linux/fs/btrfs/send.c

4658 lines
103 KiB
C
Raw Normal View History

/*
* Copyright (C) 2012 Alexander Block. 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/bsearch.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/sort.h>
#include <linux/mount.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/radix-tree.h>
#include <linux/crc32c.h>
Btrfs: using vmalloc and friends needs vmalloc.h On powerpc, we don't get the implicit vmalloc.h include, and as a result the build fails noisily: fs/btrfs/send.c: In function 'fs_path_free': fs/btrfs/send.c:185:4: error: implicit declaration of function 'vfree' [-Werror=implicit-function-declaration] fs/btrfs/send.c: In function 'fs_path_ensure_buf': fs/btrfs/send.c:215:4: error: implicit declaration of function 'vmalloc' [-Werror=implicit-function-declaration] fs/btrfs/send.c:215:12: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c:225:12: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c:233:13: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c: In function 'iterate_dir_item': fs/btrfs/send.c:900:10: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c:909:11: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c: In function 'btrfs_ioctl_send': fs/btrfs/send.c:4463:17: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c:4469:17: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c:4475:2: error: implicit declaration of function 'vzalloc' [-Werror=implicit-function-declaration] fs/btrfs/send.c:4475:20: warning: assignment makes pointer from integer without a cast [enabled by default] fs/btrfs/send.c:4483:21: warning: assignment makes pointer from integer without a cast [enabled by default] Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-27 00:11:13 +00:00
#include <linux/vmalloc.h>
#include "send.h"
#include "backref.h"
#include "locking.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "transaction.h"
static int g_verbose = 0;
#define verbose_printk(...) if (g_verbose) printk(__VA_ARGS__)
/*
* A fs_path is a helper to dynamically build path names with unknown size.
* It reallocates the internal buffer on demand.
* It allows fast adding of path elements on the right side (normal path) and
* fast adding to the left side (reversed path). A reversed path can also be
* unreversed if needed.
*/
struct fs_path {
union {
struct {
char *start;
char *end;
char *prepared;
char *buf;
int buf_len;
int reversed:1;
int virtual_mem:1;
char inline_buf[];
};
char pad[PAGE_SIZE];
};
};
#define FS_PATH_INLINE_SIZE \
(sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf))
/* reused for each extent */
struct clone_root {
struct btrfs_root *root;
u64 ino;
u64 offset;
u64 found_refs;
};
#define SEND_CTX_MAX_NAME_CACHE_SIZE 128
#define SEND_CTX_NAME_CACHE_CLEAN_SIZE (SEND_CTX_MAX_NAME_CACHE_SIZE * 2)
struct send_ctx {
struct file *send_filp;
loff_t send_off;
char *send_buf;
u32 send_size;
u32 send_max_size;
u64 total_send_size;
u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
struct vfsmount *mnt;
struct btrfs_root *send_root;
struct btrfs_root *parent_root;
struct clone_root *clone_roots;
int clone_roots_cnt;
/* current state of the compare_tree call */
struct btrfs_path *left_path;
struct btrfs_path *right_path;
struct btrfs_key *cmp_key;
/*
* infos of the currently processed inode. In case of deleted inodes,
* these are the values from the deleted inode.
*/
u64 cur_ino;
u64 cur_inode_gen;
int cur_inode_new;
int cur_inode_new_gen;
int cur_inode_deleted;
u64 cur_inode_size;
u64 cur_inode_mode;
u64 send_progress;
struct list_head new_refs;
struct list_head deleted_refs;
struct radix_tree_root name_cache;
struct list_head name_cache_list;
int name_cache_size;
struct file *cur_inode_filp;
char *read_buf;
};
struct name_cache_entry {
struct list_head list;
/*
* radix_tree has only 32bit entries but we need to handle 64bit inums.
* We use the lower 32bit of the 64bit inum to store it in the tree. If
* more then one inum would fall into the same entry, we use radix_list
* to store the additional entries. radix_list is also used to store
* entries where two entries have the same inum but different
* generations.
*/
struct list_head radix_list;
u64 ino;
u64 gen;
u64 parent_ino;
u64 parent_gen;
int ret;
int need_later_update;
int name_len;
char name[];
};
static void fs_path_reset(struct fs_path *p)
{
if (p->reversed) {
p->start = p->buf + p->buf_len - 1;
p->end = p->start;
*p->start = 0;
} else {
p->start = p->buf;
p->end = p->start;
*p->start = 0;
}
}
static struct fs_path *fs_path_alloc(struct send_ctx *sctx)
{
struct fs_path *p;
p = kmalloc(sizeof(*p), GFP_NOFS);
if (!p)
return NULL;
p->reversed = 0;
p->virtual_mem = 0;
p->buf = p->inline_buf;
p->buf_len = FS_PATH_INLINE_SIZE;
fs_path_reset(p);
return p;
}
static struct fs_path *fs_path_alloc_reversed(struct send_ctx *sctx)
{
struct fs_path *p;
p = fs_path_alloc(sctx);
if (!p)
return NULL;
p->reversed = 1;
fs_path_reset(p);
return p;
}
static void fs_path_free(struct send_ctx *sctx, struct fs_path *p)
{
if (!p)
return;
if (p->buf != p->inline_buf) {
if (p->virtual_mem)
vfree(p->buf);
else
kfree(p->buf);
}
kfree(p);
}
static int fs_path_len(struct fs_path *p)
{
return p->end - p->start;
}
static int fs_path_ensure_buf(struct fs_path *p, int len)
{
char *tmp_buf;
int path_len;
int old_buf_len;
len++;
if (p->buf_len >= len)
return 0;
path_len = p->end - p->start;
old_buf_len = p->buf_len;
len = PAGE_ALIGN(len);
if (p->buf == p->inline_buf) {
tmp_buf = kmalloc(len, GFP_NOFS);
if (!tmp_buf) {
tmp_buf = vmalloc(len);
if (!tmp_buf)
return -ENOMEM;
p->virtual_mem = 1;
}
memcpy(tmp_buf, p->buf, p->buf_len);
p->buf = tmp_buf;
p->buf_len = len;
} else {
if (p->virtual_mem) {
tmp_buf = vmalloc(len);
if (!tmp_buf)
return -ENOMEM;
memcpy(tmp_buf, p->buf, p->buf_len);
vfree(p->buf);
} else {
tmp_buf = krealloc(p->buf, len, GFP_NOFS);
if (!tmp_buf) {
tmp_buf = vmalloc(len);
if (!tmp_buf)
return -ENOMEM;
memcpy(tmp_buf, p->buf, p->buf_len);
kfree(p->buf);
p->virtual_mem = 1;
}
}
p->buf = tmp_buf;
p->buf_len = len;
}
if (p->reversed) {
tmp_buf = p->buf + old_buf_len - path_len - 1;
p->end = p->buf + p->buf_len - 1;
p->start = p->end - path_len;
memmove(p->start, tmp_buf, path_len + 1);
} else {
p->start = p->buf;
p->end = p->start + path_len;
}
return 0;
}
static int fs_path_prepare_for_add(struct fs_path *p, int name_len)
{
int ret;
int new_len;
new_len = p->end - p->start + name_len;
if (p->start != p->end)
new_len++;
ret = fs_path_ensure_buf(p, new_len);
if (ret < 0)
goto out;
if (p->reversed) {
if (p->start != p->end)
*--p->start = '/';
p->start -= name_len;
p->prepared = p->start;
} else {
if (p->start != p->end)
*p->end++ = '/';
p->prepared = p->end;
p->end += name_len;
*p->end = 0;
}
out:
return ret;
}
static int fs_path_add(struct fs_path *p, const char *name, int name_len)
{
int ret;
ret = fs_path_prepare_for_add(p, name_len);
if (ret < 0)
goto out;
memcpy(p->prepared, name, name_len);
p->prepared = NULL;
out:
return ret;
}
static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
{
int ret;
ret = fs_path_prepare_for_add(p, p2->end - p2->start);
if (ret < 0)
goto out;
memcpy(p->prepared, p2->start, p2->end - p2->start);
p->prepared = NULL;
out:
return ret;
}
static int fs_path_add_from_extent_buffer(struct fs_path *p,
struct extent_buffer *eb,
unsigned long off, int len)
{
int ret;
ret = fs_path_prepare_for_add(p, len);
if (ret < 0)
goto out;
read_extent_buffer(eb, p->prepared, off, len);
p->prepared = NULL;
out:
return ret;
}
#if 0
static void fs_path_remove(struct fs_path *p)
{
BUG_ON(p->reversed);
while (p->start != p->end && *p->end != '/')
p->end--;
*p->end = 0;
}
#endif
static int fs_path_copy(struct fs_path *p, struct fs_path *from)
{
int ret;
p->reversed = from->reversed;
fs_path_reset(p);
ret = fs_path_add_path(p, from);
return ret;
}
static void fs_path_unreverse(struct fs_path *p)
{
char *tmp;
int len;
if (!p->reversed)
return;
tmp = p->start;
len = p->end - p->start;
p->start = p->buf;
p->end = p->start + len;
memmove(p->start, tmp, len + 1);
p->reversed = 0;
}
static struct btrfs_path *alloc_path_for_send(void)
{
struct btrfs_path *path;
path = btrfs_alloc_path();
if (!path)
return NULL;
path->search_commit_root = 1;
path->skip_locking = 1;
return path;
}
static int write_buf(struct send_ctx *sctx, const void *buf, u32 len)
{
int ret;
mm_segment_t old_fs;
u32 pos = 0;
old_fs = get_fs();
set_fs(KERNEL_DS);
while (pos < len) {
ret = vfs_write(sctx->send_filp, (char *)buf + pos, len - pos,
&sctx->send_off);
/* TODO handle that correctly */
/*if (ret == -ERESTARTSYS) {
continue;
}*/
if (ret < 0)
goto out;
if (ret == 0) {
ret = -EIO;
goto out;
}
pos += ret;
}
ret = 0;
out:
set_fs(old_fs);
return ret;
}
static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
{
struct btrfs_tlv_header *hdr;
int total_len = sizeof(*hdr) + len;
int left = sctx->send_max_size - sctx->send_size;
if (unlikely(left < total_len))
return -EOVERFLOW;
hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size);
hdr->tlv_type = cpu_to_le16(attr);
hdr->tlv_len = cpu_to_le16(len);
memcpy(hdr + 1, data, len);
sctx->send_size += total_len;
return 0;
}
#if 0
static int tlv_put_u8(struct send_ctx *sctx, u16 attr, u8 value)
{
return tlv_put(sctx, attr, &value, sizeof(value));
}
static int tlv_put_u16(struct send_ctx *sctx, u16 attr, u16 value)
{
__le16 tmp = cpu_to_le16(value);
return tlv_put(sctx, attr, &tmp, sizeof(tmp));
}
static int tlv_put_u32(struct send_ctx *sctx, u16 attr, u32 value)
{
__le32 tmp = cpu_to_le32(value);
return tlv_put(sctx, attr, &tmp, sizeof(tmp));
}
#endif
static int tlv_put_u64(struct send_ctx *sctx, u16 attr, u64 value)
{
__le64 tmp = cpu_to_le64(value);
return tlv_put(sctx, attr, &tmp, sizeof(tmp));
}
static int tlv_put_string(struct send_ctx *sctx, u16 attr,
const char *str, int len)
{
if (len == -1)
len = strlen(str);
return tlv_put(sctx, attr, str, len);
}
static int tlv_put_uuid(struct send_ctx *sctx, u16 attr,
const u8 *uuid)
{
return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE);
}
#if 0
static int tlv_put_timespec(struct send_ctx *sctx, u16 attr,
struct timespec *ts)
{
struct btrfs_timespec bts;
bts.sec = cpu_to_le64(ts->tv_sec);
bts.nsec = cpu_to_le32(ts->tv_nsec);
return tlv_put(sctx, attr, &bts, sizeof(bts));
}
#endif
static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr,
struct extent_buffer *eb,
struct btrfs_timespec *ts)
{
struct btrfs_timespec bts;
read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts));
return tlv_put(sctx, attr, &bts, sizeof(bts));
}
#define TLV_PUT(sctx, attrtype, attrlen, data) \
do { \
ret = tlv_put(sctx, attrtype, attrlen, data); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_INT(sctx, attrtype, bits, value) \
do { \
ret = tlv_put_u##bits(sctx, attrtype, value); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data)
#define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data)
#define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data)
#define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data)
#define TLV_PUT_STRING(sctx, attrtype, str, len) \
do { \
ret = tlv_put_string(sctx, attrtype, str, len); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_PATH(sctx, attrtype, p) \
do { \
ret = tlv_put_string(sctx, attrtype, p->start, \
p->end - p->start); \
if (ret < 0) \
goto tlv_put_failure; \
} while(0)
#define TLV_PUT_UUID(sctx, attrtype, uuid) \
do { \
ret = tlv_put_uuid(sctx, attrtype, uuid); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_TIMESPEC(sctx, attrtype, ts) \
do { \
ret = tlv_put_timespec(sctx, attrtype, ts); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \
do { \
ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
static int send_header(struct send_ctx *sctx)
{
struct btrfs_stream_header hdr;
strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION);
return write_buf(sctx, &hdr, sizeof(hdr));
}
/*
* For each command/item we want to send to userspace, we call this function.
