Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / f2fs / data.c
diff --git a/kernel/fs/f2fs/data.c b/kernel/fs/f2fs/data.c
new file mode 100644 (file)
index 0000000..1e1aae6
--- /dev/null
@@ -0,0 +1,1864 @@
+/*
+ * fs/f2fs/data.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/fs.h>
+#include <linux/f2fs_fs.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/prefetch.h>
+#include <linux/uio.h>
+
+#include "f2fs.h"
+#include "node.h"
+#include "segment.h"
+#include "trace.h"
+#include <trace/events/f2fs.h>
+
+static struct kmem_cache *extent_tree_slab;
+static struct kmem_cache *extent_node_slab;
+
+static void f2fs_read_end_io(struct bio *bio, int err)
+{
+       struct bio_vec *bvec;
+       int i;
+
+       bio_for_each_segment_all(bvec, bio, i) {
+               struct page *page = bvec->bv_page;
+
+               if (!err) {
+                       SetPageUptodate(page);
+               } else {
+                       ClearPageUptodate(page);
+                       SetPageError(page);
+               }
+               unlock_page(page);
+       }
+       bio_put(bio);
+}
+
+static void f2fs_write_end_io(struct bio *bio, int err)
+{
+       struct f2fs_sb_info *sbi = bio->bi_private;
+       struct bio_vec *bvec;
+       int i;
+
+       bio_for_each_segment_all(bvec, bio, i) {
+               struct page *page = bvec->bv_page;
+
+               if (unlikely(err)) {
+                       set_page_dirty(page);
+                       set_bit(AS_EIO, &page->mapping->flags);
+                       f2fs_stop_checkpoint(sbi);
+               }
+               end_page_writeback(page);
+               dec_page_count(sbi, F2FS_WRITEBACK);
+       }
+
+       if (!get_pages(sbi, F2FS_WRITEBACK) &&
+                       !list_empty(&sbi->cp_wait.task_list))
+               wake_up(&sbi->cp_wait);
+
+       bio_put(bio);
+}
+
+/*
+ * Low-level block read/write IO operations.
+ */
+static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
+                               int npages, bool is_read)
+{
+       struct bio *bio;
+
+       /* No failure on bio allocation */
+       bio = bio_alloc(GFP_NOIO, npages);
+
+       bio->bi_bdev = sbi->sb->s_bdev;
+       bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blk_addr);
+       bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;
+       bio->bi_private = sbi;
+
+       return bio;
+}
+
+static void __submit_merged_bio(struct f2fs_bio_info *io)
+{
+       struct f2fs_io_info *fio = &io->fio;
+
+       if (!io->bio)
+               return;
+
+       if (is_read_io(fio->rw))
+               trace_f2fs_submit_read_bio(io->sbi->sb, fio, io->bio);
+       else
+               trace_f2fs_submit_write_bio(io->sbi->sb, fio, io->bio);
+
+       submit_bio(fio->rw, io->bio);
+       io->bio = NULL;
+}
+
+void f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
+                               enum page_type type, int rw)
+{
+       enum page_type btype = PAGE_TYPE_OF_BIO(type);
+       struct f2fs_bio_info *io;
+
+       io = is_read_io(rw) ? &sbi->read_io : &sbi->write_io[btype];
+
+       down_write(&io->io_rwsem);
+
+       /* change META to META_FLUSH in the checkpoint procedure */
+       if (type >= META_FLUSH) {
+               io->fio.type = META_FLUSH;
+               if (test_opt(sbi, NOBARRIER))
+                       io->fio.rw = WRITE_FLUSH | REQ_META | REQ_PRIO;
+               else
+                       io->fio.rw = WRITE_FLUSH_FUA | REQ_META | REQ_PRIO;
+       }
+       __submit_merged_bio(io);
+       up_write(&io->io_rwsem);
+}
+
+/*
+ * Fill the locked page with data located in the block address.
+ * Return unlocked page.
+ */
+int f2fs_submit_page_bio(struct f2fs_sb_info *sbi, struct page *page,
+                                       struct f2fs_io_info *fio)
+{
+       struct bio *bio;
+
+       trace_f2fs_submit_page_bio(page, fio);
+       f2fs_trace_ios(page, fio, 0);
+
+       /* Allocate a new bio */
+       bio = __bio_alloc(sbi, fio->blk_addr, 1, is_read_io(fio->rw));
+
+       if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
+               bio_put(bio);
+               f2fs_put_page(page, 1);
+               return -EFAULT;
+       }
+
+       submit_bio(fio->rw, bio);
+       return 0;
+}
+
+void f2fs_submit_page_mbio(struct f2fs_sb_info *sbi, struct page *page,
+                                       struct f2fs_io_info *fio)
+{
+       enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);
+       struct f2fs_bio_info *io;
+       bool is_read = is_read_io(fio->rw);
+
+       io = is_read ? &sbi->read_io : &sbi->write_io[btype];
+
+       verify_block_addr(sbi, fio->blk_addr);
+
+       down_write(&io->io_rwsem);
+
+       if (!is_read)
+               inc_page_count(sbi, F2FS_WRITEBACK);
+
+       if (io->bio && (io->last_block_in_bio != fio->blk_addr - 1 ||
+                                               io->fio.rw != fio->rw))
+               __submit_merged_bio(io);
+alloc_new:
+       if (io->bio == NULL) {
+               int bio_blocks = MAX_BIO_BLOCKS(sbi);
+
+               io->bio = __bio_alloc(sbi, fio->blk_addr, bio_blocks, is_read);
+               io->fio = *fio;
+       }
+
+       if (bio_add_page(io->bio, page, PAGE_CACHE_SIZE, 0) <
+                                                       PAGE_CACHE_SIZE) {
+               __submit_merged_bio(io);
+               goto alloc_new;
+       }
+
+       io->last_block_in_bio = fio->blk_addr;
+       f2fs_trace_ios(page, fio, 0);
+
+       up_write(&io->io_rwsem);
+       trace_f2fs_submit_page_mbio(page, fio);
+}
+
+/*
+ * Lock ordering for the change of data block address:
+ * ->data_page
+ *  ->node_page
+ *    update block addresses in the node page
+ */
+void set_data_blkaddr(struct dnode_of_data *dn)
+{
+       struct f2fs_node *rn;
+       __le32 *addr_array;
+       struct page *node_page = dn->node_page;
+       unsigned int ofs_in_node = dn->ofs_in_node;
+
+       f2fs_wait_on_page_writeback(node_page, NODE);
+
+       rn = F2FS_NODE(node_page);
+
+       /* Get physical address of data block */
+       addr_array = blkaddr_in_node(rn);
+       addr_array[ofs_in_node] = cpu_to_le32(dn->data_blkaddr);
+       set_page_dirty(node_page);
+}
+
+int reserve_new_block(struct dnode_of_data *dn)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
+
+       if (unlikely(is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC)))
+               return -EPERM;
+       if (unlikely(!inc_valid_block_count(sbi, dn->inode, 1)))
+               return -ENOSPC;
+
+       trace_f2fs_reserve_new_block(dn->inode, dn->nid, dn->ofs_in_node);
+
+       dn->data_blkaddr = NEW_ADDR;
+       set_data_blkaddr(dn);
+       mark_inode_dirty(dn->inode);
+       sync_inode_page(dn);
+       return 0;
+}
+
+int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index)
+{
+       bool need_put = dn->inode_page ? false : true;
+       int err;
+
+       err = get_dnode_of_data(dn, index, ALLOC_NODE);
+       if (err)
+               return err;
+
+       if (dn->data_blkaddr == NULL_ADDR)
+               err = reserve_new_block(dn);
+       if (err || need_put)
+               f2fs_put_dnode(dn);
+       return err;
+}
+
+static void f2fs_map_bh(struct super_block *sb, pgoff_t pgofs,
