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Btrfs: Extent based page cache code. This uses an rbtree of extents and tests

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instead of buffer heads.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-08-27 16:49:44 -04:00 committed by David Woodhouse
parent 83df7c1d8b
commit a52d9a8033
9 changed files with 2213 additions and 679 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
fs/btrfs/Makefile
View file

@ -4,7 +4,8 @@ ifneq ($(KERNELRELEASE),)
obj-m := btrfs.o obj-m := btrfs.o
btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \ btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
hash.o file-item.o inode-item.o inode-map.o disk-io.o \ hash.o file-item.o inode-item.o inode-map.o disk-io.o \
transaction.o bit-radix.o inode.o file.o tree-defrag.o transaction.o bit-radix.o inode.o file.o tree-defrag.o \
extent_map.o
#btrfs-y := ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \ #btrfs-y := ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
# root-tree.o dir-item.o hash.o file-item.o inode-item.o \ # root-tree.o dir-item.o hash.o file-item.o inode-item.o \

3
fs/btrfs/btrfs_inode.h
View file

@ -19,11 +19,14 @@
#ifndef __BTRFS_I__ #ifndef __BTRFS_I__
#define __BTRFS_I__ #define __BTRFS_I__
#include "extent_map.h"
/* in memory btrfs inode */ /* in memory btrfs inode */
struct btrfs_inode { struct btrfs_inode {
struct btrfs_root *root; struct btrfs_root *root;
struct btrfs_block_group_cache *block_group; struct btrfs_block_group_cache *block_group;
struct btrfs_key location; struct btrfs_key location;
struct extent_map_tree extent_tree;
struct inode vfs_inode; struct inode vfs_inode;
/* /*

7
fs/btrfs/ctree.h
View file

@ -1176,7 +1176,14 @@ int btrfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to); unsigned from, unsigned to);
int btrfs_get_block(struct inode *inode, sector_t iblock, int btrfs_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create); struct buffer_head *result, int create);
struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
size_t page_offset, u64 start, u64 end,
int create);
int btrfs_update_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode);
/* file.c */ /* file.c */
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end);
extern struct file_operations btrfs_file_operations; extern struct file_operations btrfs_file_operations;
int btrfs_drop_extents(struct btrfs_trans_handle *trans, int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode, struct btrfs_root *root, struct inode *inode,

1
fs/btrfs/disk-io.h
View file

@ -77,7 +77,6 @@ int btrfs_insert_dev_radix(struct btrfs_root *root,
u64 num_blocks); u64 num_blocks);
int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh, int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
u64 logical); u64 logical);
int btrfs_releasepage(struct page *page, gfp_t flags);
void btrfs_btree_balance_dirty(struct btrfs_root *root); void btrfs_btree_balance_dirty(struct btrfs_root *root);
int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root); int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root);
void btrfs_mark_buffer_dirty(struct buffer_head *bh); void btrfs_mark_buffer_dirty(struct buffer_head *bh);

1656
fs/btrfs/extent_map.c Normal file
View file

File diff suppressed because it is too large Load diff

89
fs/btrfs/extent_map.h Normal file
View file

@ -0,0 +1,89 @@
#ifndef __EXTENTMAP__
#define __EXTENTMAP__
#include <linux/rbtree.h>
#define EXTENT_MAP_INLINE (u64)-2
#define EXTENT_MAP_DELALLOC (u64)-1
struct extent_map_tree {
struct rb_root map;
struct rb_root state;
struct address_space *mapping;
rwlock_t lock;
};
/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
struct extent_map {
u64 start;
u64 end; /* inclusive */
int in_tree;
struct rb_node rb_node;
/* block_start and block_end are in bytes */
u64 block_start;
u64 block_end; /* inclusive */
struct block_device *bdev;
atomic_t refs;
};
/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
struct extent_state {
u64 start;
u64 end; /* inclusive */
int in_tree;
struct rb_node rb_node;
wait_queue_head_t wq;
atomic_t refs;
unsigned long state;
struct list_head list;
};
struct extent_buffer {
u64 start;
u64 end; /* inclusive */
char *addr;
struct page *pages[];
};
typedef struct extent_map *(get_extent_t)(struct inode *inode,
struct page *page,
size_t page_offset,
u64 start, u64 end,
int create);
void extent_map_tree_init(struct extent_map_tree *tree,
struct address_space *mapping, gfp_t mask);
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 end);
int add_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em);
int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page);
int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
struct extent_map *alloc_extent_map(gfp_t mask);
void free_extent_map(struct extent_map *em);
int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
get_extent_t *get_extent);
void __init extent_map_init(void);
void __exit extent_map_exit(void);
int extent_clean_all_trees(struct extent_map_tree *tree);
int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask);
int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask);
int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask);
int extent_invalidatepage(struct extent_map_tree *tree,
struct page *page, unsigned long offset);
int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
get_extent_t *get_extent,
struct writeback_control *wbc);
int extent_prepare_write(struct extent_map_tree *tree,
struct inode *inode, struct page *page,
unsigned from, unsigned to, get_extent_t *get_extent);
int extent_commit_write(struct extent_map_tree *tree,
struct inode *inode, struct page *page,
unsigned from, unsigned to);
int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end);
#endif

