cifs: convert tlink_tree to a rbtree
Radix trees are ideal when you want to track a bunch of pointers and can't embed a tracking structure within the target of those pointers. The tradeoff is an increase in memory, particularly if the tree is sparse. In CIFS, we use the tlink_tree to track tcon_link structs. A tcon_link can never be in more than one tlink_tree, so there's no impediment to using a rb_tree here instead of a radix tree. Convert the new multiuser mount code to use a rb_tree instead. This should reduce the memory required to manage the tlink_tree. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Jeff Layton
Steve French
Родитель
413e661c13
Коммит
b647c35f77
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@ -15,7 +15,7 @@
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* the GNU Lesser General Public License for more details.
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*
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*/
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#include <linux/radix-tree.h>
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#include <linux/rbtree.h>
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#ifndef _CIFS_FS_SB_H
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#define _CIFS_FS_SB_H
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@ -42,7 +42,7 @@
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#define CIFS_MOUNT_MULTIUSER 0x20000 /* multiuser mount */
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struct cifs_sb_info {
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struct radix_tree_root tlink_tree;
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struct rb_root tlink_tree;
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spinlock_t tlink_tree_lock;
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struct tcon_link *master_tlink;
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struct nls_table *local_nls;
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@ -116,7 +116,7 @@ cifs_read_super(struct super_block *sb, void *data,
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return -ENOMEM;
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spin_lock_init(&cifs_sb->tlink_tree_lock);
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INIT_RADIX_TREE(&cifs_sb->tlink_tree, GFP_KERNEL);
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cifs_sb->tlink_tree = RB_ROOT;
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rc = bdi_setup_and_register(&cifs_sb->bdi, "cifs", BDI_CAP_MAP_COPY);
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if (rc) {
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@ -336,7 +336,8 @@ struct cifsTconInfo {
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* "get" on the container.
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*/
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struct tcon_link {
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unsigned long tl_index;
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struct rb_node tl_rbnode;
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uid_t tl_uid;
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unsigned long tl_flags;
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#define TCON_LINK_MASTER 0
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#define TCON_LINK_PENDING 1
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@ -116,6 +116,7 @@ struct smb_vol {
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static int ipv4_connect(struct TCP_Server_Info *server);
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static int ipv6_connect(struct TCP_Server_Info *server);
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static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
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static void cifs_prune_tlinks(struct work_struct *work);
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/*
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@ -2900,24 +2901,16 @@ remote_path_check:
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goto mount_fail_check;
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}
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tlink->tl_index = pSesInfo->linux_uid;
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tlink->tl_uid = pSesInfo->linux_uid;
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tlink->tl_tcon = tcon;
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tlink->tl_time = jiffies;
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set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
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set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
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rc = radix_tree_preload(GFP_KERNEL);
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if (rc == -ENOMEM) {
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kfree(tlink);
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goto mount_fail_check;
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}
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spin_lock(&cifs_sb->tlink_tree_lock);
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radix_tree_insert(&cifs_sb->tlink_tree, pSesInfo->linux_uid, tlink);
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spin_unlock(&cifs_sb->tlink_tree_lock);
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radix_tree_preload_end();
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cifs_sb->master_tlink = tlink;
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spin_lock(&cifs_sb->tlink_tree_lock);
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tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
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spin_unlock(&cifs_sb->tlink_tree_lock);
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queue_delayed_work(system_nrt_wq, &cifs_sb->prune_tlinks,
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TLINK_IDLE_EXPIRE);
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@ -3107,32 +3100,25 @@ CIFSTCon(unsigned int xid, struct cifsSesInfo *ses,
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int
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cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
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{