+                       struct extent_info *ei, struct buffer_head *bh_result)
+{
+       unsigned int blkbits = sb->s_blocksize_bits;
+       size_t max_size = bh_result->b_size;
+       size_t mapped_size;
+
+       clear_buffer_new(bh_result);
+       map_bh(bh_result, sb, ei->blk + pgofs - ei->fofs);
+       mapped_size = (ei->fofs + ei->len - pgofs) << blkbits;
+       bh_result->b_size = min(max_size, mapped_size);
+}
+
+static bool lookup_extent_info(struct inode *inode, pgoff_t pgofs,
+                                                       struct extent_info *ei)
+{
+       struct f2fs_inode_info *fi = F2FS_I(inode);
+       pgoff_t start_fofs, end_fofs;
+       block_t start_blkaddr;
+
+       read_lock(&fi->ext_lock);
+       if (fi->ext.len == 0) {
+               read_unlock(&fi->ext_lock);
+               return false;
+       }
+
+       stat_inc_total_hit(inode->i_sb);
+
+       start_fofs = fi->ext.fofs;
+       end_fofs = fi->ext.fofs + fi->ext.len - 1;
+       start_blkaddr = fi->ext.blk;
+
+       if (pgofs >= start_fofs && pgofs <= end_fofs) {
+               *ei = fi->ext;
+               stat_inc_read_hit(inode->i_sb);
+               read_unlock(&fi->ext_lock);
+               return true;
+       }
+       read_unlock(&fi->ext_lock);
+       return false;
+}
+
+static bool update_extent_info(struct inode *inode, pgoff_t fofs,
+                                                               block_t blkaddr)
+{
+       struct f2fs_inode_info *fi = F2FS_I(inode);
+       pgoff_t start_fofs, end_fofs;
+       block_t start_blkaddr, end_blkaddr;
+       int need_update = true;
+
+       write_lock(&fi->ext_lock);
+
+       start_fofs = fi->ext.fofs;
+       end_fofs = fi->ext.fofs + fi->ext.len - 1;
+       start_blkaddr = fi->ext.blk;
+       end_blkaddr = fi->ext.blk + fi->ext.len - 1;
+
+       /* Drop and initialize the matched extent */
+       if (fi->ext.len == 1 && fofs == start_fofs)
+               fi->ext.len = 0;
+
+       /* Initial extent */
+       if (fi->ext.len == 0) {
+               if (blkaddr != NULL_ADDR) {
+                       fi->ext.fofs = fofs;
+                       fi->ext.blk = blkaddr;
+                       fi->ext.len = 1;
+               }
+               goto end_update;
+       }
+
+       /* Front merge */
+       if (fofs == start_fofs - 1 && blkaddr == start_blkaddr - 1) {
+               fi->ext.fofs--;
+               fi->ext.blk--;
+               fi->ext.len++;
+               goto end_update;
+       }
+
+       /* Back merge */
+       if (fofs == end_fofs + 1 && blkaddr == end_blkaddr + 1) {
+               fi->ext.len++;
+               goto end_update;
+       }
+
+       /* Split the existing extent */
+       if (fi->ext.len > 1 &&
+               fofs >= start_fofs && fofs <= end_fofs) {
+               if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
+                       fi->ext.len = fofs - start_fofs;
+               } else {
+                       fi->ext.fofs = fofs + 1;
+                       fi->ext.blk = start_blkaddr + fofs - start_fofs + 1;
+                       fi->ext.len -= fofs - start_fofs + 1;
+               }
+       } else {
+               need_update = false;
+       }
+
+       /* Finally, if the extent is very fragmented, let's drop the cache. */
+       if (fi->ext.len < F2FS_MIN_EXTENT_LEN) {
+               fi->ext.len = 0;
+               set_inode_flag(fi, FI_NO_EXTENT);
+               need_update = true;
+       }
+end_update:
+       write_unlock(&fi->ext_lock);
+       return need_update;
+}
+
+static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_info *ei,
+                               struct rb_node *parent, struct rb_node **p)
+{
+       struct extent_node *en;
+
+       en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC);
+       if (!en)
+               return NULL;
+
+       en->ei = *ei;
+       INIT_LIST_HEAD(&en->list);
+
+       rb_link_node(&en->rb_node, parent, p);
+       rb_insert_color(&en->rb_node, &et->root);
+       et->count++;
+       atomic_inc(&sbi->total_ext_node);
+       return en;
+}
+
+static void __detach_extent_node(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_node *en)
+{
+       rb_erase(&en->rb_node, &et->root);
+       et->count--;
+       atomic_dec(&sbi->total_ext_node);
+
+       if (et->cached_en == en)
+               et->cached_en = NULL;
+}
+
+static struct extent_tree *__find_extent_tree(struct f2fs_sb_info *sbi,
+                                                       nid_t ino)
+{
+       struct extent_tree *et;
+
+       down_read(&sbi->extent_tree_lock);
+       et = radix_tree_lookup(&sbi->extent_tree_root, ino);
+       if (!et) {
+               up_read(&sbi->extent_tree_lock);
+               return NULL;
+       }
+       atomic_inc(&et->refcount);
+       up_read(&sbi->extent_tree_lock);
+
+       return et;
+}
+
+static struct extent_tree *__grab_extent_tree(struct inode *inode)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct extent_tree *et;
+       nid_t ino = inode->i_ino;
+
+       down_write(&sbi->extent_tree_lock);
+       et = radix_tree_lookup(&sbi->extent_tree_root, ino);
+       if (!et) {
+               et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS);
+               f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et);
+               memset(et, 0, sizeof(struct extent_tree));
+               et->ino = ino;
+               et->root = RB_ROOT;
+               et->cached_en = NULL;
+               rwlock_init(&et->lock);
+               atomic_set(&et->refcount, 0);
+               et->count = 0;
+               sbi->total_ext_tree++;
+       }
+       atomic_inc(&et->refcount);
+       up_write(&sbi->extent_tree_lock);
+
+       return et;
+}
+
+static struct extent_node *__lookup_extent_tree(struct extent_tree *et,
+                                                       unsigned int fofs)
+{
+       struct rb_node *node = et->root.rb_node;
+       struct extent_node *en;
+
+       if (et->cached_en) {
+               struct extent_info *cei = &et->cached_en->ei;
+
+               if (cei->fofs <= fofs && cei->fofs + cei->len > fofs)
+                       return et->cached_en;
+       }
+
+       while (node) {
+               en = rb_entry(node, struct extent_node, rb_node);
+
+               if (fofs < en->ei.fofs) {
+                       node = node->rb_left;
+               } else if (fofs >= en->ei.fofs + en->ei.len) {
+                       node = node->rb_right;
+               } else {
+                       et->cached_en = en;
+                       return en;
+               }
+       }
+       return NULL;
+}
+
+static struct extent_node *__try_back_merge(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_node *en)
+{
+       struct extent_node *prev;
+       struct rb_node *node;
+
+       node = rb_prev(&en->rb_node);
+       if (!node)
+               return NULL;
+
+       prev = rb_entry(node, struct extent_node, rb_node);
+       if (__is_back_mergeable(&en->ei, &prev->ei)) {
+               en->ei.fofs = prev->ei.fofs;
+               en->ei.blk = prev->ei.blk;
+               en->ei.len += prev->ei.len;
+               __detach_extent_node(sbi, et, prev);
+               return prev;
+       }