295
fs/btrfs/file.c
View file

@ -81,14 +81,14 @@ static void btrfs_drop_pages(struct page **pages, size_t num_pages)
} }
} }
static int insert_inline_extent(struct btrfs_root *root, struct inode *inode, static int insert_inline_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
u64 offset, ssize_t size, u64 offset, ssize_t size,
struct buffer_head *bh) struct page *page, size_t page_offset)
{ {
struct btrfs_key key; struct btrfs_key key;
struct btrfs_path *path; struct btrfs_path *path;
char *ptr, *kaddr; char *ptr, *kaddr;
struct btrfs_trans_handle *trans;
struct btrfs_file_extent_item *ei; struct btrfs_file_extent_item *ei;
u32 datasize; u32 datasize;
int err = 0; int err = 0;
@ -98,8 +98,6 @@ static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
if (!path) if (!path)
return -ENOMEM; return -ENOMEM;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode); btrfs_set_trans_block_group(trans, inode);
key.objectid = inode->i_ino; key.objectid = inode->i_ino;
@ -122,18 +120,13 @@ static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
BTRFS_FILE_EXTENT_INLINE); BTRFS_FILE_EXTENT_INLINE);
ptr = btrfs_file_extent_inline_start(ei); ptr = btrfs_file_extent_inline_start(ei);
kaddr = kmap_atomic(bh->b_page, KM_USER0); kaddr = kmap_atomic(page, KM_USER0);
btrfs_memcpy(root, path->nodes[0]->b_data, btrfs_memcpy(root, path->nodes[0]->b_data,
ptr, kaddr + bh_offset(bh), ptr, kaddr + page_offset, size);
size);
kunmap_atomic(kaddr, KM_USER0); kunmap_atomic(kaddr, KM_USER0);
btrfs_mark_buffer_dirty(path->nodes[0]); btrfs_mark_buffer_dirty(path->nodes[0]);
fail: fail:
btrfs_free_path(path); btrfs_free_path(path);
ret = btrfs_end_transaction(trans, root);
if (ret && !err)
err = ret;
mutex_unlock(&root->fs_info->fs_mutex);
return err; return err;
} }
@ -145,45 +138,143 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
loff_t pos, loff_t pos,
size_t write_bytes) size_t write_bytes)
{ {
int i;
int offset;
int err = 0; int err = 0;
int ret; int i;
int this_write;
struct inode *inode = file->f_path.dentry->d_inode; struct inode *inode = file->f_path.dentry->d_inode;
struct buffer_head *bh; struct extent_map *em;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct btrfs_key ins;
u64 hint_block;
u64 num_blocks;
u64 start_pos;
u64 end_of_last_block;
u64 end_pos = pos + write_bytes;
loff_t isize = i_size_read(inode);
em = alloc_extent_map(GFP_NOFS);
if (!em)
return -ENOMEM;
em->bdev = inode->i_sb->s_bdev;
start_pos = pos & ~((u64)root->blocksize - 1);
num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
inode->i_blkbits;
end_of_last_block = start_pos + (num_blocks << inode->i_blkbits) - 1;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
goto out_unlock;
}
btrfs_set_trans_block_group(trans, inode);
inode->i_blocks += num_blocks << 3;
hint_block = 0;
if ((end_of_last_block & 4095) == 0) {
printk("strange end of last %Lu %lu %Lu\n", start_pos, write_bytes, end_of_last_block);
}
set_extent_uptodate(em_tree, start_pos, end_of_last_block, GFP_NOFS);
/* FIXME...EIEIO, ENOSPC and more */
/* step one, delete the existing extents in this range */
/* FIXME blocksize != pagesize */
if (start_pos < inode->i_size) {
err = btrfs_drop_extents(trans, root, inode,
start_pos, (pos + write_bytes + root->blocksize -1) &
~((u64)root->blocksize - 1), &hint_block);
if (err)
goto failed;
}
/* insert any holes we need to create */
if (inode->i_size < start_pos) {
u64 last_pos_in_file;
u64 hole_size;
u64 mask = root->blocksize - 1;
last_pos_in_file = (isize + mask) & ~mask;
hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
hole_size >>= inode->i_blkbits;
if (last_pos_in_file < start_pos) {
err = btrfs_insert_file_extent(trans, root,
inode->i_ino,
last_pos_in_file,
0, 0, hole_size);
}
if (err)
goto failed;
}
/*
* either allocate an extent for the new bytes or setup the key
* to show we are doing inline data in the extent
*/
if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
err = btrfs_alloc_extent(trans, root, inode->i_ino,
num_blocks, 0, hint_block, (u64)-1,
&ins, 1);
BUG_ON(err);
err = btrfs_insert_file_extent(trans, root, inode->i_ino,
start_pos, ins.objectid, ins.offset,
ins.offset);
BUG_ON(err);
em->start = start_pos;
em->end = end_of_last_block;
em->block_start = ins.objectid << inode->i_blkbits;
em->block_end = em->block_start +
(ins.offset << inode->i_blkbits) - 1;
set_extent_dirty(em_tree, start_pos, end_of_last_block,
GFP_NOFS);
err = add_extent_mapping(em_tree, em);
for (i = 0; i < num_pages; i++) { for (i = 0; i < num_pages; i++) {
offset = pos & (PAGE_CACHE_SIZE -1); struct page *p = pages[i];
this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes); SetPageUptodate(p);
__set_page_dirty_nobuffers(p);
/* FIXME, one block at a time */
bh = page_buffers(pages[i]);
if (buffer_mapped(bh) && bh->b_blocknr == 0) {
ret = insert_inline_extent(root, inode,
pages[i]->index << PAGE_CACHE_SHIFT,
offset + this_write, bh);
if (ret) {
err = ret;
goto failed;
} }
} else {
struct page *p = pages[0];
err = insert_inline_extent(trans, root, inode, start_pos,
end_pos - start_pos, p, 0);
BUG_ON(err);
em->start = start_pos;
em->end = end_pos;
em->block_start = EXTENT_MAP_INLINE;
em->block_end = EXTENT_MAP_INLINE;
add_extent_mapping(em_tree, em);
} }
if (end_pos > isize) {
ret = btrfs_commit_write(file, pages[i], offset, i_size_write(inode, end_pos);
