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linux/fs/btrfs/send.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 Alexander Block. All rights reserved.
*/
#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/vmalloc.h>
#include <linux/string.h>
#include <linux/compat.h>
#include <linux/crc32c.h>
#include "send.h"
#include "backref.h"
#include "locking.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "compression.h"
/*
* 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 *buf;
unsigned short buf_len:15;
unsigned short reversed:1;
char inline_buf[];
};
/*
* Average path length does not exceed 200 bytes, we'll have
* better packing in the slab and higher chance to satisfy
* a allocation later during send.
*/
char pad[256];
};
};
#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];
u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */
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 cur_inode_rdev;
u64 cur_inode_last_extent;
u64 cur_inode_next_write_offset;
bool ignore_cur_inode;
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_ra_state ra;
char *read_buf;
/*
* We process inodes by their increasing order, so if before an
* incremental send we reverse the parent/child relationship of
* directories such that a directory with a lower inode number was
* the parent of a directory with a higher inode number, and the one
* becoming the new parent got renamed too, we can't rename/move the
* directory with lower inode number when we finish processing it - we
* must process the directory with higher inode number first, then
* rename/move it and then rename/move the directory with lower inode
* number. Example follows.
*
* Tree state when the first send was performed:
*
* .
* |-- a (ino 257)
* |-- b (ino 258)
* |
* |
* |-- c (ino 259)
* | |-- d (ino 260)
* |
* |-- c2 (ino 261)
*
* Tree state when the second (incremental) send is performed:
*
* .
* |-- a (ino 257)
* |-- b (ino 258)
* |-- c2 (ino 261)
* |-- d2 (ino 260)
* |-- cc (ino 259)
*
* The sequence of steps that lead to the second state was:
*
* mv /a/b/c/d /a/b/c2/d2
* mv /a/b/c /a/b/c2/d2/cc
*
* "c" has lower inode number, but we can't move it (2nd mv operation)
* before we move "d", which has higher inode number.
*
* So we just memorize which move/rename operations must be performed
* later when their respective parent is processed and moved/renamed.
*/
/* Indexed by parent directory inode number. */
struct rb_root pending_dir_moves;
/*
* Reverse index, indexed by the inode number of a directory that
* is waiting for the move/rename of its immediate parent before its
* own move/rename can be performed.
*/
struct rb_root waiting_dir_moves;
/*
* A directory that is going to be rm'ed might have a child directory
* which is in the pending directory moves index above. In this case,
* the directory can only be removed after the move/rename of its child
* is performed. Example:
*
* Parent snapshot:
*
* . (ino 256)
* |-- a/ (ino 257)
* |-- b/ (ino 258)
* |-- c/ (ino 259)
* | |-- x/ (ino 260)
* |
* |-- y/ (ino 261)
*
* Send snapshot:
*
* . (ino 256)
* |-- a/ (ino 257)
* |-- b/ (ino 258)
* |-- YY/ (ino 261)
* |-- x/ (ino 260)
*
* Sequence of steps that lead to the send snapshot:
* rm -f /a/b/c/foo.txt
* mv /a/b/y /a/b/YY
* mv /a/b/c/x /a/b/YY
* rmdir /a/b/c
*
* When the child is processed, its move/rename is delayed until its
* parent is processed (as explained above), but all other operations
* like update utimes, chown, chgrp, etc, are performed and the paths
* that it uses for those operations must use the orphanized name of
* its parent (the directory we're going to rm later), so we need to
* memorize that name.
*
* Indexed by the inode number of the directory to be deleted.
*/
struct rb_root orphan_dirs;
};
struct pending_dir_move {
struct rb_node node;
struct list_head list;
u64 parent_ino;
u64 ino;
u64 gen;
struct list_head update_refs;
};
struct waiting_dir_move {
struct rb_node node;
u64 ino;
/*
* There might be some directory that could not be removed because it
* was waiting for this directory inode to be moved first. Therefore
* after this directory is moved, we can try to rmdir the ino rmdir_ino.