+       return NULL;
+}
+
+static struct extent_node *__try_front_merge(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_node *en)
+{
+       struct extent_node *next;
+       struct rb_node *node;
+
+       node = rb_next(&en->rb_node);
+       if (!node)
+               return NULL;
+
+       next = rb_entry(node, struct extent_node, rb_node);
+       if (__is_front_mergeable(&en->ei, &next->ei)) {
+               en->ei.len += next->ei.len;
+               __detach_extent_node(sbi, et, next);
+               return next;
+       }
+       return NULL;
+}
+
+static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_info *ei,
+                               struct extent_node **den)
+{
+       struct rb_node **p = &et->root.rb_node;
+       struct rb_node *parent = NULL;
+       struct extent_node *en;
+
+       while (*p) {
+               parent = *p;
+               en = rb_entry(parent, struct extent_node, rb_node);
+
+               if (ei->fofs < en->ei.fofs) {
+                       if (__is_front_mergeable(ei, &en->ei)) {
+                               f2fs_bug_on(sbi, !den);
+                               en->ei.fofs = ei->fofs;
+                               en->ei.blk = ei->blk;
+                               en->ei.len += ei->len;
+                               *den = __try_back_merge(sbi, et, en);
+                               return en;
+                       }
+                       p = &(*p)->rb_left;
+               } else if (ei->fofs >= en->ei.fofs + en->ei.len) {
+                       if (__is_back_mergeable(ei, &en->ei)) {
+                               f2fs_bug_on(sbi, !den);
+                               en->ei.len += ei->len;
+                               *den = __try_front_merge(sbi, et, en);
+                               return en;
+                       }
+                       p = &(*p)->rb_right;
+               } else {
+                       f2fs_bug_on(sbi, 1);
+               }
+       }
+
+       return __attach_extent_node(sbi, et, ei, parent, p);
+}
+
+static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
+                                       struct extent_tree *et, bool free_all)
+{
+       struct rb_node *node, *next;
+       struct extent_node *en;
+       unsigned int count = et->count;
+
+       node = rb_first(&et->root);
+       while (node) {
+               next = rb_next(node);
+               en = rb_entry(node, struct extent_node, rb_node);
+
+               if (free_all) {
+                       spin_lock(&sbi->extent_lock);
+                       if (!list_empty(&en->list))
+                               list_del_init(&en->list);
+                       spin_unlock(&sbi->extent_lock);
+               }
+
+               if (free_all || list_empty(&en->list)) {
+                       __detach_extent_node(sbi, et, en);
+                       kmem_cache_free(extent_node_slab, en);
+               }
+               node = next;
+       }
+
+       return count - et->count;
+}
+
+static void f2fs_init_extent_tree(struct inode *inode,
+                                               struct f2fs_extent *i_ext)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct extent_tree *et;
+       struct extent_node *en;
+       struct extent_info ei;
+
+       if (le32_to_cpu(i_ext->len) < F2FS_MIN_EXTENT_LEN)
+               return;
+
+       et = __grab_extent_tree(inode);
+
+       write_lock(&et->lock);
+       if (et->count)
+               goto out;
+
+       set_extent_info(&ei, le32_to_cpu(i_ext->fofs),
+               le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len));
+
+       en = __insert_extent_tree(sbi, et, &ei, NULL);
+       if (en) {
+               et->cached_en = en;
+
+               spin_lock(&sbi->extent_lock);
+               list_add_tail(&en->list, &sbi->extent_list);
+               spin_unlock(&sbi->extent_lock);
+       }
+out:
+       write_unlock(&et->lock);
+       atomic_dec(&et->refcount);
+}
+
+static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
+                                                       struct extent_info *ei)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct extent_tree *et;
+       struct extent_node *en;
+
+       trace_f2fs_lookup_extent_tree_start(inode, pgofs);
+
+       et = __find_extent_tree(sbi, inode->i_ino);
+       if (!et)
+               return false;
+
+       read_lock(&et->lock);
+       en = __lookup_extent_tree(et, pgofs);
+       if (en) {
+               *ei = en->ei;
+               spin_lock(&sbi->extent_lock);
+               if (!list_empty(&en->list))
+                       list_move_tail(&en->list, &sbi->extent_list);
+               spin_unlock(&sbi->extent_lock);
+               stat_inc_read_hit(sbi->sb);
+       }
+       stat_inc_total_hit(sbi->sb);
+       read_unlock(&et->lock);
+
+       trace_f2fs_lookup_extent_tree_end(inode, pgofs, en);
+
+       atomic_dec(&et->refcount);
+       return en ? true : false;
+}
+
+static void f2fs_update_extent_tree(struct inode *inode, pgoff_t fofs,
+                                                       block_t blkaddr)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct extent_tree *et;
+       struct extent_node *en = NULL, *en1 = NULL, *en2 = NULL, *en3 = NULL;
+       struct extent_node *den = NULL;
+       struct extent_info ei, dei;
+       unsigned int endofs;
+
+       trace_f2fs_update_extent_tree(inode, fofs, blkaddr);
+
+       et = __grab_extent_tree(inode);
+
+       write_lock(&et->lock);
+
+       /* 1. lookup and remove existing extent info in cache */
+       en = __lookup_extent_tree(et, fofs);
+       if (!en)
+               goto update_extent;
+
+       dei = en->ei;
+       __detach_extent_node(sbi, et, en);
+
+       /* 2. if extent can be split more, split and insert the left part */
+       if (dei.len > 1) {
+               /*  insert left part of split extent into cache */
+               if (fofs - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
+                       set_extent_info(&ei, dei.fofs, dei.blk,
+                                                       fofs - dei.fofs);
+                       en1 = __insert_extent_tree(sbi, et, &ei, NULL);
+               }
+
+               /* insert right part of split extent into cache */
+               endofs = dei.fofs + dei.len - 1;
+               if (endofs - fofs >= F2FS_MIN_EXTENT_LEN) {
+                       set_extent_info(&ei, fofs + 1,
+                               fofs - dei.fofs + dei.blk, endofs - fofs);
+                       en2 = __insert_extent_tree(sbi, et, &ei, NULL);
+               }
+       }
+
+update_extent:
+       /* 3. update extent in extent cache */
+       if (blkaddr) {
+               set_extent_info(&ei, fofs, blkaddr, 1);
+               en3 = __insert_extent_tree(sbi, et, &ei, &den);
+       }
+
+       /* 4. update in global extent list */
+       spin_lock(&sbi->extent_lock);
+       if (en && !list_empty(&en->list))
+               list_del(&en->list);
+       /*
+        * en1 and en2 split from en, they will become more and more smaller
+        * fragments after splitting several times. So if the length is smaller
+        * than F2FS_MIN_EXTENT_LEN, we will not add them into extent tree.