offset + this_write); btrfs_update_inode(trans, root, inode);
pos += this_write;
if (ret) {
err = ret;
goto failed;
}
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
} }
failed: failed:
err = btrfs_end_transaction(trans, root);
out_unlock:
mutex_unlock(&root->fs_info->fs_mutex);
free_extent_map(em);
return err; return err;
} }
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
{
struct extent_map *em;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
while(1) {
em = lookup_extent_mapping(em_tree, start, end);
if (!em)
break;
remove_extent_mapping(em_tree, em);
/* once for us */
free_extent_map(em);
/* once for the tree*/
free_extent_map(em);
}
return 0;
}
/* /*
* this is very complex, but the basic idea is to drop all extents * 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 * in the range start - end. hint_block is filled in with a block number
@ -213,6 +304,8 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
int found_inline; int found_inline;
int recow; int recow;
btrfs_drop_extent_cache(inode, start, end - 1);
path = btrfs_alloc_path(); path = btrfs_alloc_path();
if (!path) if (!path)
return -ENOMEM; return -ENOMEM;
@ -434,18 +527,9 @@ static int prepare_pages(struct btrfs_root *root,
int i; int i;
unsigned long index = pos >> PAGE_CACHE_SHIFT; unsigned long index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = file->f_path.dentry->d_inode; struct inode *inode = file->f_path.dentry->d_inode;
int offset;
int err = 0; int err = 0;
int this_write;
struct buffer_head *bh;
struct buffer_head *head;
loff_t isize = i_size_read(inode);
struct btrfs_trans_handle *trans;
u64 hint_block;
u64 num_blocks; u64 num_blocks;
u64 alloc_extent_start;
u64 start_pos; u64 start_pos;
struct btrfs_key ins;
start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1); start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >> num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
@ -457,119 +541,17 @@ static int prepare_pages(struct btrfs_root *root,
pages[i] = grab_cache_page(inode->i_mapping, index + i); pages[i] = grab_cache_page(inode->i_mapping, index + i);
if (!pages[i]) { if (!pages[i]) {
err = -ENOMEM; err = -ENOMEM;
goto failed_release; BUG_ON(1);
} }
cancel_dirty_page(pages[i], PAGE_CACHE_SIZE); cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
wait_on_page_writeback(pages[i]); wait_on_page_writeback(pages[i]);
if (!PagePrivate(pages[i])) {
SetPagePrivate(pages[i]);
set_page_private(pages[i], 1);
page_cache_get(pages[i]);
} }
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
mutex_unlock(&root->fs_info->fs_mutex);
goto out_unlock;
}
btrfs_set_trans_block_group(trans, inode);
/* FIXME blocksize != 4096 */
inode->i_blocks += num_blocks << 3;
hint_block = 0;
/* FIXME...EIEIO, ENOSPC and more */
/* step one, delete the existing extents in this range */
/* FIXME blocksize != pagesize */
if (start_pos < inode->i_size) {
err = btrfs_drop_extents(trans, root, inode,
start_pos, (pos + write_bytes + root->blocksize -1) &
~((u64)root->blocksize - 1), &hint_block);
if (err)
goto failed_release;
}
/* insert any holes we need to create */
if (inode->i_size < start_pos) {
u64 last_pos_in_file;
u64 hole_size;
u64 mask = root->blocksize - 1;
last_pos_in_file = (isize + mask) & ~mask;
hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
hole_size >>= inode->i_blkbits;
if (last_pos_in_file < start_pos) {
err = btrfs_insert_file_extent(trans, root,
inode->i_ino,
last_pos_in_file,
0, 0, hole_size);
}
if (err)
goto failed_release;
}
/*
* either allocate an extent for the new bytes or setup the key
* to show we are doing inline data in the extent
*/
if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
err = btrfs_alloc_extent(trans, root, inode->i_ino,
num_blocks, 0, hint_block, (u64)-1,
&ins, 1);
if (err)
goto failed_truncate;
err = btrfs_insert_file_extent(trans, root, inode->i_ino,
start_pos, ins.objectid, ins.offset,
ins.offset);
if (err)
goto failed_truncate;
} else {
ins.offset = 0;
ins.objectid = 0;
}
BUG_ON(err);
alloc_extent_start = ins.objectid;
err = btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
for (i = 0; i < num_pages; i++) {
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
if (!page_has_buffers(pages[i])) {
create_empty_buffers(pages[i],
root->fs_info->sb->s_blocksize,
(1 << BH_Uptodate));
}
head = page_buffers(pages[i]);
bh = head;
do {
err = btrfs_map_bh_to_logical(root, bh,
alloc_extent_start);
BUG_ON(err);
if (err)
goto failed_truncate;
bh = bh->b_this_page;
if (alloc_extent_start)
alloc_extent_start++;
} while (bh != head);
pos += this_write;
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
} }
return 0; return 0;
failed_release:
btrfs_drop_pages(pages, num_pages);
return err;
failed_truncate:
btrfs_drop_pages(pages, num_pages);
if (pos > isize)
vmtruncate(inode, isize);
return err;
out_unlock:
mutex_unlock(&root->fs_info->fs_mutex);
goto failed_release;
} }
static ssize_t btrfs_file_write(struct file *file, const char __user *buf, static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
@ -685,7 +667,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
page_cache_release(pinned[1]); page_cache_release(pinned[1]);
*ppos = pos; *ppos = pos;
current->backing_dev_info = NULL; current->backing_dev_info = NULL;
mark_inode_dirty(inode);
return num_written ? num_written : err; return num_written ? num_written : err;
} }

