diff options
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 2860 |
1 files changed, 2860 insertions, 0 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c new file mode 100644 index 000000000..b072e1747 --- /dev/null +++ b/fs/btrfs/file.c @@ -0,0 +1,2860 @@ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include <linux/time.h> +#include <linux/init.h> +#include <linux/string.h> +#include <linux/backing-dev.h> +#include <linux/mpage.h> +#include <linux/falloc.h> +#include <linux/swap.h> +#include <linux/writeback.h> +#include <linux/statfs.h> +#include <linux/compat.h> +#include <linux/slab.h> +#include <linux/btrfs.h> +#include <linux/uio.h> +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "btrfs_inode.h" +#include "print-tree.h" +#include "tree-log.h" +#include "locking.h" +#include "volumes.h" +#include "qgroup.h" + +static struct kmem_cache *btrfs_inode_defrag_cachep; +/* + * when auto defrag is enabled we + * queue up these defrag structs to remember which + * inodes need defragging passes + */ +struct inode_defrag { + struct rb_node rb_node; + /* objectid */ + u64 ino; + /* + * transid where the defrag was added, we search for + * extents newer than this + */ + u64 transid; + + /* root objectid */ + u64 root; + + /* last offset we were able to defrag */ + u64 last_offset; + + /* if we've wrapped around back to zero once already */ + int cycled; +}; + +static int __compare_inode_defrag(struct inode_defrag *defrag1, + struct inode_defrag *defrag2) +{ + if (defrag1->root > defrag2->root) + return 1; + else if (defrag1->root < defrag2->root) + return -1; + else if (defrag1->ino > defrag2->ino) + return 1; + else if (defrag1->ino < defrag2->ino) + return -1; + else + return 0; +} + +/* pop a record for an inode into the defrag tree. The lock + * must be held already + * + * If you're inserting a record for an older transid than an + * existing record, the transid already in the tree is lowered + * + * If an existing record is found the defrag item you + * pass in is freed + */ +static int __btrfs_add_inode_defrag(struct inode *inode, + struct inode_defrag *defrag) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct inode_defrag *entry; + struct rb_node **p; + struct rb_node *parent = NULL; + int ret; + + p = &root->fs_info->defrag_inodes.rb_node; + while (*p) { + parent = *p; + entry = rb_entry(parent, struct inode_defrag, rb_node); + + ret = __compare_inode_defrag(defrag, entry); + if (ret < 0) + p = &parent->rb_left; + else if (ret > 0) + p = &parent->rb_right; + else { + /* if we're reinserting an entry for + * an old defrag run, make sure to + * lower the transid of our existing record + */ + if (defrag->transid < entry->transid) + entry->transid = defrag->transid; + if (defrag->last_offset > entry->last_offset) + entry->last_offset = defrag->last_offset; + return -EEXIST; + } + } + set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags); + rb_link_node(&defrag->rb_node, parent, p); + rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes); + return 0; +} + +static inline int __need_auto_defrag(struct btrfs_root *root) +{ + if (!btrfs_test_opt(root, AUTO_DEFRAG)) + return 0; + + if (btrfs_fs_closing(root->fs_info)) + return 0; + + return 1; +} + +/* + * insert a defrag record for this inode if auto defrag is + * enabled + */ +int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans, + struct inode *inode) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct inode_defrag *defrag; + u64 transid; + int ret; + + if (!__need_auto_defrag(root)) + return 0; + + if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) + return 0; + + if (trans) + transid = trans->transid; + else + transid = BTRFS_I(inode)->root->last_trans; + + defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS); + if (!defrag) + return -ENOMEM; + + defrag->ino = btrfs_ino(inode); + defrag->transid = transid; + defrag->root = root->root_key.objectid; + + spin_lock(&root->fs_info->defrag_inodes_lock); + if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) { + /* + * If we set IN_DEFRAG flag and evict the inode from memory, + * and then re-read this inode, this new inode doesn't have + * IN_DEFRAG flag. At the case, we may find the existed defrag. + */ + ret = __btrfs_add_inode_defrag(inode, defrag); + if (ret) + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); + } else { + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); + } + spin_unlock(&root->fs_info->defrag_inodes_lock); + return 0; +} + +/* + * Requeue the defrag object. If there is a defrag object that points to + * the same inode in the tree, we will merge them together (by + * __btrfs_add_inode_defrag()) and free the one that we want to requeue. + */ +static void btrfs_requeue_inode_defrag(struct inode *inode, + struct inode_defrag *defrag) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret; + + if (!__need_auto_defrag(root)) + goto out; + + /* + * Here we don't check the IN_DEFRAG flag, because we need merge + * them together. + */ + spin_lock(&root->fs_info->defrag_inodes_lock); + ret = __btrfs_add_inode_defrag(inode, defrag); + spin_unlock(&root->fs_info->defrag_inodes_lock); + if (ret) + goto out; + return; +out: + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); +} + +/* + * pick the defragable inode that we want, if it doesn't exist, we will get + * the next one. + */ +static struct inode_defrag * +btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino) +{ + struct inode_defrag *entry = NULL; + struct inode_defrag tmp; + struct rb_node *p; + struct rb_node *parent = NULL; + int ret; + + tmp.ino = ino; + tmp.root = root; + + spin_lock(&fs_info->defrag_inodes_lock); + p = fs_info->defrag_inodes.rb_node; + while (p) { + parent = p; + entry = rb_entry(parent, struct inode_defrag, rb_node); + + ret = __compare_inode_defrag(&tmp, entry); + if (ret < 0) + p = parent->rb_left; + else if (ret > 0) + p = parent->rb_right; + else + goto out; + } + + if (parent && __compare_inode_defrag(&tmp, entry) > 0) { + parent = rb_next(parent); + if (parent) + entry = rb_entry(parent, struct inode_defrag, rb_node); + else + entry = NULL; + } +out: + if (entry) + rb_erase(parent, &fs_info->defrag_inodes); + spin_unlock(&fs_info->defrag_inodes_lock); + return entry; +} + +void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info) +{ + struct inode_defrag *defrag; + struct rb_node *node; + + spin_lock(&fs_info->defrag_inodes_lock); + node = rb_first(&fs_info->defrag_inodes); + while (node) { + rb_erase(node, &fs_info->defrag_inodes); + defrag = rb_entry(node, struct inode_defrag, rb_node); + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); + + cond_resched_lock(&fs_info->defrag_inodes_lock); + + node = rb_first(&fs_info->defrag_inodes); + } + spin_unlock(&fs_info->defrag_inodes_lock); +} + +#define BTRFS_DEFRAG_BATCH 1024 + +static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info, + struct inode_defrag *defrag) +{ + struct btrfs_root *inode_root; + struct inode *inode; + struct btrfs_key key; + struct btrfs_ioctl_defrag_range_args range; + int num_defrag; + int index; + int ret; + + /* get the inode */ + key.objectid = defrag->root; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = (u64)-1; + + index = srcu_read_lock(&fs_info->subvol_srcu); + + inode_root = btrfs_read_fs_root_no_name(fs_info, &key); + if (IS_ERR(inode_root)) { + ret = PTR_ERR(inode_root); + goto cleanup; + } + + key.objectid = defrag->ino; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL); + if (IS_ERR(inode)) { + ret = PTR_ERR(inode); + goto cleanup; + } + srcu_read_unlock(&fs_info->subvol_srcu, index); + + /* do a chunk of defrag */ + clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags); + memset(&range, 0, sizeof(range)); + range.len = (u64)-1; + range.start = defrag->last_offset; + + sb_start_write(fs_info->sb); + num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid, + BTRFS_DEFRAG_BATCH); + sb_end_write(fs_info->sb); + /* + * if we filled the whole defrag batch, there + * must be more work to do. Queue this defrag + * again + */ + if (num_defrag == BTRFS_DEFRAG_BATCH) { + defrag->last_offset = range.start; + btrfs_requeue_inode_defrag(inode, defrag); + } else if (defrag->last_offset && !defrag->cycled) { + /* + * we didn't fill our defrag batch, but + * we didn't start at zero. Make sure we loop + * around to the start of the file. + */ + defrag->last_offset = 0; + defrag->cycled = 1; + btrfs_requeue_inode_defrag(inode, defrag); + } else { + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); + } + + iput(inode); + return 0; +cleanup: + srcu_read_unlock(&fs_info->subvol_srcu, index); + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); + return ret; +} + +/* + * run through the list of inodes in the FS that need + * defragging + */ +int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info) +{ + struct inode_defrag *defrag; + u64 first_ino = 0; + u64 root_objectid = 0; + + atomic_inc(&fs_info->defrag_running); + while (1) { + /* Pause the auto defragger. */ + if (test_bit(BTRFS_FS_STATE_REMOUNTING, + &fs_info->fs_state)) + break; + + if (!