+        */
+       if (en1)
+               list_add_tail(&en1->list, &sbi->extent_list);
+       if (en2)
+               list_add_tail(&en2->list, &sbi->extent_list);
+       if (en3) {
+               if (list_empty(&en3->list))
+                       list_add_tail(&en3->list, &sbi->extent_list);
+               else
+                       list_move_tail(&en3->list, &sbi->extent_list);
+       }
+       if (den && !list_empty(&den->list))
+               list_del(&den->list);
+       spin_unlock(&sbi->extent_lock);
+
+       /* 5. release extent node */
+       if (en)
+               kmem_cache_free(extent_node_slab, en);
+       if (den)
+               kmem_cache_free(extent_node_slab, den);
+
+       write_unlock(&et->lock);
+       atomic_dec(&et->refcount);
+}
+
+void f2fs_preserve_extent_tree(struct inode *inode)
+{
+       struct extent_tree *et;
+       struct extent_info *ext = &F2FS_I(inode)->ext;
+       bool sync = false;
+
+       if (!test_opt(F2FS_I_SB(inode), EXTENT_CACHE))
+               return;
+
+       et = __find_extent_tree(F2FS_I_SB(inode), inode->i_ino);
+       if (!et) {
+               if (ext->len) {
+                       ext->len = 0;
+                       update_inode_page(inode);
+               }
+               return;
+       }
+
+       read_lock(&et->lock);
+       if (et->count) {
+               struct extent_node *en;
+
+               if (et->cached_en) {
+                       en = et->cached_en;
+               } else {
+                       struct rb_node *node = rb_first(&et->root);
+
+                       if (!node)
+                               node = rb_last(&et->root);
+                       en = rb_entry(node, struct extent_node, rb_node);
+               }
+
+               if (__is_extent_same(ext, &en->ei))
+                       goto out;
+
+               *ext = en->ei;
+               sync = true;
+       } else if (ext->len) {
+               ext->len = 0;
+               sync = true;
+       }
+out:
+       read_unlock(&et->lock);
+       atomic_dec(&et->refcount);
+
+       if (sync)
+               update_inode_page(inode);
+}
+
+void f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
+{
+       struct extent_tree *treevec[EXT_TREE_VEC_SIZE];
+       struct extent_node *en, *tmp;
+       unsigned long ino = F2FS_ROOT_INO(sbi);
+       struct radix_tree_iter iter;
+       void **slot;
+       unsigned int found;
+       unsigned int node_cnt = 0, tree_cnt = 0;
+
+       if (!test_opt(sbi, EXTENT_CACHE))
+               return;
+
+       if (available_free_memory(sbi, EXTENT_CACHE))
+               return;
+
+       spin_lock(&sbi->extent_lock);
+       list_for_each_entry_safe(en, tmp, &sbi->extent_list, list) {
+               if (!nr_shrink--)
+                       break;
+               list_del_init(&en->list);
+       }
+       spin_unlock(&sbi->extent_lock);
+
+       down_read(&sbi->extent_tree_lock);
+       while ((found = radix_tree_gang_lookup(&sbi->extent_tree_root,
+                               (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
+               unsigned i;
+
+               ino = treevec[found - 1]->ino + 1;
+               for (i = 0; i < found; i++) {
+                       struct extent_tree *et = treevec[i];
+
+                       atomic_inc(&et->refcount);
+                       write_lock(&et->lock);
+                       node_cnt += __free_extent_tree(sbi, et, false);
+                       write_unlock(&et->lock);
+                       atomic_dec(&et->refcount);
+               }
+       }
+       up_read(&sbi->extent_tree_lock);
+
+       down_write(&sbi->extent_tree_lock);
+       radix_tree_for_each_slot(slot, &sbi->extent_tree_root, &iter,
+                                                       F2FS_ROOT_INO(sbi)) {
+               struct extent_tree *et = (struct extent_tree *)*slot;
+
+               if (!atomic_read(&et->refcount) && !et->count) {
+                       radix_tree_delete(&sbi->extent_tree_root, et->ino);
+                       kmem_cache_free(extent_tree_slab, et);
+                       sbi->total_ext_tree--;
+                       tree_cnt++;
+               }
+       }
+       up_write(&sbi->extent_tree_lock);
+
+       trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);
+}
+
+void f2fs_destroy_extent_tree(struct inode *inode)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct extent_tree *et;
+       unsigned int node_cnt = 0;
+
+       if (!test_opt(sbi, EXTENT_CACHE))
+               return;
+
+       et = __find_extent_tree(sbi, inode->i_ino);
+       if (!et)
+               goto out;
+
+       /* free all extent info belong to this extent tree */
+       write_lock(&et->lock);
+       node_cnt = __free_extent_tree(sbi, et, true);
+       write_unlock(&et->lock);
+
+       atomic_dec(&et->refcount);
+
+       /* try to find and delete extent tree entry in radix tree */
+       down_write(&sbi->extent_tree_lock);
+       et = radix_tree_lookup(&sbi->extent_tree_root, inode->i_ino);
+       if (!et) {
+               up_write(&sbi->extent_tree_lock);
+               goto out;
+       }
+       f2fs_bug_on(sbi, atomic_read(&et->refcount) || et->count);
+       radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
+       kmem_cache_free(extent_tree_slab, et);
+       sbi->total_ext_tree--;
+       up_write(&sbi->extent_tree_lock);
+out:
+       trace_f2fs_destroy_extent_tree(inode, node_cnt);
+       return;
+}
+
+void f2fs_init_extent_cache(struct inode *inode, struct f2fs_extent *i_ext)
+{
+       if (test_opt(F2FS_I_SB(inode), EXTENT_CACHE))
+               f2fs_init_extent_tree(inode, i_ext);
+
+       write_lock(&F2FS_I(inode)->ext_lock);
+       get_extent_info(&F2FS_I(inode)->ext, *i_ext);
+       write_unlock(&F2FS_I(inode)->ext_lock);
+}
+
+static bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
+                                                       struct extent_info *ei)
+{
+       if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT))
+               return false;
+
+       if (test_opt(F2FS_I_SB(inode), EXTENT_CACHE))
+               return f2fs_lookup_extent_tree(inode, pgofs, ei);
+
+       return lookup_extent_info(inode, pgofs, ei);
+}
+
+void f2fs_update_extent_cache(struct dnode_of_data *dn)
+{
+       struct f2fs_inode_info *fi = F2FS_I(dn->inode);
+       pgoff_t fofs;
+
+       f2fs_bug_on(F2FS_I_SB(dn->inode), dn->data_blkaddr == NEW_ADDR);
+
+       if (is_inode_flag_set(fi, FI_NO_EXTENT))
+               return;
+
+       fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
+                                                       dn->ofs_in_node;
+
+       if (test_opt(F2FS_I_SB(dn->inode), EXTENT_CACHE))
+               return f2fs_update_extent_tree(dn->inode, fofs,
+                                                       dn->data_blkaddr);
+
+       if (update_extent_info(dn->inode, fofs, dn->data_blkaddr))
+               sync_inode_page(dn);
+}
+
+struct page *find_data_page(struct inode *inode, pgoff_t index, bool sync)
+{
+       struct address_space *mapping = inode->i_mapping;
+       struct dnode_of_data dn;
+       struct page *page;
+       struct extent_info ei;
+       int err;
+       struct f2fs_io_info fio = {
+               .type = DATA,
+               .rw = sync ? READ_SYNC : READA,
+       };
+
+       /*
+        * If sync is false, it needs to check its block allocation.
+        * This is need and triggered by two flows:
+        *   gc and truncate_partial_data_page.