838
fs/btrfs/inode.c
View file

@ -121,6 +121,8 @@ void btrfs_read_locked_inode(struct inode *inode)
switch (inode->i_mode & S_IFMT) { switch (inode->i_mode & S_IFMT) {
case S_IFREG: case S_IFREG:
inode->i_mapping->a_ops = &btrfs_aops; inode->i_mapping->a_ops = &btrfs_aops;
extent_map_tree_init(&BTRFS_I(inode)->extent_tree,
inode->i_mapping, GFP_NOFS);
inode->i_fop = &btrfs_file_operations; inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations; inode->i_op = &btrfs_file_inode_operations;
break; break;
@ -169,7 +171,7 @@ static void fill_inode_item(struct btrfs_inode_item *item,
BTRFS_I(inode)->block_group->key.objectid); BTRFS_I(inode)->block_group->key.objectid);
} }
static int btrfs_update_inode(struct btrfs_trans_handle *trans, int btrfs_update_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_root *root,
struct inode *inode) struct inode *inode)
{ {
@ -400,6 +402,7 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
int found_extent; int found_extent;
int del_item; int del_item;
btrfs_drop_extent_cache(inode, inode->i_size, (u64)-1);
path = btrfs_alloc_path(); path = btrfs_alloc_path();
path->reada = -1; path->reada = -1;
BUG_ON(!path); BUG_ON(!path);
@ -511,47 +514,27 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
return ret; return ret;
} }
/* static int btrfs_cow_one_page(struct btrfs_trans_handle *trans,
* taken from block_truncate_page, but does cow as it zeros out struct inode *inode, struct page *page,
* any bytes left in the last page in the file. size_t zero_start)
*/
static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
{ {
struct inode *inode = mapping->host;
unsigned blocksize = 1 << inode->i_blkbits;
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
struct page *page;
char *kaddr; char *kaddr;
int ret = 0; int ret = 0;
struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_root *root = BTRFS_I(inode)->root;
u64 alloc_hint = 0; u64 alloc_hint = 0;
u64 page_start = page->index << PAGE_CACHE_SHIFT;
struct btrfs_key ins; struct btrfs_key ins;
struct btrfs_trans_handle *trans;
if ((offset & (blocksize - 1)) == 0) if (!PagePrivate(page)) {
goto out; SetPagePrivate(page);
set_page_private(page, 1);
ret = -ENOMEM; page_cache_get(page);
page = grab_cache_page(mapping, index);
if (!page)
goto out;
if (!PageUptodate(page)) {
ret = btrfs_readpage(NULL, page);
lock_page(page);
if (!PageUptodate(page)) {
ret = -EIO;
goto out;
} }
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode); btrfs_set_trans_block_group(trans, inode);
ret = btrfs_drop_extents(trans, root, inode, ret = btrfs_drop_extents(trans, root, inode,
page->index << PAGE_CACHE_SHIFT, page_start, page_start + PAGE_CACHE_SIZE,
(page->index + 1) << PAGE_CACHE_SHIFT,
&alloc_hint); &alloc_hint);
if (ret) if (ret)
goto out; goto out;
@ -560,22 +543,70 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
if (ret) if (ret)
goto out; goto out;
ret = btrfs_insert_file_extent(trans, root, inode->i_ino, ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
page->index << PAGE_CACHE_SHIFT, page_start, ins.objectid, 1, 1);
ins.objectid, 1, 1);
if (ret) if (ret)
goto out; goto out;
SetPageChecked(page); SetPageChecked(page);
kaddr = kmap(page); kaddr = kmap(page);
memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); if (zero_start != PAGE_CACHE_SIZE) {
memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
flush_dcache_page(page); flush_dcache_page(page);
ret = btrfs_csum_file_block(trans, root, inode->i_ino, }
page->index << PAGE_CACHE_SHIFT,
kaddr, PAGE_CACHE_SIZE);
kunmap(page); kunmap(page);
out:
return ret;
}
/*
* taken from block_truncate_page, but does cow as it zeros out
* any bytes left in the last page in the file.
*/
static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
{
struct inode *inode = mapping->host;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
unsigned blocksize = 1 << inode->i_blkbits;
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
struct page *page;
int ret = 0;
u64 page_start;
if ((offset & (blocksize - 1)) == 0)
goto out;
ret = -ENOMEM;
page = grab_cache_page(mapping, index);
if (!page)
goto out;
if (!PageUptodate(page)) {
ret = btrfs_readpage(NULL, page);
lock_page(page);
if (!PageUptodate(page)) {
ret = -EIO;
goto out;
}
}
page_start = page->index << PAGE_CACHE_SHIFT;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
ret = btrfs_cow_one_page(trans, inode, page, offset);
if (!ret) {
char *kaddr = kmap(page);
ret = btrfs_csum_file_block(trans, root, inode->i_ino,
page_start, kaddr, PAGE_CACHE_SIZE);
kunmap(page);
}
set_extent_dirty(&BTRFS_I(inode)->extent_tree,
page_start, page_start + PAGE_CACHE_SIZE - 1,
GFP_NOFS);
set_page_dirty(page);
btrfs_end_transaction(trans, root); btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex); mutex_unlock(&root->fs_info->fs_mutex);
set_page_dirty(page);
unlock_page(page); unlock_page(page);
page_cache_release(page); page_cache_release(page);
out: out:
@ -1095,6 +1126,8 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
inode->i_mapping->a_ops = &btrfs_aops; inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations; inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations; inode->i_op = &btrfs_file_inode_operations;
extent_map_tree_init(&BTRFS_I(inode)->extent_tree,
inode->i_mapping, GFP_NOFS);
} }
dir->i_sb->s_dirt = 1; dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, inode); btrfs_update_inode_block_group(trans, inode);
@ -1238,6 +1271,182 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