*/
u64 rmdir_ino;
bool orphanized;
};
struct orphan_dir_info {
struct rb_node node;
u64 ino;
u64 gen;
u64 last_dir_index_offset;
};
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[];
};
__cold
static void inconsistent_snapshot_error(struct send_ctx *sctx,
enum btrfs_compare_tree_result result,
const char *what)
{
const char *result_string;
switch (result) {
case BTRFS_COMPARE_TREE_NEW:
result_string = "new";
break;
case BTRFS_COMPARE_TREE_DELETED:
result_string = "deleted";
break;
case BTRFS_COMPARE_TREE_CHANGED:
result_string = "updated";
break;
case BTRFS_COMPARE_TREE_SAME:
ASSERT(0);
result_string = "unchanged";
break;
default:
ASSERT(0);
result_string = "unexpected";
}
btrfs_err(sctx->send_root->fs_info,
"Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu",
result_string, what, sctx->cmp_key->objectid,
sctx->send_root->root_key.objectid,
(sctx->parent_root ?
sctx->parent_root->root_key.objectid : 0));
}
static int is_waiting_for_move(struct send_ctx *sctx, u64 ino);
static struct waiting_dir_move *
get_waiting_dir_move(struct send_ctx *sctx, u64 ino);
static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino);
static int need_send_hole(struct send_ctx *sctx)
{
return (sctx->parent_root && !sctx->cur_inode_new &&
!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted &&
S_ISREG(sctx->cur_inode_mode));
}
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(void)
{
struct fs_path *p;
p = kmalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return NULL;
p->reversed = 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(void)
{
struct fs_path *p;
p = fs_path_alloc();
if (!p)
return NULL;
p->reversed = 1;
fs_path_reset(p);
return p;
}
static void fs_path_free(struct fs_path *p)
{
if (!p)
return;
if (p->buf != p->inline_buf)
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;
if (len > PATH_MAX) {
WARN_ON(1);
return -ENOMEM;
}
path_len = p->end - p->start;
old_buf_len = p->buf_len;
/*
* First time the inline_buf does not suffice
*/
if (p->buf == p->inline_buf) {
tmp_buf = kmalloc(len, GFP_KERNEL);
if (tmp_buf)
memcpy(tmp_buf, p->buf, old_buf_len);
} else {
tmp_buf = krealloc(p->buf, len, GFP_KERNEL);
}
if (!tmp_buf)
return -ENOMEM;
p->buf = tmp_buf;
/*
* The real size of the buffer is bigger, this will let the fast path
* happen most of the time
*/
p->buf_len = ksize(p->buf);
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,
char **prepared)
{
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;
*prepared = p->start;
} else {
if (p->start != p->end)
*p->end++ = '/';
*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;
char *prepared;
ret = fs_path_prepare_for_add(p, name_len, &prepared);
if (ret < 0)
goto out;
memcpy(prepared, name, name_len);
out:
return ret;
}
static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
{
int ret;
char *prepared;
ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared);
if (ret < 0)
goto out;
memcpy(prepared, p2->start, p2->end - p2->start);
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;
char *prepared;
ret = fs_path_prepare_for_add(p, len, &prepared);
if (ret < 0)
goto out;
read_extent_buffer(eb, prepared, off, len);
out:
return ret;
}
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;
path->need_commit_sem = 1;
return path;
}
static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off)
{
int ret;
u32 pos = 0;
while (pos < len) {
ret = kernel_write(filp, buf + pos, len - pos, off);
/* TODO handle that correctly */
/*if (ret == -ERESTARTSYS) {
continue;
}*/
if (ret < 0)
return ret;
if (ret == 0) {
return -EIO;
}
pos += ret;
}
return 0;
}
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;
}
#define TLV_PUT_DEFINE_INT(bits) \
static int tlv_put_u##bits(struct send_ctx *sctx, \
u##bits attr, u##bits value) \
{ \
__le##bits __tmp = cpu_to_le##bits(value); \
return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \
}
TLV_PUT_DEFINE_INT(64)
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);
}
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, data, attrlen) \
do { \
ret = tlv_put(sctx, attrtype, data, attrlen); \
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_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->send_filp, &hdr, sizeof(hdr),
&sctx->send_off);
}
/*
* 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 (WARN_ON(!sctx->send_buf))
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 = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
hdr->crc = cpu_to_le32(crc);
ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
&sctx->send_off);
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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_rename %s -> %s", 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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_link %s -> %s", 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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_unlink %s", 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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_rmdir %s", 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, struct btrfs_path *path,
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;
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret) {
if (ret > 0)
ret = -ENOENT;
return ret;
}
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);
return ret;
}
static int get_inode_info(struct btrfs_root *root,
u64 ino, u64 *size, u64 *gen,
u64 *mode, u64 *uid, u64 *gid,
u64 *rdev)
{
struct btrfs_path *path;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
ret = __get_inode_info(root, path, ino, size, gen, mode, uid, gid,
rdev);
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 or
* btrfs_inode_extref.