+        */
+       if (!sync)
+               goto search;
+
+       page = find_get_page(mapping, index);
+       if (page && PageUptodate(page))
+               return page;
+       f2fs_put_page(page, 0);
+search:
+       if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+               dn.data_blkaddr = ei.blk + index - ei.fofs;
+               goto got_it;
+       }
+
+       set_new_dnode(&dn, inode, NULL, NULL, 0);
+       err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
+       if (err)
+               return ERR_PTR(err);
+       f2fs_put_dnode(&dn);
+
+       if (dn.data_blkaddr == NULL_ADDR)
+               return ERR_PTR(-ENOENT);
+
+       /* By fallocate(), there is no cached page, but with NEW_ADDR */
+       if (unlikely(dn.data_blkaddr == NEW_ADDR))
+               return ERR_PTR(-EINVAL);
+
+got_it:
+       page = grab_cache_page(mapping, index);
+       if (!page)
+               return ERR_PTR(-ENOMEM);
+
+       if (PageUptodate(page)) {
+               unlock_page(page);
+               return page;
+       }
+
+       fio.blk_addr = dn.data_blkaddr;
+       err = f2fs_submit_page_bio(F2FS_I_SB(inode), page, &fio);
+       if (err)
+               return ERR_PTR(err);
+
+       if (sync) {
+               wait_on_page_locked(page);
+               if (unlikely(!PageUptodate(page))) {
+                       f2fs_put_page(page, 0);
+                       return ERR_PTR(-EIO);
+               }
+       }
+       return page;
+}
+
+/*
+ * If it tries to access a hole, return an error.
+ * Because, the callers, functions in dir.c and GC, should be able to know
+ * whether this page exists or not.
+ */
+struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
+{
+       struct address_space *mapping = inode->i_mapping;
+       struct dnode_of_data dn;
+       struct page *page;
+       struct extent_info ei;
+       int err;
+       struct f2fs_io_info fio = {
+               .type = DATA,
+               .rw = READ_SYNC,
+       };
+repeat:
+       page = grab_cache_page(mapping, index);
+       if (!page)
+               return ERR_PTR(-ENOMEM);
+
+       if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+               dn.data_blkaddr = ei.blk + index - ei.fofs;
+               goto got_it;
+       }
+
+       set_new_dnode(&dn, inode, NULL, NULL, 0);
+       err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
+       if (err) {
+               f2fs_put_page(page, 1);
+               return ERR_PTR(err);
+       }
+       f2fs_put_dnode(&dn);
+
+       if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
+               f2fs_put_page(page, 1);
+               return ERR_PTR(-ENOENT);
+       }
+
+got_it:
+       if (PageUptodate(page))
+               return page;
+
+       /*
+        * A new dentry page is allocated but not able to be written, since its
+        * new inode page couldn't be allocated due to -ENOSPC.
+        * In such the case, its blkaddr can be remained as NEW_ADDR.
+        * see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
+        */
+       if (dn.data_blkaddr == NEW_ADDR) {
+               zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+               SetPageUptodate(page);
+               return page;
+       }
+
+       fio.blk_addr = dn.data_blkaddr;
+       err = f2fs_submit_page_bio(F2FS_I_SB(inode), page, &fio);
+       if (err)
+               return ERR_PTR(err);
+
+       lock_page(page);
+       if (unlikely(!PageUptodate(page))) {
+               f2fs_put_page(page, 1);
+               return ERR_PTR(-EIO);
+       }
+       if (unlikely(page->mapping != mapping)) {
+               f2fs_put_page(page, 1);
+               goto repeat;
+       }
+       return page;
+}
+
+/*
+ * Caller ensures that this data page is never allocated.
+ * A new zero-filled data page is allocated in the page cache.
+ *
+ * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
+ * f2fs_unlock_op().
+ * Note that, ipage is set only by make_empty_dir.
+ */
+struct page *get_new_data_page(struct inode *inode,
+               struct page *ipage, pgoff_t index, bool new_i_size)
+{
+       struct address_space *mapping = inode->i_mapping;
+       struct page *page;
+       struct dnode_of_data dn;
+       int err;
+
+       set_new_dnode(&dn, inode, ipage, NULL, 0);
+       err = f2fs_reserve_block(&dn, index);
+       if (err)
+               return ERR_PTR(err);
+repeat:
+       page = grab_cache_page(mapping, index);
+       if (!page) {
+               err = -ENOMEM;
+               goto put_err;
+       }
+
+       if (PageUptodate(page))
+               return page;
+
+       if (dn.data_blkaddr == NEW_ADDR) {
+               zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+               SetPageUptodate(page);
+       } else {
+               struct f2fs_io_info fio = {
+                       .type = DATA,
+                       .rw = READ_SYNC,
+                       .blk_addr = dn.data_blkaddr,
+               };
+               err = f2fs_submit_page_bio(F2FS_I_SB(inode), page, &fio);
+               if (err)
+                       goto put_err;
+
+               lock_page(page);
+               if (unlikely(!PageUptodate(page))) {
+                       f2fs_put_page(page, 1);
+                       err = -EIO;
+                       goto put_err;
+               }
+               if (unlikely(page->mapping != mapping)) {
+                       f2fs_put_page(page, 1);
+                       goto repeat;
+               }
+       }
+
+       if (new_i_size &&
+               i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
+               i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
+               /* Only the directory inode sets new_i_size */
+               set_inode_flag(F2FS_I(inode), FI_UPDATE_DIR);
+       }
+       return page;
+
+put_err:
+       f2fs_put_dnode(&dn);
+       return ERR_PTR(err);
+}
+
+static int __allocate_data_block(struct dnode_of_data *dn)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
+       struct f2fs_inode_info *fi = F2FS_I(dn->inode);
+       struct f2fs_summary sum;
+       struct node_info ni;
+       int seg = CURSEG_WARM_DATA;
+       pgoff_t fofs;
+
+       if (unlikely(is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC)))
+               return -EPERM;
+
+       dn->data_blkaddr = datablock_addr(dn->node_page, dn->ofs_in_node);
+       if (dn->data_blkaddr == NEW_ADDR)
+               goto alloc;
+
+       if (unlikely(!inc_valid_block_count(sbi, dn->inode, 1)))
+               return -ENOSPC;
+
+alloc:
+       get_node_info(sbi, dn->nid, &ni);
+       set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
+
+       if (dn->ofs_in_node == 0 && dn->inode_page == dn->node_page)
+               seg = CURSEG_DIRECT_IO;
+
+       allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr,
+                                                               &sum, seg);
+
+       /* direct IO doesn't use extent cache to maximize the performance */
+       set_data_blkaddr(dn);
+
+       /* update i_size */
+       fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
+                                                       dn->ofs_in_node;
+       if (i_size_read(dn->inode) < ((fofs + 1) << PAGE_CACHE_SHIFT))
+               i_size_write(dn->inode, ((fofs + 1) << PAGE_CACHE_SHIFT));
+
+       return 0;
+}
+
+static void __allocate_data_blocks(struct inode *inode, loff_t offset,
+                                                       size_t count)
+{
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct dnode_of_data dn;
+       u64 start = F2FS_BYTES_TO_BLK(offset);
+       u64 len = F2FS_BYTES_TO_BLK(count);
+       bool allocated;
+       u64 end_offset;
+
+       while (len) {
+               f2fs_balance_fs(sbi);
+               f2fs_lock_op(sbi);
+
+               /* When reading holes, we need its node page */
+               set_new_dnode(&dn, inode, NULL, NULL, 0);
+               if (get_dnode_of_data(&dn, start, ALLOC_NODE))
+                       goto out;
+
+               allocated = false;
+               end_offset = ADDRS_PER_PAGE(dn.node_page, F2FS_I(inode));
+
+               while (dn.ofs_in_node < end_offset && len) {
+                       block_t blkaddr;
+
+                       blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
+                       if (blkaddr == NULL_ADDR || blkaddr == NEW_ADDR) {
+                               if (__allocate_data_block(&dn))
+                                       goto sync_out;
+                               allocated = true;
+                       }
+                       len--;
+                       start++;
+                       dn.ofs_in_node++;
+               }
+
+               if (allocated)
+                       sync_inode_page(&dn);
+
+               f2fs_put_dnode(&dn);
+               f2fs_unlock_op(sbi);
+       }
+       return;
+
+sync_out:
+       if (allocated)
+               sync_inode_page(&dn);
+       f2fs_put_dnode(&dn);
+out:
+       f2fs_unlock_op(sbi);
+       return;
+}
+
+/*
+ * get_data_block() now supported readahead/bmap/rw direct_IO with mapped bh.