__need_auto_defrag(fs_info->tree_root)) + break; + + /* find an inode to defrag */ + defrag = btrfs_pick_defrag_inode(fs_info, root_objectid, + first_ino); + if (!defrag) { + if (root_objectid || first_ino) { + root_objectid = 0; + first_ino = 0; + continue; + } else { + break; + } + } + + first_ino = defrag->ino + 1; + root_objectid = defrag->root; + + __btrfs_run_defrag_inode(fs_info, defrag); + } + atomic_dec(&fs_info->defrag_running); + + /* + * during unmount, we use the transaction_wait queue to + * wait for the defragger to stop + */ + wake_up(&fs_info->transaction_wait); + return 0; +} + +/* simple helper to fault in pages and copy. This should go away + * and be replaced with calls into generic code. + */ +static noinline int btrfs_copy_from_user(loff_t pos, int num_pages, + size_t write_bytes, + struct page **prepared_pages, + struct iov_iter *i) +{ + size_t copied = 0; + size_t total_copied = 0; + int pg = 0; + int offset = pos & (PAGE_CACHE_SIZE - 1); + + while (write_bytes > 0) { + size_t count = min_t(size_t, + PAGE_CACHE_SIZE - offset, write_bytes); + struct page *page = prepared_pages[pg]; + /* + * Copy data from userspace to the current page + */ + copied = iov_iter_copy_from_user_atomic(page, i, offset, count); + + /* Flush processor's dcache for this page */ + flush_dcache_page(page); + + /* + * if we get a partial write, we can end up with + * partially up to date pages. These add + * a lot of complexity, so make sure they don't + * happen by forcing this copy to be retried. + * + * The rest of the btrfs_file_write code will fall + * back to page at a time copies after we return 0. + */ + if (!PageUptodate(page) && copied < count) + copied = 0; + + iov_iter_advance(i, copied); + write_bytes -= copied; + total_copied += copied; + + /* Return to btrfs_file_write_iter to fault page */ + if (unlikely(copied == 0)) + break; + + if (copied < PAGE_CACHE_SIZE - offset) { + offset += copied; + } else { + pg++; + offset = 0; + } + } + return total_copied; +} + +/* + * unlocks pages after btrfs_file_write is done with them + */ +static void btrfs_drop_pages(struct page **pages, size_t num_pages) +{ + size_t i; + for (i = 0; i < num_pages; i++) { + /* page checked is some magic around finding pages that + * have been modified without going through btrfs_set_page_dirty + * clear it here. There should be no need to mark the pages + * accessed as prepare_pages should have marked them accessed + * in prepare_pages via find_or_create_page() + */ + ClearPageChecked(pages[i]); + unlock_page(pages[i]); + page_cache_release(pages[i]); + } +} + +/* + * after copy_from_user, pages need to be dirtied and we need to make + * sure holes are created between the current EOF and the start of + * any next extents (if required). + * + * this also makes the decision about creating an inline extent vs + * doing real data extents, marking pages dirty and delalloc as required. + */ +int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode, + struct page **pages, size_t num_pages, + loff_t pos, size_t write_bytes, + struct extent_state **cached) +{ + int err = 0; + int i; + u64 num_bytes; + u64 start_pos; + u64 end_of_last_block; + u64 end_pos = pos + write_bytes; + loff_t isize = i_size_read(inode); + + start_pos = pos & ~((u64)root->sectorsize - 1); + num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize); + + end_of_last_block = start_pos + num_bytes - 1; + err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block, + cached); + if (err) + return err; + + for (i = 0; i < num_pages; i++) { + struct page *p = pages[i]; + SetPageUptodate(p); + ClearPageChecked(p); + set_page_dirty(p); + } + + /* + * we've only changed i_size in ram, and we haven't updated + * the disk i_size. There is no need to log the inode + * at this time. + */ + if (end_pos > isize) + i_size_write(inode, end_pos); + return 0; +} + +/* + * this drops all the extents in the cache that intersect the range + * [start, end]. Existing extents are split as required. + */ +void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end, + int skip_pinned) +{ + struct extent_map *em; + struct extent_map *split = NULL; + struct extent_map *split2 = NULL; + struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; + u64 len = end - start + 1; + u64 gen; + int ret; + int testend = 1; + unsigned long flags; + int compressed = 0; + bool modified; + + WARN_ON(end < start); + if (end == (u64)-1) { + len = (u64)-1; + testend = 0; + } + while (1) { + int no_splits = 0; + + modified = false; + if (!split) + split = alloc_extent_map(); + if (!split2) + split2 = alloc_extent_map(); + if (!split || !split2) + no_splits = 1; + + write_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, start, len); + if (!em) { + write_unlock(&em_tree->lock); + break; + } + flags = em->flags; + gen = em->generation; + if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) { + if (testend && em->start + em->len >= start + len) { + free_extent_map(em); + write_unlock(&em_tree->lock); + break; + } + start = em->start + em->len; + if (testend) + len = start + len - (em->start + em->len); + free_extent_map(em); + write_unlock(&em_tree->lock); + continue; + } + compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags); + clear_bit(EXTENT_FLAG_PINNED, &em->flags); + clear_bit(EXTENT_FLAG_LOGGING, &flags); + modified = !list_empty(&em->list); + if (no_splits) + goto next; + + if (em->start < start) { + split->start = em->start; + split->len = start - em->start; + + if (em->block_start < EXTENT_MAP_LAST_BYTE) { + split->orig_start = em->orig_start; + split->block_start = em->block_start; + + if (compressed) + split->block_len = em->block_len; + else + split->block_len = split->len; + split->orig_block_len = max(split->block_len, + em->orig_block_len); + split->ram_bytes = em->ram_bytes; + } else { + split->orig_start = split->start; + split->block_len = 0; + split->block_start = em->block_start; + split->orig_block_len = 0; + split->ram_bytes = split->len; + } + + split->generation = gen; + split->bdev = em->bdev; + split->flags = flags; + split->compress_type = em->compress_type; + replace_extent_mapping(em_tree, em, split, modified); + free_extent_map(split); + split = split2; + split2 = NULL; + } + if (testend && em->start + em->len > start + len) { + u64 diff = start + len - em->start; + + split->start = start + len; + split->len = em->start + em->len - (start + len); + split->bdev = em->bdev; + split->flags = flags; + split->compress_type = em->compress_type; + split->generation = gen; + + if (em->block_start < EXTENT_MAP_LAST_BYTE) { + split->orig_block_len = max(em->block_len, + em->orig_block_len); + + split->ram_bytes = em->ram_bytes; + if (compressed) { + split->block_len = em->block_len; + split->block_start = em->block_start; + split->orig_start = em->orig_start; + } else { + split->block_len = split->len; + split->block_start = em->block_start + + diff; + split->orig_start = em->orig_start; + } + } else { + split->ram_bytes = split->len; + split->orig_start = split->start; + split->block_len = 0; + split->block_start = em->block_start; + split->orig_block_len = 0; + } + + if (extent_map_in_tree(em)) { + replace_extent_mapping(em_tree, em, split, + modified); + } else { + ret = add_extent_mapping(em_tree, split, + modified); + ASSERT(ret == 0); /* Logic error */ + } + free_extent_map(split); + split = NULL; + } +next: + if (extent_map_in_tree(em)) + remove_extent_mapping(em_tree, em); + write_unlock(&em_tree->lock); + + /* once for us */ + free_extent_map(em); + /* once for the tree*/ + free_extent_map(em); + } + if (split) + free_extent_map(split); + if (split2) + free_extent_map(split2); +} + +/* + * this is very complex, but the basic idea is to drop all extents + * in the range start - end. hint_block is filled in with a block number + * that would be a good hint to the block allocator for this file. + * + * If an extent intersects the range but is not entirely inside the range + * it is either truncated or split. Anything entirely inside the range + * is deleted from the tree. + */ +int __btrfs_drop_extents(struct btrfs_trans_handle *trans, + struct btrfs_root *root, struct inode *inode, + struct btrfs_path *path, u64 start, u64 end, + u64 *drop_end, int drop_cache, + int replace_extent, + u32 extent_item_size, + int *key_inserted) +{ + struct extent_buffer *leaf; + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + struct btrfs_key new_key; + u64 ino = btrfs_ino(inode); + u64 search_start = start; + u64 disk_bytenr = 0; + u64 num_bytes = 0; + u64 extent_offset = 0; + u64 extent_end = 0; + int del_nr = 0; + int del_slot = 0; + int extent_type; + int recow; + int ret; + int modify_tree = -1; + int update_refs; + int found = 0; + int leafs_visited = 0; + + if (drop_cache) + btrfs_drop_extent_cache(inode, start, end - 1, 0); + + if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent) + modify_tree = 0; + + update_refs = (test_bit(BTRFS_ROOT_REF_COWS, &root->state) || + root == root->fs_info->tree_root); + while (1) { + recow = 0; + ret = btrfs_lookup_file_extent(trans, root, path, ino, + search_start, modify_tree); + if (ret < 0) + break; + if (ret > 0 && path->slots[0] > 0 && search_start == start) { + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); + if (key.objectid == ino && + key.type == BTRFS_EXTENT_DATA_KEY) + path->slots[0]--; + } + ret = 0; + leafs_visited++; +next_slot: + leaf = path->nodes[0]; + if (path->slots[0] >= btrfs_header_nritems(leaf)) { + BUG_ON(del_nr > 0); + ret = btrfs_next_leaf(root, path); + if (ret < 0) + break; + if (ret > 0) { + ret = 0; + break; + } + leafs_visited++; + leaf = path->nodes[0]; + recow = 1; + } + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.objectid > ino || + key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) + break; + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + extent_type = btrfs_file_extent_type(leaf, fi); + + if (extent_type == BTRFS_FILE_EXTENT_REG || + extent_type == BTRFS_FILE_EXTENT_PREALLOC) { + disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); + extent_offset = btrfs_file_extent_offset(leaf, fi); + extent_end = key.offset + + btrfs_file_extent_num_bytes(leaf, fi); + } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + extent_end = key.offset + + btrfs_file_extent_inline_len(leaf, + path->slots[0], fi); + } else { + WARN_ON(1); + extent_end = search_start; + } + + /* + * Don't skip extent items representing 0 byte lengths. They + * used to be created (bug) if while punching holes we hit + * -ENOSPC condition. So if we find one here, just ensure we + * delete it, otherwise we would insert a new file extent item + * with the same key (offset) as that 0 bytes length file + * extent item in the call to setup_items_for_insert() later + * in this function. + */ + if (extent_end == key.offset && extent_end >= search_start) + goto delete_extent_item; + + if (extent_end <= search_start) { + path->slots[0]++; + goto next_slot; + } + + found = 1; + search_start = max(key.offset, start); + if (recow || !modify_tree) { + modify_tree = -1; + btrfs_release_path(path); + continue; + } + + /* + * | - range to drop - | + * | -------- extent -------- | + */ + if (start > key.offset && end < extent_end) { + BUG_ON(del_nr > 0); + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + ret = -EOPNOTSUPP; + break; + } + + memcpy(&new_key, &key, sizeof(new_key)); + new_key.offset = start; + ret = btrfs_duplicate_item(trans, root, path, + &new_key); + if (ret == -EAGAIN) { + btrfs_release_path(path); + continue; + } + if (ret < 0) + break; + + leaf = path->nodes[0]; + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + + extent_offset += start - key.offset; + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - start); + btrfs_mark_buffer_dirty(leaf); + + if (update_refs && disk_bytenr > 0) { + ret = btrfs_inc_extent_ref(trans, root, + disk_bytenr, num_bytes, 0, + root->root_key.objectid, + new_key.objectid, + start - extent_offset, 1); + BUG_ON(ret); /* -ENOMEM */ + } + key.offset = start; + } + /* + * | ---- range to drop ----- | + * | -------- extent -------- | + */ + if (start <= key.offset && end < extent_end) { + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + ret = -EOPNOTSUPP; + break; + } + + memcpy(&new_key, &key, sizeof(new_key)); + new_key.offset = end; + btrfs_set_item_key_safe(root->fs_info, path, &new_key); + + extent_offset += end - key.offset; + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - end); + btrfs_mark_buffer_dirty(leaf); + if (update_refs && disk_bytenr > 0) + inode_sub_bytes(inode, end - key.offset); + break; + } + + search_start = extent_end; + /* + * | ---- range to drop ----- | + * | -------- extent -------- | + */ + if (start > key.offset && end >= extent_end) { + BUG_ON(del_nr > 0); + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + ret = -EOPNOTSUPP; + break; + } + + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + btrfs_mark_buffer_dirty(leaf); + if (update_refs && disk_bytenr > 0) + inode_sub_bytes(inode, extent_end - start); + if (end == extent_end) + break; + + path->slots[0]++; + goto next_slot; + } + + /* + * | ---- range to drop ----- | + * | ------ extent ------ | + */ + if (start <= key.offset && end >= extent_end) { +delete_extent_item: + if (del_nr == 0) { + del_slot = path->slots[0]; + del_nr = 1; + } else { + BUG_ON(del_slot + del_nr != path->slots[0]); + del_nr++; + } + + if (update_refs && + extent_type == BTRFS_FILE_EXTENT_INLINE) { + inode_sub_bytes(inode, + extent_end - key.offset); + extent_end = ALIGN(extent_end, + root->sectorsize); + } else if (update_refs && disk_bytenr > 0) { + ret = btrfs_free_extent(trans, root, + disk_bytenr, num_bytes, 0, + root->root_key.objectid, + key.objectid, key.offset - + extent_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + inode_sub_bytes(inode, + extent_end - key.offset); + } + + if (end == extent_end) + break; + + if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) { + path->slots[0]++; + goto next_slot; + } + + ret = btrfs_del_items(trans, root, path, del_slot, + del_nr); + if (ret) { + btrfs_abort_transaction(trans, root, ret); + break; + } + + del_nr = 0; + del_slot = 0; + + btrfs_release_path(path); + continue; + } + + BUG_ON(1); + } + + if (!ret && del_nr > 0) { + /* + * Set path->slots[0] to first slot, so that after the delete + * if items are move off from our leaf to its immediate left or + * right neighbor leafs, we end up with a correct and adjusted + * path->slots[0] for our insertion (if replace_extent != 0). + */ + path->slots[0] = del_slot; + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + if (ret) + btrfs_abort_transaction(trans, root, ret); + } + + leaf = path->nodes[0]; + /* + * If btrfs_del_items() was called, it might have deleted a leaf, in + * which case it unlocked our path, so check path->locks[0] matches a + * write lock. + */ + if (!ret && replace_extent && leafs_visited == 1 && + (path->locks[0] == BTRFS_WRITE_LOCK_BLOCKING || + path->locks[0] == BTRFS_WRITE_LOCK) && + btrfs_leaf_free_space(root, leaf) >= + sizeof(struct btrfs_item) + extent_item_size) { + + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = start; + if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) { + struct btrfs_key slot_key; + + btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]); + if (btrfs_comp_cpu_keys(&key, &slot_key) > 0) + path->slots[0]++; + } + setup_items_for_insert(root, path, &key, + &extent_item_size, + extent_item_size, + sizeof(struct btrfs_item) + + extent_item_size, 1); + *key_inserted = 1; + } + + if (!replace_extent || !(*key_inserted)) + btrfs_release_path(path); + if (drop_end) + *drop_end = found ? min(end, extent_end) : end; + return ret; +} + +int btrfs_drop_extents(struct btrfs_trans_handle *trans, + struct btrfs_root *root, struct inode *inode, u64 start, + u64 end, int drop_cache) +{ + struct btrfs_path *path; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL, + drop_cache, 0, 0, NULL); + btrfs_free_path(path); + return ret; +} + +static int extent_mergeable(struct extent_buffer *leaf, int slot, + u64 objectid, u64 bytenr, u64 orig_offset, + u64 *start, u64 *end) +{ + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + u64 extent_end; + + if (slot < 0 || slot >= btrfs_header_nritems(leaf)) + return 0; + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY) + return 0; + + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG || + btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr || + btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset || + btrfs_file_extent_compression(leaf, fi) || + btrfs_file_extent_encryption(leaf, fi) || + btrfs_file_extent_other_encoding(leaf, fi)) + return 0; + + extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); + if ((*start && *start != key.offset) || (*end && *end != extent_end)) + return 0; + + *start = key.offset; + *end = extent_end; + return 1; +} + +/* + * Mark extent in the range start - end as written. + * + * This changes extent type from 'pre-allocated' to 'regular'. If only + * part of extent is marked as written, the extent will be split into + * two or three. + */ +int btrfs_mark_extent_written(struct btrfs_trans_handle *trans, + struct inode *inode, u64 start, u64 end) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_buffer *leaf; + struct btrfs_path *path; + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + struct btrfs_key new_key; + u64 bytenr; + u64 num_bytes; + u64 extent_end; + u64 orig_offset; + u64 other_start; + u64 other_end; + u64 split; + int del_nr = 0; + int del_slot = 0; + int recow; + int ret; + u64 ino = btrfs_ino(inode); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; +again: + recow = 0; + split = start; + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = split; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret < 0) + goto out; + if (ret > 0 && path->slots[0] > 0) + path->slots[0]--; + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + BUG_ON(btrfs_file_extent_type(leaf, fi) != + BTRFS_FILE_EXTENT_PREALLOC); + extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); + BUG_ON(key.offset > start || extent_end < end); + + bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); + orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi); + memcpy(&new_key, &key, sizeof(new_key)); + + if (start == key.offset && end < extent_end) { + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + new_key.offset = end; + btrfs_set_item_key_safe(root->fs_info, path, &new_key); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - end); + btrfs_set_file_extent_offset(leaf, fi, + end - orig_offset); + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + end - other_start); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } + + if (start > key.offset && end == extent_end) { + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + path->slots[0]++; + new_key.offset = start; + btrfs_set_item_key_safe(root->fs_info, path, &new_key); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + other_end - start); + btrfs_set_file_extent_offset(leaf, fi, + start - orig_offset); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } + + while (start > key.offset || end < extent_end) { + if (key.offset == start) + split = end; + + new_key.offset = split; + ret = btrfs_duplicate_item(trans, root, path, &new_key); + if (ret == -EAGAIN) { + btrfs_release_path(path); + goto again; + } + if (ret < 0) { + btrfs_abort_transaction(trans, root, ret); + goto out; + } + + leaf = path->nodes[0]; + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + split - key.offset); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_set_file_extent_offset(leaf, fi, split - orig_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - split); + btrfs_mark_buffer_dirty(leaf); + + ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0, + root->root_key.objectid, + ino, orig_offset, 1); + BUG_ON(ret); /* -ENOMEM */ + + if (split == start) { + key.offset = start; + } else { + BUG_ON(start != key.offset); + path->slots[0]--; + extent_end = end; + } + recow = 1; + } + + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(path); + goto again; + } + extent_end = other_end; + del_slot = path->slots[0] + 1; + del_nr++; + ret = btrfs_free_extent(trans, root, bytenr, num_bytes, + 0, root->root_key.objectid, + ino, orig_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + } + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(path); + goto again; + } + key.offset = other_start; + del_slot = path->slots[0]; + del_nr++; + ret = btrfs_free_extent(trans, root, bytenr, num_bytes, + 0, root->root_key.objectid, + ino, orig_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + } + if (del_nr == 0) { + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_mark_buffer_dirty(leaf); + } else { + fi = btrfs_item_ptr(leaf, del_slot - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - key.offset); + btrfs_mark_buffer_dirty(leaf); + + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + if (ret < 0) { + btrfs_abort_transaction(trans, root, ret); + goto out; + } + } +out: + btrfs_free_path(path); + return 0; +} + +/* + * on error we return an unlocked page and the error value + * on success we return a locked page and 0 + */ +static int prepare_uptodate_page(struct page *page, u64 pos, + bool force_uptodate) +{ + int ret = 0; + + if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) && + !PageUptodate(page)) { + ret = btrfs_readpage(NULL, page); + if (ret) + return ret; + lock_page(page); + if (!PageUptodate(page)) { + unlock_page(page); + return -EIO; + } + } + return 0; +} + +/* + * this just gets pages into the page cache and locks them down. + */ +static noinline int prepare_pages(struct inode *inode, struct page **pages, + size_t num_pages, loff_t pos, + size_t write_bytes, bool force_uptodate) +{ + int i; + unsigned long index = pos >> PAGE_CACHE_SHIFT; + gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); + int err = 0; + int faili; + + for (i = 0; i < num_pages; i++) { + pages[i] = find_or_create_page(inode->i_mapping, index + i, + mask | __GFP_WRITE); + if (!pages[i]) { + faili = i - 1; + err = -ENOMEM; + goto fail; + } + + if (i == 0) + err = prepare_uptodate_page(pages[i], pos, + force_uptodate); + if (i == num_pages - 1) + err = prepare_uptodate_page(pages[i], + pos + write_bytes, false); + if (err) { + page_cache_release(pages[i]); + faili = i - 1; + goto fail; + } + wait_on_page_writeback(pages[i]); + } + + return 0; +fail: + while (faili >= 0) { + unlock_page(pages[faili]); + page_cache_release(pages[faili]); + faili--; + } + return err; + +} + +/* + * This function locks the extent and properly waits for data=ordered extents + * to finish before allowing the pages to be modified if need. + * + * The return value: + * 1 - the extent is locked + * 0 - the extent is not locked, and everything is OK + * -EAGAIN - need re-prepare the pages + * the other < 0 number - Something wrong happens + */ +static noinline int +lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages, + size_t num_pages, loff_t pos, + u64 *lockstart, u64 *lockend, + struct extent_state **cached_state) +{ + u64 start_pos; + u64 last_pos; + int i; + int ret = 0; + + start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1); + last_pos = start_pos + ((u64)num_pages << PAGE_CACHE_SHIFT) - 1; + + if (start_pos < inode->i_size) { + struct btrfs_ordered_extent *ordered; + lock_extent_bits(&BTRFS_I(inode)->io_tree, + start_pos, last_pos, 0, cached_state); + ordered = btrfs_lookup_ordered_range(inode, start_pos, + last_pos - start_pos + 1); + if (ordered && + ordered->file_offset + ordered->len > start_pos && + ordered->file_offset <= last_pos) { + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + start_pos, last_pos, + cached_state, GFP_NOFS); + for (i = 0; i < num_pages; i++) { + unlock_page(pages[i]); + page_cache_release(pages[i]); + } + btrfs_start_ordered_extent(inode, ordered, 1); + btrfs_put_ordered_extent(ordered); + return -EAGAIN; + } + if (ordered) + btrfs_put_ordered_extent(ordered); + + clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos, + last_pos, EXTENT_DIRTY | EXTENT_DELALLOC | + EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, + 0, 0, cached_state, GFP_NOFS); + *lockstart = start_pos; + *lockend = last_pos; + ret = 1; + } + + for (i = 0; i < num_pages; i++) { + if (clear_page_dirty_for_io(pages[i])) + account_page_redirty(pages[i]); + set_page_extent_mapped(pages[i]); + WARN_ON(!PageLocked(pages[i])); + } + + return ret; +} + +static noinline int check_can_nocow(struct inode *inode, loff_t pos, + size_t *write_bytes) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_ordered_extent *ordered; + u64 lockstart, lockend; + u64 num_bytes; + int ret; + + ret = btrfs_start_write_no_snapshoting(root); + if (!ret) + return -ENOSPC; + + lockstart = round_down(pos, root->sectorsize); + lockend = round_up(pos + *write_bytes, root->sectorsize) - 1; + + while (1) { + lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend); + ordered = btrfs_lookup_ordered_range(inode, lockstart, + lockend - lockstart + 1); + if (!ordered) { + break; + } + unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend); + btrfs_start_ordered_extent(inode, ordered, 1); + btrfs_put_ordered_extent(ordered); + } + + num_bytes = lockend - lockstart + 1; + ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL); + if (ret <= 0) { + ret = 0; + btrfs_end_write_no_snapshoting(root); + } else { + *write_bytes = min_t(size_t, *write_bytes , + num_bytes - pos + lockstart); + } + + unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend); + + return ret; +} + +static noinline ssize_t __btrfs_buffered_write(struct file *file, + struct iov_iter *i, + loff_t pos) +{ + struct inode *inode = file_inode(file); + struct btrfs_root *root = BTRFS_I(inode)->root; + struct page **pages = NULL; + struct extent_state *cached_state = NULL; + u64 release_bytes = 0; + u64 lockstart; + u64 lockend; + unsigned long first_index; + size_t num_written = 0; + int nrptrs; + int ret = 0; + bool only_release_metadata = false; + bool force_page_uptodate = false; + bool need_unlock; + + nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_CACHE_SIZE), + PAGE_CACHE_SIZE / (sizeof(struct page *))); + nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied); + nrptrs = max(nrptrs, 8); + pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL); + if (!pages) + return -ENOMEM; + + first_index = pos >> PAGE_CACHE_SHIFT; + + while (iov_iter_count(i) > 0) { + size_t offset = pos & (PAGE_CACHE_SIZE - 1); + size_t write_bytes = min(iov_iter_count(i), + nrptrs * (size_t)PAGE_CACHE_SIZE - + offset); + size_t num_pages = DIV_ROUND_UP(write_bytes + offset, + PAGE_CACHE_SIZE); + size_t reserve_bytes; + size_t dirty_pages; + size_t copied; + + WARN_ON(num_pages > nrptrs); + + /* + * Fault pages before locking them in prepare_pages + * to avoid recursive lock + */ + if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) { + ret = -EFAULT; + break; + } + + reserve_bytes = num_pages << PAGE_CACHE_SHIFT; + ret = btrfs_check_data_free_space(inode, reserve_bytes, write_bytes); + if (ret == -ENOSPC && + (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | + BTRFS_INODE_PREALLOC))) { + ret = check_can_nocow(inode, pos, &write_bytes); + if (ret > 0) { + only_release_metadata = true; + /* + * our prealloc extent may be smaller than + * write_bytes, so scale down. + */ + num_pages = DIV_ROUND_UP(write_bytes + offset, + PAGE_CACHE_SIZE); + reserve_bytes = num_pages << PAGE_CACHE_SHIFT; + ret = 0; + } else { + ret = -ENOSPC; + } + } + + if (ret) + break; + + ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes); + if (ret) { + if (!only_release_metadata) + btrfs_free_reserved_data_space(inode, + reserve_bytes); + else + btrfs_end_write_no_snapshoting(root); + break; + } + + release_bytes = reserve_bytes; + need_unlock = false; +again: + /* + * This is going to setup the pages array with the number of + * pages we want, so we don't really need to worry about the + * contents of pages from loop to loop + */ + ret = prepare_pages(inode, pages, num_pages, + pos, write_bytes, + force_page_uptodate); + if (ret) + break; + + ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages, + pos, &lockstart, &lockend, + &cached_state); + if (ret < 0) { + if (ret == -EAGAIN) + goto again; + break; + } else if (ret > 0) { + need_unlock = true; + ret = 0; + } + + copied = btrfs_copy_from_user(pos, num_pages, + write_bytes, pages, i); + + /* + * if we have trouble faulting in the pages, fall + * back to one page at a time + */ + if (copied < write_bytes) + nrptrs = 1; + + if (copied == 0) { + force_page_uptodate = true; + dirty_pages = 0; + } else { + force_page_uptodate = false; + dirty_pages = DIV_ROUND_UP(copied + offset, + PAGE_CACHE_SIZE); + } + + /* + * If we had a short copy we need to release the excess delaloc + * bytes we reserved. We need to increment outstanding_extents + * because btrfs_delalloc_release_space will decrement it, but + * we still have an outstanding extent for the chunk we actually + * managed to copy. + */ + if (num_pages > dirty_pages) { + release_bytes = (num_pages - dirty_pages) << + PAGE_CACHE_SHIFT; + if (copied > 0) { + spin_lock(&BTRFS_I(inode)->lock); + BTRFS_I(inode)->outstanding_extents++; + spin_unlock(&BTRFS_I(inode)->lock); + } + if (only_release_metadata) + btrfs_delalloc_release_metadata(inode, + release_bytes); + else + btrfs_delalloc_release_space(inode, + release_bytes); + } + + release_bytes = dirty_pages << PAGE_CACHE_SHIFT; + + if (copied > 0) + ret = btrfs_dirty_pages(root, inode, pages, + dirty_pages, pos, copied, + NULL); + if (need_unlock) + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + lockstart, lockend, &cached_state, + GFP_NOFS); + if (ret) { + btrfs_drop_pages(pages, num_pages); + break; + } + + release_bytes = 0; + if (only_release_metadata) + btrfs_end_write_no_snapshoting(root); + + if (only_release_metadata && copied > 0) { + lockstart = round_down(pos, root->sectorsize); + lockend = lockstart + + (dirty_pages << PAGE_CACHE_SHIFT) - 1; + + set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, + lockend, EXTENT_NORESERVE, NULL, + NULL, GFP_NOFS); + only_release_metadata = false; + } + + btrfs_drop_pages(pages, num_pages); + + cond_resched(); + + balance_dirty_pages_ratelimited(inode->i_mapping); + if (dirty_pages < (root->nodesize >> PAGE_CACHE_SHIFT) + 1) + btrfs_btree_balance_dirty(root); + + pos += copied; + num_written += copied; + } + + kfree(pages); + + if (release_bytes) { + if (only_release_metadata) { + btrfs_end_write_no_snapshoting(root); + btrfs_delalloc_release_metadata(inode, release_bytes); + } else { + btrfs_delalloc_release_space(inode, release_bytes); + } + } + + return num_written ? num_written : ret; +} + +static ssize_t __btrfs_direct_write(struct kiocb *iocb, + struct iov_iter *from, + loff_t pos) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + ssize_t written; + ssize_t written_buffered; + loff_t endbyte; + int err; + + written = generic_file_direct_write(iocb, from, pos); + + if (written < 0 || !iov_iter_count(from)) + return written; + + pos += written; + written_buffered = __btrfs_buffered_write(file, from, pos); + if (written_buffered < 0) { + err = written_buffered; + goto out; + } + /* + * Ensure all data is persisted. We want the next direct IO read to be + * able to read what was just written. + */ + endbyte = pos + written_buffered - 1; + err = btrfs_fdatawrite_range(inode, pos, endbyte); + if (err) + goto out; + err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte); + if (err) + goto out; + written += written_buffered; + iocb->ki_pos = pos + written_buffered; + invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT, + endbyte >> PAGE_CACHE_SHIFT); +out: + return written ? written : err; +} + +static void update_time_for_write(struct inode *inode) +{ + struct timespec now; + + if (IS_NOCMTIME(inode)) + return; + + now = current_fs_time(inode->i_sb); + if (!timespec_equal(&inode->i_mtime, &now)) + inode->i_mtime = now; + + if (!timespec_equal(&inode->i_ctime, &now)) + inode->i_ctime = now; + + if (IS_I_VERSION(inode)) + inode_inc_iversion(inode); +} + +static ssize_t btrfs_file_write_iter(struct kiocb *iocb, + struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + struct btrfs_root *root = BTRFS_I(inode)->root; + u64 start_pos; + u64 end_pos; + ssize_t num_written = 0; + bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host); + ssize_t err; + loff_t pos; + size_t count; + + mutex_lock(&inode->i_mutex); + err = generic_write_checks(iocb, from); + if (err <= 0) { + mutex_unlock(&inode->i_mutex); + return err; + } + + current->backing_dev_info = inode_to_bdi(inode); + err = file_remove_suid(file); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + + /* + * If BTRFS flips readonly due to some impossible error + * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR), + * although we have opened a file as writable, we have + * to stop this write operation to ensure FS consistency. + */ + if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) { + mutex_unlock(&inode->i_mutex); + err = -EROFS; + goto out; + } + + /* + * We reserve space for updating the inode when we reserve space for the + * extent we are going to write, so we will enospc out there. We don't + * need to start yet another transaction to update the inode as we will + * update the inode when we finish writing whatever data we write. + */ + update_time_for_write(inode); + + pos = iocb->ki_pos; + count = iov_iter_count(from); + start_pos = round_down(pos, root->sectorsize); + if (start_pos > i_size_read(inode)) { + /* Expand hole size to cover write data, preventing empty gap */ + end_pos = round_up(pos + count, root->sectorsize); + err = btrfs_cont_expand(inode, i_size_read(inode), end_pos); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + } + + if (sync) + atomic_inc(&BTRFS_I(inode)->sync_writers); + + if (iocb->ki_flags & IOCB_DIRECT) { + num_written = __btrfs_direct_write(iocb, from, pos); + } else { + num_written = __btrfs_buffered_write(file, from, pos); + if (num_written > 0) + iocb->ki_pos = pos + num_written; + } + + mutex_unlock(&inode->i_mutex); + + /* + * We also have to set last_sub_trans to the current log transid, + * otherwise subsequent syncs to a file that's been synced in this + * transaction will appear to have already occured. + */ + spin_lock(&BTRFS_I(inode)->lock); + BTRFS_I(inode)->last_sub_trans = root->log_transid; + spin_unlock(&BTRFS_I(inode)->lock); + if (num_written > 0) { + err = generic_write_sync(file, pos, num_written); + if (err < 0) + num_written = err; + } + + if (sync) + atomic_dec(&BTRFS_I(inode)->sync_writers); +out: + current->backing_dev_info = NULL; + return num_written ? num_written : err; +} + +int btrfs_release_file(struct inode *inode, struct file *filp) +{ + if (filp->private_data) + btrfs_ioctl_trans_end(filp); + /* + * ordered_data_close is set by settattr when we are about to truncate + * a file from a non-zero size to a zero size. This tries to + * flush down new bytes that may have been written if the + * application were using truncate to replace a file in place. + */ + if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE, + &BTRFS_I(inode)->runtime_flags)) + filemap_flush(inode->i_mapping); + return 0; +} + +static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end) +{ + int ret; + + atomic_inc(&BTRFS_I(inode)->sync_writers); + ret = btrfs_fdatawrite_range(inode, start, end); + atomic_dec(&BTRFS_I(inode)->sync_writers); + + return ret; +} + +/* + * fsync call for both files and directories. This logs the inode into + * the tree log instead of forcing full commits whenever possible. + * + * It needs to call filemap_fdatawait so that all ordered extent updates are + * in the metadata btree are up to date for copying to the log. + * + * It drops the inode mutex before doing the tree log commit. This is an + * important optimization for directories because holding the mutex prevents + * new operations on the dir while we write to disk. + */ +int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) +{ + struct dentry *dentry = file->f_path.dentry; + struct inode *inode = d_inode(dentry); + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_trans_handle *trans; + struct btrfs_log_ctx ctx; + int ret = 0; + bool full_sync = 0; + + trace_btrfs_sync_file(file, datasync); + + /* + * We