*/
static int begin_cmd(struct send_ctx *sctx, int cmd)
{
struct btrfs_cmd_header *hdr;
if (!sctx->send_buf) {
WARN_ON(1);
return -EINVAL;
}
BUG_ON(sctx->send_size);
sctx->send_size += sizeof(*hdr);
hdr = (struct btrfs_cmd_header *)sctx->send_buf;
hdr->cmd = cpu_to_le16(cmd);
return 0;
}
static int send_cmd(struct send_ctx *sctx)
{
int ret;
struct btrfs_cmd_header *hdr;
u32 crc;
hdr = (struct btrfs_cmd_header *)sctx->send_buf;
hdr->len = cpu_to_le32(sctx->send_size - sizeof(*hdr));
hdr->crc = 0;
crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
hdr->crc = cpu_to_le32(crc);
ret = write_buf(sctx, sctx->send_buf, sctx->send_size);
sctx->total_send_size += sctx->send_size;
sctx->cmd_send_size[le16_to_cpu(hdr->cmd)] += sctx->send_size;
sctx->send_size = 0;
return ret;
}
/*
* Sends a move instruction to user space
*/
static int send_rename(struct send_ctx *sctx,
struct fs_path *from, struct fs_path *to)
{
int ret;
verbose_printk("btrfs: send_rename %s -> %s\n", from->start, to->start);
ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from);
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to);
ret = send_cmd(sctx);
tlv_put_failure:
out:
return ret;
}
/*
* Sends a link instruction to user space
*/
static int send_link(struct send_ctx *sctx,
struct fs_path *path, struct fs_path *lnk)
{
int ret;
verbose_printk("btrfs: send_link %s -> %s\n", path->start, lnk->start);
ret = begin_cmd(sctx, BTRFS_SEND_C_LINK);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk);
ret = send_cmd(sctx);
tlv_put_failure:
out:
return ret;
}
/*
* Sends an unlink instruction to user space
*/
static int send_unlink(struct send_ctx *sctx, struct fs_path *path)
{
int ret;
verbose_printk("btrfs: send_unlink %s\n", path->start);
ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
ret = send_cmd(sctx);
tlv_put_failure:
out:
return ret;
}
/*
* Sends a rmdir instruction to user space
*/
static int send_rmdir(struct send_ctx *sctx, struct fs_path *path)
{
int ret;
verbose_printk("btrfs: send_rmdir %s\n", path->start);
ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
ret = send_cmd(sctx);
tlv_put_failure:
out:
return ret;
}
/*
* Helper function to retrieve some fields from an inode item.
*/
static int get_inode_info(struct btrfs_root *root,
u64 ino, u64 *size, u64 *gen,
u64 *mode, u64 *uid, u64 *gid,
u64 *rdev)
{
int ret;
struct btrfs_inode_item *ii;
struct btrfs_key key;
struct btrfs_path *path;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret) {
ret = -ENOENT;
goto out;
}
ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
if (size)
*size = btrfs_inode_size(path->nodes[0], ii);
if (gen)
*gen = btrfs_inode_generation(path->nodes[0], ii);
if (mode)
*mode = btrfs_inode_mode(path->nodes[0], ii);
if (uid)
*uid = btrfs_inode_uid(path->nodes[0], ii);
if (gid)
*gid = btrfs_inode_gid(path->nodes[0], ii);
if (rdev)
*rdev = btrfs_inode_rdev(path->nodes[0], ii);
out:
btrfs_free_path(path);
return ret;
}
typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index,
struct fs_path *p,
void *ctx);
/*
* Helper function to iterate the entries in ONE btrfs_inode_ref.
* The iterate callback may return a non zero value to stop iteration. This can
* be a negative value for error codes or 1 to simply stop it.
*
* path must point to the INODE_REF when called.
*/
static int iterate_inode_ref(struct send_ctx *sctx,
struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *found_key, int resolve,
iterate_inode_ref_t iterate, void *ctx)
{
struct extent_buffer *eb;
struct btrfs_item *item;
struct btrfs_inode_ref *iref;
struct btrfs_path *tmp_path;
struct fs_path *p;
u32 cur;
u32 len;
u32 total;
int slot;
u32 name_len;
char *start;
int ret = 0;
int num;
int index;
p = fs_path_alloc_reversed(sctx);
if (!p)
return -ENOMEM;
tmp_path = alloc_path_for_send();
if (!tmp_path) {
fs_path_free(sctx, p);
return -ENOMEM;
}
eb = path->nodes[0];
slot = path->slots[0];
item = btrfs_item_nr(eb, slot);
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
cur = 0;
len = 0;
total = btrfs_item_size(eb, item);
num = 0;
while (cur < total) {
fs_path_reset(p);
name_len = btrfs_inode_ref_name_len(eb, iref);
index = btrfs_inode_ref_index(eb, iref);
if (resolve) {
start = btrfs_iref_to_path(root, tmp_path, iref, eb,
found_key->offset, p->buf,
p->buf_len);
if (IS_ERR(start)) {
ret = PTR_ERR(start);
goto out;
}
if (start < p->buf) {
/* overflow , try again with larger buffer */
ret = fs_path_ensure_buf(p,
p->buf_len + p->buf - start);
if (ret < 0)
goto out;
start = btrfs_iref_to_path(root, tmp_path, iref,
eb, found_key->offset, p->buf,
p->buf_len);
if (IS_ERR(start)) {
ret = PTR_ERR(start);
goto out;
}
BUG_ON(start < p->buf);
}
p->start = start;
} else {
ret = fs_path_add_from_extent_buffer(p, eb,
(unsigned long)(iref + 1), name_len);
if (ret < 0)
goto out;
}
len = sizeof(*iref) + name_len;
iref = (struct btrfs_inode_ref *)((char *)iref + len);
cur += len;
ret = iterate(num, found_key->offset, index, p, ctx);
if (ret)
goto out;
num++;
}
out:
btrfs_free_path(tmp_path);
fs_path_free(sctx, p);
return ret;
}
typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *ctx);
/*
* Helper function to iterate the entries in ONE btrfs_dir_item.
* The iterate callback may return a non zero value to stop iteration. This can
* be a negative value for error codes or 1 to simply stop it.
*
* path must point to the dir item when called.
*/
static int iterate_dir_item(struct send_ctx *sctx,
struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *found_key,
iterate_dir_item_t iterate, void *ctx)
{
int ret = 0;
struct extent_buffer *eb;
struct btrfs_item *item;
struct btrfs_dir_item *di;
struct btrfs_key di_key;
char *buf = NULL;
char *buf2 = NULL;
int buf_len;
int buf_virtual = 0;
u32 name_len;
u32 data_len;
u32 cur;
u32 len;
u32 total;
int slot;
int num;
u8 type;
buf_len = PAGE_SIZE;
buf = kmalloc(buf_len, GFP_NOFS);
if (!buf) {
ret = -ENOMEM;
goto out;
}
eb = path->nodes[0];
slot = path->slots[0];
item = btrfs_item_nr(eb, slot);
di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
cur = 0;
len = 0;
total = btrfs_item_size(eb, item);
num = 0;
while (cur < total) {
name_len = btrfs_dir_name_len(eb, di);
data_len = btrfs_dir_data_len(eb, di);
type = btrfs_dir_type(eb, di);
btrfs_dir_item_key_to_cpu(eb, di, &di_key);
if (name_len + data_len > buf_len) {
buf_len = PAGE_ALIGN(name_len + data_len);
if (buf_virtual) {
buf2 = vmalloc(buf_len);
if (!buf2) {
ret = -ENOMEM;
goto out;
}
vfree(buf);
} else {
buf2 = krealloc(buf, buf_len, GFP_NOFS);
if (!buf2) {
buf2 = vmalloc(buf_len);
if (!buf2) {
ret = -ENOMEM;
goto out;
}
kfree(buf);
buf_virtual = 1;
}
}
buf = buf2;
buf2 = NULL;
}
read_extent_buffer(eb, buf, (unsigned long)(di + 1),
name_len + data_len);
len = sizeof(*di) + name_len + data_len;
di = (struct btrfs_dir_item *)((char *)di + len);
cur += len;
ret = iterate(num, &di_key, buf, name_len, buf + name_len,
data_len, type, ctx);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
num++;
}
out:
if (buf_virtual)
vfree(buf);
else
kfree(buf);
return ret;
}
static int __copy_first_ref(int num, u64 dir, int index,
struct fs_path *p, void *ctx)
{
int ret;
struct fs_path *pt = ctx;
ret = fs_path_copy(pt, p);
if (ret < 0)
return ret;
/* we want the first only */
return 1;
}
/*
* Retrieve the first path of an inode. If an inode has more then one
* ref/hardlink, this is ignored.
*/
static int get_inode_path(struct send_ctx *sctx, struct btrfs_root *root,
u64 ino, struct fs_path *path)
{
int ret;
struct btrfs_key key, found_key;
struct btrfs_path *p;
p = alloc_path_for_send();
if (!p)
return -ENOMEM;
fs_path_reset(path);
key.objectid = ino;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot_for_read(root, &key, p, 1, 0);
if (ret < 0)
goto out;
if (ret) {
ret = 1;
goto out;
}
btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]);
if (found_key.objectid != ino ||
found_key.type != BTRFS_INODE_REF_KEY) {
ret = -ENOENT;
goto out;
}
ret = iterate_inode_ref(sctx, root, p, &found_key, 1,
__copy_first_ref, path);
if (ret < 0)
goto out;
ret = 0;
out:
btrfs_free_path(p);
return ret;
}
struct backref_ctx {
struct send_ctx *sctx;
/* number of total found references */
u64 found;
/*
* used for clones found in send_root. clones found behind cur_objectid
* and cur_offset are not considered as allowed clones.
*/
u64 cur_objectid;
u64 cur_offset;
/* may be truncated in case it's the last extent in a file */
u64 extent_len;
/* Just to check for bugs in backref resolving */
int found_itself;
};
static int __clone_root_cmp_bsearch(const void *key, const void *elt)
{
u64 root = (u64)key;
struct clone_root *cr = (struct clone_root *)elt;
if (root < cr->root->objectid)
return -1;
if (root > cr->root->objectid)
return 1;
return 0;
}
static int __clone_root_cmp_sort(const void *e1, const void *e2)
{
struct clone_root *cr1 = (struct clone_root *)e1;
struct clone_root *cr2 = (struct clone_root *)e2;
if (cr1->root->objectid < cr2->root->objectid)
return -1;
if (cr1->root->objectid > cr2->root->objectid)
return 1;
return 0;
}
/*
* Called for every backref that is found for the current extent.
* Results are collected in sctx->clone_roots->ino/offset/found_refs
*/
static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
{
struct backref_ctx *bctx = ctx_;
struct clone_root *found;
int ret;
u64 i_size;
/* First check if the root is in the list of accepted clone sources */
found = bsearch((void *)root, bctx->sctx->clone_roots,
bctx->sctx->clone_roots_cnt,
sizeof(struct clone_root),
__clone_root_cmp_bsearch);
if (!found)
return 0;
if (found->root == bctx->sctx->send_root &&
ino == bctx->cur_objectid &&
offset == bctx->cur_offset) {
bctx->found_itself = 1;
}
/*
* There are inodes that have extents that lie behind its i_size. Don't
* accept clones from these extents.
*/
ret = get_inode_info(found->root, ino, &i_size, NULL, NULL, NULL, NULL,
NULL);
if (ret < 0)
return ret;
if (offset + bctx->extent_len > i_size)
return 0;
/*
* Make sure we don't consider clones from send_root that are
* behind the current inode/offset.
*/
if (found->root == bctx->sctx->send_root) {
/*
* TODO for the moment we don't accept clones from the inode
* that is currently send. We may change this when
* BTRFS_IOC_CLONE_RANGE supports cloning from and to the same
* file.
*/
if (ino >= bctx->cur_objectid)
return 0;
#if 0
if (ino > bctx->cur_objectid)
return 0;
if (offset + bctx->extent_len > bctx->cur_offset)
return 0;
#endif
}
bctx->found++;
found->found_refs++;
if (ino < found->ino) {
found->ino = ino;
found->offset = offset;
} else if (found->ino == ino) {
/*
* same extent found more then once in the same file.
*/
if (found->offset > offset + bctx->extent_len)
found->offset = offset;
}
return 0;
}
/*
* Given an inode, offset and extent item, it finds a good clone for a clone
* instruction. Returns -ENOENT when none could be found. The function makes
* sure that the returned clone is usable at the point where sending is at the
* moment. This means, that no clones are accepted which lie behind the current
* inode+offset.
*
* path must point to the extent item when called.
*/
static int find_extent_clone(struct send_ctx *sctx,
struct btrfs_path *path,
u64 ino, u64 data_offset,
u64 ino_size,
struct clone_root **found)
{
int ret;
int extent_type;
u64 logical;
u64 disk_byte;
u64 num_bytes;
u64 extent_item_pos;
struct btrfs_file_extent_item *fi;
struct extent_buffer *eb = path->nodes[0];
struct backref_ctx *backref_ctx = NULL;
struct clone_root *cur_clone_root;
struct btrfs_key found_key;
struct btrfs_path *tmp_path;
int compressed;
u32 i;
tmp_path = alloc_path_for_send();
if (!tmp_path)
return -ENOMEM;
backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_NOFS);
if (!backref_ctx) {
ret = -ENOMEM;
goto out;
}
if (data_offset >= ino_size) {
/*
* There may be extents that lie behind the file's size.
