The commit is pushed to "branch-rh9-5.14.vz9.1.x-ovz" and will appear at
https://src.openvz.org/scm/ovz/vzkernel.git
after ark-5.14
------>
commit b81834199f260515aacbf853c87b409d352731fa
Author: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
Date: Fri Oct 1 19:38:35 2021 +0300
ipc: add export_operations to mqueue sb
criu uses fhandle from fdinfo to dump inotify objects, but mqueue has no
export_operations in super block. However, they are needed if we want to
operate with files using fhandles.
Add hash table as a storage for exported inodes.
https://jira.sw.ru/browse/PSBM-103727
Signed-off-by: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
Reviewed-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
(cherry picked from commit 8be62f28e79838fc0b5a1a4f4fb191857c49d1d8)
Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com>
(cherry-picked from vz8 commit 60e37dae8e3f ("ipc: add export_operations
to mqueue sb"))
Signed-off-by: Nikita Yushchenko <nikita.yushche...@virtuozzo.com>
---
ipc/mqueue.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 150 insertions(+)
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 3177c2b3c950..1682285cc239 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -36,6 +36,8 @@
#include <linux/ipc_namespace.h>
#include <linux/user_namespace.h>
#include <linux/slab.h>
+#include <linux/exportfs.h>
+#include <linux/random.h>
#include <linux/sched/wake_q.h>
#include <linux/sched/signal.h>
#include <linux/sched/user.h>
@@ -156,6 +158,7 @@ struct mqueue_inode_info {
static struct file_system_type mqueue_fs_type;
static const struct inode_operations mqueue_dir_inode_operations;
+static const struct export_operations mqueue_export_ops;
static const struct file_operations mqueue_file_operations;
static const struct super_operations mqueue_super_ops;
static const struct fs_context_operations mqueue_fs_context_ops;
@@ -188,6 +191,144 @@ static struct ipc_namespace *get_ns_from_inode(struct
inode *inode)
return ns;
}
+/*
+ * hashtable for inodes that have exported fhandles.
+ * When we export fhandle, we add it's inode into
+ * hashtable so we can find it fast
+ */
+
+#define MQUEUE_INODE_HASH_BITS 7
+static DEFINE_HASHTABLE(mqueue_inode_table, MQUEUE_INODE_HASH_BITS);
+static DEFINE_SPINLOCK(mqueue_inode_table_lock);
+
+struct mq_inode_hitem {
+ struct inode *inode;
+ struct hlist_node hlist;
+};
+
+static inline unsigned long mqueue_inode_get_hash(unsigned int i_ino)
+{
+ return hash_32(i_ino, MQUEUE_INODE_HASH_BITS);
+}
+
+static struct mq_inode_hitem *mqueue_find_item_no_lock(unsigned long fh[2])
+{
+ struct mq_inode_hitem *i;
+ struct hlist_head *head = mqueue_inode_table
+ + mqueue_inode_get_hash(fh[1]);
+ struct mq_inode_hitem *found = NULL;
+
+ hlist_for_each_entry(i, head, hlist) {
+ if (i->inode->i_generation == fh[0] &&
+ i->inode->i_ino == fh[1]) {
+ found = i;
+ break;
+ }
+ }
+
+ return found;
+}
+
+static struct inode *mqueue_find_inode(unsigned long fh[2], char take_ref)
+{
+ struct mq_inode_hitem *item;
+ struct inode *ret = NULL;
+
+ spin_lock(&mqueue_inode_table_lock);
+ item = mqueue_find_item_no_lock(fh);
+ if (item && take_ref && !igrab(item->inode))
+ item = NULL;
+ spin_unlock(&mqueue_inode_table_lock);
