diff options
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 1288 |
1 files changed, 1288 insertions, 0 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c new file mode 100644 index 00000000000..90268334145 --- /dev/null +++ b/fs/btrfs/file.c @@ -0,0 +1,1288 @@ +/* + * 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/smp_lock.h> +#include <linux/backing-dev.h> +#include <linux/mpage.h> +#include <linux/swap.h> +#include <linux/writeback.h> +#include <linux/statfs.h> +#include <linux/compat.h> +#include <linux/version.h> +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "btrfs_inode.h" +#include "ioctl.h" +#include "print-tree.h" +#include "tree-log.h" +#include "locking.h" +#include "compat.h" + + +/* 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, + int write_bytes, + struct page **prepared_pages, + const char __user *buf) +{ + long page_fault = 0; + int i; + int offset = pos & (PAGE_CACHE_SIZE - 1); + + for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) { + size_t count = min_t(size_t, + PAGE_CACHE_SIZE - offset, write_bytes); + struct page *page = prepared_pages[i]; + fault_in_pages_readable(buf, count); + + /* Copy data from userspace to the current page */ + kmap(page); + page_fault = __copy_from_user(page_address(page) + offset, + buf, count); + /* Flush processor's dcache for this page */ + flush_dcache_page(page); + kunmap(page); + buf += count; + write_bytes -= count; + + if (page_fault) + break; + } + return page_fault ? -EFAULT : 0; +} + +/* + * unlocks pages after btrfs_file_write is done with them + */ +static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages) +{ + size_t i; + for (i = 0; i < num_pages; i++) { + if (!pages[i]) + break; + /* page checked is some magic around finding pages that + * have been modified without going through btrfs_set_page_dirty + * clear it here + */ + ClearPageChecked(pages[i]); + unlock_page(pages[i]); + mark_page_accessed(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. + */ +static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct file *file, + struct page **pages, + size_t num_pages, + loff_t pos, + size_t write_bytes) +{ + int err = 0; + int i; + struct inode *inode = fdentry(file)->d_inode; + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + u64 hint_byte; + 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 = (write_bytes + pos - start_pos + + root->sectorsize - 1) & ~((u64)root->sectorsize - 1); + + end_of_last_block = start_pos + num_bytes - 1; + + lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS); + trans = btrfs_join_transaction(root, 1); + if (!trans) { + err = -ENOMEM; + goto out_unlock; + } + btrfs_set_trans_block_group(trans, inode); + hint_byte = 0; + + set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS); + + /* check for reserved extents on each page, we don't want + * to reset the delalloc bit on things that already have + * extents reserved. + */ + btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block); + for (i = 0; i < num_pages; i++) { + struct page *p = pages[i]; + SetPageUptodate(p); + ClearPageChecked(p); + set_page_dirty(p); + } + if (end_pos > isize) { + i_size_write(inode, end_pos); + btrfs_update_inode(trans, root, inode); + } + err = btrfs_end_transaction(trans, root); +out_unlock: + unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS); + return err; +} + +/* + * this drops all the extents in the cache that intersect the range + * [start, end]. Existing extents are split as required. + */ +int 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; + int ret; + int testend = 1; + unsigned long flags; + int compressed = 0; + + WARN_ON(end < start); + if (end == (u64)-1) { + len = (u64)-1; + testend = 0; + } + while (1) { + if (!split) + split = alloc_extent_map(GFP_NOFS); + if (!split2) + split2 = alloc_extent_map(GFP_NOFS); + + spin_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, start, len); + if (!em) { + spin_unlock(&em_tree->lock); + break; + } + flags = em->flags; + if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) { + spin_unlock(&em_tree->lock); + if (em->start <= start && + (!testend || em->start + em->len >= start + len)) { + free_extent_map(em); + break; + } + if (start < em->start) { + len = em->start - start; + } else { + len = start + len - (em->start + em->len); + start = em->start + em->len; + } + free_extent_map(em); + continue; + } + compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags); + clear_bit(EXTENT_FLAG_PINNED, &em->flags); + remove_extent_mapping(em_tree, em); + + if (em->block_start < EXTENT_MAP_LAST_BYTE && + em->start < start) { + split->start = em->start; + split->len = start - em->start; + 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->bdev = em->bdev; + split->flags = flags; + ret = add_extent_mapping(em_tree, split); + BUG_ON(ret); + free_extent_map(split); + split = split2; + split2 = NULL; + } + if (em->block_start < EXTENT_MAP_LAST_BYTE && + 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; + + 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 = split->start; + } + + ret = add_extent_mapping(em_tree, split); + BUG_ON(ret); + free_extent_map(split); + split = NULL; + } + spin_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); + return 0; +} + +int btrfs_check_file(struct btrfs_root *root, struct inode *inode) +{ + return 0; +#if 0 + struct btrfs_path *path; + struct btrfs_key found_key; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *extent; + u64 last_offset = 0; + int nritems; + int slot; + int found_type; + int ret; + int err = 0; + u64 extent_end = 0; + + path = btrfs_alloc_path(); + ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino, + last_offset, 0); + while (1) { + nritems = btrfs_header_nritems(path->nodes[0]); + if (path->slots[0] >= nritems) { + ret = btrfs_next_leaf(root, path); + if (ret) + goto out; + nritems = btrfs_header_nritems(path->nodes[0]); + } + slot = path->slots[0]; + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &found_key, slot); + if (found_key.objectid != inode->i_ino) + break; + if (found_key.type != BTRFS_EXTENT_DATA_KEY) + goto out; + + if (found_key.offset < last_offset) { + WARN_ON(1); + btrfs_print_leaf(root, leaf); + printk(KERN_ERR "inode %lu found offset %llu " + "expected %llu\n", inode->i_ino, + (unsigned long long)found_key.offset, + (unsigned long long)last_offset); + err = 1; + goto out; + } + extent = btrfs_item_ptr(leaf, slot, + struct btrfs_file_extent_item); + found_type = btrfs_file_extent_type(leaf, extent); + if (found_type == BTRFS_FILE_EXTENT_REG) { + extent_end = found_key.offset + + btrfs_file_extent_num_bytes(leaf, extent); + } else if (found_type == BTRFS_FILE_EXTENT_INLINE) { + struct btrfs_item *item; + item = btrfs_item_nr(leaf, slot); + extent_end = found_key.offset + + btrfs_file_extent_inline_len(leaf, extent); + extent_end = (extent_end + root->sectorsize - 1) & + ~((u64)root->sectorsize - 1); + } + last_offset = extent_end; + path->slots[0]++; + } + if (0 && last_offset < inode->i_size) { + WARN_ON(1); + btrfs_print_leaf(root, leaf); + printk(KERN_ERR "inode %lu found offset %llu size %llu\n", + inode->i_ino, (unsigned long long)last_offset, + (unsigned long long)inode->i_size); + err = 1; + + } +out: + btrfs_free_path(path); + return err; +#endif +} + +/* + * 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. + * + * inline_limit is used to tell this code which offsets in the file to keep + * if they contain inline extents. + */ +noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans, + struct btrfs_root *root, struct inode *inode, + u64 start, u64 end, u64 inline_limit, u64 *hint_byte) +{ + u64 extent_end = 0; + u64 locked_end = end; + u64 search_start = start; + u64 leaf_start; + u64 ram_bytes = 0; + u64 orig_parent = 0; + u64 disk_bytenr = 0; + u8 compression; + u8 encryption; + u16 other_encoding = 0; + u64 root_gen; + u64 root_owner; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *extent; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_file_extent_item old; + int keep; + int slot; + int bookend; + int found_type = 0; + int found_extent; + int found_inline; + int recow; + int ret; + + inline_limit = 0; + btrfs_drop_extent_cache(inode, start, end - 1, 0); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + while (1) { + recow = 0; + btrfs_release_path(root, path); + ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, + search_start, -1); + if (ret < 0) + goto out; + if (ret > 0) { + if (path->slots[0] == 0) { + ret = 0; + goto out; + } + path->slots[0]--; + } +next_slot: + keep = 0; + bookend = 0; + found_extent = 0; + found_inline = 0; + leaf_start = 0; + root_gen = 0; + root_owner = 0; + compression = 0; + encryption = 0; + extent = NULL; + leaf = path->nodes[0]; + slot = path->slots[0]; + ret = 0; + btrfs_item_key_to_cpu(leaf, &key, slot); + if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY && + key.offset >= end) { + goto out; + } + if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY || + key.objectid != inode->i_ino) { + goto out; + } + if (recow) { + search_start = max(key.offset, start); + continue; + } + if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) { + extent = btrfs_item_ptr(leaf, slot, + struct btrfs_file_extent_item); + found_type = btrfs_file_extent_type(leaf, extent); + compression = btrfs_file_extent_compression(leaf, + extent); + encryption = btrfs_file_extent_encryption(leaf, + extent); + other_encoding = btrfs_file_extent_other_encoding(leaf, + extent); + if (found_type == BTRFS_FILE_EXTENT_REG || + found_type == BTRFS_FILE_EXTENT_PREALLOC) { + extent_end = + btrfs_file_extent_disk_bytenr(leaf, + extent); + if (extent_end) + *hint_byte = extent_end; + + extent_end = key.offset + + btrfs_file_extent_num_bytes(leaf, extent); + ram_bytes = btrfs_file_extent_ram_bytes(leaf, + extent); + found_extent = 1; + } else if (found_type == BTRFS_FILE_EXTENT_INLINE) { + found_inline = 1; + extent_end = key.offset + + btrfs_file_extent_inline_len(leaf, extent); + } + } else { + extent_end = search_start; + } + + /* we found nothing we can drop */ + if ((!found_extent && !found_inline) || + search_start >= extent_end) { + int nextret; + u32 nritems; + nritems = btrfs_header_nritems(leaf); + if (slot >= nritems - 1) { + nextret = btrfs_next_leaf(root, path); + if (nextret) + goto out; + recow = 1; + } else { + path->slots[0]++; + } + goto next_slot; + } + + if (end <= extent_end && start >= key.offset && found_inline) + *hint_byte = EXTENT_MAP_INLINE; + + if (found_extent) { + read_extent_buffer(leaf, &old, (unsigned long)extent, + sizeof(old)); + root_gen = btrfs_header_generation(leaf); + root_owner = btrfs_header_owner(leaf); + leaf_start = leaf->start; + } + + if (end < extent_end && end >= key.offset) { + bookend = 1; + if (found_inline && start <= key.offset) + keep = 1; + } + + if (bookend && found_extent) { + if (locked_end < extent_end) { + ret = try_lock_extent(&BTRFS_I(inode)->io_tree, + locked_end, extent_end - 1, + GFP_NOFS); + if (!ret) { + btrfs_release_path(root, path); + lock_extent(&BTRFS_I(inode)->io_tree, + locked_end, extent_end - 1, + GFP_NOFS); + locked_end = extent_end; + continue; + } + locked_end = extent_end; + } + orig_parent = path->nodes[0]->start; + disk_bytenr = le64_to_cpu(old.disk_bytenr); + if (disk_bytenr != 0) { + ret = btrfs_inc_extent_ref(trans, root, + disk_bytenr, + le64_to_cpu(old.disk_num_bytes), + orig_parent, root->root_key.objectid, + trans->transid, inode->i_ino); + BUG_ON(ret); + } + } + + if (found_inline) { + u64 mask = root->sectorsize - 1; + search_start = (extent_end + mask) & ~mask; + } else + search_start = extent_end; + + /* truncate existing extent */ + if (start > key.offset) { + u64 new_num; + u64 old_num; + keep = 1; + WARN_ON(start & (root->sectorsize - 1)); + if (found_extent) { + new_num = start - key.offset; + old_num = btrfs_file_extent_num_bytes(leaf, + extent); + *hint_byte = + btrfs_file_extent_disk_bytenr(leaf, + extent); + if (btrfs_file_extent_disk_bytenr(leaf, + extent)) { + inode_sub_bytes(inode, old_num - + new_num); + } + btrfs_set_file_extent_num_bytes(leaf, + extent, new_num); + btrfs_mark_buffer_dirty(leaf); + } else if (key.offset < inline_limit && + (end > extent_end) && + (inline_limit < extent_end)) { + u32 new_size; + new_size = btrfs_file_extent_calc_inline_size( + inline_limit - key.offset); + inode_sub_bytes(inode, extent_end - + inline_limit); + btrfs_set_file_extent_ram_bytes(leaf, extent, + new_size); + if (!compression && !encryption) { + btrfs_truncate_item(trans, root, path, + new_size, 1); + } + } + } + /* delete the entire extent */ + if (!keep) { + if (found_inline) + inode_sub_bytes(inode, extent_end - + key.offset); + ret = btrfs_del_item(trans, root, path); + /* TODO update progress marker and return */ + BUG_ON(ret); + extent = NULL; + btrfs_release_path(root, path); + /* the extent will be freed later */ + } + if (bookend && found_inline && start <= key.offset) { + u32 new_size; + new_size = btrfs_file_extent_calc_inline_size( + extent_end - end); + inode_sub_bytes(inode, end - key.offset); + btrfs_set_file_extent_ram_bytes(leaf, extent, + new_size); + if (!compression && !encryption) + ret = btrfs_truncate_item(trans, root, path, + new_size, 0); + BUG_ON(ret); + } + /* create bookend, splitting the extent in two */ + if (bookend && found_extent) { + struct btrfs_key ins; + ins.objectid = inode->i_ino; + ins.offset = end; + btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY); + + btrfs_release_path(root, path); + ret = btrfs_insert_empty_item(trans, root, path, &ins, + sizeof(*extent)); + BUG_ON(ret); + + leaf = path->nodes[0]; + extent = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + write_extent_buffer(leaf, &old, + (unsigned long)extent, sizeof(old)); + + btrfs_set_file_extent_compression(leaf, extent, + compression); + btrfs_set_file_extent_encryption(leaf, extent, + encryption); + btrfs_set_file_extent_other_encoding(leaf, extent, + other_encoding); + btrfs_set_file_extent_offset(leaf, extent, + le64_to_cpu(old.offset) + end - key.offset); + WARN_ON(le64_to_cpu(old.num_bytes) < + (extent_end - end)); + btrfs_set_file_extent_num_bytes(leaf, extent, + extent_end - end); + + /* + * set the ram bytes to the size of the full extent + * before splitting. This is a worst case flag, + * but its the best we can do because we don't know + * how splitting affects compression + */ + btrfs_set_file_extent_ram_bytes(leaf, extent, + ram_bytes); + btrfs_set_file_extent_type(leaf, extent, found_type); + + btrfs_mark_buffer_dirty(path->nodes[0]); + + if (disk_bytenr != 0) { + ret = btrfs_update_extent_ref(trans, root, + disk_bytenr, orig_parent, + leaf->start, + root->root_key.objectid, + trans->transid, ins.objectid); + + BUG_ON(ret); + } + btrfs_release_path(root, path); + if (disk_bytenr != 0) + inode_add_bytes(inode, extent_end - end); + } + + if (found_extent && !keep) { + u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr); + + if (old_disk_bytenr != 0) { + inode_sub_bytes(inode, + le64_to_cpu(old.num_bytes)); + ret = btrfs_free_extent(trans, root, + old_disk_bytenr, + le64_to_cpu(old.disk_num_bytes), + leaf_start, root_owner, + root_gen, key.objectid, 0); + BUG_ON(ret); + *hint_byte = old_disk_bytenr; + } + } + + if (search_start >= end) { + ret = 0; + goto out; + } + } +out: + btrfs_free_path(path); + if (locked_end > end) { + unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1, + GFP_NOFS); + } + btrfs_check_file(root, inode); + return ret; +} + +static int extent_mergeable(struct extent_buffer *leaf, int slot, + u64 objectid, u64 bytenr, 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_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 btrfs_root *root, + struct inode *inode, u64 start, u64 end) +{ + struct extent_buffer *leaf; + struct btrfs_path *path; + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + u64 bytenr; + u64 num_bytes; + u64 extent_end; + u64 extent_offset; + u64 other_start; + u64 other_end; + u64 split = start; + u64 locked_end = end; + u64 orig_parent; + int extent_type; + int split_end = 1; + int ret; + + btrfs_drop_extent_cache(inode, start, end - 1, 0); + + path = btrfs_alloc_path(); + BUG_ON(!path); +again: + key.objectid = inode->i_ino; + key.type = BTRFS_EXTENT_DATA_KEY; + if (split == start) + key.offset = split; + else + key.offset = split - 1; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + 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 != inode->i_ino || + key.type != BTRFS_EXTENT_DATA_KEY); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + extent_type = btrfs_file_extent_type(leaf, fi); + BUG_ON(extent_type != 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); + extent_offset = btrfs_file_extent_offset(leaf, fi); + + if (key.offset == start) + split = end; + + if (key.offset == start && extent_end == end) { + int del_nr = 0; + int del_slot = 0; + u64 leaf_owner = btrfs_header_owner(leaf); + u64 leaf_gen = btrfs_header_generation(leaf); + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino, + bytenr, &other_start, &other_end)) { + extent_end = other_end; + del_slot = path->slots[0] + 1; + del_nr++; + ret = btrfs_free_extent(trans, root, bytenr, num_bytes, + leaf->start, leaf_owner, + leaf_gen, inode->i_ino, 0); + BUG_ON(ret); + } + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino, + bytenr, &other_start, &other_end)) { + key.offset = other_start; + del_slot = path->slots[0]; + del_nr++; + ret = btrfs_free_extent(trans, root, bytenr, num_bytes, + leaf->start, leaf_owner, + leaf_gen, inode->i_ino, 0); + BUG_ON(ret); + } + split_end = 0; + if (del_nr == 0) { + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + goto done; + } + + 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_num_bytes(leaf, fi, + extent_end - key.offset); + btrfs_mark_buffer_dirty(leaf); + + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + BUG_ON(ret); + goto done; + } else if (split == start) { + if (locked_end < extent_end) { + ret = try_lock_extent(&BTRFS_I(inode)->io_tree, + locked_end, extent_end - 1, GFP_NOFS); + if (!ret) { + btrfs_release_path(root, path); + lock_extent(&BTRFS_I(inode)->io_tree, + locked_end, extent_end - 1, GFP_NOFS); + locked_end = extent_end; + goto again; + } + locked_end = extent_end; + } + btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset); + extent_offset += split - key.offset; + } else { + BUG_ON(key.offset != start); + btrfs_set_file_extent_offset(leaf, fi, extent_offset + + split - key.offset); + btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split); + key.offset = split; + btrfs_set_item_key_safe(trans, root, path, &key); + extent_end = split; + } + + if (extent_end == end) { + split_end = 0; + extent_type = BTRFS_FILE_EXTENT_REG; + } + if (extent_end == end && split == start) { + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino, + bytenr, &other_start, &other_end)) { + path->slots[0]++; + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + key.offset = split; + btrfs_set_item_key_safe(trans, root, path, &key); + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + other_end - split); + goto done; + } + } + if (extent_end == end && split == end) { + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino, + bytenr, &other_start, &other_end)) { + path->slots[0]--; + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - + other_start); + goto done; + } + } + + btrfs_mark_buffer_dirty(leaf); + + orig_parent = leaf->start; + ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, + orig_parent, root->root_key.objectid, + trans->transid, inode->i_ino); + BUG_ON(ret); + btrfs_release_path(root, path); + + key.offset = start; + ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi)); + BUG_ON(ret); + + leaf = path->nodes[0]; + 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_type(leaf, fi, extent_type); + btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr); + btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset); + btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_compression(leaf, fi, 0); + btrfs_set_file_extent_encryption(leaf, fi, 0); + btrfs_set_file_extent_other_encoding(leaf, fi, 0); + + if (orig_parent != leaf->start) { + ret = btrfs_update_extent_ref(trans, root, bytenr, + orig_parent, leaf->start, + root->root_key.objectid, + trans->transid, inode->i_ino); + BUG_ON(ret); + } +done: + btrfs_mark_buffer_dirty(leaf); + btrfs_release_path(root, path); + if (split_end && split == start) { + split = end; + goto again; + } + if (locked_end > end) { + unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1, + GFP_NOFS); + } + btrfs_free_path(path); + return 0; +} + +/* + * this gets pages into the page cache and locks them down, it also properly + * waits for data=ordered extents