return err; return err;
} }
struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
size_t page_offset, u64 start, u64 end,
int create)
{
int ret;
int err = 0;
u64 blocknr;
u64 extent_start = 0;
u64 extent_end = 0;
u64 objectid = inode->i_ino;
u32 found_type;
int failed_insert = 0;
struct btrfs_path *path;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_file_extent_item *item;
struct btrfs_leaf *leaf;
struct btrfs_disk_key *found_key;
struct extent_map *em = NULL;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct btrfs_trans_handle *trans = NULL;
path = btrfs_alloc_path();
BUG_ON(!path);
mutex_lock(&root->fs_info->fs_mutex);
again:
em = lookup_extent_mapping(em_tree, start, end);
if (em) {
goto out;
}
if (!em) {
em = alloc_extent_map(GFP_NOFS);
if (!em) {
err = -ENOMEM;
goto out;
}
em->start = 0;
em->end = 0;
}
em->bdev = inode->i_sb->s_bdev;
ret = btrfs_lookup_file_extent(NULL, root, path,
objectid, start, 0);
if (ret < 0) {
err = ret;
goto out;
}
if (ret != 0) {
if (path->slots[0] == 0)
goto not_found;
path->slots[0]--;
}
item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_file_extent_item);
leaf = btrfs_buffer_leaf(path->nodes[0]);
blocknr = btrfs_file_extent_disk_blocknr(item);
blocknr += btrfs_file_extent_offset(item);
/* are we inside the extent that was found? */
found_key = &leaf->items[path->slots[0]].key;
found_type = btrfs_disk_key_type(found_key);
if (btrfs_disk_key_objectid(found_key) != objectid ||
found_type != BTRFS_EXTENT_DATA_KEY) {
goto not_found;
}
found_type = btrfs_file_extent_type(item);
extent_start = btrfs_disk_key_offset(&leaf->items[path->slots[0]].key);
if (found_type == BTRFS_FILE_EXTENT_REG) {
extent_end = extent_start +
(btrfs_file_extent_num_blocks(item) << inode->i_blkbits);
err = 0;
if (start < extent_start || start > extent_end) {
em->start = start;
if (start < extent_start) {
em->end = extent_end - 1;
} else {
em->end = end;
}
goto not_found_em;
}
if (btrfs_file_extent_disk_blocknr(item) == 0) {
em->start = extent_start;
em->end = extent_end - 1;
em->block_start = 0;
em->block_end = 0;
goto insert;
}
em->block_start = blocknr << inode->i_blkbits;
em->block_end = em->block_start +
(btrfs_file_extent_num_blocks(item) <<
inode->i_blkbits) - 1;
em->start = extent_start;
em->end = extent_end - 1;
goto insert;
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
char *ptr;
char *map;
u32 size;
size = btrfs_file_extent_inline_len(leaf->items +
path->slots[0]);
extent_end = extent_start + size;
if (start < extent_start || start > extent_end) {
em->start = start;
if (start < extent_start) {
em->end = extent_end - 1;
} else {
em->end = end;
}
goto not_found_em;
}
em->block_start = EXTENT_MAP_INLINE;
em->block_end = EXTENT_MAP_INLINE;
em->start = extent_start;
em->end = extent_end - 1;
if (!page) {
goto insert;
}
ptr = btrfs_file_extent_inline_start(item);
map = kmap(page);
memcpy(map + page_offset, ptr, size);
flush_dcache_page(result->b_page);
kunmap(page);
set_extent_uptodate(em_tree, extent_start,
extent_end, GFP_NOFS);
goto insert;
} else {
printk("unkknown found_type %d\n", found_type);
WARN_ON(1);
}
not_found:
em->start = start;
em->end = end;
not_found_em:
em->block_start = 0;
em->block_end = 0;
insert:
btrfs_release_path(root, path);
if (em->start > start || em->end < start) {
printk("bad extent! %Lu %Lu start %Lu end %Lu\n", em->start, em->end, start, end);
WARN_ON(1);
err = -EIO;
goto out;
}
ret = add_extent_mapping(em_tree, em);
if (ret == -EEXIST) {
free_extent_map(em);
failed_insert++;
if (failed_insert > 5) {
printk("failing to insert %Lu %Lu\n", start, end);
err = -EIO;
goto out;
}
em = NULL;
goto again;
}
err = 0;
out:
btrfs_free_path(path);
if (trans) {
ret = btrfs_end_transaction(trans, root);
if (!err)
err = ret;
}
mutex_unlock(&root->fs_info->fs_mutex);
if (err) {
free_extent_map(em);
WARN_ON(1);
return ERR_PTR(err);
}
return em;
}
/* /*
* FIBMAP and others want to pass in a fake buffer head. They need to * FIBMAP and others want to pass in a fake buffer head. They need to
* use BTRFS_GET_BLOCK_NO_DIRECT to make sure we don't try to memcpy * use BTRFS_GET_BLOCK_NO_DIRECT to make sure we don't try to memcpy
@ -1398,46 +1607,22 @@ int btrfs_get_block(struct inode *inode, sector_t iblock,
return err; return err;
} }
static int btrfs_get_block_csum(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create)
{
int ret;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct page *page = result->b_page;
u64 offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(result);
struct btrfs_csum_item *item;
struct btrfs_path *path = NULL;
mutex_lock(&root->fs_info->fs_mutex);
ret = btrfs_get_block_lock(inode, iblock, result, create);
if (ret)
goto out;
path = btrfs_alloc_path();
item = btrfs_lookup_csum(NULL, root, path, inode->i_ino, offset, 0);
if (IS_ERR(item)) {
ret = PTR_ERR(item);
/* a csum that isn't present is a preallocated region. */
if (ret == -ENOENT || ret == -EFBIG)
ret = 0;
result->b_private = NULL;
goto out;
}
memcpy((char *)&result->b_private, &item->csum, BTRFS_CRC32_SIZE);
out:
if (path)
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
return ret;
}
static int btrfs_get_block_bmap(struct inode *inode, sector_t iblock, static int btrfs_get_block_bmap(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create) struct buffer_head *result, int create)
{ {
struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_root *root = BTRFS_I(inode)->root;
mutex_lock(&root->fs_info->fs_mutex); u64 start = iblock << inode->i_blkbits;