* I at least had this in combination with snapshotting while
* writing large files.
*/
ret = 0;
goto out;
}
fi = btrfs_item_ptr(eb, path->slots[0],
struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(eb, fi);
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
ret = -ENOENT;
goto out;
}
compressed = btrfs_file_extent_compression(eb, fi);
num_bytes = btrfs_file_extent_num_bytes(eb, fi);
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
if (disk_byte == 0) {
ret = -ENOENT;
goto out;
}
logical = disk_byte + btrfs_file_extent_offset(eb, fi);
ret = extent_from_logical(sctx->send_root->fs_info,
disk_byte, tmp_path, &found_key);
btrfs_release_path(tmp_path);
if (ret < 0)
goto out;
if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
ret = -EIO;
goto out;
}
/*
* Setup the clone roots.
*/
for (i = 0; i < sctx->clone_roots_cnt; i++) {
cur_clone_root = sctx->clone_roots + i;
cur_clone_root->ino = (u64)-1;
cur_clone_root->offset = 0;
cur_clone_root->found_refs = 0;
}
backref_ctx->sctx = sctx;
backref_ctx->found = 0;
backref_ctx->cur_objectid = ino;
backref_ctx->cur_offset = data_offset;
backref_ctx->found_itself = 0;
backref_ctx->extent_len = num_bytes;
/*
* The last extent of a file may be too large due to page alignment.
* We need to adjust extent_len in this case so that the checks in
* __iterate_backrefs work.
*/
if (data_offset + num_bytes >= ino_size)
backref_ctx->extent_len = ino_size - data_offset;
/*
* Now collect all backrefs.
*/
if (compressed == BTRFS_COMPRESS_NONE)
extent_item_pos = logical - found_key.objectid;
else
extent_item_pos = 0;
extent_item_pos = logical - found_key.objectid;
ret = iterate_extent_inodes(sctx->send_root->fs_info,
found_key.objectid, extent_item_pos, 1,
__iterate_backrefs, backref_ctx);
if (ret < 0)
goto out;
if (!backref_ctx->found_itself) {
/* found a bug in backref code? */
ret = -EIO;
printk(KERN_ERR "btrfs: ERROR did not find backref in "
"send_root. inode=%llu, offset=%llu, "
"disk_byte=%llu found extent=%llu\n",
ino, data_offset, disk_byte, found_key.objectid);
goto out;
}
verbose_printk(KERN_DEBUG "btrfs: find_extent_clone: data_offset=%llu, "
"ino=%llu, "
"num_bytes=%llu, logical=%llu\n",
data_offset, ino, num_bytes, logical);
if (!backref_ctx->found)
verbose_printk("btrfs: no clones found\n");
cur_clone_root = NULL;
for (i = 0; i < sctx->clone_roots_cnt; i++) {
if (sctx->clone_roots[i].found_refs) {
if (!cur_clone_root)
cur_clone_root = sctx->clone_roots + i;
else if (sctx->clone_roots[i].root == sctx->send_root)
/* prefer clones from send_root over others */
cur_clone_root = sctx->clone_roots + i;
}
}
if (cur_clone_root) {
*found = cur_clone_root;
ret = 0;
} else {
ret = -ENOENT;
}
out:
btrfs_free_path(tmp_path);
kfree(backref_ctx);
return ret;
}
static int read_symlink(struct send_ctx *sctx,
struct btrfs_root *root,
u64 ino,
struct fs_path *dest)
{
int ret;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_file_extent_item *ei;
u8 type;
u8 compression;
unsigned long off;
int len;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
BUG_ON(ret);
ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
type = btrfs_file_extent_type(path->nodes[0], ei);
compression = btrfs_file_extent_compression(path->nodes[0], ei);
BUG_ON(type != BTRFS_FILE_EXTENT_INLINE);
BUG_ON(compression);
off = btrfs_file_extent_inline_start(ei);
len = btrfs_file_extent_inline_len(path->nodes[0], ei);
ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len);
out:
btrfs_free_path(path);
return ret;
}
/*
* Helper function to generate a file name that is unique in the root of
* send_root and parent_root. This is used to generate names for orphan inodes.
*/
static int gen_unique_name(struct send_ctx *sctx,
u64 ino, u64 gen,
struct fs_path *dest)
{
int ret = 0;
struct btrfs_path *path;
struct btrfs_dir_item *di;
char tmp[64];
int len;
u64 idx = 0;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
while (1) {
len = snprintf(tmp, sizeof(tmp) - 1, "o%llu-%llu-%llu",
ino, gen, idx);
if (len >= sizeof(tmp)) {
/* should really not happen */
ret = -EOVERFLOW;
goto out;
}
di = btrfs_lookup_dir_item(NULL, sctx->send_root,
path, BTRFS_FIRST_FREE_OBJECTID,
tmp, strlen(tmp), 0);
btrfs_release_path(path);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out;
}
if (di) {
/* not unique, try again */
idx++;
continue;
}
if (!sctx->parent_root) {
/* unique */
ret = 0;
break;
}
di = btrfs_lookup_dir_item(NULL, sctx->parent_root,
path, BTRFS_FIRST_FREE_OBJECTID,
tmp, strlen(tmp), 0);
btrfs_release_path(path);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out;
}
if (di) {
/* not unique, try again */
idx++;
continue;
}
/* unique */
break;
}
ret = fs_path_add(dest, tmp, strlen(tmp));
out:
btrfs_free_path(path);
return ret;
}
enum inode_state {
inode_state_no_change,
inode_state_will_create,
inode_state_did_create,
inode_state_will_delete,
inode_state_did_delete,
};
static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen)
{
int ret;
int left_ret;
int right_ret;
u64 left_gen;
u64 right_gen;
ret = get_inode_info(sctx->send_root, ino, NULL, &left_gen, NULL, NULL,
NULL, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
left_ret = ret;
if (!sctx->parent_root) {
right_ret = -ENOENT;
} else {
ret = get_inode_info(sctx->parent_root, ino, NULL, &right_gen,
NULL, NULL, NULL, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
right_ret = ret;
}
if (!left_ret && !right_ret) {
if (left_gen == gen && right_gen == gen) {
ret = inode_state_no_change;
} else if (left_gen == gen) {
if (ino < sctx->send_progress)
ret = inode_state_did_create;
else
ret = inode_state_will_create;
} else if (right_gen == gen) {
if (ino < sctx->send_progress)
ret = inode_state_did_delete;
else
ret = inode_state_will_delete;
} else {
ret = -ENOENT;
}
} else if (!left_ret) {
if (left_gen == gen) {
if (ino < sctx->send_progress)
ret = inode_state_did_create;
else
ret = inode_state_will_create;
} else {
ret = -ENOENT;
}
} else if (!right_ret) {
if (right_gen == gen) {
if (ino < sctx->send_progress)
ret = inode_state_did_delete;
else
ret = inode_state_will_delete;
} else {
ret = -ENOENT;
}
} else {
ret = -ENOENT;
}
out:
return ret;
}
static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen)
{
int ret;
ret = get_cur_inode_state(sctx, ino, gen);
if (ret < 0)
goto out;
if (ret == inode_state_no_change ||
ret == inode_state_did_create ||
ret == inode_state_will_delete)
ret = 1;
else
ret = 0;
out:
return ret;
}
/*
* Helper function to lookup a dir item in a dir.
*/
static int lookup_dir_item_inode(struct btrfs_root *root,
u64 dir, const char *name, int name_len,
u64 *found_inode,
u8 *found_type)
{
int ret = 0;
struct btrfs_dir_item *di;
struct btrfs_key key;
struct btrfs_path *path;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
di = btrfs_lookup_dir_item(NULL, root, path,
dir, name, name_len, 0);
if (!di) {
ret = -ENOENT;
goto out;
}
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
*found_inode = key.objectid;
*found_type = btrfs_dir_type(path->nodes[0], di);
out:
btrfs_free_path(path);
return ret;
}
/*
* Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir,
* generation of the parent dir and the name of the dir entry.
*/
static int get_first_ref(struct send_ctx *sctx,
struct btrfs_root *root, u64 ino,
u64 *dir, u64 *dir_gen, struct fs_path *name)
{
int ret;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_path *path;
struct btrfs_inode_ref *iref;
int len;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = ino;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (!ret)
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (ret || found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = -ENOENT;
goto out;
}
iref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
len = btrfs_inode_ref_name_len(path->nodes[0], iref);
ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
(unsigned long)(iref + 1), len);
if (ret < 0)
goto out;
btrfs_release_path(path);
ret = get_inode_info(root, found_key.offset, NULL, dir_gen, NULL, NULL,
NULL, NULL);
if (ret < 0)
goto out;
*dir = found_key.offset;
out:
btrfs_free_path(path);
return ret;
}
static int is_first_ref(struct send_ctx *sctx,
struct btrfs_root *root,
u64 ino, u64 dir,
const char *name, int name_len)
{
int ret;
struct fs_path *tmp_name;
u64 tmp_dir;
u64 tmp_dir_gen;
tmp_name = fs_path_alloc(sctx);
if (!tmp_name)
return -ENOMEM;
ret = get_first_ref(sctx, root, ino, &tmp_dir, &tmp_dir_gen, tmp_name);
if (ret < 0)
goto out;
if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) {
ret = 0;
goto out;
}
ret = !memcmp(tmp_name->start, name, name_len);
out:
fs_path_free(sctx, tmp_name);
return ret;
}
/*
* Used by process_recorded_refs to determine if a new ref would overwrite an
* already existing ref. In case it detects an overwrite, it returns the
* inode/gen in who_ino/who_gen.
* When an overwrite is detected, process_recorded_refs does proper orphanizing
* to make sure later references to the overwritten inode are possible.
* Orphanizing is however only required for the first ref of an inode.
* process_recorded_refs does an additional is_first_ref check to see if
* orphanizing is really required.
*/
static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
const char *name, int name_len,
u64 *who_ino, u64 *who_gen)
{
int ret = 0;
u64 other_inode = 0;
u8 other_type = 0;
if (!sctx->parent_root)
goto out;
ret = is_inode_existent(sctx, dir, dir_gen);
if (ret <= 0)
goto out;
ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
&other_inode, &other_type);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
ret = 0;
goto out;
}
/*
* Check if the overwritten ref was already processed. If yes, the ref
* was already unlinked/moved, so we can safely assume that we will not
* overwrite anything at this point in time.
*/
if (other_inode > sctx->send_progress) {
ret = get_inode_info(sctx->parent_root, other_inode, NULL,
who_gen, NULL, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = 1;
*who_ino = other_inode;
} else {
ret = 0;
}
out:
return ret;
}
/*
* Checks if the ref was overwritten by an already processed inode. This is
* used by __get_cur_name_and_parent to find out if the ref was orphanized and
* thus the orphan name needs be used.
* process_recorded_refs also uses it to avoid unlinking of refs that were
* overwritten.
*/
static int did_overwrite_ref(struct send_ctx *sctx,
u64 dir, u64 dir_gen,
u64 ino, u64 ino_gen,
const char *name, int name_len)
{
int ret = 0;
u64 gen;
u64 ow_inode;
u8 other_type;
if (!sctx->parent_root)
goto out;
ret = is_inode_existent(sctx, dir, dir_gen);
if (ret <= 0)
goto out;
/* check if the ref was overwritten by another ref */
ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
&ow_inode, &other_type);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
/* was never and will never be overwritten */
ret = 0;
goto out;
}
ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL,
NULL, NULL);
if (ret < 0)
goto out;
if (ow_inode == ino && gen == ino_gen) {
ret = 0;
goto out;
}
/* we know that it is or will be overwritten. check this now */
if (ow_inode < sctx->send_progress)
ret = 1;
else
ret = 0;
out:
return ret;
}
/*
* Same as did_overwrite_ref, but also checks if it is the first ref of an inode
* that got overwritten. This is used by process_recorded_refs to determine
* if it has to use the path as returned by get_cur_path or the orphan name.
*/
static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen)
{
int ret = 0;
struct fs_path *name = NULL;
u64 dir;
u64 dir_gen;
if (!sctx->parent_root)
goto out;
name = fs_path_alloc(sctx);
if (!name)
return -ENOMEM;
ret = get_first_ref(sctx, sctx->parent_root, ino, &dir, &dir_gen, name);
if (ret < 0)
goto out;
ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen,
name->start, fs_path_len(name));
out:
fs_path_free(sctx, name);
return ret;
}
/*
* Insert a name cache entry. On 32bit kernels the radix tree index is 32bit,
* so we need to do some special handling in case we have clashes. This function
* takes care of this with the help of name_cache_entry::radix_list.
* In case of error, nce is kfreed.
