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ceph: drop negative child dentries before try pruning inode's alias

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Negative child dentry holds reference on inode's alias, it makes
d_prune_aliases() do nothing.

Cc: stable@vger.kernel.org
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Yan, Zheng 2017-11-30 11:59:22 +08:00 committed by Ilya Dryomov
parent ae64f9bd1d
commit 040d786032
1 changed files with 38 additions and 4 deletions
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42
fs/ceph/mds_client.c
View file

@ -1440,6 +1440,29 @@ static int __close_session(struct ceph_mds_client *mdsc,
return request_close_session(mdsc, session);
}
static bool drop_negative_children(struct dentry *dentry)
{
struct dentry *child;
bool all_negative = true;
if (!d_is_dir(dentry))
goto out;
spin_lock(&dentry->d_lock);
list_for_each_entry(child, &dentry->d_subdirs, d_child) {
if (d_really_is_positive(child)) {
all_negative = false;
break;
}
}
spin_unlock(&dentry->d_lock);
if (all_negative)
shrink_dcache_parent(dentry);
out:
return all_negative;
}
/*
* Trim old(er) caps.
*
@ -1490,16 +1513,27 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
if ((used | wanted) & ~oissued & mine)
goto out; /* we need these caps */
session->s_trim_caps--;
if (oissued) {
/* we aren't the only cap.. just remove us */
__ceph_remove_cap(cap, true);
session->s_trim_caps--;
} else {
struct dentry *dentry;
/* try dropping referring dentries */
spin_unlock(&ci->i_ceph_lock);
d_prune_aliases(inode);
dout("trim_caps_cb %p cap %p pruned, count now %d\n",
inode, cap, atomic_read(&inode->i_count));
dentry = d_find_any_alias(inode);
if (dentry && drop_negative_children(dentry)) {
int count;
dput(dentry);
d_prune_aliases(inode);
count = atomic_read(&inode->i_count);
if (count == 1)
session->s_trim_caps--;
dout("trim_caps_cb %p cap %p pruned, count now %d\n",
inode, cap, count);
} else {
dput(dentry);
}
return 0;
}