SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/btrfs/ordered-data.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/gfp.h>
  20 #include <linux/slab.h>
  21 #include <linux/blkdev.h>
  22 #include "ctree.h"
  23 #include "transaction.h"
  24 #include "btrfs_inode.h"
  25
  26 struct tree_entry {
  27         u64 root_objectid;
  28         u64 objectid;
  29         struct inode *inode;
  30         struct rb_node rb_node;
  31 };
  32
  33 /*
  34  * returns > 0 if entry passed (root, objectid) is > entry,
  35  * < 0 if (root, objectid) < entry and zero if they are equal
  36  */
  37 static int comp_entry(struct tree_entry *entry, u64 root_objectid,
  38                       u64 objectid)
  39 {
  40         if (root_objectid < entry->root_objectid)
  41                 return -1;
  42         if (root_objectid > entry->root_objectid)
  43                 return 1;
  44         if (objectid < entry->objectid)
  45                 return -1;
  46         if (objectid > entry->objectid)
  47                 return 1;
  48         return 0;
  49 }
  50
  51 static struct rb_node *tree_insert(struct rb_root *root, u64 root_objectid,
  52                                    u64 objectid, struct rb_node *node)
  53 {
  54         struct rb_node ** p = &root->rb_node;
  55         struct rb_node * parent = NULL;
  56         struct tree_entry *entry;
  57         int comp;
  58
  59         while(*p) {
  60                 parent = *p;
  61                 entry = rb_entry(parent, struct tree_entry, rb_node);
  62
  63                 comp = comp_entry(entry, root_objectid, objectid);
  64                 if (comp < 0)
  65                         p = &(*p)->rb_left;
  66                 else if (comp > 0)
  67                         p = &(*p)->rb_right;
  68                 else
  69                         return parent;
  70         }
  71
  72         rb_link_node(node, parent, p);
  73         rb_insert_color(node, root);
  74         return NULL;
  75 }
  76
  77 static struct rb_node *__tree_search(struct rb_root *root, u64 root_objectid,
  78                                      u64 objectid, struct rb_node **prev_ret)
  79 {
  80         struct rb_node * n = root->rb_node;
  81         struct rb_node *prev = NULL;
  82         struct tree_entry *entry;
  83         struct tree_entry *prev_entry = NULL;
  84         int comp;
  85
  86         while(n) {
  87                 entry = rb_entry(n, struct tree_entry, rb_node);
  88                 prev = n;
  89                 prev_entry = entry;
  90                 comp = comp_entry(entry, root_objectid, objectid);
  91
  92                 if (comp < 0)
  93                         n = n->rb_left;
  94                 else if (comp > 0)
  95                         n = n->rb_right;
  96                 else
  97                         return n;
  98         }
  99         if (!prev_ret)
 100                 return NULL;
 101
 102         while(prev && comp_entry(prev_entry, root_objectid, objectid) >= 0) {
 103                 prev = rb_next(prev);
 104                 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 105         }
 106         *prev_ret = prev;
 107         return NULL;
 108 }
 109
 110 static inline struct rb_node *tree_search(struct rb_root *root,
 111                                           u64 root_objectid, u64 objectid)
 112 {
 113         struct rb_node *prev;
 114         struct rb_node *ret;
 115         ret = __tree_search(root, root_objectid, objectid, &prev);
 116         if (!ret)
 117                 return prev;
 118         return ret;
 119 }
 120
 121 int btrfs_add_ordered_inode(struct inode *inode)
 122 {
 123         struct btrfs_root *root = BTRFS_I(inode)->root;
 124         u64 root_objectid = root->root_key.objectid;
 125         u64 transid = root->fs_info->running_transaction->transid;
 126         struct tree_entry *entry;
 127         struct rb_node *node;
 128         struct btrfs_ordered_inode_tree *tree;
 129
 130         if (transid <= BTRFS_I(inode)->ordered_trans)
 131                 return 0;
 132
 133         tree = &root->fs_info->running_transaction->ordered_inode_tree;
 134
 135         read_lock(&tree->lock);
 136         node = __tree_search(&tree->tree, root_objectid, inode->i_ino, NULL);
 137         read_unlock(&tree->lock);
 138         if (node) {
 139                 return 0;
 140         }
 141
 142         entry = kmalloc(sizeof(*entry), GFP_NOFS);
 143         if (!entry)
 144                 return -ENOMEM;
 145
 146         write_lock(&tree->lock);
 147         entry->objectid = inode->i_ino;
 148         entry->root_objectid = root_objectid;
 149         entry->inode = inode;
 150
 151         node = tree_insert(&tree->tree, root_objectid,
 152                            inode->i_ino, &entry->rb_node);
 153
 154         BTRFS_I(inode)->ordered_trans = transid;
 155
 156         write_unlock(&tree->lock);
 157         if (node)
 158                 kfree(entry);
 159         else