write the dirty pages in the range and wait until they complete + * out of the ->i_mutex. If so, we can flush the dirty pages by + * multi-task, and make the performance up. See + * btrfs_wait_ordered_range for an explanation of the ASYNC check. + */ + ret = start_ordered_ops(inode, start, end); + if (ret) + return ret; + + mutex_lock(&inode->i_mutex); + atomic_inc(&root->log_batch); + full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, + &BTRFS_I(inode)->runtime_flags); + /* + * We might have have had more pages made dirty after calling + * start_ordered_ops and before acquiring the inode's i_mutex. + */ + if (full_sync) { + /* + * For a full sync, we need to make sure any ordered operations + * start and finish before we start logging the inode, so that + * all extents are persisted and the respective file extent + * items are in the fs/subvol btree. + */ + ret = btrfs_wait_ordered_range(inode, start, end - start + 1); + } else { + /* + * Start any new ordered operations before starting to log the + * inode. We will wait for them to finish in btrfs_sync_log(). + * + * Right before acquiring the inode's mutex, we might have new + * writes dirtying pages, which won't immediately start the + * respective ordered operations - that is done through the + * fill_delalloc callbacks invoked from the writepage and + * writepages address space operations. So make sure we start + * all ordered operations before starting to log our inode. Not + * doing this means that while logging the inode, writeback + * could start and invoke writepage/writepages, which would call + * the fill_delalloc callbacks (cow_file_range, + * submit_compressed_extents). These callbacks add first an + * extent map to the modified list of extents and then create + * the respective ordered operation, which means in + * tree-log.c:btrfs_log_inode() we might capture all existing + * ordered operations (with btrfs_get_logged_extents()) before + * the fill_delalloc callback adds its ordered operation, and by + * the time we visit the modified list of extent maps (with + * btrfs_log_changed_extents()), we see and process the extent + * map they created. We then use the extent map to construct a + * file extent item for logging without waiting for the + * respective ordered operation to finish - this file extent + * item points to a disk location that might not have yet been + * written to, containing random data - so after a crash a log + * replay will make our inode have file extent items that point + * to disk locations containing invalid data, as we returned + * success to userspace without waiting for the respective + * ordered operation to finish, because it wasn't captured by + * btrfs_get_logged_extents(). + */ + ret = start_ordered_ops(inode, start, end); + } + if (ret) { + mutex_unlock(&inode->i_mutex); + goto out; + } + atomic_inc(&root->log_batch); + + /* + * If the last transaction that changed this file was before the current + * transaction and we have the full sync flag set in our inode, we can + * bail out now without any syncing. + * + * Note that we can't bail out if the full sync flag isn't set. This is + * because when the full sync flag is set we start all ordered extents + * and wait for them to fully complete - when they complete they update + * the inode's last_trans field through: + * + * btrfs_finish_ordered_io() -> + * btrfs_update_inode_fallback() -> + * btrfs_update_inode() -> + * btrfs_set_inode_last_trans() + * + * So we are sure that last_trans is up to date and can do this check to + * bail out safely. For the fast path, when the full sync flag is not + * set in our inode, we can not do it because we start only our ordered + * extents and don't wait for them to complete (that is when + * btrfs_finish_ordered_io runs), so here at this point their last_trans + * value might be less than or equals to fs_info->last_trans_committed, + * and setting a speculative last_trans for an inode when a buffered + * write is made (such as fs_info->generation + 1 for example) would not + * be reliable since after setting the value and before fsync is called + * any number of transactions can start and commit (transaction kthread + * commits the current transaction periodically), and a transaction + * commit does not start nor waits for ordered extents to complete. + */ + smp_mb(); + if (btrfs_inode_in_log(inode, root->fs_info->generation) || + (full_sync && BTRFS_I(inode)->last_trans <= + root->fs_info->last_trans_committed)) { + /* + * We'v had everything committed since the last time we were + * modified so clear this flag in case it was set for whatever + * reason, it's no longer relevant. + */ + clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC, + &BTRFS_I(inode)->runtime_flags); + mutex_unlock(&inode->i_mutex); + goto out; + } + + /* + * ok we haven't committed the transaction yet, lets do a commit + */ + if (file->private_data) + btrfs_ioctl_trans_end(file); + + /* + * We use start here because we will need to wait on the IO to complete + * in btrfs_sync_log, which could require joining a transaction (for + * example checking cross references in the nocow path). If we use join + * here we could get into a situation where we're waiting on IO to + * happen that is blocked on a transaction trying to commit. With start + * we inc the extwriter counter, so we wait for all extwriters to exit + * before we start blocking join'ers. This comment is to keep somebody + * from thinking they are super smart and changing this to + * btrfs_join_transaction *cough*Josef*cough*. + */ + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + mutex_unlock(&inode->i_mutex); + goto out; + } + trans->sync = true; + + btrfs_init_log_ctx(&ctx); + + ret = btrfs_log_dentry_safe(trans, root, dentry, start, end, &ctx); + if (ret < 0) { + /* Fallthrough and commit/free transaction. */ + ret = 1; + } + + /* we've logged all the items and now have a consistent + * version of the file in the log. It is possible that + * someone will come in and modify the file, but that's + * fine because the log is consistent on disk, and we + * have references to all of the file's extents + * + * It is possible that someone will come in and log the + * file again, but that will end up using the synchronization + * inside btrfs_sync_log to keep things safe. + */ + mutex_unlock(&inode->i_mutex); + + /* + * If any of the ordered extents had an error, just return it to user + * space, so that the application knows some writes didn't succeed and + * can take proper action (retry for e.g.). Blindly committing the + * transaction in this case, would fool userspace that everything was + * successful. And we also want to make sure our log doesn't contain + * file extent items pointing to extents that weren't fully written to - + * just like in the non fast fsync path, where we check for the ordered + * operation's error flag before writing to the log tree and return -EIO + * if any of them had this flag set (btrfs_wait_ordered_range) - + * therefore we need to check for errors in the ordered operations, + * which are indicated by ctx.io_err. + */ + if (ctx.io_err) { + btrfs_end_transaction(trans, root); + ret = ctx.io_err; + goto out; + } + + if (ret != BTRFS_NO_LOG_SYNC) { + if (!ret) { + ret = btrfs_sync_log(trans, root, &ctx); + if (!ret) { + ret = btrfs_end_transaction(trans, root); + goto out; + } + } + if (!full_sync) { + ret = btrfs_wait_ordered_range(inode, start, + end - start + 1); + if (ret) { + btrfs_end_transaction(trans, root); + goto out; + } + } + ret = btrfs_commit_transaction(trans, root); + } else { + ret = btrfs_end_transaction(trans, root); + } +out: + return ret > 0 ? -EIO : ret; +} + +static const struct vm_operations_struct btrfs_file_vm_ops = { + .fault = filemap_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = btrfs_page_mkwrite, +}; + +static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct address_space *mapping = filp->f_mapping; + + if (!mapping->a_ops->readpage) + return -ENOEXEC; + + file_accessed(filp); + vma->vm_ops = &btrfs_file_vm_ops; + + return 0; +} + +static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf, + int slot, u64 start, u64 end) +{ + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + + if (slot < 0 || slot >= btrfs_header_nritems(leaf)) + return 0; + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != btrfs_ino(inode) || + key.type != BTRFS_EXTENT_DATA_KEY) + return 0; + + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + + if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG) + return 0; + + if (btrfs_file_extent_disk_bytenr(leaf, fi)) + return 0; + + if (key.offset == end) + return 1; + if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start) + return 1; + return 0; +} + +static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode, + struct btrfs_path *path, u64 offset, u64 end) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *fi; + struct extent_map *hole_em; + struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; + struct btrfs_key key; + int ret; + + if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) + goto out; + + key.objectid = btrfs_ino(inode); + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = offset; + + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret < 0) + return ret; + BUG_ON(!ret); + + leaf = path->nodes[0]; + if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) { + u64 num_bytes; + + path->slots[0]--; + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + + end - offset; + btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_offset(leaf, fi, 0); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + + if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) { + u64 num_bytes; + + key.offset = offset; + btrfs_set_item_key_safe(root->fs_info, path, &key); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end - + offset; + btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_offset(leaf, fi, 0); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + btrfs_release_path(path); + + ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset, + 0, 0, end - offset, 0, end - offset, + 0, 0, 0); + if (ret) + return ret; + +out: + btrfs_release_path(path); + + hole_em = alloc_extent_map(); + if (!hole_em) { + btrfs_drop_extent_cache(inode, offset, end - 1, 0); + set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, + &BTRFS_I(inode)->runtime_flags); + } else { + hole_em->start = offset; + hole_em->len = end - offset; + hole_em->ram_bytes = hole_em->len; + hole_em->orig_start = offset; + + hole_em->block_start = EXTENT_MAP_HOLE; + hole_em->block_len = 0; + hole_em->orig_block_len = 0; + hole_em->bdev = root->fs_info->fs_devices->latest_bdev; + hole_em->compress_type = BTRFS_COMPRESS_NONE; + hole_em->generation = trans->transid; + + do { + btrfs_drop_extent_cache(inode, offset, end - 1, 0); + write_lock(&em_tree->lock); + ret = add_extent_mapping(em_tree, hole_em, 1); + write_unlock(&em_tree->lock); + } while (ret == -EEXIST); + free_extent_map(hole_em); + if (ret) + set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, + &BTRFS_I(inode)->runtime_flags); + } + + return 0; +} + +/* + * Find a hole extent on given inode and change start/len to the end of hole + * extent.(hole/vacuum extent whose em->start <= start && + * em->start + em->len > start) + * When a hole extent is found, return 1 and modify start/len. + */ +static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len) +{ + struct extent_map *em; + int ret = 0; + + em = btrfs_get_extent(inode, NULL, 0, *start, *len, 0); + if (IS_ERR_OR_NULL(em)) { + if (!em) + ret = -ENOMEM; + else + ret = PTR_ERR(em); + return ret; + } + + /* Hole or vacuum extent(only exists in no-hole mode) */ + if (em->block_start == EXTENT_MAP_HOLE) { + ret = 1; + *len = em->start + em->len > *start + *len ? + 0 : *start + *len - em->start - em->len; + *start = em->start + em->len; + } + free_extent_map(em); + return ret; +} + +static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_state *cached_state = NULL; + struct btrfs_path *path; + struct btrfs_block_rsv *rsv; + struct btrfs_trans_handle *trans; + u64 lockstart; + u64 lockend; + u64 tail_start; + u64 tail_len; + u64 orig_start = offset; + u64 cur_offset; + u64 min_size = btrfs_calc_trunc_metadata_size(root, 1); + u64 drop_end; + int ret = 0; + int err = 0; + int rsv_count; + bool same_page; + bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES); + u64 ino_size; + bool truncated_page = false; + bool updated_inode = false; + + ret = btrfs_wait_ordered_range(inode, offset, len); + if (ret) + return ret; + + mutex_lock(&inode->i_mutex); + ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE); + ret = find_first_non_hole(inode, &offset, &len); + if (ret < 0) + goto out_only_mutex; + if (ret && !len) { + /* Already in a large hole */ + ret = 0; + goto out_only_mutex; + } + + lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize); + lockend = round_down(offset + len, + BTRFS_I(inode)->root->sectorsize) - 1; + same_page = ((offset >> PAGE_CACHE_SHIFT) == + ((offset + len - 1) >> PAGE_CACHE_SHIFT)); + + /* + * We needn't truncate any page which is beyond the end of the file + * because we are sure there is no data there. + */ + /* + * Only do this if we are in the same page and we aren't doing the + * entire page. + */ + if (same_page && len < PAGE_CACHE_SIZE) { + if (offset < ino_size) { + truncated_page = true; + ret = btrfs_truncate_page(inode, offset, len, 0); + } else { + ret = 0; + } + goto out_only_mutex; + } + + /* zero back part of the first page */ + if (offset < ino_size) { + truncated_page = true; + ret = btrfs_truncate_page(inode, offset, 0, 0); + if (ret) { + mutex_unlock(&inode->i_mutex); + return ret; + } + } + + /* Check the aligned pages after the first unaligned page, + * if offset != orig_start, which means the first unaligned page + * including serveral following pages are already in holes, + * the extra check can be skipped */ + if (offset == orig_start) { + /* after truncate page, check hole again */ + len = offset + len - lockstart; + offset = lockstart; + ret = find_first_non_hole(inode, &offset, &len); + if (ret < 0) + goto out_only_mutex; + if (ret && !len) { + ret = 0; + goto out_only_mutex; + } + lockstart = offset; + } + + /* Check the tail unaligned part is in a hole */ + tail_start = lockend + 1; + tail_len = offset + len - tail_start; + if (tail_len) { + ret = find_first_non_hole(inode, &tail_start, &tail_len); + if (unlikely(ret < 0)) + goto out_only_mutex; + if (!ret) { + /* zero the front end of the last page */ + if (tail_start + tail_len < ino_size) { + truncated_page = true; + ret = btrfs_truncate_page(inode, + tail_start + tail_len, 0, 1); + if (ret) + goto out_only_mutex; + } + } + } + + if (lockend < lockstart) { + ret = 0; + goto out_only_mutex; + } + + while (1) { + struct btrfs_ordered_extent *ordered; + + truncate_pagecache_range(inode, lockstart, lockend); + + lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, + 0, &cached_state); + ordered = btrfs_lookup_first_ordered_extent(inode, lockend); + + /* + * We need to make sure we have no ordered extents in this range + * and nobody raced in and read a page in this range, if we did + * we need to try again. + */ + if ((!ordered || + (ordered->file_offset + ordered->len <= lockstart || + ordered->file_offset > lockend)) && + !btrfs_page_exists_in_range(inode, lockstart, lockend)) { + if (ordered) + btrfs_put_ordered_extent(ordered); + break; + } + if (ordered) + btrfs_put_ordered_extent(ordered); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, + lockend, &cached_state, GFP_NOFS); + ret = btrfs_wait_ordered_range(inode, lockstart, + lockend - lockstart + 1); + if (ret) { + mutex_unlock(&inode->i_mutex); + return ret; + } + } + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP); + if (!rsv) { + ret = -ENOMEM; + goto out_free; + } + rsv->size = btrfs_calc_trunc_metadata_size(root, 1); + rsv->failfast = 1; + + /* + * 1 - update the inode + * 1 - removing the extents in the range + * 1 - adding the hole extent if no_holes isn't set + */ + rsv_count = no_holes ? 2 : 3; + trans = btrfs_start_transaction(root, rsv_count); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + goto out_free; + } + + ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv, + min_size); + BUG_ON(ret); + trans->block_rsv = rsv; + + cur_offset = lockstart; + len = lockend - cur_offset; + while (cur_offset < lockend) { + ret = __btrfs_drop_extents(trans, root, inode, path, + cur_offset, lockend + 1, + &drop_end, 1, 0, 0, NULL); + if (ret != -ENOSPC) + break; + + trans->block_rsv = &root->fs_info->trans_block_rsv; + + if (cur_offset < ino_size) { + ret = fill_holes(trans, inode, path, cur_offset, + drop_end); + if (ret) { + err = ret; + break; + } + } + + cur_offset = drop_end; + + ret = btrfs_update_inode(trans, root, inode); + if (ret) { + err = ret; + break; + } + + btrfs_end_transaction(trans, root); + btrfs_btree_balance_dirty(root); + + trans = btrfs_start_transaction(root, rsv_count); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + trans = NULL; + break; + } + + ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, + rsv, min_size); + BUG_ON(ret); /* shouldn't happen */ + trans->block_rsv = rsv; + + ret = find_first_non_hole(inode, &cur_offset, &len); + if (unlikely(ret < 0)) + break; + if (ret && !len) { + ret = 0; + break; + } + } + + if (ret) { + err = ret; + goto out_trans; + } + + trans->block_rsv = &root->fs_info->trans_block_rsv; + /* + * Don't insert file hole extent item if it's for a range beyond eof + * (because it's useless) or if it represents a 0 bytes range (when + * cur_offset == drop_end). + */ + if (cur_offset < ino_size && cur_offset < drop_end) { + ret = fill_holes(trans, inode, path, cur_offset, drop_end); + if (ret) { + err = ret; + goto out_trans; + } + } + +out_trans: + if (!trans) + goto out_free; + + inode_inc_iversion(inode); + inode->i_mtime = inode->i_ctime = CURRENT_TIME; + + trans->block_rsv = &root->fs_info->trans_block_rsv; + ret = btrfs_update_inode(trans, root, inode); + updated_inode = true; + btrfs_end_transaction(trans, root); + btrfs_btree_balance_dirty(root); +out_free: + btrfs_free_path(path); + btrfs_free_block_rsv(root, rsv); +out: + unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend, + &cached_state, GFP_NOFS); +out_only_mutex: + if (!updated_inode && truncated_page && !ret && !err) { + /* + * If we only end up zeroing part of a page, we still need to + * update the inode item, so that all the time fields are + * updated as well as the necessary btrfs inode in memory fields + * for detecting, at fsync time, if the inode isn't yet in the + * log tree or it's there but not up to date. + */ + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + } else { + err = btrfs_update_inode(trans, root, inode); + ret = btrfs_end_transaction(trans, root); + } + } + mutex_unlock(&inode->i_mutex); + if (ret && !err) + err = ret; + return err; +} + +static long btrfs_fallocate(struct file *file, int mode, + loff_t offset, loff_t len) +{ + struct inode *inode = file_inode(file); + struct extent_state *cached_state = NULL; + u64 cur_offset; + u64 last_byte; + u64 alloc_start; + u64 alloc_end; + u64 alloc_hint = 0; + u64 locked_end; + struct extent_map *em; + int blocksize = BTRFS_I(inode)->root->sectorsize; + int ret; + + alloc_start = round_down(offset, blocksize); + alloc_end = round_up(offset + len, blocksize); + + /* Make sure we aren't being give some crap mode */ + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) + return -EOPNOTSUPP; + + if (mode & FALLOC_FL_PUNCH_HOLE) + return btrfs_punch_hole(inode, offset, len); + + /* + * Make sure we have enough space before we do the + * allocation. + */ + ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start, alloc_end - alloc_start); + if (ret) + return ret; + + mutex_lock(&inode->i_mutex); + ret = inode_newsize_ok(inode, alloc_end); + if (ret) + goto out; + + if (alloc_start > inode->i_size) { + ret = btrfs_cont_expand(inode, i_size_read(inode), + alloc_start); + if (ret) + goto out; + } else { + /* + * If we are fallocating from the end of the file onward we + * need to zero out the end of the page if i_size lands in the + * middle of a page. + */ + ret = btrfs_truncate_page(inode, inode->i_size, 0, 0); + if (ret) + goto out; + } + + /* + * wait for ordered IO before we have any locks. We'll loop again + * below with the locks held. + */ + ret = btrfs_wait_ordered_range(inode, alloc_start, + alloc_end - alloc_start); + if (ret) + goto out; + + locked_end = alloc_end - 1; + while (1) { + struct btrfs_ordered_extent *ordered; + + /* the extent lock is ordered inside the running + * transaction + */ + lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start, + locked_end, 0, &cached_state); + ordered = btrfs_lookup_first_ordered_extent(inode, + alloc_end - 1); + if (ordered && + ordered->file_offset + ordered->len > alloc_start && + ordered->file_offset < alloc_end) { + btrfs_put_ordered_extent(ordered); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + alloc_start, locked_end, + &cached_state, GFP_NOFS); + /* + * we can't wait on the range with the transaction + * running or with the extent lock held + */ + ret = btrfs_wait_ordered_range(inode, alloc_start, + alloc_end - alloc_start); + if (ret) + goto out; + } else { + if (ordered) + btrfs_put_ordered_extent(ordered); + break; + } + } + + cur_offset = alloc_start; + while (1) { + u64 actual_end; + + em = btrfs_get_extent(inode, NULL, 0, cur_offset, + alloc_end - cur_offset, 0); + if (IS_ERR_OR_NULL(em)) { + if (!em) + ret = -ENOMEM; + else + ret = PTR_ERR(em); + break; + } + last_byte = min(extent_map_end(em), alloc_end); + actual_end = min_t(u64, extent_map_end(em), offset + len); + last_byte = ALIGN(last_byte, blocksize); + + if (em->block_start == EXTENT_MAP_HOLE || + (cur_offset >= inode->i_size && + !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) { + ret = btrfs_prealloc_file_range(inode, mode, cur_offset, + last_byte - cur_offset, + 1 << inode->i_blkbits, + offset + len, + &alloc_hint); + } else if (actual_end > inode->i_size && + !(mode & FALLOC_FL_KEEP_SIZE)) { + struct btrfs_trans_handle *trans; + struct btrfs_root *root = BTRFS_I(inode)->root; + + /* + * We didn't need to allocate any more space, but we + * still extended the size of the file so we need to + * update i_size and the inode item. + */ + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + } else { + inode->i_ctime = CURRENT_TIME; + i_size_write(inode, actual_end); + btrfs_ordered_update_i_size(inode, actual_end, + NULL); + ret = btrfs_update_inode(trans, root, inode); + if (ret) + btrfs_end_transaction(trans, root); + else + ret = btrfs_end_transaction(trans, + root); + } + } + free_extent_map(em); + if (ret < 0) + break; + + cur_offset = last_byte; + if (cur_offset >= alloc_end) { + ret = 0; + break; + } + } + unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end, + &cached_state, GFP_NOFS); +out: + mutex_unlock(&inode->i_mutex); + /* Let go of our reservation. */ + btrfs_free_reserved_data_space(inode, alloc_end - alloc_start); + return ret; +} + +static int find_desired_extent(struct inode *inode, loff_t *offset, int whence) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_map *em = NULL; + struct extent_state *cached_state = NULL; + u64 lockstart; + u64 lockend; + u64 start; + u64 len; + int ret = 0; + + if (inode->i_size == 0) + return -ENXIO; + + /* + * *offset can be negative, in this case we start finding DATA/HOLE from + * the very start of the file. + */ + start = max_t(loff_t, 0, *offset); + + lockstart = round_down(start, root->sectorsize); + lockend = round_up(i_size_read(inode), root->sectorsize); + if (lockend <= lockstart) + lockend = lockstart + root->sectorsize; + lockend--; + len = lockend - lockstart + 1; + + lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0, + &cached_state); + + while (start < inode->i_size) { + em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + em = NULL; + break; + } + + if (whence == SEEK_HOLE && + (em->block_start == EXTENT_MAP_HOLE || + test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) + break; + else if (whence == SEEK_DATA && + (em->block_start != EXTENT_MAP_HOLE && + !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) + break; + + start = em->start + em->len; + free_extent_map(em); + em = NULL; + cond_resched(); + } + free_extent_map(em); + if (!ret) { + if (whence == SEEK_DATA && start >= inode->i_size) + ret = -ENXIO; + else + *offset = min_t(loff_t, start, inode->i_size); + } + unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend, + &cached_state, GFP_NOFS); + return ret; +} + +static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_mapping->host; + int ret; + + mutex_lock(&inode->i_mutex); + switch (whence) { + case SEEK_END: + case SEEK_CUR: + offset = generic_file_llseek(file, offset, whence); + goto out; + case SEEK_DATA: + case SEEK_HOLE: + if (offset >= i_size_read(inode)) { + mutex_unlock(&inode->i_mutex); + return -ENXIO; + } + + ret = find_desired_extent(inode, &offset, whence); + if (ret) { + mutex_unlock(&inode->i_mutex); + return ret; + } + } + + offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes); +out: + mutex_unlock(&inode->i_mutex); + return offset; +} + +const struct file_operations btrfs_file_operations = { + .llseek = btrfs_file_llseek, + .read_iter = generic_file_read_iter, + .splice_read = generic_file_splice_read, + .write_iter = btrfs_file_write_iter, + .mmap = btrfs_file_mmap, + .open = generic_file_open, + .release = btrfs_release_file, + .fsync = btrfs_sync_file, + .fallocate = btrfs_fallocate, + .unlocked_ioctl = btrfs_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = btrfs_ioctl, +#endif +}; + +void btrfs_auto_defrag_exit(void) +{ + if (btrfs_inode_defrag_cachep) + kmem_cache_destroy(btrfs_inode_defrag_cachep); +} + +int btrfs_auto_defrag_init(void) +{ + btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag", + sizeof(struct inode_defrag), 0, + SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, + NULL); + if (!btrfs_inode_defrag_cachep) + return -ENOMEM; + + return 0; +} + +int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end) +{ + int ret; + + /* + * So with compression we will find and lock a dirty page and clear the + * first one as dirty, setup an async extent, and immediately return + * with the entire range locked but with nobody actually marked with + * writeback. So we can't just filemap_write_and_wait_range() and + * expect it to work since it will just kick off a thread to do the + * actual work. So we need to call filemap_fdatawrite_range _again_ + * since it will wait on the page lock, which won't be unlocked until + * after the pages have been marked as writeback and so we're good to go + * from there. We have to do this otherwise we'll miss the ordered + * extents and that results in badness. Please Josef, do not think you + * know better and pull this out at some point in the future, it is + * right and you are wrong. + */ + ret = filemap_fdatawrite_range(inode->i_mapping, start, end); + if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT, + &BTRFS_I(inode)->runtime_flags)) + ret = filemap_fdatawrite_range(inode->i_mapping, start, end); + + return ret; +} |