to finish before allowing the pages to be + * modified. + */ +static noinline int prepare_pages(struct btrfs_root *root, struct file *file, + struct page **pages, size_t num_pages, + loff_t pos, unsigned long first_index, + unsigned long last_index, size_t write_bytes) +{ + int i; + unsigned long index = pos >> PAGE_CACHE_SHIFT; + struct inode *inode = fdentry(file)->d_inode; + int err = 0; + u64 start_pos; + u64 last_pos; + + start_pos = pos & ~((u64)root->sectorsize - 1); + last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT; + + if (start_pos > inode->i_size) { + err = btrfs_cont_expand(inode, start_pos); + if (err) + return err; + } + + memset(pages, 0, num_pages * sizeof(struct page *)); +again: + for (i = 0; i < num_pages; i++) { + pages[i] = grab_cache_page(inode->i_mapping, index + i); + if (!pages[i]) { + err = -ENOMEM; + BUG_ON(1); + } + wait_on_page_writeback(pages[i]); + } + if (start_pos < inode->i_size) { + struct btrfs_ordered_extent *ordered; + lock_extent(&BTRFS_I(inode)->io_tree, + start_pos, last_pos - 1, GFP_NOFS); + ordered = btrfs_lookup_first_ordered_extent(inode, + last_pos - 1); + if (ordered && + ordered->file_offset + ordered->len > start_pos && + ordered->file_offset < last_pos) { + btrfs_put_ordered_extent(ordered); + unlock_extent(&BTRFS_I(inode)->io_tree, + start_pos, last_pos - 1, GFP_NOFS); + for (i = 0; i < num_pages; i++) { + unlock_page(pages[i]); + page_cache_release(pages[i]); + } + btrfs_wait_ordered_range(inode, start_pos, + last_pos - start_pos); + goto again; + } + if (ordered) + btrfs_put_ordered_extent(ordered); + + clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos, + last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC, + GFP_NOFS); + unlock_extent(&BTRFS_I(inode)->io_tree, + start_pos, last_pos - 1, GFP_NOFS); + } + for (i = 0; i < num_pages; i++) { + clear_page_dirty_for_io(pages[i]); + set_page_extent_mapped(pages[i]); + WARN_ON(!PageLocked(pages[i])); + } + return 0; +} + +static ssize_t btrfs_file_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + loff_t pos; + loff_t start_pos; + ssize_t num_written = 0; + ssize_t err = 0; + int ret = 0; + struct inode *inode = fdentry(file)->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + struct page **pages = NULL; + int nrptrs; + struct page *pinned[2]; + unsigned long first_index; + unsigned long last_index; + int will_write; + + will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) || + (file->f_flags & O_DIRECT)); + + nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE, + PAGE_CACHE_SIZE / (sizeof(struct page *))); + pinned[0] = NULL; + pinned[1] = NULL; + + pos = *ppos; + start_pos = pos; + + vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + current->backing_dev_info = inode->i_mapping->backing_dev_info; + err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); + if (err) + goto out_nolock; + if (count == 0) + goto out_nolock; + + err = file_remove_suid(file); + if (err) + goto out_nolock; + file_update_time(file); + + pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); + + mutex_lock(&inode->i_mutex); + BTRFS_I(inode)->sequence++; + first_index = pos >> PAGE_CACHE_SHIFT; + last_index = (pos + count) >> PAGE_CACHE_SHIFT; + + /* + * there are lots of better ways to do this, but this code + * makes sure the first and last page in the file range are + * up to date and ready for cow + */ + if ((pos & (PAGE_CACHE_SIZE - 1))) { + pinned[0] = grab_cache_page(inode->i_mapping, first_index); + if (!PageUptodate(pinned[0])) { + ret = btrfs_readpage(NULL, pinned[0]); + BUG_ON(ret); + wait_on_page_locked(pinned[0]); + } else { + unlock_page(pinned[0]); + } + } + if ((pos + count) & (PAGE_CACHE_SIZE - 1)) { + pinned[1] = grab_cache_page(inode->i_mapping, last_index); + if (!PageUptodate(pinned[1])) { + ret = btrfs_readpage(NULL, pinned[1]); + BUG_ON(ret); + wait_on_page_locked(pinned[1]); + } else { + unlock_page(pinned[1]); + } + } + + while (count > 0) { + size_t offset = pos & (PAGE_CACHE_SIZE - 1); + size_t write_bytes = min(count, nrptrs * + (size_t)PAGE_CACHE_SIZE - + offset); + size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >> + PAGE_CACHE_SHIFT; + + WARN_ON(num_pages > nrptrs); + memset(pages, 0, sizeof(struct page *) * nrptrs); + + ret = btrfs_check_free_space(root, write_bytes, 0); + if (ret) + goto out; + + ret = prepare_pages(root, file, pages, num_pages, + pos, first_index, last_index, + write_bytes); + if (ret) + goto out; + + ret = btrfs_copy_from_user(pos, num_pages, + write_bytes, pages, buf); + if (ret) { + btrfs_drop_pages(pages, num_pages); + goto out; + } + + ret = dirty_and_release_pages(NULL, root, file, pages, + num_pages, pos, write_bytes); + btrfs_drop_pages(pages, num_pages); + if (ret) + goto out; + + if (will_write) { + btrfs_fdatawrite_range(inode->i_mapping, pos, + pos + write_bytes - 1, + WB_SYNC_NONE); + } else { + balance_dirty_pages_ratelimited_nr(inode->i_mapping, + num_pages); + if (num_pages < + (root->leafsize >> PAGE_CACHE_SHIFT) + 1) + btrfs_btree_balance_dirty(root, 1); + btrfs_throttle(root); + } + + buf += write_bytes; + count -= write_bytes; + pos += write_bytes; + num_written += write_bytes; + + cond_resched(); + } +out: + mutex_unlock(&inode->i_mutex); + +out_nolock: + kfree(pages); + if (pinned[0]) + page_cache_release(pinned[0]); + if (pinned[1]) + page_cache_release(pinned[1]); + *ppos = pos; + + if (num_written > 0 && will_write) { + struct btrfs_trans_handle *trans; + + err = btrfs_wait_ordered_range(inode, start_pos, num_written); + if (err) + num_written = err; + + if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) { + trans = btrfs_start_transaction(root, 1); + ret = btrfs_log_dentry_safe(trans, root, + file->f_dentry); + if (ret == 0) { + btrfs_sync_log(trans, root); + btrfs_end_transaction(trans, root); + } else { + btrfs_commit_transaction(trans, root); + } + } + if (file->f_flags & O_DIRECT) { + invalidate_mapping_pages(inode->i_mapping, + start_pos >> PAGE_CACHE_SHIFT, + (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT); + } + } + 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); + return 0; +} + +/* + * 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, struct dentry *dentry, int datasync) +{ + struct inode *inode = dentry->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret = 0; + struct btrfs_trans_handle *trans; + + /* + * check the transaction that last modified this inode + * and see if its already been committed + */ + if (!BTRFS_I(inode)->last_trans) + goto out; + + mutex_lock(&root->fs_info->trans_mutex); + if (BTRFS_I(inode)->last_trans <= + root->fs_info->last_trans_committed) { + BTRFS_I(inode)->last_trans = 0; + mutex_unlock(&root->fs_info->trans_mutex); + goto out; + } + mutex_unlock(&root->fs_info->trans_mutex); + + root->fs_info->tree_log_batch++; + filemap_fdatawrite(inode->i_mapping); + btrfs_wait_ordered_range(inode, 0, (u64)-1); + root->fs_info->tree_log_batch++; + + /* + * ok we haven't committed the transaction yet, lets do a commit + */ + if (file->private_data) + btrfs_ioctl_trans_end(file); + + trans = btrfs_start_transaction(root, 1); + if (!trans) { + ret = -ENOMEM; + goto out; + } + + ret = btrfs_log_dentry_safe(trans, root, file->f_dentry); + if (ret < 0) + goto out; + + /* 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(&file->f_dentry->d_inode->i_mutex); + + if (ret > 0) { + ret = btrfs_commit_transaction(trans, root); + } else { + btrfs_sync_log(trans, root); + ret = btrfs_end_transaction(trans, root); + } + mutex_lock(&file->f_dentry->d_inode->i_mutex); +out: + return ret > 0 ? EIO : ret; +} + +static struct vm_operations_struct btrfs_file_vm_ops = { + .fault = filemap_fault, + .page_mkwrite = btrfs_page_mkwrite, +}; + +static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) +{ + vma->vm_ops = &btrfs_file_vm_ops; + file_accessed(filp); + return 0; +} + +struct file_operations btrfs_file_operations = { + .llseek = generic_file_llseek, + .read = do_sync_read, + .aio_read = generic_file_aio_read, + .splice_read = generic_file_splice_read, + .write = btrfs_file_write, + .mmap = btrfs_file_mmap, + .open = generic_file_open, + .release = btrfs_release_file, + .fsync = btrfs_sync_file, + .unlocked_ioctl = btrfs_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = btrfs_ioctl, +#endif +}; |