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int i, ret;
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struct rb_root *root = &cifs_sb->tlink_tree;
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struct rb_node *node;
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struct tcon_link *tlink;
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char *tmp;
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struct tcon_link *tlink[8];
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unsigned long index = 0;
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cancel_delayed_work_sync(&cifs_sb->prune_tlinks);
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do {
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spin_lock(&cifs_sb->tlink_tree_lock);
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ret = radix_tree_gang_lookup(&cifs_sb->tlink_tree,
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(void **)tlink, index,
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ARRAY_SIZE(tlink));
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/* increment index for next pass */
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if (ret > 0)
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index = tlink[ret - 1]->tl_index + 1;
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for (i = 0; i < ret; i++) {
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cifs_get_tlink(tlink[i]);
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clear_bit(TCON_LINK_IN_TREE, &tlink[i]->tl_flags);
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radix_tree_delete(&cifs_sb->tlink_tree,
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tlink[i]->tl_index);
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}
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spin_unlock(&cifs_sb->tlink_tree_lock);
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spin_lock(&cifs_sb->tlink_tree_lock);
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while ((node = rb_first(root))) {
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tlink = rb_entry(node, struct tcon_link, tl_rbnode);
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cifs_get_tlink(tlink);
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clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
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rb_erase(node, root);
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for (i = 0; i < ret; i++)
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cifs_put_tlink(tlink[i]);
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} while (ret != 0);
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spin_unlock(&cifs_sb->tlink_tree_lock);
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cifs_put_tlink(tlink);
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spin_lock(&cifs_sb->tlink_tree_lock);
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}
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spin_unlock(&cifs_sb->tlink_tree_lock);
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tmp = cifs_sb->prepath;
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cifs_sb->prepathlen = 0;
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@ -3290,6 +3276,47 @@ cifs_sb_tcon_pending_wait(void *unused)
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return signal_pending(current) ? -ERESTARTSYS : 0;
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}
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/* find and return a tlink with given uid */
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static struct tcon_link *
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tlink_rb_search(struct rb_root *root, uid_t uid)
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{
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struct rb_node *node = root->rb_node;
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struct tcon_link *tlink;
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while (node) {
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tlink = rb_entry(node, struct tcon_link, tl_rbnode);
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if (tlink->tl_uid > uid)
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node = node->rb_left;
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else if (tlink->tl_uid < uid)
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node = node->rb_right;
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else
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return tlink;
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}
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return NULL;
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}
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/* insert a tcon_link into the tree */
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static void
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tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
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{
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struct rb_node **new = &(root->rb_node), *parent = NULL;
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struct tcon_link *tlink;
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while (*new) {
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tlink = rb_entry(*new, struct tcon_link, tl_rbnode);
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parent = *new;
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if (tlink->tl_uid > new_tlink->tl_uid)
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new = &((*new)->rb_left);
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else
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new = &((*new)->rb_right);
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}
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rb_link_node(&new_tlink->tl_rbnode, parent, new);
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rb_insert_color(&new_tlink->tl_rbnode, root);
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}
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/*
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* Find or construct an appropriate tcon given a cifs_sb and the fsuid of the
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* current task.
