4.4-stable review patch. If anyone has any objections, please let me know.
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From: Yan, Zheng zyan@redhat.com
commit 040d786032bf59002d374b86d75b04d97624005c upstream.
Negative child dentry holds reference on inode's alias, it makes d_prune_aliases() do nothing.
Signed-off-by: "Yan, Zheng" zyan@redhat.com Reviewed-by: Jeff Layton jlayton@redhat.com Signed-off-by: Ilya Dryomov idryomov@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ceph/mds_client.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-)
--- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -1400,6 +1400,29 @@ static int __close_session(struct ceph_m 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. * @@ -1445,16 +1468,27 @@ static int trim_caps_cb(struct inode *in 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; }