 160                 igrab(inode);
 161         return 0;
 162 }
 163
 164 int btrfs_find_first_ordered_inode(struct btrfs_ordered_inode_tree *tree,
 165                                    u64 *root_objectid, u64 *objectid,
 166                                    struct inode **inode)
 167 {
 168         struct tree_entry *entry;
 169         struct rb_node *node;
 170
 171         write_lock(&tree->lock);
 172         node = tree_search(&tree->tree, *root_objectid, *objectid);
 173         if (!node) {
 174                 write_unlock(&tree->lock);
 175                 return 0;
 176         }
 177         entry = rb_entry(node, struct tree_entry, rb_node);
 178
 179         while(comp_entry(entry, *root_objectid, *objectid) >= 0) {
 180                 node = rb_next(node);
 181                 if (!node)
 182                         break;
 183                 entry = rb_entry(node, struct tree_entry, rb_node);
 184         }
 185         if (!node) {
 186                 write_unlock(&tree->lock);
 187                 return 0;
 188         }
 189
 190         *root_objectid = entry->root_objectid;
 191         *inode = entry->inode;
 192         atomic_inc(&entry->inode->i_count);
 193         *objectid = entry->objectid;
 194         write_unlock(&tree->lock);
 195         return 1;
 196 }
 197
 198 int btrfs_find_del_first_ordered_inode(struct btrfs_ordered_inode_tree *tree,
 199                                        u64 *root_objectid, u64 *objectid,
 200                                        struct inode **inode)
 201 {
 202         struct tree_entry *entry;
 203         struct rb_node *node;
 204
 205         write_lock(&tree->lock);
 206         node = tree_search(&tree->tree, *root_objectid, *objectid);
 207         if (!node) {
 208                 write_unlock(&tree->lock);
 209                 return 0;
 210         }
 211
 212         entry = rb_entry(node, struct tree_entry, rb_node);
 213         while(comp_entry(entry, *root_objectid, *objectid) >= 0) {
 214                 node = rb_next(node);
 215                 if (!node)
 216                         break;
 217                 entry = rb_entry(node, struct tree_entry, rb_node);
 218         }
 219         if (!node) {
 220                 write_unlock(&tree->lock);
 221                 return 0;
 222         }
 223
 224         *root_objectid = entry->root_objectid;
 225         *objectid = entry->objectid;
 226         *inode = entry->inode;
 227         atomic_inc(&entry->inode->i_count);
 228         rb_erase(node, &tree->tree);
 229         write_unlock(&tree->lock);
 230         kfree(entry);
 231         return 1;
 232 }
 233
 234 static void __btrfs_del_ordered_inode(struct btrfs_ordered_inode_tree *tree,
 235                                      struct inode *inode,
 236                                      u64 root_objectid, u64 objectid)
 237 {
 238         struct tree_entry *entry;
 239         struct rb_node *node;
 240         struct rb_node *prev;
 241
 242         write_lock(&tree->lock);
 243         node = __tree_search(&tree->tree, root_objectid, objectid, &prev);
 244         if (!node) {
 245                 write_unlock(&tree->lock);
 246                 return;
 247         }
 248         rb_erase(node, &tree->tree);
 249         BTRFS_I(inode)->ordered_trans = 0;
 250         write_unlock(&tree->lock);
 251         atomic_dec(&inode->i_count);
 252         entry = rb_entry(node, struct tree_entry, rb_node);
 253         kfree(entry);
 254         return;
 255 }
 256
 257 void btrfs_del_ordered_inode(struct inode *inode)
 258 {
 259         struct btrfs_root *root = BTRFS_I(inode)->root;
 260         u64 root_objectid = root->root_key.objectid;
 261
 262         if (!BTRFS_I(inode)->ordered_trans) {
 263                 return;
 264         }
 265
 266         if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY) ||
 267             mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
 268                 return;
 269
 270         spin_lock(&root->fs_info->new_trans_lock);
 271         if (root->fs_info->running_transaction) {
 272                 struct btrfs_ordered_inode_tree *tree;
 273                 tree = &root->fs_info->running_transaction->ordered_inode_tree;
 274                  __btrfs_del_ordered_inode(tree, inode, root_objectid,
 275                                                 inode->i_ino);
 276         }
 277         spin_unlock(&root->fs_info->new_trans_lock);
 278 }
 279
 280 int btrfs_ordered_throttle(struct btrfs_root *root, struct inode *inode)
 281 {
 282         struct btrfs_transaction *cur = root->fs_info->running_transaction;
 283         while(cur == root->fs_info->running_transaction &&
 284               atomic_read(&BTRFS_I(inode)->ordered_writeback)) {
 285 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18)
 286                 congestion_wait(WRITE, HZ/20);
 287 #else
 288                 blk_congestion_wait(WRITE, HZ/20);
 289 #endif
 290         }
 291         return 0;
 292 }