*/
static int name_cache_insert(struct send_ctx *sctx,
struct name_cache_entry *nce)
{
int ret = 0;
struct list_head *nce_head;
nce_head = radix_tree_lookup(&sctx->name_cache,
(unsigned long)nce->ino);
if (!nce_head) {
nce_head = kmalloc(sizeof(*nce_head), GFP_NOFS);
if (!nce_head)
return -ENOMEM;
INIT_LIST_HEAD(nce_head);
ret = radix_tree_insert(&sctx->name_cache, nce->ino, nce_head);
if (ret < 0) {
kfree(nce_head);
kfree(nce);
return ret;
}
}
list_add_tail(&nce->radix_list, nce_head);
list_add_tail(&nce->list, &sctx->name_cache_list);
sctx->name_cache_size++;
return ret;
}
static void name_cache_delete(struct send_ctx *sctx,
struct name_cache_entry *nce)
{
struct list_head *nce_head;
nce_head = radix_tree_lookup(&sctx->name_cache,
(unsigned long)nce->ino);
BUG_ON(!nce_head);
list_del(&nce->radix_list);
list_del(&nce->list);
sctx->name_cache_size--;
if (list_empty(nce_head)) {
radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino);
kfree(nce_head);
}
}
static struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
u64 ino, u64 gen)
{
struct list_head *nce_head;
struct name_cache_entry *cur;
nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino);
if (!nce_head)
return NULL;
list_for_each_entry(cur, nce_head, radix_list) {
if (cur->ino == ino && cur->gen == gen)
return cur;
}
return NULL;
}
/*
* Removes the entry from the list and adds it back to the end. This marks the
* entry as recently used so that name_cache_clean_unused does not remove it.
*/
static void name_cache_used(struct send_ctx *sctx, struct name_cache_entry *nce)
{
list_del(&nce->list);
list_add_tail(&nce->list, &sctx->name_cache_list);
}
/*
* Remove some entries from the beginning of name_cache_list.
*/
static void name_cache_clean_unused(struct send_ctx *sctx)
{
struct name_cache_entry *nce;
if (sctx->name_cache_size < SEND_CTX_NAME_CACHE_CLEAN_SIZE)
return;
while (sctx->name_cache_size > SEND_CTX_MAX_NAME_CACHE_SIZE) {
nce = list_entry(sctx->name_cache_list.next,
struct name_cache_entry, list);
name_cache_delete(sctx, nce);
kfree(nce);
}
}
static void name_cache_free(struct send_ctx *sctx)
{
struct name_cache_entry *nce;
while (!list_empty(&sctx->name_cache_list)) {
nce = list_entry(sctx->name_cache_list.next,
struct name_cache_entry, list);
name_cache_delete(sctx, nce);
kfree(nce);
}
}
/*
* Used by get_cur_path for each ref up to the root.
* Returns 0 if it succeeded.
* Returns 1 if the inode is not existent or got overwritten. In that case, the
* name is an orphan name. This instructs get_cur_path to stop iterating. If 1
* is returned, parent_ino/parent_gen are not guaranteed to be valid.
* Returns <0 in case of error.
*/
static int __get_cur_name_and_parent(struct send_ctx *sctx,
u64 ino, u64 gen,
u64 *parent_ino,
u64 *parent_gen,
struct fs_path *dest)
{
int ret;
int nce_ret;
struct btrfs_path *path = NULL;
struct name_cache_entry *nce = NULL;
/*
* First check if we already did a call to this function with the same
* ino/gen. If yes, check if the cache entry is still up-to-date. If yes
* return the cached result.
*/
nce = name_cache_search(sctx, ino, gen);
if (nce) {
if (ino < sctx->send_progress && nce->need_later_update) {
name_cache_delete(sctx, nce);
kfree(nce);
nce = NULL;
} else {
name_cache_used(sctx, nce);
*parent_ino = nce->parent_ino;
*parent_gen = nce->parent_gen;
ret = fs_path_add(dest, nce->name, nce->name_len);
if (ret < 0)
goto out;
ret = nce->ret;
goto out;
}
}
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
/*
* If the inode is not existent yet, add the orphan name and return 1.
* This should only happen for the parent dir that we determine in
* __record_new_ref
*/
ret = is_inode_existent(sctx, ino, gen);
if (ret < 0)
goto out;
if (!ret) {
ret = gen_unique_name(sctx, ino, gen, dest);
if (ret < 0)
goto out;
ret = 1;
goto out_cache;
}
/*
* Depending on whether the inode was already processed or not, use
* send_root or parent_root for ref lookup.
*/
if (ino < sctx->send_progress)
ret = get_first_ref(sctx, sctx->send_root, ino,
parent_ino, parent_gen, dest);
else
ret = get_first_ref(sctx, sctx->parent_root, ino,
parent_ino, parent_gen, dest);
if (ret < 0)
goto out;
/*
* Check if the ref was overwritten by an inode's ref that was processed
* earlier. If yes, treat as orphan and return 1.
*/
ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen,
dest->start, dest->end - dest->start);
if (ret < 0)
goto out;
if (ret) {
fs_path_reset(dest);
ret = gen_unique_name(sctx, ino, gen, dest);
if (ret < 0)
goto out;
ret = 1;
}
out_cache:
/*
* Store the result of the lookup in the name cache.
*/
nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_NOFS);
if (!nce) {
ret = -ENOMEM;
goto out;
}
nce->ino = ino;
nce->gen = gen;
nce->parent_ino = *parent_ino;
nce->parent_gen = *parent_gen;
nce->name_len = fs_path_len(dest);
nce->ret = ret;
strcpy(nce->name, dest->start);
if (ino < sctx->send_progress)
nce->need_later_update = 0;
else
nce->need_later_update = 1;
nce_ret = name_cache_insert(sctx, nce);
if (nce_ret < 0)
ret = nce_ret;
name_cache_clean_unused(sctx);
out:
btrfs_free_path(path);
return ret;
}
/*
* Magic happens here. This function returns the first ref to an inode as it
* would look like while receiving the stream at this point in time.
* We walk the path up to the root. For every inode in between, we check if it
* was already processed/sent. If yes, we continue with the parent as found
* in send_root. If not, we continue with the parent as found in parent_root.
* If we encounter an inode that was deleted at this point in time, we use the
* inodes "orphan" name instead of the real name and stop. Same with new inodes
* that were not created yet and overwritten inodes/refs.
*
* When do we have have orphan inodes:
* 1. When an inode is freshly created and thus no valid refs are available yet
* 2. When a directory lost all it's refs (deleted) but still has dir items
* inside which were not processed yet (pending for move/delete). If anyone
* tried to get the path to the dir items, it would get a path inside that
* orphan directory.
* 3. When an inode is moved around or gets new links, it may overwrite the ref
* of an unprocessed inode. If in that case the first ref would be
* overwritten, the overwritten inode gets "orphanized". Later when we
* process this overwritten inode, it is restored at a new place by moving
* the orphan inode.
*
* sctx->send_progress tells this function at which point in time receiving
* would be.
*/
static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
struct fs_path *dest)
{
int ret = 0;
struct fs_path *name = NULL;
u64 parent_inode = 0;
u64 parent_gen = 0;
int stop = 0;
name = fs_path_alloc(sctx);
if (!name) {
ret = -ENOMEM;
goto out;
}
dest->reversed = 1;
fs_path_reset(dest);
while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
fs_path_reset(name);
ret = __get_cur_name_and_parent(sctx, ino, gen,
&parent_inode, &parent_gen, name);
if (ret < 0)
goto out;
if (ret)
stop = 1;
ret = fs_path_add_path(dest, name);
if (ret < 0)
goto out;
ino = parent_inode;
gen = parent_gen;
}
out:
fs_path_free(sctx, name);
if (!ret)
fs_path_unreverse(dest);
return ret;
}
/*
* Called for regular files when sending extents data. Opens a struct file
* to read from the file.
*/
static int open_cur_inode_file(struct send_ctx *sctx)
{
int ret = 0;
struct btrfs_key key;
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull large btrfs update from Chris Mason: "This pull request is very large, and the two main features in here have been under testing/devel for quite a while. We have subvolume quotas from the strato developers. This enables full tracking of how many blocks are allocated to each subvolume (and all snapshots) and you can set limits on a per-subvolume basis. You can also create quota groups and toss multiple subvolumes into a big group. It's everything you need to be a web hosting company and give each user their own subvolume. The userland side of the quotas is being refreshed, they'll send out details on where to grab it soon. Next is the kernel side of btrfs send/receive from Alexander Block. This leverages the same infrastructure as the quota code to figure out relationships between blocks and their owners. It can then compute the difference between two snapshots and sends the diffs in a neutral format into userland. The basic model: create a snapshot send that snapshot as the initial backup make changes create a second snapshot send the incremental as a backup delete the first snapshot (use the second snapshot for the next incremental) The receive portion is all in userland, and in the 'next' branch of my btrfs-progs repo. There's still some work to do in terms of optimizing the send side from kernel to userland. The really important part is figuring out how two snapshots are different, and this is where we are concentrating right now. The initial send of a dataset is a little slower than tar, but the incremental sends are dramatically faster than what rsync can do. On top of all of that, we have a nice queue of fixes, cleanups and optimizations." Fix up trivial modify/del conflict in fs/btrfs/ioctl.c Also fix up semantic conflict in fs/btrfs/send.c: the interface to dentry_open() changed in commit 765927b2d508 ("switch dentry_open() to struct path, make it grab references itself"), and since it now grabs whatever references it needs, we should no longer do the mntget() on the mnt (and we need to dput() the dentry reference we took). * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (65 commits) Btrfs: uninit variable fixes in send/receive Btrfs: introduce BTRFS_IOC_SEND for btrfs send/receive Btrfs: add btrfs_compare_trees function Btrfs: introduce subvol uuids and times Btrfs: make iref_to_path non static Btrfs: add a barrier before a waitqueue_active check Btrfs: call the ordered free operation without any locks held Btrfs: Check INCOMPAT flags on remount and add helper function Btrfs: add helper for tree enumeration btrfs: allow cross-subvolume file clone Btrfs: improve multi-thread buffer read Btrfs: make btrfs's allocation smoothly with preallocation Btrfs: lock the transition from dirty to writeback for an eb Btrfs: fix potential race in extent buffer freeing Btrfs: don't return true in releasepage unless we actually freed the eb Btrfs: suppress printk() if all device I/O stats are zero Btrfs: remove unwanted printk() for btrfs device I/O stats Btrfs: rewrite BTRFS_SETGET_FUNCS Btrfs: zero unused bytes in inode item Btrfs: kill free_space pointer from inode structure ... Conflicts: fs/btrfs/ioctl.c
2012-07-26 21:48:55 +00:00
struct path path;
struct inode *inode;
struct dentry *dentry;
struct file *filp;
int new = 0;
if (sctx->cur_inode_filp)
goto out;
key.objectid = sctx->cur_ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
inode = btrfs_iget(sctx->send_root->fs_info->sb, &key, sctx->send_root,
&new);
if (IS_ERR(inode)) {
ret = PTR_ERR(inode);
goto out;
}
dentry = d_obtain_alias(inode);
inode = NULL;
if (IS_ERR(dentry)) {
ret = PTR_ERR(dentry);
goto out;
}
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull large btrfs update from Chris Mason: "This pull request is very large, and the two main features in here have been under testing/devel for quite a while. We have subvolume quotas from the strato developers. This enables full tracking of how many blocks are allocated to each subvolume (and all snapshots) and you can set limits on a per-subvolume basis. You can also create quota groups and toss multiple subvolumes into a big group. It's everything you need to be a web hosting company and give each user their own subvolume. The userland side of the quotas is being refreshed, they'll send out details on where to grab it soon. Next is the kernel side of btrfs send/receive from Alexander Block. This leverages the same infrastructure as the quota code to figure out relationships between blocks and their owners. It can then compute the difference between two snapshots and sends the diffs in a neutral format into userland. The basic model: create a snapshot send that snapshot as the initial backup make changes create a second snapshot send the incremental as a backup delete the first snapshot (use the second snapshot for the next incremental) The receive portion is all in userland, and in the 'next' branch of my btrfs-progs repo. There's still some work to do in terms of optimizing the send side from kernel to userland. The really important part is figuring out how two snapshots are different, and this is where we are concentrating right now. The initial send of a dataset is a little slower than tar, but the incremental sends are dramatically faster than what rsync can do. On top of all of that, we have a nice queue of fixes, cleanups and optimizations." Fix up trivial modify/del conflict in fs/btrfs/ioctl.c Also fix up semantic conflict in fs/btrfs/send.c: the interface to dentry_open() changed in commit 765927b2d508 ("switch dentry_open() to struct path, make it grab references itself"), and since it now grabs whatever references it needs, we should no longer do the mntget() on the mnt (and we need to dput() the dentry reference we took). * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (65 commits) Btrfs: uninit variable fixes in send/receive Btrfs: introduce BTRFS_IOC_SEND for btrfs send/receive Btrfs: add btrfs_compare_trees function Btrfs: introduce subvol uuids and times Btrfs: make iref_to_path non static Btrfs: add a barrier before a waitqueue_active check Btrfs: call the ordered free operation without any locks held Btrfs: Check INCOMPAT flags on remount and add helper function Btrfs: add helper for tree enumeration btrfs: allow cross-subvolume file clone Btrfs: improve multi-thread buffer read Btrfs: make btrfs's allocation smoothly with preallocation Btrfs: lock the transition from dirty to writeback for an eb Btrfs: fix potential race in extent buffer freeing Btrfs: don't return true in releasepage unless we actually freed the eb Btrfs: suppress printk() if all device I/O stats are zero Btrfs: remove unwanted printk() for btrfs device I/O stats Btrfs: rewrite BTRFS_SETGET_FUNCS Btrfs: zero unused bytes in inode item Btrfs: kill free_space pointer from inode structure ... Conflicts: fs/btrfs/ioctl.c
