Hey Guys,
I am wondering how to convert btrfs_find_first_hole and
btrfs_fill_holes in order to support zero range for btrfs in order to
support fallocate zero range. I am pasting my code so far and please
let me known if there is something else I am missing.
The function is called btrfs_zero_range in the file I am attaching.
Regards Nick
/*
* 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/aio.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 "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);
if (need_resched()) {
spin_unlock(&fs_info->defrag_inodes_lock);
cond_resched();
spin_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;
btrfs_set_key_type(&key, 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;
btrfs_set_key_type(&key, 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 (unlikely(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, 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, 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, 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_nocow_write(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_nocow_write(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((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
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(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 = (write_bytes + offset +
PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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);
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 = (write_bytes + offset +
PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
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_nocow_write(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 = (copied + offset +
PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
}
/*
* 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_nocow_write(root);
if (only_release_metadata && copied > 0) {
u64 lockstart = round_down(pos, root->sectorsize);
u64 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->leafsize >> 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_nocow_write(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;
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;
}
endbyte = pos + written_buffered - 1;
err = filemap_write_and_wait_range(file->f_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;
ssize_t err = 0;
size_t count = iov_iter_count(from);
bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
loff_t pos = iocb->ki_pos;
mutex_lock(&inode->i_mutex);
current->backing_dev_info = inode->i_mapping->backing_dev_info;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err) {
mutex_unlock(&inode->i_mutex);
goto out;
}
if (count == 0) {
mutex_unlock(&inode->i_mutex);
goto out;
}
iov_iter_truncate(from, count);
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);
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 (unlikely(file->f_flags & O_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 want to make sure fsync finds this change
* but we haven't joined a transaction running right now.
*
* Later on, someone is sure to update the inode and get the
* real transid recorded.
*
* We set last_trans now to the fs_info generation + 1,
* this will either be one more than the running transaction
* or the generation used for the next transaction if there isn't
* one running right now.
*
* 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.
*/
BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
BTRFS_I(inode)->last_sub_trans = root->log_transid;
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)
{
/*
* 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)) {
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
/*
* We need to block on a committing transaction to keep us from
* throwing a ordered operation on to the list and causing
* something like sync to deadlock trying to flush out this
* inode.
*/
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
btrfs_end_transaction(trans, root);
if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
filemap_flush(inode->i_mapping);
}
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, loff_t start, loff_t end, int datasync)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
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.
*/
atomic_inc(&BTRFS_I(inode)->sync_writers);
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);
atomic_dec(&BTRFS_I(inode)->sync_writers);
if (ret)
return ret;
mutex_lock(&inode->i_mutex);
/*
* We flush the dirty pages again to avoid some dirty pages in the
* range being left.
*/
atomic_inc(&root->log_batch);
full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
if (full_sync) {
ret = btrfs_wait_ordered_range(inode, start, end - start + 1);
if (ret) {
mutex_unlock(&inode->i_mutex);
goto out;
}
}
atomic_inc(&root->log_batch);
/*
* check the transaction that last modified this inode
* and see if its already been committed
*/
if (!BTRFS_I(inode)->last_trans) {
mutex_unlock(&inode->i_mutex);
goto out;
}
/*
* if the last transaction that changed this file was before
* the current transaction, we can bail out now without any
* syncing
*/
smp_mb();
if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
BTRFS_I(inode)->last_trans <=
root->fs_info->last_trans_committed) {
BTRFS_I(inode)->last_trans = 0;
/*
* 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, &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 (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,
.remap_pages = generic_file_remap_pages,
};
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]+1, offset, end)) {
u64 num_bytes;
path->slots[0]++;
key.offset = offset;
btrfs_set_item_key_safe(root, 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;
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)
ret = btrfs_truncate_page(inode, offset, len, 0);
goto out_only_mutex;
}
/* zero back part of the first page */
if (offset < ino_size) {
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) {
ret = btrfs_truncate_page(inode,
tail_start + tail_len, 0, 1);
if (ret)
goto out_only_mutex;
}
}
}
if (lockend < lockstart) {
mutex_unlock(&inode->i_mutex);
return 0;
}
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);
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:
mutex_unlock(&inode->i_mutex);
if (ret && !err)
err = ret;
return err;
}
static long btrfs_zero_range(struct inode *inode, loff_t loffset,
loff_t len,){
struct btrfs_root *root = BTRF_I(inode)->root;
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;
ret=btrfs_wait_ordered_range(inode, offset, len);
ret = find_first_non_hole(inode, &offset, &len);
if(ret)
return ret;
mutex_lock(&inode->i_mutex);
ino_size=round_up(inode->i_size, PAGE_CACHE_SHIFT);
lockstart = round_up(offset , BTRFS_I(inode)->root->sectorwise);
lockend=round_down(offset +len,
BTRFS_I(inode)->rootsectorsize)-1;
/*
* 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)
ret = btrfs_truncate_page(inode, offset, len, 0);
goto out_only_mutex;
}
/* zero back part of the first page */
if (offset < ino_size) {
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) {
ret = btrfs_truncate_page(inode,
tail_start + tail_len, 0, 1);
if (ret)
goto out_only_mutex;
}
}
}
if (lockend < lockstart) {
mutex_unlock(&inode->i_mutex);
return 0;
}
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;
}
}
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;
struct btrfs_root *root = BTRFS_I(inode)->root;
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);
if (ret)
return ret;
if (root->fs_info->quota_enabled) {
ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
if (ret)
goto out_reserve_fail;
}
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);
if (ret < 0) {
free_extent_map(em);
break;
}
} else if (actual_end > inode->i_size &&
!(mode & FALLOC_FL_KEEP_SIZE)) {
/*
* 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.
*/
inode->i_ctime = CURRENT_TIME;
i_size_write(inode, actual_end);
btrfs_ordered_update_i_size(inode, actual_end, NULL);
}
free_extent_map(em);
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);
if (root->fs_info->quota_enabled)
btrfs_qgroup_free(root, alloc_end - alloc_start);
out_reserve_fail:
/* 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 = *offset;
u64 lockend = i_size_read(inode);
u64 start = *offset;
u64 len = i_size_read(inode);
int ret = 0;
lockend = max_t(u64, root->sectorsize, lockend);
if (lockend <= lockstart)
lockend = lockstart + root->sectorsize;
lockend--;
len = lockend - lockstart + 1;
len = max_t(u64, len, root->sectorsize);
if (inode->i_size == 0)
return -ENXIO;
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 = new_sync_read,
.write = new_sync_write,
.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;
}
_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@xxxxxxxxxxxxxxxxx
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