+
+ if (item)
+ ret = item->inode;
+
+ return ret;
+}
+
+static int mqueue_hash_add(struct inode *inode)
+{
+ unsigned long fh[2] = {inode->i_generation, inode->i_ino};
+
+ if (!mqueue_find_inode(fh, 0)) {
+ struct mq_inode_hitem *item;
+ struct mq_inode_hitem *existing_item = 0;
+ struct hlist_head *head = mqueue_inode_table
+ + mqueue_inode_get_hash(inode->i_ino);
+
+ item = kmalloc(sizeof(struct mq_inode_hitem), GFP_KERNEL);
+ if (!item)
+ return -ENOMEM;
+ item->inode = inode;
+
+ spin_lock(&mqueue_inode_table_lock);
+ existing_item = mqueue_find_item_no_lock(fh);
+ if (!existing_item)
+ hlist_add_head(&item->hlist, head);
+ spin_unlock(&mqueue_inode_table_lock);
+
+ if (existing_item)
+ kfree(item);
+ }
+
+ return 0;
+}
+
+static void mqueue_hash_del(struct inode *inode)
+{
+ struct mq_inode_hitem *item;
+ unsigned long fh[2] = {inode->i_generation, inode->i_ino};
+
+ spin_lock(&mqueue_inode_table_lock);
+ item = mqueue_find_item_no_lock(fh);
+ if (item)
+ hlist_del(&item->hlist);
+ spin_unlock(&mqueue_inode_table_lock);
+
+ kfree(item);
+ return;
+}
+
+static struct dentry *mqueue_fh_to_dentry(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ struct inode *inode;
+ struct dentry *dentry = ERR_PTR(-ENOENT);
+ unsigned long fhandle[2] = {fid->raw[0], fid->raw[1]};
+
+ if (fh_len < 2)
+ return NULL;
+
+ inode = mqueue_find_inode(fhandle, 1);
+ if (inode) {
+ dentry = d_find_alias(inode);
+ iput(inode);
+ }
+ return dentry;
+}
+
+static int mqueue_encode_fh(struct inode *inode, __u32 *fh, int *len,
+ struct inode *parent)
+{
+ if (*len < 2) {
+ *len = 2;
+ return FILEID_INVALID;
+ }
+
+ /*
+ * encode_fh is expected to return 255 (FILEID_INVALID)
+ * in case of failure. We can't return ENOMEM, so
+ * return FILEID_INVALID at least.
+ */
+ if (mqueue_hash_add(inode))
+ return FILEID_INVALID;
+
+ fh[0] = inode->i_generation;
+ fh[1] = inode->i_ino;
+ *len = 2;
+ return 1;
+}
+
/* Auxiliary functions to manipulate messages' list */
static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
{
@@ -300,6 +441,7 @@ static struct inode *mqueue_get_inode(struct super_block
*sb,
goto err;
inode->i_ino = get_next_ino();
+ inode->i_generation = prandom_u32();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
@@ -412,6 +554,7 @@ static int mqueue_fill_super(struct super_block *sb, struct
fs_context *fc)
sb->s_blocksize_bits = PAGE_SHIFT;
sb->s_magic = MQUEUE_MAGIC;
sb->s_op = &mqueue_super_ops;
+ sb->s_export_op = &mqueue_export_ops;
inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
if (IS_ERR(inode))
@@ -509,6 +652,8 @@ static void mqueue_evict_inode(struct inode *inode)
if (S_ISDIR(inode->i_mode))
return;
+ mqueue_hash_del(inode);
+
ipc_ns = get_ns_from_inode(inode);
info = MQUEUE_I(inode);
spin_lock(&info->lock);
@@ -1649,6 +1794,11 @@ static const struct inode_operations
mqueue_dir_inode_operations = {
.unlink = mqueue_unlink,
};
+static const struct export_operations mqueue_export_ops = {
+ .encode_fh = mqueue_encode_fh,
+ .fh_to_dentry = mqueue_fh_to_dentry,
+};
+
static const struct file_operations mqueue_file_operations = {
.flush = mqueue_flush_file,
.poll = mqueue_poll_file,
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