2012-07-26 21:48:55 +00:00
path.mnt = sctx->mnt;
path.dentry = dentry;
filp = dentry_open(&path, O_RDONLY | O_LARGEFILE, current_cred());
dput(dentry);
dentry = NULL;
if (IS_ERR(filp)) {
ret = PTR_ERR(filp);
goto out;
}
sctx->cur_inode_filp = filp;
out:
/*
* no xxxput required here as every vfs op
* does it by itself on failure
*/
return ret;
}
/*
* Closes the struct file that was created in open_cur_inode_file
*/
static int close_cur_inode_file(struct send_ctx *sctx)
{
int ret = 0;
if (!sctx->cur_inode_filp)
goto out;
ret = filp_close(sctx->cur_inode_filp, NULL);
sctx->cur_inode_filp = NULL;
out:
return ret;
}
/*
* Sends a BTRFS_SEND_C_SUBVOL command/item to userspace
*/
static int send_subvol_begin(struct send_ctx *sctx)
{
int ret;
struct btrfs_root *send_root = sctx->send_root;
struct btrfs_root *parent_root = sctx->parent_root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_root_ref *ref;
struct extent_buffer *leaf;
char *name = NULL;
int namelen;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_NOFS);
if (!name) {
btrfs_free_path(path);
return -ENOMEM;
}
key.objectid = send_root->objectid;
key.type = BTRFS_ROOT_BACKREF_KEY;
key.offset = 0;
ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root,
&key, path, 1, 0);
if (ret < 0)
goto out;
if (ret) {
ret = -ENOENT;
goto out;
}
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.type != BTRFS_ROOT_BACKREF_KEY ||
key.objectid != send_root->objectid) {
ret = -ENOENT;
goto out;
}
ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
namelen = btrfs_root_ref_name_len(leaf, ref);
read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen);
btrfs_release_path(path);
if (parent_root) {
ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT);
if (ret < 0)
goto out;
} else {
ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL);
if (ret < 0)
goto out;
}
TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen);
TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
sctx->send_root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
sctx->send_root->root_item.ctransid);
if (parent_root) {
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
sctx->parent_root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
sctx->parent_root->root_item.ctransid);
}
ret = send_cmd(sctx);
tlv_put_failure:
out:
btrfs_free_path(path);
kfree(name);
return ret;
}
static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size)
{
int ret = 0;
struct fs_path *p;
verbose_printk("btrfs: send_truncate %llu size=%llu\n", ino, size);
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, ino, gen, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(sctx, p);
return ret;
}
static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
{
int ret = 0;
struct fs_path *p;
verbose_printk("btrfs: send_chmod %llu mode=%llu\n", ino, mode);
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, ino, gen, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(sctx, p);
return ret;
}
static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
{
int ret = 0;
struct fs_path *p;
verbose_printk("btrfs: send_chown %llu uid=%llu, gid=%llu\n", ino, uid, gid);
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, ino, gen, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(sctx, p);
return ret;
}
static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
{
int ret = 0;
struct fs_path *p = NULL;
struct btrfs_inode_item *ii;
struct btrfs_path *path = NULL;
struct extent_buffer *eb;
struct btrfs_key key;
int slot;
verbose_printk("btrfs: send_utimes %llu\n", ino);
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
path = alloc_path_for_send();
if (!path) {
ret = -ENOMEM;
goto out;
}
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
if (ret < 0)
goto out;
eb = path->nodes[0];
slot = path->slots[0];
ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, ino, gen, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb,
btrfs_inode_atime(ii));
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb,
btrfs_inode_mtime(ii));
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb,
btrfs_inode_ctime(ii));
/* TODO Add otime support when the otime patches get into upstream */
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(sctx, p);
btrfs_free_path(path);
return ret;
}
/*
* Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have
* a valid path yet because we did not process the refs yet. So, the inode
* is created as orphan.
*/
static int send_create_inode(struct send_ctx *sctx, u64 ino)
{
int ret = 0;
struct fs_path *p;
int cmd;
u64 gen;
u64 mode;
u64 rdev;
verbose_printk("btrfs: send_create_inode %llu\n", ino);
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode, NULL,
NULL, &rdev);
if (ret < 0)
goto out;
if (S_ISREG(mode)) {
cmd = BTRFS_SEND_C_MKFILE;
} else if (S_ISDIR(mode)) {
cmd = BTRFS_SEND_C_MKDIR;
} else if (S_ISLNK(mode)) {
cmd = BTRFS_SEND_C_SYMLINK;
} else if (S_ISCHR(mode) || S_ISBLK(mode)) {
cmd = BTRFS_SEND_C_MKNOD;
} else if (S_ISFIFO(mode)) {
cmd = BTRFS_SEND_C_MKFIFO;
} else if (S_ISSOCK(mode)) {
cmd = BTRFS_SEND_C_MKSOCK;
} else {
printk(KERN_WARNING "btrfs: unexpected inode type %o",
(int)(mode & S_IFMT));
ret = -ENOTSUPP;
goto out;
}
ret = begin_cmd(sctx, cmd);
if (ret < 0)
goto out;
ret = gen_unique_name(sctx, ino, gen, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino);
if (S_ISLNK(mode)) {
fs_path_reset(p);
ret = read_symlink(sctx, sctx->send_root, ino, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p);
} else if (S_ISCHR(mode) || S_ISBLK(mode) ||
S_ISFIFO(mode) || S_ISSOCK(mode)) {
TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, rdev);
}
ret = send_cmd(sctx);
if (ret < 0)
goto out;
tlv_put_failure:
out:
fs_path_free(sctx, p);
return ret;
}
/*
* We need some special handling for inodes that get processed before the parent
* directory got created. See process_recorded_refs for details.
* This function does the check if we already created the dir out of order.
*/
static int did_create_dir(struct send_ctx *sctx, u64 dir)
{
int ret = 0;
struct btrfs_path *path = NULL;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_key di_key;
struct extent_buffer *eb;
struct btrfs_dir_item *di;
int slot;
path = alloc_path_for_send();
if (!path) {
ret = -ENOMEM;
goto out;
}
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(sctx->send_root, &key, path,
1, 0);
if (ret < 0)
goto out;
if (!ret) {
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
}
if (ret || found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = 0;
goto out;
}
di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
btrfs_dir_item_key_to_cpu(eb, di, &di_key);
if (di_key.objectid < sctx->send_progress) {
ret = 1;
goto out;
}
key.offset = found_key.offset + 1;
btrfs_release_path(path);
}
out:
btrfs_free_path(path);
return ret;
}
/*
* Only creates the inode if it is:
* 1. Not a directory
* 2. Or a directory which was not created already due to out of order
* directories. See did_create_dir and process_recorded_refs for details.
*/
static int send_create_inode_if_needed(struct send_ctx *sctx)
{
int ret;
if (S_ISDIR(sctx->cur_inode_mode)) {
ret = did_create_dir(sctx, sctx->cur_ino);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
}
ret = send_create_inode(sctx, sctx->cur_ino);
if (ret < 0)
goto out;
out:
return ret;
}
struct recorded_ref {
struct list_head list;
char *dir_path;
char *name;
struct fs_path *full_path;
u64 dir;
u64 dir_gen;
int dir_path_len;
int name_len;
};
/*
* We need to process new refs before deleted refs, but compare_tree gives us
* everything mixed. So we first record all refs and later process them.
* This function is a helper to record one ref.
*/
static int record_ref(struct list_head *head, u64 dir,
u64 dir_gen, struct fs_path *path)
{
struct recorded_ref *ref;
char *tmp;
ref = kmalloc(sizeof(*ref), GFP_NOFS);
if (!ref)
return -ENOMEM;
ref->dir = dir;
ref->dir_gen = dir_gen;
ref->full_path = path;
tmp = strrchr(ref->full_path->start, '/');
if (!tmp) {
ref->name_len = ref->full_path->end - ref->full_path->start;
ref->name = ref->full_path->start;
ref->dir_path_len = 0;
ref->dir_path = ref->full_path->start;
} else {
tmp++;
ref->name_len = ref->full_path->end - tmp;
ref->name = tmp;
ref->dir_path = ref->full_path->start;
ref->dir_path_len = ref->full_path->end -
ref->full_path->start - 1 - ref->name_len;
}
list_add_tail(&ref->list, head);
return 0;
}
static void __free_recorded_refs(struct send_ctx *sctx, struct list_head *head)
{
struct recorded_ref *cur;
while (!list_empty(head)) {
cur = list_entry(head->next, struct recorded_ref, list);
fs_path_free(sctx, cur->full_path);
list_del(&cur->list);
kfree(cur);
}
}
static void free_recorded_refs(struct send_ctx *sctx)
{
__free_recorded_refs(sctx, &sctx->new_refs);
__free_recorded_refs(sctx, &sctx->deleted_refs);
}
/*
* Renames/moves a file/dir to its orphan name. Used when the first
* ref of an unprocessed inode gets overwritten and for all non empty
* directories.
*/
static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen,
struct fs_path *path)
{
int ret;
struct fs_path *orphan;
orphan = fs_path_alloc(sctx);
if (!orphan)
return -ENOMEM;
ret = gen_unique_name(sctx, ino, gen, orphan);
if (ret < 0)
goto out;
ret = send_rename(sctx, path, orphan);
out:
fs_path_free(sctx, orphan);
return ret;
}
/*
* Returns 1 if a directory can be removed at this point in time.
* We check this by iterating all dir items and checking if the inode behind
* the dir item was already processed.
*/
static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 send_progress)
{
int ret = 0;
struct btrfs_root *root = sctx->parent_root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_key loc;
struct btrfs_dir_item *di;
/*
* Don't try to rmdir the top/root subvolume dir.
*/
if (dir == BTRFS_FIRST_FREE_OBJECTID)
return 0;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (!ret) {
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
}
if (ret || found_key.objectid != key.objectid ||
found_key.type != key.type) {
break;
}
di = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_dir_item);
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc);
if (loc.objectid > send_progress) {
ret = 0;
goto out;
}
btrfs_release_path(path);
key.offset = found_key.offset + 1;
}
ret = 1;
out:
btrfs_free_path(path);
return ret;
}
/*
* This does all the move/link/unlink/rmdir magic.
*/
static int process_recorded_refs(struct send_ctx *sctx)
{
int ret = 0;
struct recorded_ref *cur;
struct recorded_ref *cur2;
struct ulist *check_dirs = NULL;
struct ulist_iterator uit;
struct ulist_node *un;
struct fs_path *valid_path = NULL;
u64 ow_inode = 0;
u64 ow_gen;
int did_overwrite = 0;
int is_orphan = 0;
verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
/*
* This should never happen as the root dir always has the same ref
* which is always '..'
*/
BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID);
valid_path = fs_path_alloc(sctx);
if (!valid_path) {
ret = -ENOMEM;
goto out;
}
check_dirs = ulist_alloc(GFP_NOFS);
if (!check_dirs) {
ret = -ENOMEM;
goto out;
}
/*
* First, check if the first ref of the current inode was overwritten
* before. If yes, we know that the current inode was already orphanized
* and thus use the orphan name. If not, we can use get_cur_path to
* get the path of the first ref as it would like while receiving at
* this point in time.
* New inodes are always orphan at the beginning, so force to use the
* orphan name in this case.
* The first ref is stored in valid_path and will be updated if it
* gets moved around.
*/
if (!sctx->cur_inode_new) {
ret = did_overwrite_first_ref(sctx, sctx->cur_ino,
sctx->cur_inode_gen);
if (ret < 0)
goto out;
if (ret)
did_overwrite = 1;
}
if (sctx->cur_inode_new || did_overwrite) {
ret = gen_unique_name(sctx, sctx->cur_ino,
sctx->cur_inode_gen, valid_path);
if (ret < 0)
goto out;
is_orphan = 1;
} else {
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen,
valid_path);
if (ret < 0)
goto out;
}
list_for_each_entry(cur, &sctx->new_refs, list) {
/*
* We may have refs where the parent directory does not exist
* yet. This happens if the parent directories inum is higher
* the the current inum. To handle this case, we create the
* parent directory out of order. But we need to check if this
* did already happen before due to other refs in the same dir.
*/
ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
if (ret == inode_state_will_create) {
ret = 0;
/*
* First check if any of the current inodes refs did
* already create the dir.
*/
list_for_each_entry(cur2, &sctx->new_refs, list) {
if (cur == cur2)
break;
if (cur2->dir == cur->dir) {
ret = 1;
break;
}
}
/*
* If that did not happen, check if a previous inode
* did already create the dir.