btrfs_get_block_lock(inode, iblock, result, BTRFS_GET_BLOCK_NO_DIRECT); u64 end = start + root->blocksize -1;
mutex_unlock(&root->fs_info->fs_mutex); struct extent_map *em;
em = btrfs_get_extent(inode, NULL, 0, start, end, 0);
if (em && !IS_ERR(em) && em->block_start != EXTENT_MAP_INLINE &&
em->block_start != 0) {
u64 offset;
offset = start - em->start;
start = (em->block_start + offset) >> inode->i_blkbits;
btrfs_map_bh_to_logical(root, result, start);
}
return 0; return 0;
} }
@ -1449,442 +1634,50 @@ static sector_t btrfs_bmap(struct address_space *as, sector_t block)
static int btrfs_prepare_write(struct file *file, struct page *page, static int btrfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to) unsigned from, unsigned to)
{ {
return block_prepare_write(page, from, to, btrfs_get_block); return extent_prepare_write(&BTRFS_I(page->mapping->host)->extent_tree,
page->mapping->host, page, from, to,
btrfs_get_extent);
} }
static void buffer_io_error(struct buffer_head *bh)
{
char b[BDEVNAME_SIZE];
printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
bdevname(bh->b_bdev, b),
(unsigned long long)bh->b_blocknr);
}
/*
* I/O completion handler for block_read_full_page() - pages
* which come unlocked at the end of I/O.
*/
static void btrfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
{
unsigned long flags;
struct buffer_head *first;
struct buffer_head *tmp;
struct page *page;
int page_uptodate = 1;
struct inode *inode;
int ret;
BUG_ON(!buffer_async_read(bh));
page = bh->b_page;
inode = page->mapping->host;
if (uptodate) {
void *kaddr;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
if (bh->b_private) {
char csum[BTRFS_CRC32_SIZE];
kaddr = kmap_atomic(page, KM_IRQ0);
ret = btrfs_csum_data(root, kaddr + bh_offset(bh),
bh->b_size, csum);
BUG_ON(ret);
if (memcmp(csum, &bh->b_private, BTRFS_CRC32_SIZE)) {
u64 offset;
offset = (page->index << PAGE_CACHE_SHIFT) +
bh_offset(bh);
printk("btrfs csum failed ino %lu off %llu\n",
page->mapping->host->i_ino,
(unsigned long long)offset);
memset(kaddr + bh_offset(bh), 1, bh->b_size);
flush_dcache_page(page);
}
kunmap_atomic(kaddr, KM_IRQ0);
}
set_buffer_uptodate(bh);
} else {
clear_buffer_uptodate(bh);
if (printk_ratelimit())
buffer_io_error(bh);
SetPageError(page);
}
/*
* Be _very_ careful from here on. Bad things can happen if
* two buffer heads end IO at almost the same time and both
* decide that the page is now completely done.
*/
first = page_buffers(page);
local_irq_save(flags);
bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
clear_buffer_async_read(bh);
unlock_buffer(bh);
tmp = bh;
do {
if (!buffer_uptodate(tmp))
page_uptodate = 0;
if (buffer_async_read(tmp)) {
BUG_ON(!buffer_locked(tmp));
goto still_busy;
}
tmp = tmp->b_this_page;
} while (tmp != bh);
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
local_irq_restore(flags);
/*
* If none of the buffers had errors and they are all
* uptodate then we can set the page uptodate.
*/
if (page_uptodate && !PageError(page))
SetPageUptodate(page);
unlock_page(page);
return;
still_busy:
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
local_irq_restore(flags);
return;
}
/*
* Generic "read page" function for block devices that have the normal
* get_block functionality. This is most of the block device filesystems.
* Reads the page asynchronously --- the unlock_buffer() and
* set/clear_buffer_uptodate() functions propagate buffer state into the
* page struct once IO has completed.
*/
int btrfs_readpage(struct file *file, struct page *page) int btrfs_readpage(struct file *file, struct page *page)
{ {
struct inode *inode = page->mapping->host; struct extent_map_tree *tree;
sector_t iblock, lblock; tree = &BTRFS_I(page->mapping->host)->extent_tree;
struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; return extent_read_full_page(tree, page, btrfs_get_extent);
unsigned int blocksize;
int nr, i;
int fully_mapped = 1;
BUG_ON(!PageLocked(page));
blocksize = 1 << inode->i_blkbits;
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
head = page_buffers(page);
iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits;
bh = head;
nr = 0;
i = 0;
do {
if (buffer_uptodate(bh))
continue;
if (!buffer_mapped(bh)) {
int err = 0;
fully_mapped = 0;
if (iblock < lblock) {
WARN_ON(bh->b_size != blocksize);
err = btrfs_get_block_csum(inode, iblock,
bh, 0);
if (err)
SetPageError(page);
} }
if (!buffer_mapped(bh)) {
void *kaddr = kmap_atomic(page, KM_USER0);
memset(kaddr + i * blocksize, 0, blocksize);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
if (!err)
set_buffer_uptodate(bh);
continue;
}
/*
* get_block() might have updated the buffer
* synchronously
*/
if (buffer_uptodate(bh))
continue;
}
arr[nr++] = bh;
} while (i++, iblock++, (bh = bh->b_this_page) != head);
if (fully_mapped)
SetPageMappedToDisk(page);
if (!nr) {
/*
* All buffers are uptodate - we can set the page uptodate
* as well. But not if get_block() returned an error.
*/
if (!PageError(page))
SetPageUptodate(page);
unlock_page(page);
return 0;
}
/* Stage two: lock the buffers */
for (i = 0; i < nr; i++) {
bh = arr[i];
lock_buffer(bh);
bh->b_end_io = btrfs_end_buffer_async_read;
set_buffer_async_read(bh);
}
/*
* Stage 3: start the IO. Check for uptodateness
* inside the buffer lock in case another process reading
* the underlying blockdev brought it uptodate (the sct fix).
*/
for (i = 0; i < nr; i++) {
bh = arr[i];
if (buffer_uptodate(bh))
btrfs_end_buffer_async_read(bh, 1);