+ * If original data blocks are allocated, then give them to blockdev.
+ * Otherwise,
+ *     a. preallocate requested block addresses
+ *     b. do not use extent cache for better performance
+ *     c. give the block addresses to blockdev
+ */
+static int __get_data_block(struct inode *inode, sector_t iblock,
+                       struct buffer_head *bh_result, int create, bool fiemap)
+{
+       unsigned int blkbits = inode->i_sb->s_blocksize_bits;
+       unsigned maxblocks = bh_result->b_size >> blkbits;
+       struct dnode_of_data dn;
+       int mode = create ? ALLOC_NODE : LOOKUP_NODE_RA;
+       pgoff_t pgofs, end_offset;
+       int err = 0, ofs = 1;
+       struct extent_info ei;
+       bool allocated = false;
+
+       /* Get the page offset from the block offset(iblock) */
+       pgofs = (pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
+
+       if (f2fs_lookup_extent_cache(inode, pgofs, &ei)) {
+               f2fs_map_bh(inode->i_sb, pgofs, &ei, bh_result);
+               goto out;
+       }
+
+       if (create)
+               f2fs_lock_op(F2FS_I_SB(inode));
+
+       /* When reading holes, we need its node page */
+       set_new_dnode(&dn, inode, NULL, NULL, 0);
+       err = get_dnode_of_data(&dn, pgofs, mode);
+       if (err) {
+               if (err == -ENOENT)
+                       err = 0;
+               goto unlock_out;
+       }
+       if (dn.data_blkaddr == NEW_ADDR && !fiemap)
+               goto put_out;
+
+       if (dn.data_blkaddr != NULL_ADDR) {
+               clear_buffer_new(bh_result);
+               map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
+       } else if (create) {
+               err = __allocate_data_block(&dn);
+               if (err)
+                       goto put_out;
+               allocated = true;
+               set_buffer_new(bh_result);
+               map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
+       } else {
+               goto put_out;
+       }
+
+       end_offset = ADDRS_PER_PAGE(dn.node_page, F2FS_I(inode));
+       bh_result->b_size = (((size_t)1) << blkbits);
+       dn.ofs_in_node++;
+       pgofs++;
+
+get_next:
+       if (dn.ofs_in_node >= end_offset) {
+               if (allocated)
+                       sync_inode_page(&dn);
+               allocated = false;
+               f2fs_put_dnode(&dn);
+
+               set_new_dnode(&dn, inode, NULL, NULL, 0);
+               err = get_dnode_of_data(&dn, pgofs, mode);
+               if (err) {
+                       if (err == -ENOENT)
+                               err = 0;
+                       goto unlock_out;
+               }
+               if (dn.data_blkaddr == NEW_ADDR && !fiemap)
+                       goto put_out;
+
+               end_offset = ADDRS_PER_PAGE(dn.node_page, F2FS_I(inode));
+       }
+
+       if (maxblocks > (bh_result->b_size >> blkbits)) {
+               block_t blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
+               if (blkaddr == NULL_ADDR && create) {
+                       err = __allocate_data_block(&dn);
+                       if (err)
+                               goto sync_out;
+                       allocated = true;
+                       set_buffer_new(bh_result);
+                       blkaddr = dn.data_blkaddr;
+               }
+               /* Give more consecutive addresses for the readahead */
+               if (blkaddr == (bh_result->b_blocknr + ofs)) {
+                       ofs++;
+                       dn.ofs_in_node++;
+                       pgofs++;
+                       bh_result->b_size += (((size_t)1) << blkbits);
+                       goto get_next;
+               }
+       }
+sync_out:
+       if (allocated)
+               sync_inode_page(&dn);
+put_out:
+       f2fs_put_dnode(&dn);
+unlock_out:
+       if (create)
+               f2fs_unlock_op(F2FS_I_SB(inode));
+out:
+       trace_f2fs_get_data_block(inode, iblock, bh_result, err);
+       return err;
+}
+
+static int get_data_block(struct inode *inode, sector_t iblock,
+                       struct buffer_head *bh_result, int create)
+{
+       return __get_data_block(inode, iblock, bh_result, create, false);
+}
+
+static int get_data_block_fiemap(struct inode *inode, sector_t iblock,
+                       struct buffer_head *bh_result, int create)
+{
+       return __get_data_block(inode, iblock, bh_result, create, true);
+}
+
+int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+               u64 start, u64 len)
+{
+       return generic_block_fiemap(inode, fieinfo,
+                               start, len, get_data_block_fiemap);
+}
+
+static int f2fs_read_data_page(struct file *file, struct page *page)
+{
+       struct inode *inode = page->mapping->host;
+       int ret = -EAGAIN;
+
+       trace_f2fs_readpage(page, DATA);
+
+       /* If the file has inline data, try to read it directly */
+       if (f2fs_has_inline_data(inode))
+               ret = f2fs_read_inline_data(inode, page);
+       if (ret == -EAGAIN)
+               ret = mpage_readpage(page, get_data_block);
+
+       return ret;
+}
+
+static int f2fs_read_data_pages(struct file *file,
+                       struct address_space *mapping,
+                       struct list_head *pages, unsigned nr_pages)
+{
+       struct inode *inode = file->f_mapping->host;
+
+       /* If the file has inline data, skip readpages */
+       if (f2fs_has_inline_data(inode))
+               return 0;
+
+       return mpage_readpages(mapping, pages, nr_pages, get_data_block);
+}
+
+int do_write_data_page(struct page *page, struct f2fs_io_info *fio)
+{
+       struct inode *inode = page->mapping->host;
+       struct dnode_of_data dn;
+       int err = 0;
+
+       set_new_dnode(&dn, inode, NULL, NULL, 0);
+       err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
+       if (err)
+               return err;
+
+       fio->blk_addr = dn.data_blkaddr;
+
+       /* This page is already truncated */
+       if (fio->blk_addr == NULL_ADDR) {
+               ClearPageUptodate(page);
+               goto out_writepage;
+       }
+
+       set_page_writeback(page);
+
+       /*
+        * If current allocation needs SSR,
+        * it had better in-place writes for updated data.