*/
if (!ret)
ret = did_create_dir(sctx, cur->dir);
if (ret < 0)
goto out;
if (!ret) {
ret = send_create_inode(sctx, cur->dir);
if (ret < 0)
goto out;
}
}
/*
* Check if this new ref would overwrite the first ref of
* another unprocessed inode. If yes, orphanize the
* overwritten inode. If we find an overwritten ref that is
* not the first ref, simply unlink it.
*/
ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen,
cur->name, cur->name_len,
&ow_inode, &ow_gen);
if (ret < 0)
goto out;
if (ret) {
ret = is_first_ref(sctx, sctx->parent_root,
ow_inode, cur->dir, cur->name,
cur->name_len);
if (ret < 0)
goto out;
if (ret) {
ret = orphanize_inode(sctx, ow_inode, ow_gen,
cur->full_path);
if (ret < 0)
goto out;
} else {
ret = send_unlink(sctx, cur->full_path);
if (ret < 0)
goto out;
}
}
/*
* link/move the ref to the new place. If we have an orphan
* inode, move it and update valid_path. If not, link or move
* it depending on the inode mode.
*/
if (is_orphan) {
ret = send_rename(sctx, valid_path, cur->full_path);
if (ret < 0)
goto out;
is_orphan = 0;
ret = fs_path_copy(valid_path, cur->full_path);
if (ret < 0)
goto out;
} else {
if (S_ISDIR(sctx->cur_inode_mode)) {
/*
* Dirs can't be linked, so move it. For moved
* dirs, we always have one new and one deleted
* ref. The deleted ref is ignored later.
*/
ret = send_rename(sctx, valid_path,
cur->full_path);
if (ret < 0)
goto out;
ret = fs_path_copy(valid_path, cur->full_path);
if (ret < 0)
goto out;
} else {
ret = send_link(sctx, cur->full_path,
valid_path);
if (ret < 0)
goto out;
}
}
ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
GFP_NOFS);
if (ret < 0)
goto out;
}
if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) {
/*
* Check if we can already rmdir the directory. If not,
* orphanize it. For every dir item inside that gets deleted
* later, we do this check again and rmdir it then if possible.
* See the use of check_dirs for more details.
*/
ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_ino);
if (ret < 0)
goto out;
if (ret) {
ret = send_rmdir(sctx, valid_path);
if (ret < 0)
goto out;
} else if (!is_orphan) {
ret = orphanize_inode(sctx, sctx->cur_ino,
sctx->cur_inode_gen, valid_path);
if (ret < 0)
goto out;
is_orphan = 1;
}
list_for_each_entry(cur, &sctx->deleted_refs, list) {
ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
GFP_NOFS);
if (ret < 0)
goto out;
}
} else if (S_ISDIR(sctx->cur_inode_mode) &&
!list_empty(&sctx->deleted_refs)) {
/*
* We have a moved dir. Add the old parent to check_dirs
*/
cur = list_entry(sctx->deleted_refs.next, struct recorded_ref,
list);
ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
GFP_NOFS);
if (ret < 0)
goto out;
} else if (!S_ISDIR(sctx->cur_inode_mode)) {
/*
* We have a non dir inode. Go through all deleted refs and
* unlink them if they were not already overwritten by other
* inodes.
*/
list_for_each_entry(cur, &sctx->deleted_refs, list) {
ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen,
sctx->cur_ino, sctx->cur_inode_gen,
cur->name, cur->name_len);
if (ret < 0)
goto out;
if (!ret) {
ret = send_unlink(sctx, cur->full_path);
if (ret < 0)
goto out;
}
ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
GFP_NOFS);
if (ret < 0)
goto out;
}
/*
* If the inode is still orphan, unlink the orphan. This may
* happen when a previous inode did overwrite the first ref
* of this inode and no new refs were added for the current
* inode. Unlinking does not mean that the inode is deleted in
* all cases. There may still be links to this inode in other
* places.
*/
if (is_orphan) {
ret = send_unlink(sctx, valid_path);
if (ret < 0)
goto out;
}
}
/*
* We did collect all parent dirs where cur_inode was once located. We
* now go through all these dirs and check if they are pending for
* deletion and if it's finally possible to perform the rmdir now.
* We also update the inode stats of the parent dirs here.
*/
ULIST_ITER_INIT(&uit);
while ((un = ulist_next(check_dirs, &uit))) {
/*
* In case we had refs into dirs that were not processed yet,
* we don't need to do the utime and rmdir logic for these dirs.
* The dir will be processed later.
*/
if (un->val > sctx->cur_ino)
continue;
ret = get_cur_inode_state(sctx, un->val, un->aux);
if (ret < 0)
goto out;
if (ret == inode_state_did_create ||
ret == inode_state_no_change) {
/* TODO delayed utimes */
ret = send_utimes(sctx, un->val, un->aux);
if (ret < 0)
goto out;
} else if (ret == inode_state_did_delete) {
ret = can_rmdir(sctx, un->val, sctx->cur_ino);
if (ret < 0)
goto out;
if (ret) {
ret = get_cur_path(sctx, un->val, un->aux,
valid_path);
if (ret < 0)
goto out;
ret = send_rmdir(sctx, valid_path);
if (ret < 0)
goto out;
}
}
}
ret = 0;
out:
free_recorded_refs(sctx);
ulist_free(check_dirs);
fs_path_free(sctx, valid_path);
return ret;
}
static int __record_new_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
int ret = 0;
struct send_ctx *sctx = ctx;
struct fs_path *p;
u64 gen;
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL, NULL,
NULL, NULL);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, dir, gen, p);
if (ret < 0)
goto out;
ret = fs_path_add_path(p, name);
if (ret < 0)
goto out;
ret = record_ref(&sctx->new_refs, dir, gen, p);
out:
if (ret)
fs_path_free(sctx, p);
return ret;
}
static int __record_deleted_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
int ret = 0;
struct send_ctx *sctx = ctx;
struct fs_path *p;
u64 gen;
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL, NULL,
NULL, NULL);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, dir, gen, p);
if (ret < 0)
goto out;
ret = fs_path_add_path(p, name);
if (ret < 0)
goto out;
ret = record_ref(&sctx->deleted_refs, dir, gen, p);
out:
if (ret)
fs_path_free(sctx, p);
return ret;
}
static int record_new_ref(struct send_ctx *sctx)
{
int ret;
ret = iterate_inode_ref(sctx, sctx->send_root, sctx->left_path,
sctx->cmp_key, 0, __record_new_ref, sctx);
if (ret < 0)
goto out;
ret = 0;
out:
return ret;
}
static int record_deleted_ref(struct send_ctx *sctx)
{
int ret;
ret = iterate_inode_ref(sctx, sctx->parent_root, sctx->right_path,
sctx->cmp_key, 0, __record_deleted_ref, sctx);
if (ret < 0)
goto out;
ret = 0;
out:
return ret;
}
struct find_ref_ctx {
u64 dir;
struct fs_path *name;
int found_idx;
};
static int __find_iref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx_)
{
struct find_ref_ctx *ctx = ctx_;
if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) &&
strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) {
ctx->found_idx = num;
return 1;
}
return 0;
}
static int find_iref(struct send_ctx *sctx,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *key,
u64 dir, struct fs_path *name)
{
int ret;
struct find_ref_ctx ctx;
ctx.dir = dir;
ctx.name = name;
ctx.found_idx = -1;
ret = iterate_inode_ref(sctx, root, path, key, 0, __find_iref, &ctx);
if (ret < 0)
return ret;
if (ctx.found_idx == -1)
return -ENOENT;
return ctx.found_idx;
}
static int __record_changed_new_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
ret = find_iref(sctx, sctx->parent_root, sctx->right_path,
sctx->cmp_key, dir, name);
if (ret == -ENOENT)
ret = __record_new_ref(num, dir, index, name, sctx);
else if (ret > 0)
ret = 0;
return ret;
}
static int __record_changed_deleted_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
ret = find_iref(sctx, sctx->send_root, sctx->left_path, sctx->cmp_key,
dir, name);
if (ret == -ENOENT)
ret = __record_deleted_ref(num, dir, index, name, sctx);
else if (ret > 0)
ret = 0;
return ret;
}
static int record_changed_ref(struct send_ctx *sctx)
{
int ret = 0;
ret = iterate_inode_ref(sctx, sctx->send_root, sctx->left_path,
sctx->cmp_key, 0, __record_changed_new_ref, sctx);
if (ret < 0)
goto out;
ret = iterate_inode_ref(sctx, sctx->parent_root, sctx->right_path,
sctx->cmp_key, 0, __record_changed_deleted_ref, sctx);
if (ret < 0)
goto out;
ret = 0;
out:
return ret;
}
/*
* Record and process all refs at once. Needed when an inode changes the
* generation number, which means that it was deleted and recreated.
*/
static int process_all_refs(struct send_ctx *sctx,
enum btrfs_compare_tree_result cmd)
{
int ret;
struct btrfs_root *root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *eb;
int slot;
iterate_inode_ref_t cb;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
if (cmd == BTRFS_COMPARE_TREE_NEW) {
root = sctx->send_root;
cb = __record_new_ref;
} else if (cmd == BTRFS_COMPARE_TREE_DELETED) {
root = sctx->parent_root;
cb = __record_deleted_ref;
} else {
BUG();
}
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret)
break;
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
found_key.type != key.type)
break;
ret = iterate_inode_ref(sctx, root, path, &found_key, 0, cb,
sctx);
btrfs_release_path(path);
if (ret < 0)
goto out;
key.offset = found_key.offset + 1;
}
btrfs_release_path(path);
ret = process_recorded_refs(sctx);
out:
btrfs_free_path(path);
return ret;
}
static int send_set_xattr(struct send_ctx *sctx,
struct fs_path *path,
const char *name, int name_len,
const char *data, int data_len)
{
int ret = 0;
ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len);
ret = send_cmd(sctx);
tlv_put_failure:
out:
return ret;
}
static int send_remove_xattr(struct send_ctx *sctx,
struct fs_path *path,
const char *name, int name_len)
{
int ret = 0;
ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
ret = send_cmd(sctx);
tlv_put_failure:
out:
return ret;
}
static int __process_new_xattr(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
struct fs_path *p;
posix_acl_xattr_header dummy_acl;
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
/*
* This hack is needed because empty acl's are stored as zero byte
* data in xattrs. Problem with that is, that receiving these zero byte
* acl's will fail later. To fix this, we send a dummy acl list that
* only contains the version number and no entries.
*/
if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) ||
!strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) {
if (data_len == 0) {
dummy_acl.a_version =
cpu_to_le32(POSIX_ACL_XATTR_VERSION);
data = (char *)&dummy_acl;
data_len = sizeof(dummy_acl);
}
}
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto out;
ret = send_set_xattr(sctx, p, name, name_len, data, data_len);
out:
fs_path_free(sctx, p);
return ret;
}
static int __process_deleted_xattr(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
struct fs_path *p;
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto out;
ret = send_remove_xattr(sctx, p, name, name_len);
out:
fs_path_free(sctx, p);
return ret;
}
static int process_new_xattr(struct send_ctx *sctx)
{
int ret = 0;
ret = iterate_dir_item(sctx, sctx->send_root, sctx->left_path,
sctx->cmp_key, __process_new_xattr, sctx);
return ret;
}
static int process_deleted_xattr(struct send_ctx *sctx)
{
int ret;
ret = iterate_dir_item(sctx, sctx->parent_root, sctx->right_path,
sctx->cmp_key, __process_deleted_xattr, sctx);
return ret;
}
struct find_xattr_ctx {
const char *name;
int name_len;
int found_idx;
char *found_data;
int found_data_len;
};
static int __find_xattr(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *vctx)
{
struct find_xattr_ctx *ctx = vctx;
if (name_len == ctx->name_len &&
strncmp(name, ctx->name, name_len) == 0) {
ctx->found_idx = num;
ctx->found_data_len = data_len;
ctx->found_data = kmalloc(data_len, GFP_NOFS);
if (!ctx->found_data)
return -ENOMEM;
memcpy(ctx->found_data, data, data_len);
return 1;
}
return 0;
}
static int find_xattr(struct send_ctx *sctx,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *key,
const char *name, int name_len,
char **data, int *data_len)
{
int ret;
struct find_xattr_ctx ctx;
ctx.name = name;
ctx.name_len = name_len;
ctx.found_idx = -1;
ctx.found_data = NULL;
ctx.found_data_len = 0;
ret = iterate_dir_item(sctx, root, path, key, __find_xattr, &ctx);
if (ret < 0)
return ret;
if (ctx.found_idx == -1)
return -ENOENT;
if (data) {
*data = ctx.found_data;
*data_len = ctx.found_data_len;
} else {
kfree(ctx.found_data);
}
return ctx.found_idx;
}
static int __process_changed_new_xattr(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
char *found_data = NULL;
int found_data_len = 0;
struct fs_path *p = NULL;
ret = find_xattr(sctx, sctx->parent_root, sctx->right_path,
sctx->cmp_key, name, name_len, &found_data,
&found_data_len);
if (ret == -ENOENT) {
ret = __process_new_xattr(num, di_key, name, name_len, data,
data_len, type, ctx);
} else if (ret >= 0) {
if (data_len != found_data_len ||
memcmp(data, found_data, data_len)) {
ret = __process_new_xattr(num, di_key, name, name_len,
data, data_len, type, ctx);
} else {
ret = 0;
}
}
kfree(found_data);
fs_path_free(sctx, p);
return ret;
}
static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
ret = find_xattr(sctx, sctx->send_root, sctx->left_path, sctx->cmp_key,
name, name_len, NULL, NULL);
if (ret == -ENOENT)
ret = __process_deleted_xattr(num, di_key, name, name_len, data,
data_len, type, ctx);
else if (ret >= 0)
ret = 0;
return ret;
}
static int process_changed_xattr(struct send_ctx *sctx)
{
int ret = 0;
ret = iterate_dir_item(sctx, sctx->send_root, sctx->left_path,
sctx->cmp_key, __process_changed_new_xattr, sctx);
if (ret < 0)
goto out;
ret = iterate_dir_item(sctx, sctx->parent_root, sctx->right_path,
sctx->cmp_key, __process_changed_deleted_xattr, sctx);
out:
return ret;
}
static int process_all_new_xattrs(struct send_ctx *sctx)
{
int ret;
struct btrfs_root *root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *eb;
int slot;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
root = sctx->send_root;
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_XATTR_ITEM_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = 0;
goto out;
}
ret = iterate_dir_item(sctx, root, path, &found_key,
__process_new_xattr, sctx);
if (ret < 0)
goto out;
btrfs_release_path(path);
key.offset = found_key.offset + 1;
}
out:
btrfs_free_path(path);
return ret;
}
/*
* Read some bytes from the current inode/file and send a write command to
* user space.