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@ -3310,14 +3337,14 @@ struct tcon_link *
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cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
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{
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int ret;
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unsigned long fsuid = (unsigned long) current_fsuid();
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uid_t fsuid = current_fsuid();
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struct tcon_link *tlink, *newtlink;
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if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
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return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
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spin_lock(&cifs_sb->tlink_tree_lock);
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tlink = radix_tree_lookup(&cifs_sb->tlink_tree, fsuid);
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tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
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if (tlink)
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cifs_get_tlink(tlink);
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spin_unlock(&cifs_sb->tlink_tree_lock);
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@ -3326,36 +3353,24 @@ cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
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newtlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
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if (newtlink == NULL)
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return ERR_PTR(-ENOMEM);
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newtlink->tl_index = fsuid;
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newtlink->tl_uid = fsuid;
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newtlink->tl_tcon = ERR_PTR(-EACCES);
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set_bit(TCON_LINK_PENDING, &newtlink->tl_flags);
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set_bit(TCON_LINK_IN_TREE, &newtlink->tl_flags);
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cifs_get_tlink(newtlink);
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ret = radix_tree_preload(GFP_KERNEL);
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if (ret != 0) {
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kfree(newtlink);
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return ERR_PTR(ret);
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}
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spin_lock(&cifs_sb->tlink_tree_lock);
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/* was one inserted after previous search? */
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tlink = radix_tree_lookup(&cifs_sb->tlink_tree, fsuid);
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tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
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if (tlink) {
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cifs_get_tlink(tlink);
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spin_unlock(&cifs_sb->tlink_tree_lock);
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radix_tree_preload_end();
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kfree(newtlink);
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goto wait_for_construction;
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}
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ret = radix_tree_insert(&cifs_sb->tlink_tree, fsuid, newtlink);
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spin_unlock(&cifs_sb->tlink_tree_lock);
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radix_tree_preload_end();
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if (ret) {
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kfree(newtlink);
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return ERR_PTR(ret);
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}
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tlink = newtlink;
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tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
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spin_unlock(&cifs_sb->tlink_tree_lock);
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} else {
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wait_for_construction:
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ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
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@ -3401,39 +3416,39 @@ cifs_prune_tlinks(struct work_struct *work)
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{
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struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
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prune_tlinks.work);
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struct tcon_link *tlink[8];
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unsigned long now = jiffies;
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unsigned long index = 0;
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int i, ret;
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struct rb_root *root = &cifs_sb->tlink_tree;
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struct rb_node *node = rb_first(root);
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struct rb_node *tmp;
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struct tcon_link *tlink;
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/*
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* Because we drop the spinlock in the loop in order to put the tlink
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* it's not guarded against removal of links from the tree. The only
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* places that remove entries from the tree are this function and
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* umounts. Because this function is non-reentrant and is canceled
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* before umount can proceed, this is safe.
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*/
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spin_lock(&cifs_sb->tlink_tree_lock);
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node = rb_first(root);
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while (node != NULL) {
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tmp = node;
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node = rb_next(tmp);
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tlink = rb_entry(tmp, struct tcon_link, tl_rbnode);
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if (test_bit(TCON_LINK_MASTER, &tlink->tl_flags) ||
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atomic_read(&tlink->tl_count) != 0 ||
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time_after(tlink->tl_time + TLINK_IDLE_EXPIRE, jiffies))
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continue;
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cifs_get_tlink(tlink);
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clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
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rb_erase(tmp, root);
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do {
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spin_lock(&cifs_sb->tlink_tree_lock);
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ret = radix_tree_gang_lookup(&cifs_sb->tlink_tree,
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(void **)tlink, index,
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ARRAY_SIZE(tlink));
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/* increment index for next pass */
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if (ret > 0)
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index = tlink[ret - 1]->tl_index + 1;
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for (i = 0; i < ret; i++) {
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if (test_bit(TCON_LINK_MASTER, &tlink[i]->tl_flags) ||
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atomic_read(&tlink[i]->tl_count) != 0 ||
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time_after(tlink[i]->tl_time + TLINK_IDLE_EXPIRE,
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now)) {
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tlink[i] = NULL;
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continue;
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}
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cifs_get_tlink(tlink[i]);
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clear_bit(TCON_LINK_IN_TREE, &tlink[i]->tl_flags);
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radix_tree_delete(&cifs_sb->tlink_tree,
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tlink[i]->tl_index);
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}
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spin_unlock(&cifs_sb->tlink_tree_lock);
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for (i = 0; i < ret; i++) {
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if (tlink[i] != NULL)
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cifs_put_tlink(tlink[i]);
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}
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} while (ret != 0);
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cifs_put_tlink(tlink);
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spin_lock(&cifs_sb->tlink_tree_lock);
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}
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spin_unlock(&cifs_sb->tlink_tree_lock);
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queue_delayed_work(system_nrt_wq, &cifs_sb->prune_tlinks,
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TLINK_IDLE_EXPIRE);
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