+        */
+       if (unlikely(fio->blk_addr != NEW_ADDR &&
+                       !is_cold_data(page) &&
+                       need_inplace_update(inode))) {
+               rewrite_data_page(page, fio);
+               set_inode_flag(F2FS_I(inode), FI_UPDATE_WRITE);
+               trace_f2fs_do_write_data_page(page, IPU);
+       } else {
+               write_data_page(page, &dn, fio);
+               set_data_blkaddr(&dn);
+               f2fs_update_extent_cache(&dn);
+               trace_f2fs_do_write_data_page(page, OPU);
+               set_inode_flag(F2FS_I(inode), FI_APPEND_WRITE);
+               if (page->index == 0)
+                       set_inode_flag(F2FS_I(inode), FI_FIRST_BLOCK_WRITTEN);
+       }
+out_writepage:
+       f2fs_put_dnode(&dn);
+       return err;
+}
+
+static int f2fs_write_data_page(struct page *page,
+                                       struct writeback_control *wbc)
+{
+       struct inode *inode = page->mapping->host;
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       loff_t i_size = i_size_read(inode);
+       const pgoff_t end_index = ((unsigned long long) i_size)
+                                                       >> PAGE_CACHE_SHIFT;
+       unsigned offset = 0;
+       bool need_balance_fs = false;
+       int err = 0;
+       struct f2fs_io_info fio = {
+               .type = DATA,
+               .rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE,
+       };
+
+       trace_f2fs_writepage(page, DATA);
+
+       if (page->index < end_index)
+               goto write;
+
+       /*
+        * If the offset is out-of-range of file size,
+        * this page does not have to be written to disk.
+        */
+       offset = i_size & (PAGE_CACHE_SIZE - 1);
+       if ((page->index >= end_index + 1) || !offset)
+               goto out;
+
+       zero_user_segment(page, offset, PAGE_CACHE_SIZE);
+write:
+       if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
+               goto redirty_out;
+       if (f2fs_is_drop_cache(inode))
+               goto out;
+       if (f2fs_is_volatile_file(inode) && !wbc->for_reclaim &&
+                       available_free_memory(sbi, BASE_CHECK))
+               goto redirty_out;
+
+       /* Dentry blocks are controlled by checkpoint */
+       if (S_ISDIR(inode->i_mode)) {
+               if (unlikely(f2fs_cp_error(sbi)))
+                       goto redirty_out;
+               err = do_write_data_page(page, &fio);
+               goto done;
+       }
+
+       /* we should bypass data pages to proceed the kworkder jobs */
+       if (unlikely(f2fs_cp_error(sbi))) {
+               SetPageError(page);
+               goto out;
+       }
+
+       if (!wbc->for_reclaim)
+               need_balance_fs = true;
+       else if (has_not_enough_free_secs(sbi, 0))
+               goto redirty_out;
+
+       err = -EAGAIN;
+       f2fs_lock_op(sbi);
+       if (f2fs_has_inline_data(inode))
+               err = f2fs_write_inline_data(inode, page);
+       if (err == -EAGAIN)
+               err = do_write_data_page(page, &fio);
+       f2fs_unlock_op(sbi);
+done:
+       if (err && err != -ENOENT)
+               goto redirty_out;
+
+       clear_cold_data(page);
+out:
+       inode_dec_dirty_pages(inode);
+       if (err)
+               ClearPageUptodate(page);
+       unlock_page(page);
+       if (need_balance_fs)
+               f2fs_balance_fs(sbi);
+       if (wbc->for_reclaim)
+               f2fs_submit_merged_bio(sbi, DATA, WRITE);
+       return 0;
+
+redirty_out:
+       redirty_page_for_writepage(wbc, page);
+       return AOP_WRITEPAGE_ACTIVATE;
+}
+
+static int __f2fs_writepage(struct page *page, struct writeback_control *wbc,
+                       void *data)
+{
+       struct address_space *mapping = data;
+       int ret = mapping->a_ops->writepage(page, wbc);
+       mapping_set_error(mapping, ret);
+       return ret;
+}
+
+static int f2fs_write_data_pages(struct address_space *mapping,
+                           struct writeback_control *wbc)
+{
+       struct inode *inode = mapping->host;
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       bool locked = false;
+       int ret;
+       long diff;
+
+       trace_f2fs_writepages(mapping->host, wbc, DATA);
+
+       /* deal with chardevs and other special file */
+       if (!mapping->a_ops->writepage)
+               return 0;
+
+       if (S_ISDIR(inode->i_mode) && wbc->sync_mode == WB_SYNC_NONE &&
+                       get_dirty_pages(inode) < nr_pages_to_skip(sbi, DATA) &&
+                       available_free_memory(sbi, DIRTY_DENTS))
+               goto skip_write;
+
+       /* during POR, we don't need to trigger writepage at all. */
+       if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
+               goto skip_write;
+
+       diff = nr_pages_to_write(sbi, DATA, wbc);
+
+       if (!S_ISDIR(inode->i_mode)) {
+               mutex_lock(&sbi->writepages);
+               locked = true;
+       }
+       ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
+       if (locked)
+               mutex_unlock(&sbi->writepages);
+
+       f2fs_submit_merged_bio(sbi, DATA, WRITE);
+
+       remove_dirty_dir_inode(inode);
+
+       wbc->nr_to_write = max((long)0, wbc->nr_to_write - diff);
+       return ret;
+
+skip_write:
+       wbc->pages_skipped += get_dirty_pages(inode);
+       return 0;
+}
+
+static void f2fs_write_failed(struct address_space *mapping, loff_t to)
+{
+       struct inode *inode = mapping->host;
+
+       if (to > inode->i_size) {
+               truncate_pagecache(inode, inode->i_size);
+               truncate_blocks(inode, inode->i_size, true);
+       }
+}
+
+static int f2fs_write_begin(struct file *file, struct address_space *mapping,
+               loff_t pos, unsigned len, unsigned flags,
+               struct page **pagep, void **fsdata)
+{
+       struct inode *inode = mapping->host;
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct page *page, *ipage;
+       pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
+       struct dnode_of_data dn;
+       int err = 0;
+
+       trace_f2fs_write_begin(inode, pos, len, flags);
+
+       f2fs_balance_fs(sbi);
+
+       /*
+        * We should check this at this moment to avoid deadlock on inode page
+        * and #0 page. The locking rule for inline_data conversion should be:
+        * lock_page(page #0) -> lock_page(inode_page)
+        */
+       if (index != 0) {
+               err = f2fs_convert_inline_inode(inode);
+               if (err)
+                       goto fail;
+       }
+repeat:
+       page = grab_cache_page_write_begin(mapping, index, flags);
+       if (!page) {
+               err = -ENOMEM;
+               goto fail;
+       }
+
+       *pagep = page;
+
+       f2fs_lock_op(sbi);
+
+       /* check inline_data */
+       ipage = get_node_page(sbi, inode->i_ino);
+       if (IS_ERR(ipage)) {
+               err = PTR_ERR(ipage);
+               goto unlock_fail;
+       }
+
+       set_new_dnode(&dn, inode, ipage, ipage, 0);
+
+       if (f2fs_has_inline_data(inode)) {
+               if (pos + len <= MAX_INLINE_DATA) {
+                       read_inline_data(page, ipage);
+                       set_inode_flag(F2FS_I(inode), FI_DATA_EXIST);
+                       sync_inode_page(&dn);
+                       goto put_next;
+               }
+               err = f2fs_convert_inline_page(&dn, page);