*/
static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
{
int ret = 0;
struct fs_path *p;
loff_t pos = offset;
int num_read = 0;
mm_segment_t old_fs;
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
/*
* vfs normally only accepts user space buffers for security reasons.
* we only read from the file and also only provide the read_buf buffer
* to vfs. As this buffer does not come from a user space call, it's
* ok to temporary allow kernel space buffers.
*/
old_fs = get_fs();
set_fs(KERNEL_DS);
verbose_printk("btrfs: send_write offset=%llu, len=%d\n", offset, len);
ret = open_cur_inode_file(sctx);
if (ret < 0)
goto out;
ret = vfs_read(sctx->cur_inode_filp, sctx->read_buf, len, &pos);
if (ret < 0)
goto out;
num_read = ret;
if (!num_read)
goto out;
ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(sctx, p);
set_fs(old_fs);
if (ret < 0)
return ret;
return num_read;
}
/*
* Send a clone command to user space.
*/
static int send_clone(struct send_ctx *sctx,
u64 offset, u32 len,
struct clone_root *clone_root)
{
int ret = 0;
struct fs_path *p;
u64 gen;
verbose_printk("btrfs: send_clone offset=%llu, len=%d, clone_root=%llu, "
"clone_inode=%llu, clone_offset=%llu\n", offset, len,
clone_root->root->objectid, clone_root->ino,
clone_root->offset);
p = fs_path_alloc(sctx);
if (!p)
return -ENOMEM;
ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto out;
TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len);
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
if (clone_root->root == sctx->send_root) {
ret = get_inode_info(sctx->send_root, clone_root->ino, NULL,
&gen, NULL, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, clone_root->ino, gen, p);
} else {
ret = get_inode_path(sctx, clone_root->root,
clone_root->ino, p);
}
if (ret < 0)
goto out;
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
clone_root->root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
clone_root->root->root_item.ctransid);
TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET,
clone_root->offset);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(sctx, p);
return ret;
}
static int send_write_or_clone(struct send_ctx *sctx,
struct btrfs_path *path,
struct btrfs_key *key,
struct clone_root *clone_root)
{
int ret = 0;
struct btrfs_file_extent_item *ei;
u64 offset = key->offset;
u64 pos = 0;
u64 len;
u32 l;
u8 type;
ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
type = btrfs_file_extent_type(path->nodes[0], ei);
if (type == BTRFS_FILE_EXTENT_INLINE) {
len = btrfs_file_extent_inline_len(path->nodes[0], ei);
/*
* it is possible the inline item won't cover the whole page,
* but there may be items after this page. Make
* sure to send the whole thing
*/
len = PAGE_CACHE_ALIGN(len);
} else {
len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
}
if (offset + len > sctx->cur_inode_size)
len = sctx->cur_inode_size - offset;
if (len == 0) {
ret = 0;
goto out;
}
if (!clone_root) {
while (pos < len) {
l = len - pos;
if (l > BTRFS_SEND_READ_SIZE)
l = BTRFS_SEND_READ_SIZE;
ret = send_write(sctx, pos + offset, l);
if (ret < 0)
goto out;
if (!ret)
break;
pos += ret;
}
ret = 0;
} else {
ret = send_clone(sctx, offset, len, clone_root);
}
out:
return ret;
}
static int is_extent_unchanged(struct send_ctx *sctx,
struct btrfs_path *left_path,
struct btrfs_key *ekey)
{
int ret = 0;
struct btrfs_key key;
struct btrfs_path *path = NULL;
struct extent_buffer *eb;
int slot;
struct btrfs_key found_key;
struct btrfs_file_extent_item *ei;
u64 left_disknr;
u64 right_disknr;
u64 left_offset;
u64 right_offset;
u64 left_offset_fixed;
u64 left_len;
u64 right_len;
u64 left_gen;
u64 right_gen;
u8 left_type;
u8 right_type;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
eb = left_path->nodes[0];
slot = left_path->slots[0];
ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
left_type = btrfs_file_extent_type(eb, ei);
if (left_type != BTRFS_FILE_EXTENT_REG) {
ret = 0;
goto out;
}
left_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
left_len = btrfs_file_extent_num_bytes(eb, ei);
left_offset = btrfs_file_extent_offset(eb, ei);
left_gen = btrfs_file_extent_generation(eb, ei);
/*
* Following comments will refer to these graphics. L is the left
* extents which we are checking at the moment. 1-8 are the right
* extents that we iterate.
*
* |-----L-----|
* |-1-|-2a-|-3-|-4-|-5-|-6-|
*
* |-----L-----|
* |--1--|-2b-|...(same as above)
*
* Alternative situation. Happens on files where extents got split.
* |-----L-----|
* |-----------7-----------|-6-|
*
* Alternative situation. Happens on files which got larger.
* |-----L-----|
* |-8-|
* Nothing follows after 8.
*/
key.objectid = ekey->objectid;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = ekey->offset;
ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
/*
* Handle special case where the right side has no extents at all.
*/
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = 0;
goto out;
}
/*
* We're now on 2a, 2b or 7.
*/
key = found_key;
while (key.offset < ekey->offset + left_len) {
ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
right_type = btrfs_file_extent_type(eb, ei);
right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
right_len = btrfs_file_extent_num_bytes(eb, ei);
right_offset = btrfs_file_extent_offset(eb, ei);
right_gen = btrfs_file_extent_generation(eb, ei);
if (right_type != BTRFS_FILE_EXTENT_REG) {
ret = 0;
goto out;
}
/*
* Are we at extent 8? If yes, we know the extent is changed.
* This may only happen on the first iteration.
*/
if (found_key.offset + right_len <= ekey->offset) {
ret = 0;
goto out;
}
left_offset_fixed = left_offset;
if (key.offset < ekey->offset) {
/* Fix the right offset for 2a and 7. */
right_offset += ekey->offset - key.offset;
} else {
/* Fix the left offset for all behind 2a and 2b */
left_offset_fixed += key.offset - ekey->offset;
}
/*
* Check if we have the same extent.
*/
if (left_disknr != right_disknr ||
left_offset_fixed != right_offset ||
left_gen != right_gen) {
ret = 0;
goto out;
}
/*
* Go to the next extent.
*/
ret = btrfs_next_item(sctx->parent_root, path);
if (ret < 0)
goto out;
if (!ret) {
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
}
if (ret || found_key.objectid != key.objectid ||
found_key.type != key.type) {
key.offset += right_len;
break;
} else {
if (found_key.offset != key.offset + right_len) {
/* Should really not happen */
ret = -EIO;
goto out;
}
}
key = found_key;
}
/*
* We're now behind the left extent (treat as unchanged) or at the end
* of the right side (treat as changed).
*/
if (key.offset >= ekey->offset + left_len)
ret = 1;
else
ret = 0;
out:
btrfs_free_path(path);
return ret;
}
static int process_extent(struct send_ctx *sctx,
struct btrfs_path *path,
struct btrfs_key *key)
{
int ret = 0;
struct clone_root *found_clone = NULL;
if (S_ISLNK(sctx->cur_inode_mode))
return 0;
if (sctx->parent_root && !sctx->cur_inode_new) {
ret = is_extent_unchanged(sctx, path, key);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
}
ret = find_extent_clone(sctx, path, key->objectid, key->offset,
sctx->cur_inode_size, &found_clone);
if (ret != -ENOENT && ret < 0)
goto out;
ret = send_write_or_clone(sctx, path, key, found_clone);
out:
return ret;
}
static int process_all_extents(struct send_ctx *sctx)
{
int ret;
struct btrfs_root *root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *eb;
int slot;
root = sctx->send_root;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = 0;
goto out;
}
ret = process_extent(sctx, path, &found_key);
if (ret < 0)
goto out;
btrfs_release_path(path);
key.offset = found_key.offset + 1;
}
out:
btrfs_free_path(path);
return ret;
}
static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end)
{
int ret = 0;
if (sctx->cur_ino == 0)
goto out;
if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid &&
sctx->cmp_key->type <= BTRFS_INODE_REF_KEY)
goto out;
if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
goto out;
ret = process_recorded_refs(sctx);
if (ret < 0)
goto out;
/*
* We have processed the refs and thus need to advance send_progress.
* Now, calls to get_cur_xxx will take the updated refs of the current
* inode into account.
*/
sctx->send_progress = sctx->cur_ino + 1;
out:
return ret;
}
static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
{
int ret = 0;
u64 left_mode;
u64 left_uid;
u64 left_gid;
u64 right_mode;
u64 right_uid;
u64 right_gid;
int need_chmod = 0;
int need_chown = 0;
ret = process_recorded_refs_if_needed(sctx, at_end);
if (ret < 0)
goto out;
if (sctx->cur_ino == 0 || sctx->cur_inode_deleted)
goto out;
if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino)
goto out;
ret = get_inode_info(sctx->send_root, sctx->cur_ino, NULL, NULL,
&left_mode, &left_uid, &left_gid, NULL);
if (ret < 0)
goto out;
if (!S_ISLNK(sctx->cur_inode_mode)) {
if (!sctx->parent_root || sctx->cur_inode_new) {
need_chmod = 1;
need_chown = 1;
} else {
ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
NULL, NULL, &right_mode, &right_uid,
&right_gid, NULL);
if (ret < 0)
goto out;
if (left_uid != right_uid || left_gid != right_gid)
need_chown = 1;
if (left_mode != right_mode)
need_chmod = 1;
}
}
if (S_ISREG(sctx->cur_inode_mode)) {
ret = send_truncate(sctx, sctx->cur_ino, sctx->cur_inode_gen,
sctx->cur_inode_size);
if (ret < 0)
goto out;
}
if (need_chown) {
ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen,
left_uid, left_gid);
if (ret < 0)
goto out;
}
if (need_chmod) {
ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen,
left_mode);
if (ret < 0)
goto out;
}
/*
* Need to send that every time, no matter if it actually changed
* between the two trees as we have done changes to the inode before.
*/
ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
if (ret < 0)
goto out;
out:
return ret;
}
static int changed_inode(struct send_ctx *sctx,
enum btrfs_compare_tree_result result)
{
int ret = 0;
struct btrfs_key *key = sctx->cmp_key;
struct btrfs_inode_item *left_ii = NULL;
struct btrfs_inode_item *right_ii = NULL;
u64 left_gen = 0;
u64 right_gen = 0;
ret = close_cur_inode_file(sctx);
if (ret < 0)
goto out;
sctx->cur_ino = key->objectid;
sctx->cur_inode_new_gen = 0;
/*
* Set send_progress to current inode. This will tell all get_cur_xxx
* functions that the current inode's refs are not updated yet. Later,
* when process_recorded_refs is finished, it is set to cur_ino + 1.
*/
sctx->send_progress = sctx->cur_ino;
if (result == BTRFS_COMPARE_TREE_NEW ||
result == BTRFS_COMPARE_TREE_CHANGED) {
left_ii = btrfs_item_ptr(sctx->left_path->nodes[0],
sctx->left_path->slots[0],
struct btrfs_inode_item);
left_gen = btrfs_inode_generation(sctx->left_path->nodes[0],
left_ii);
} else {
right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
sctx->right_path->slots[0],
struct btrfs_inode_item);
right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
right_ii);
}
if (result == BTRFS_COMPARE_TREE_CHANGED) {
right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
sctx->right_path->slots[0],
struct btrfs_inode_item);
right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
right_ii);
/*
* The cur_ino = root dir case is special here. We can't treat
* the inode as deleted+reused because it would generate a
* stream that tries to delete/mkdir the root dir.