else
submit_bh(READ, bh);
}
return 0;
}
/*
* Aside from a tiny bit of packed file data handling, this is the
* same as the generic code.
*
* While block_write_full_page is writing back the dirty buffers under
* the page lock, whoever dirtied the buffers may decide to clean them
* again at any time. We handle that by only looking at the buffer
* state inside lock_buffer().
*
* If block_write_full_page() is called for regular writeback
* (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a
* locked buffer. This only can happen if someone has written the buffer
* directly, with submit_bh(). At the address_space level PageWriteback
* prevents this contention from occurring.
*/
static int __btrfs_write_full_page(struct inode *inode, struct page *page,
struct writeback_control *wbc)
{
int err;
sector_t block;
sector_t last_block;
struct buffer_head *bh, *head;
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
struct btrfs_root *root = BTRFS_I(inode)->root;
BUG_ON(!PageLocked(page));
last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
/* no csumming allowed when from PF_MEMALLOC */
if (current->flags & PF_MEMALLOC) {
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
if (!page_has_buffers(page)) {
create_empty_buffers(page, blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
}
/*
* Be very careful. We have no exclusion from __set_page_dirty_buffers
* here, and the (potentially unmapped) buffers may become dirty at
* any time. If a buffer becomes dirty here after we've inspected it
* then we just miss that fact, and the page stays dirty.
*
* Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
* handle that here by just cleaning them.
*/
block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
head = page_buffers(page);
bh = head;
/*
* Get all the dirty buffers mapped to disk addresses and
* handle any aliases from the underlying blockdev's mapping.
*/
do {
if (block > last_block) {
/*
* mapped buffers outside i_size will occur, because
* this page can be outside i_size when there is a
* truncate in progress.
*/
/*
* The buffer was zeroed by block_write_full_page()
*/
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
} else if (!buffer_mapped(bh) && buffer_dirty(bh)) {
WARN_ON(bh->b_size != blocksize);
err = btrfs_get_block(inode, block, bh, 0);
if (err) {
goto recover;
}
if (buffer_new(bh)) {
/* blockdev mappings never come here */
clear_buffer_new(bh);
}
}
bh = bh->b_this_page;
block++;
} while (bh != head);
do {
if (!buffer_mapped(bh))
continue;
/*
* If it's a fully non-blocking write attempt and we cannot
* lock the buffer then redirty the page. Note that this can
* potentially cause a busy-wait loop from pdflush and kswapd
* activity, but those code paths have their own higher-level
* throttling.
*/
if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
lock_buffer(bh);
} else if (test_set_buffer_locked(bh)) {
redirty_page_for_writepage(wbc, page);
continue;
}
if (test_clear_buffer_dirty(bh) && bh->b_blocknr != 0) {
struct btrfs_trans_handle *trans;
int ret;
u64 off = page->index << PAGE_CACHE_SHIFT;
char *kaddr;
off += bh_offset(bh);
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
kaddr = kmap(page);
btrfs_csum_file_block(trans, root, inode->i_ino,
off, kaddr + bh_offset(bh),
bh->b_size);
kunmap(page);
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
mark_buffer_async_write(bh);
} else {
unlock_buffer(bh);
}
} while ((bh = bh->b_this_page) != head);
/*
* The page and its buffers are protected by PageWriteback(), so we can
* drop the bh refcounts early.
*/
BUG_ON(PageWriteback(page));
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
submit_bh(WRITE, bh);
nr_underway++;
}
bh = next;
} while (bh != head);
unlock_page(page);
err = 0;
done:
if (nr_underway == 0) {
/*
* The page was marked dirty, but the buffers were
* clean. Someone wrote them back by hand with
* ll_rw_block/submit_bh. A rare case.
*/
int uptodate = 1;
do {
if (!buffer_uptodate(bh)) {
uptodate = 0;
break;
}
bh = bh->b_this_page;
} while (bh != head);
if (uptodate)
SetPageUptodate(page);
end_page_writeback(page);
}
return err;
recover:
/*
* ENOSPC, or some other error. We may already have added some
* blocks to the file, so we need to write these out to avoid
* exposing stale data.
* The page is currently locked and not marked for writeback
*/
bh = head;
/* Recovery: lock and submit the mapped buffers */
do {
if (buffer_mapped(bh) && buffer_dirty(bh)) {
lock_buffer(bh);
mark_buffer_async_write(bh);
} else {
/*
* The buffer may have been set dirty during
* attachment to a dirty page.
*/
clear_buffer_dirty(bh);
}
} while ((bh = bh->b_this_page) != head);
SetPageError(page);
BUG_ON(PageWriteback(page));
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
clear_buffer_dirty(bh);
submit_bh(WRITE, bh);
nr_underway++;
}
bh = next;
} while (bh != head);
unlock_page(page);
goto done;
}
static int btrfs_writepage(struct page *page, struct writeback_control *wbc) static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
{ {
struct inode * const inode = page->mapping->host; struct extent_map_tree *tree;
loff_t i_size = i_size_read(inode); tree = &BTRFS_I(page->mapping->host)->extent_tree;
const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
unsigned offset;
void *kaddr;
/* Is the page fully inside i_size? */
if (page->index < end_index)
return __btrfs_write_full_page(inode, page, wbc);
/* Is the page fully outside i_size? (truncate in progress) */
offset = i_size & (PAGE_CACHE_SIZE-1);