+               if (err)
+                       goto put_fail;
+       }
+       err = f2fs_reserve_block(&dn, index);
+       if (err)
+               goto put_fail;
+put_next:
+       f2fs_put_dnode(&dn);
+       f2fs_unlock_op(sbi);
+
+       if ((len == PAGE_CACHE_SIZE) || PageUptodate(page))
+               return 0;
+
+       f2fs_wait_on_page_writeback(page, DATA);
+
+       if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
+               unsigned start = pos & (PAGE_CACHE_SIZE - 1);
+               unsigned end = start + len;
+
+               /* Reading beyond i_size is simple: memset to zero */
+               zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
+               goto out;
+       }
+
+       if (dn.data_blkaddr == NEW_ADDR) {
+               zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+       } else {
+               struct f2fs_io_info fio = {
+                       .type = DATA,
+                       .rw = READ_SYNC,
+                       .blk_addr = dn.data_blkaddr,
+               };
+               err = f2fs_submit_page_bio(sbi, page, &fio);
+               if (err)
+                       goto fail;
+
+               lock_page(page);
+               if (unlikely(!PageUptodate(page))) {
+                       f2fs_put_page(page, 1);
+                       err = -EIO;
+                       goto fail;
+               }
+               if (unlikely(page->mapping != mapping)) {
+                       f2fs_put_page(page, 1);
+                       goto repeat;
+               }
+       }
+out:
+       SetPageUptodate(page);
+       clear_cold_data(page);
+       return 0;
+
+put_fail:
+       f2fs_put_dnode(&dn);
+unlock_fail:
+       f2fs_unlock_op(sbi);
+       f2fs_put_page(page, 1);
+fail:
+       f2fs_write_failed(mapping, pos + len);
+       return err;
+}
+
+static int f2fs_write_end(struct file *file,
+                       struct address_space *mapping,
+                       loff_t pos, unsigned len, unsigned copied,
+                       struct page *page, void *fsdata)
+{
+       struct inode *inode = page->mapping->host;
+
+       trace_f2fs_write_end(inode, pos, len, copied);
+
+       set_page_dirty(page);
+
+       if (pos + copied > i_size_read(inode)) {
+               i_size_write(inode, pos + copied);
+               mark_inode_dirty(inode);
+               update_inode_page(inode);
+       }
+
+       f2fs_put_page(page, 1);
+       return copied;
+}
+
+static int check_direct_IO(struct inode *inode, struct iov_iter *iter,
+                          loff_t offset)
+{
+       unsigned blocksize_mask = inode->i_sb->s_blocksize - 1;
+
+       if (iov_iter_rw(iter) == READ)
+               return 0;
+
+       if (offset & blocksize_mask)
+               return -EINVAL;
+
+       if (iov_iter_alignment(iter) & blocksize_mask)
+               return -EINVAL;
+
+       return 0;
+}
+
+static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+                             loff_t offset)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
+       size_t count = iov_iter_count(iter);
+       int err;
+
+       /* we don't need to use inline_data strictly */
+       if (f2fs_has_inline_data(inode)) {
+               err = f2fs_convert_inline_inode(inode);
+               if (err)
+                       return err;
+       }
+
+       if (check_direct_IO(inode, iter, offset))
+               return 0;
+
+       trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
+
+       if (iov_iter_rw(iter) == WRITE)
+               __allocate_data_blocks(inode, offset, count);
+
+       err = blockdev_direct_IO(iocb, inode, iter, offset, get_data_block);
+       if (err < 0 && iov_iter_rw(iter) == WRITE)
+               f2fs_write_failed(mapping, offset + count);
+
+       trace_f2fs_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), err);
+
+       return err;
+}
+
+void f2fs_invalidate_page(struct page *page, unsigned int offset,
+                                                       unsigned int length)
+{
+       struct inode *inode = page->mapping->host;
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+
+       if (inode->i_ino >= F2FS_ROOT_INO(sbi) &&
+               (offset % PAGE_CACHE_SIZE || length != PAGE_CACHE_SIZE))
+               return;
+
+       if (PageDirty(page)) {
+               if (inode->i_ino == F2FS_META_INO(sbi))
+                       dec_page_count(sbi, F2FS_DIRTY_META);
+               else if (inode->i_ino == F2FS_NODE_INO(sbi))
+                       dec_page_count(sbi, F2FS_DIRTY_NODES);
+               else
+                       inode_dec_dirty_pages(inode);
+       }
+       ClearPagePrivate(page);
+}
+
+int f2fs_release_page(struct page *page, gfp_t wait)
+{
+       /* If this is dirty page, keep PagePrivate */
+       if (PageDirty(page))
+               return 0;
+
+       ClearPagePrivate(page);
+       return 1;
+}
+
+static int f2fs_set_data_page_dirty(struct page *page)
+{
+       struct address_space *mapping = page->mapping;
+       struct inode *inode = mapping->host;
+
+       trace_f2fs_set_page_dirty(page, DATA);
+
+       SetPageUptodate(page);
+
+       if (f2fs_is_atomic_file(inode)) {
+               register_inmem_page(inode, page);
+               return 1;
+       }
+
+       mark_inode_dirty(inode);
+
+       if (!PageDirty(page)) {
+               __set_page_dirty_nobuffers(page);
+               update_dirty_page(inode, page);
+               return 1;
+       }
+       return 0;
+}
+
+static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
+{
+       struct inode *inode = mapping->host;
+
+       /* we don't need to use inline_data strictly */
+       if (f2fs_has_inline_data(inode)) {
+               int err = f2fs_convert_inline_inode(inode);
+               if (err)
+                       return err;
+       }
+       return generic_block_bmap(mapping, block, get_data_block);
+}
+
+void init_extent_cache_info(struct f2fs_sb_info *sbi)
+{
+       INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
+       init_rwsem(&sbi->extent_tree_lock);
+       INIT_LIST_HEAD(&sbi->extent_list);
+       spin_lock_init(&sbi->extent_lock);
+       sbi->total_ext_tree = 0;
+       atomic_set(&sbi->total_ext_node, 0);
+}
+
+int __init create_extent_cache(void)
+{
+       extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree",
+                       sizeof(struct extent_tree));
+       if (!extent_tree_slab)
+               return -ENOMEM;
+       extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node",
+                       sizeof(struct extent_node));
+       if (!extent_node_slab) {
+               kmem_cache_destroy(extent_tree_slab);
+               return -ENOMEM;
+       }
+       return 0;
+}
+
+void destroy_extent_cache(void)
+{
+       kmem_cache_destroy(extent_node_slab);
+       kmem_cache_destroy(extent_tree_slab);
+}
+
+const struct address_space_operations f2fs_dblock_aops = {
+       .readpage       = f2fs_read_data_page,
+       .readpages      = f2fs_read_data_pages,
+       .writepage      = f2fs_write_data_page,
+       .writepages     = f2fs_write_data_pages,
+       .write_begin    = f2fs_write_begin,
+       .write_end      = f2fs_write_end,
+       .set_page_dirty = f2fs_set_data_page_dirty,
+       .invalidatepage = f2fs_invalidate_page,
+       .releasepage    = f2fs_release_page,
+       .direct_IO      = f2fs_direct_IO,
+       .bmap           = f2fs_bmap,
+};