*/
if (left_gen != right_gen &&
sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
sctx->cur_inode_new_gen = 1;
}
if (result == BTRFS_COMPARE_TREE_NEW) {
sctx->cur_inode_gen = left_gen;
sctx->cur_inode_new = 1;
sctx->cur_inode_deleted = 0;
sctx->cur_inode_size = btrfs_inode_size(
sctx->left_path->nodes[0], left_ii);
sctx->cur_inode_mode = btrfs_inode_mode(
sctx->left_path->nodes[0], left_ii);
if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
ret = send_create_inode_if_needed(sctx);
} else if (result == BTRFS_COMPARE_TREE_DELETED) {
sctx->cur_inode_gen = right_gen;
sctx->cur_inode_new = 0;
sctx->cur_inode_deleted = 1;
sctx->cur_inode_size = btrfs_inode_size(
sctx->right_path->nodes[0], right_ii);
sctx->cur_inode_mode = btrfs_inode_mode(
sctx->right_path->nodes[0], right_ii);
} else if (result == BTRFS_COMPARE_TREE_CHANGED) {
/*
* We need to do some special handling in case the inode was
* reported as changed with a changed generation number. This
* means that the original inode was deleted and new inode
* reused the same inum. So we have to treat the old inode as
* deleted and the new one as new.
*/
if (sctx->cur_inode_new_gen) {
/*
* First, process the inode as if it was deleted.
*/
sctx->cur_inode_gen = right_gen;
sctx->cur_inode_new = 0;
sctx->cur_inode_deleted = 1;
sctx->cur_inode_size = btrfs_inode_size(
sctx->right_path->nodes[0], right_ii);
sctx->cur_inode_mode = btrfs_inode_mode(
sctx->right_path->nodes[0], right_ii);
ret = process_all_refs(sctx,
BTRFS_COMPARE_TREE_DELETED);
if (ret < 0)
goto out;
/*
* Now process the inode as if it was new.
*/
sctx->cur_inode_gen = left_gen;
sctx->cur_inode_new = 1;
sctx->cur_inode_deleted = 0;
sctx->cur_inode_size = btrfs_inode_size(
sctx->left_path->nodes[0], left_ii);
sctx->cur_inode_mode = btrfs_inode_mode(
sctx->left_path->nodes[0], left_ii);
ret = send_create_inode_if_needed(sctx);
if (ret < 0)
goto out;
ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW);
if (ret < 0)
goto out;
/*
* Advance send_progress now as we did not get into
* process_recorded_refs_if_needed in the new_gen case.
*/
sctx->send_progress = sctx->cur_ino + 1;
/*
* Now process all extents and xattrs of the inode as if
* they were all new.
*/
ret = process_all_extents(sctx);
if (ret < 0)
goto out;
ret = process_all_new_xattrs(sctx);
if (ret < 0)
goto out;
} else {
sctx->cur_inode_gen = left_gen;
sctx->cur_inode_new = 0;
sctx->cur_inode_new_gen = 0;
sctx->cur_inode_deleted = 0;
sctx->cur_inode_size = btrfs_inode_size(
sctx->left_path->nodes[0], left_ii);
sctx->cur_inode_mode = btrfs_inode_mode(
sctx->left_path->nodes[0], left_ii);
}
}
out:
return ret;
}
/*
* We have to process new refs before deleted refs, but compare_trees gives us
* the new and deleted refs mixed. To fix this, we record the new/deleted refs
* first and later process them in process_recorded_refs.
* For the cur_inode_new_gen case, we skip recording completely because
* changed_inode did already initiate processing of refs. The reason for this is
* that in this case, compare_tree actually compares the refs of 2 different
* inodes. To fix this, process_all_refs is used in changed_inode to handle all
* refs of the right tree as deleted and all refs of the left tree as new.
*/
static int changed_ref(struct send_ctx *sctx,
enum btrfs_compare_tree_result result)
{
int ret = 0;
BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
if (!sctx->cur_inode_new_gen &&
sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) {
if (result == BTRFS_COMPARE_TREE_NEW)
ret = record_new_ref(sctx);
else if (result == BTRFS_COMPARE_TREE_DELETED)
ret = record_deleted_ref(sctx);
else if (result == BTRFS_COMPARE_TREE_CHANGED)
ret = record_changed_ref(sctx);
}
return ret;
}
/*
* Process new/deleted/changed xattrs. We skip processing in the
* cur_inode_new_gen case because changed_inode did already initiate processing
* of xattrs. The reason is the same as in changed_ref
*/
static int changed_xattr(struct send_ctx *sctx,
enum btrfs_compare_tree_result result)
{
int ret = 0;
BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
if (result == BTRFS_COMPARE_TREE_NEW)
ret = process_new_xattr(sctx);
else if (result == BTRFS_COMPARE_TREE_DELETED)
ret = process_deleted_xattr(sctx);
else if (result == BTRFS_COMPARE_TREE_CHANGED)
ret = process_changed_xattr(sctx);
}
return ret;
}
/*
* Process new/deleted/changed extents. We skip processing in the
* cur_inode_new_gen case because changed_inode did already initiate processing
* of extents. The reason is the same as in changed_ref
*/
static int changed_extent(struct send_ctx *sctx,
enum btrfs_compare_tree_result result)
{
int ret = 0;
BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
if (result != BTRFS_COMPARE_TREE_DELETED)
ret = process_extent(sctx, sctx->left_path,
sctx->cmp_key);
}
return ret;
}
/*
* Updates compare related fields in sctx and simply forwards to the actual
* changed_xxx functions.
*/
static int changed_cb(struct btrfs_root *left_root,
struct btrfs_root *right_root,
struct btrfs_path *left_path,
struct btrfs_path *right_path,
struct btrfs_key *key,
enum btrfs_compare_tree_result result,
void *ctx)
{
int ret = 0;
struct send_ctx *sctx = ctx;
sctx->left_path = left_path;
sctx->right_path = right_path;
sctx->cmp_key = key;
ret = finish_inode_if_needed(sctx, 0);
if (ret < 0)
goto out;
/* Ignore non-FS objects */
if (key->objectid == BTRFS_FREE_INO_OBJECTID ||
key->objectid == BTRFS_FREE_SPACE_OBJECTID)
goto out;
if (key->type == BTRFS_INODE_ITEM_KEY)
ret = changed_inode(sctx, result);
else if (key->type == BTRFS_INODE_REF_KEY)
ret = changed_ref(sctx, result);
else if (key->type == BTRFS_XATTR_ITEM_KEY)
ret = changed_xattr(sctx, result);
else if (key->type == BTRFS_EXTENT_DATA_KEY)
ret = changed_extent(sctx, result);
out:
return ret;
}
static int full_send_tree(struct send_ctx *sctx)
{
int ret;
struct btrfs_trans_handle *trans = NULL;
struct btrfs_root *send_root = sctx->send_root;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_path *path;
struct extent_buffer *eb;
int slot;
u64 start_ctransid;
u64 ctransid;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
spin_lock(&send_root->root_times_lock);
start_ctransid = btrfs_root_ctransid(&send_root->root_item);
spin_unlock(&send_root->root_times_lock);
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
join_trans:
/*
* We need to make sure the transaction does not get committed
* while we do anything on commit roots. Join a transaction to prevent
* this.
*/
trans = btrfs_join_transaction(send_root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
goto out;
}
/*
* Make sure the tree has not changed after re-joining. We detect this
* by comparing start_ctransid and ctransid. They should always match.
*/
spin_lock(&send_root->root_times_lock);
ctransid = btrfs_root_ctransid(&send_root->root_item);
spin_unlock(&send_root->root_times_lock);
if (ctransid != start_ctransid) {
WARN(1, KERN_WARNING "btrfs: the root that you're trying to "
"send was modified in between. This is "
"probably a bug.\n");
ret = -EIO;
goto out;
}
ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret)
goto out_finish;
while (1) {
/*
* When someone want to commit while we iterate, end the
* joined transaction and rejoin.
*/
if (btrfs_should_end_transaction(trans, send_root)) {
ret = btrfs_end_transaction(trans, send_root);
trans = NULL;
if (ret < 0)
goto out;
btrfs_release_path(path);
goto join_trans;
}
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
ret = changed_cb(send_root, NULL, path, NULL,
&found_key, BTRFS_COMPARE_TREE_NEW, sctx);
if (ret < 0)
goto out;
key.objectid = found_key.objectid;
key.type = found_key.type;
key.offset = found_key.offset + 1;
ret = btrfs_next_item(send_root, path);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
break;
}
}
out_finish:
ret = finish_inode_if_needed(sctx, 1);
out:
btrfs_free_path(path);
if (trans) {
if (!ret)
ret = btrfs_end_transaction(trans, send_root);
else
btrfs_end_transaction(trans, send_root);
}
return ret;
}
static int send_subvol(struct send_ctx *sctx)
{
int ret;
ret = send_header(sctx);
if (ret < 0)
goto out;
ret = send_subvol_begin(sctx);
if (ret < 0)
goto out;
if (sctx->parent_root) {
ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root,
changed_cb, sctx);
if (ret < 0)
goto out;
ret = finish_inode_if_needed(sctx, 1);
if (ret < 0)
goto out;
} else {
ret = full_send_tree(sctx);
if (ret < 0)
goto out;
}
out:
if (!ret)
ret = close_cur_inode_file(sctx);
else
close_cur_inode_file(sctx);
free_recorded_refs(sctx);
return ret;
}
long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
{
int ret = 0;
struct btrfs_root *send_root;
struct btrfs_root *clone_root;
struct btrfs_fs_info *fs_info;
struct btrfs_ioctl_send_args *arg = NULL;
struct btrfs_key key;
struct file *filp = NULL;
struct send_ctx *sctx = NULL;
u32 i;
u64 *clone_sources_tmp = NULL;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
send_root = BTRFS_I(fdentry(mnt_file)->d_inode)->root;
fs_info = send_root->fs_info;
arg = memdup_user(arg_, sizeof(*arg));
if (IS_ERR(arg)) {
ret = PTR_ERR(arg);
arg = NULL;
goto out;
}
if (!access_ok(VERIFY_READ, arg->clone_sources,
sizeof(*arg->clone_sources *
arg->clone_sources_count))) {
ret = -EFAULT;
goto out;
}
sctx = kzalloc(sizeof(struct send_ctx), GFP_NOFS);
if (!sctx) {
ret = -ENOMEM;
goto out;
}
INIT_LIST_HEAD(&sctx->new_refs);
INIT_LIST_HEAD(&sctx->deleted_refs);
INIT_RADIX_TREE(&sctx->name_cache, GFP_NOFS);
INIT_LIST_HEAD(&sctx->name_cache_list);
sctx->send_filp = fget(arg->send_fd);
if (IS_ERR(sctx->send_filp)) {
ret = PTR_ERR(sctx->send_filp);
goto out;
}
sctx->mnt = mnt_file->f_path.mnt;
sctx->send_root = send_root;
sctx->clone_roots_cnt = arg->clone_sources_count;
sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
sctx->send_buf = vmalloc(sctx->send_max_size);
if (!sctx->send_buf) {
ret = -ENOMEM;
goto out;
}
sctx->read_buf = vmalloc(BTRFS_SEND_READ_SIZE);
if (!sctx->read_buf) {
ret = -ENOMEM;
goto out;
}
sctx->clone_roots = vzalloc(sizeof(struct clone_root) *
(arg->clone_sources_count + 1));
if (!sctx->clone_roots) {
ret = -ENOMEM;
goto out;
}
if (arg->clone_sources_count) {
clone_sources_tmp = vmalloc(arg->clone_sources_count *
sizeof(*arg->clone_sources));
if (!clone_sources_tmp) {
ret = -ENOMEM;
goto out;
}
ret = copy_from_user(clone_sources_tmp, arg->clone_sources,
arg->clone_sources_count *
sizeof(*arg->clone_sources));
if (ret) {
ret = -EFAULT;
goto out;
}
for (i = 0; i < arg->clone_sources_count; i++) {
key.objectid = clone_sources_tmp[i];
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = (u64)-1;
clone_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (!clone_root) {
ret = -EINVAL;
goto out;
}
if (IS_ERR(clone_root)) {
ret = PTR_ERR(clone_root);
goto out;
}
sctx->clone_roots[i].root = clone_root;
}
vfree(clone_sources_tmp);
clone_sources_tmp = NULL;
}
if (arg->parent_root) {
key.objectid = arg->parent_root;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = (u64)-1;
sctx->parent_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (!sctx->parent_root) {
ret = -EINVAL;
goto out;
}
}
/*
* Clones from send_root are allowed, but only if the clone source
* is behind the current send position. This is checked while searching
* for possible clone sources.
*/
sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root;
/* We do a bsearch later */
sort(sctx->clone_roots, sctx->clone_roots_cnt,
sizeof(*sctx->clone_roots), __clone_root_cmp_sort,
NULL);
ret = send_subvol(sctx);
if (ret < 0)
goto out;
ret = begin_cmd(sctx, BTRFS_SEND_C_END);
if (ret < 0)
goto out;
ret = send_cmd(sctx);
if (ret < 0)
goto out;
out:
if (filp)
fput(filp);
kfree(arg);
vfree(clone_sources_tmp);
if (sctx) {
if (sctx->send_filp)
fput(sctx->send_filp);
vfree(sctx->clone_roots);
vfree(sctx->send_buf);
vfree(sctx->read_buf);
name_cache_free(sctx);
kfree(sctx);
}
return ret;
}