inodes_with_caps_lock);
list_for_each_entry(ci, &realm->inodes_with_caps,
i_snap_realm_item) {
struct inode *inode = igrab(&ci->vfs_inode);
if (!inode)
continue;
spin_unlock(&realm->inodes_with_caps_lock);
if (lastinode)
iput(lastinode);
lastinode = inode;
ceph_queue_cap_snap(ci);
spin_lock(&realm->inodes_with_caps_lock);
}
spin_unlock(&realm->inodes_with_caps_lock);
if (lastinode)
iput(lastinode);
dout("queue_realm_cap_snaps %p %llx children\n", realm, realm->ino);
list_for_each_entry(child, &realm->children, child_item)
queue_realm_cap_snaps(child);
dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
}
/* /*
* Parse and apply a snapblob "snap trace" from the MDS. This specifies * Parse and apply a snapblob "snap trace" from the MDS. This specifies
@@ -598,29 +633,8 @@ more:
* *
* ...unless it's a snap deletion! * ...unless it's a snap deletion!
*/ */
if (!deletion) { if (!deletion)
struct ceph_inode_info *ci; queue_realm_cap_snaps(realm);
struct inode *lastinode = NULL;
spin_lock(&realm->inodes_with_caps_lock);
list_for_each_entry(ci, &realm->inodes_with_caps,
i_snap_realm_item) {
struct inode *inode = igrab(&ci->vfs_inode);
if (!inode)
continue;
spin_unlock(&realm->inodes_with_caps_lock);
if (lastinode)
iput(lastinode);
lastinode = inode;
ceph_queue_cap_snap(ci);
spin_lock(&realm->inodes_with_caps_lock);
}
spin_unlock(&realm->inodes_with_caps_lock);
if (lastinode)
iput(lastinode);
dout("update_snap_trace cap_snaps queued\n");
}
} else { } else {
dout("update_snap_trace %llx %p seq %lld unchanged\n", dout("update_snap_trace %llx %p seq %lld unchanged\n",
realm->ino, realm, realm->seq); realm->ino, realm, realm->seq);