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ceph: fix snap realm splits 

The snap realm split was checking i_snap_realm, not the list_head, to
determine if an inode belonged in the new realm.  The check always failed,
which meant we always moved the inode, corrupting the old realm's list and
causing various crashes.

Also wait to release old realm reference to avoid possibility of use after
free.

Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil 2010-04-19 10:15:44 -07:00
parent c10f5e12ba
commit 91dee39eeb
1 changed files with 14 additions and 10 deletions
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24
fs/ceph/snap.c
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@ -869,16 +869,20 @@ skip_inode:
continue;
ci = ceph_inode(inode);
spin_lock(&inode->i_lock);
if (!ci->i_snap_realm)
goto split_skip_inode;
ceph_put_snap_realm(mdsc, ci->i_snap_realm);
spin_lock(&realm->inodes_with_caps_lock);
list_add(&ci->i_snap_realm_item,
&realm->inodes_with_caps);
ci->i_snap_realm = realm;
spin_unlock(&realm->inodes_with_caps_lock);
ceph_get_snap_realm(mdsc, realm);
split_skip_inode:
if (list_empty(&ci->i_snap_realm_item)) {
struct ceph_snap_realm *oldrealm =
ci->i_snap_realm;
dout(" moving %p to split realm %llx %p\n",
inode, realm->ino, realm);
spin_lock(&realm->inodes_with_caps_lock);
list_add(&ci->i_snap_realm_item,
&realm->inodes_with_caps);
ci->i_snap_realm = realm;
spin_unlock(&realm->inodes_with_caps_lock);
ceph_get_snap_realm(mdsc, realm);
ceph_put_snap_realm(mdsc, oldrealm);
}
spin_unlock(&inode->i_lock);
iput(inode);
}