if (page->index >= end_index+1 || !offset) {
/*
* The page may have dirty, unmapped buffers. For example,
* they may have been added in ext3_writepage(). Make them
* freeable here, so the page does not leak.
*/
block_invalidatepage(page, 0);
unlock_page(page);
return 0; /* don't care */
} }
/* static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags)
* The page straddles i_size. It must be zeroed out on each and every {
* writepage invokation because it may be mmapped. "A file is mapped struct extent_map_tree *tree;
* in multiples of the page size. For a file that is not a multiple of int ret;
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file." if (page->private != 1) {
*/ WARN_ON(1);
kaddr = kmap_atomic(page, KM_USER0); return try_to_free_buffers(page);
memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); }
flush_dcache_page(page); tree = &BTRFS_I(page->mapping->host)->extent_tree;
kunmap_atomic(kaddr, KM_USER0); ret = try_release_extent_mapping(tree, page);
return __btrfs_write_full_page(inode, page, wbc); if (ret == 1) {
ClearPagePrivate(page);
set_page_private(page, 0);
page_cache_release(page);
}
return ret;
}
static void btrfs_invalidatepage(struct page *page, unsigned long offset)
{
struct extent_map_tree *tree;
tree = &BTRFS_I(page->mapping->host)->extent_tree;
extent_invalidatepage(tree, page, offset);
btrfs_releasepage(page, GFP_NOFS);
} }
/* /*
@ -1905,28 +1698,39 @@ static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page) int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
{ {
struct inode *inode = vma->vm_file->f_path.dentry->d_inode; struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
unsigned long end; unsigned long end;
loff_t size; loff_t size;
int ret = -EINVAL; int ret = -EINVAL;
u64 page_start;
lock_page(page); lock_page(page);
wait_on_page_writeback(page); wait_on_page_writeback(page);
size = i_size_read(inode); size = i_size_read(inode);
page_start = page->index << PAGE_CACHE_SHIFT;
if ((page->mapping != inode->i_mapping) || if ((page->mapping != inode->i_mapping) ||
((page->index << PAGE_CACHE_SHIFT) > size)) { (page_start > size)) {
/* page got truncated out from underneath us */ /* page got truncated out from underneath us */
goto out_unlock; goto out_unlock;
} }
/* page is wholly or partially inside EOF */ /* page is wholly or partially inside EOF */
if (((page->index + 1) << PAGE_CACHE_SHIFT) > size) if (page_start + PAGE_CACHE_SIZE > size)
end = size & ~PAGE_CACHE_MASK; end = size & ~PAGE_CACHE_MASK;
else else
end = PAGE_CACHE_SIZE; end = PAGE_CACHE_SIZE;
ret = btrfs_prepare_write(NULL, page, 0, end); mutex_lock(&root->fs_info->fs_mutex);
if (!ret) trans = btrfs_start_transaction(root, 1);
ret = btrfs_commit_write(NULL, page, 0, end); ret = btrfs_cow_one_page(trans, inode, page, end);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
set_extent_dirty(&BTRFS_I(inode)->extent_tree,
page_start, page_start + PAGE_CACHE_SIZE - 1,
GFP_NOFS);
set_page_dirty(page);
out_unlock: out_unlock:
unlock_page(page); unlock_page(page);
@ -1962,21 +1766,8 @@ static void btrfs_truncate(struct inode *inode)
int btrfs_commit_write(struct file *file, struct page *page, int btrfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to) unsigned from, unsigned to)
{ {
struct inode *inode = page->mapping->host; return extent_commit_write(&BTRFS_I(page->mapping->host)->extent_tree,
struct buffer_head *bh; page->mapping->host, page, from, to);
loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
SetPageUptodate(page);
bh = page_buffers(page);
set_buffer_uptodate(bh);
if (buffer_mapped(bh) && bh->b_blocknr != 0) {
set_page_dirty(page);
}
if (pos > inode->i_size) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
}
return 0;
} }
static int create_subvol(struct btrfs_root *root, char *name, int namelen) static int create_subvol(struct btrfs_root *root, char *name, int namelen)
@ -2471,6 +2262,8 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
inode->i_mapping->a_ops = &btrfs_aops; inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations; inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations; inode->i_op = &btrfs_file_inode_operations;
extent_map_tree_init(&BTRFS_I(inode)->extent_tree,
inode->i_mapping, GFP_NOFS);
} }
dir->i_sb->s_dirt = 1; dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, inode); btrfs_update_inode_block_group(trans, inode);
@ -2553,6 +2346,9 @@ static struct address_space_operations btrfs_aops = {
.prepare_write = btrfs_prepare_write, .prepare_write = btrfs_prepare_write,
.commit_write = btrfs_commit_write, .commit_write = btrfs_commit_write,
.bmap = btrfs_bmap, .bmap = btrfs_bmap,
.invalidatepage = btrfs_invalidatepage,
.releasepage = btrfs_releasepage,
.set_page_dirty = __set_page_dirty_nobuffers,
}; };
static struct address_space_operations btrfs_symlink_aops = { static struct address_space_operations btrfs_symlink_aops = {

2
fs/btrfs/super.c
View file

@ -185,6 +185,7 @@ static int __init init_btrfs_fs(void)
err = btrfs_init_cachep(); err = btrfs_init_cachep();
if (err) if (err)
return err; return err;
extent_map_init();
return register_filesystem(&btrfs_fs_type); return register_filesystem(&btrfs_fs_type);
} }
@ -192,6 +193,7 @@ static void __exit exit_btrfs_fs(void)
{ {
btrfs_exit_transaction_sys(); btrfs_exit_transaction_sys();
btrfs_destroy_cachep(); btrfs_destroy_cachep();
extent_map_exit();
unregister_filesystem(&btrfs_fs_type); unregister_filesystem(&btrfs_fs_type);
} }