* 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 or INODE_EXTREF when called.
*/
static int iterate_inode_ref(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 = path->nodes[0];
struct btrfs_item *item;
struct btrfs_inode_ref *iref;
struct btrfs_inode_extref *extref;
struct btrfs_path *tmp_path;
struct fs_path *p;
u32 cur = 0;
u32 total;
int slot = path->slots[0];
u32 name_len;
char *start;
int ret = 0;
int num = 0;
int index;
u64 dir;
unsigned long name_off;
unsigned long elem_size;
unsigned long ptr;
p = fs_path_alloc_reversed();
if (!p)
return -ENOMEM;
tmp_path = alloc_path_for_send();
if (!tmp_path) {
fs_path_free(p);
return -ENOMEM;
}
if (found_key->type == BTRFS_INODE_REF_KEY) {
ptr = (unsigned long)btrfs_item_ptr(eb, slot,
struct btrfs_inode_ref);
item = btrfs_item_nr(slot);
total = btrfs_item_size(eb, item);
elem_size = sizeof(*iref);
} else {
ptr = btrfs_item_ptr_offset(eb, slot);
total = btrfs_item_size_nr(eb, slot);
elem_size = sizeof(*extref);
}
while (cur < total) {
fs_path_reset(p);
if (found_key->type == BTRFS_INODE_REF_KEY) {
iref = (struct btrfs_inode_ref *)(ptr + cur);
name_len = btrfs_inode_ref_name_len(eb, iref);
name_off = (unsigned long)(iref + 1);
index = btrfs_inode_ref_index(eb, iref);
dir = found_key->offset;
} else {
extref = (struct btrfs_inode_extref *)(ptr + cur);
name_len = btrfs_inode_extref_name_len(eb, extref);
name_off = (unsigned long)&extref->name;
index = btrfs_inode_extref_index(eb, extref);
dir = btrfs_inode_extref_parent(eb, extref);
}
if (resolve) {
start = btrfs_ref_to_path(root, tmp_path, name_len,
name_off, eb, dir,
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_ref_to_path(root, tmp_path,
name_len, name_off,
eb, dir,
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, name_off,
name_len);
if (ret < 0)
goto out;
}
cur += elem_size + name_len;
ret = iterate(num, dir, index, p, ctx);
if (ret)
goto out;
num++;
}
out:
btrfs_free_path(tmp_path);
fs_path_free(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 btrfs_root *root, struct btrfs_path *path,
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;
int buf_len;
u32 name_len;
u32 data_len;
u32 cur;
u32 len;
u32 total;
int slot;
int num;
u8 type;
/*
* Start with a small buffer (1 page). If later we end up needing more
* space, which can happen for xattrs on a fs with a leaf size greater
* then the page size, attempt to increase the buffer. Typically xattr
* values are small.
*/
buf_len = PATH_MAX;
buf = kmalloc(buf_len, GFP_KERNEL);
if (!buf) {
ret = -ENOMEM;
goto out;
}
eb = path->nodes[0];
slot = path->slots[0];
item = btrfs_item_nr(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 (type == BTRFS_FT_XATTR) {
if (name_len > XATTR_NAME_MAX) {
ret = -ENAMETOOLONG;
goto out;
}
if (name_len + data_len >
BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
ret = -E2BIG;
goto out;
}
} else {
/*
* Path too long
*/
if (name_len + data_len > PATH_MAX) {
ret = -ENAMETOOLONG;
goto out;
}
}
if (name_len + data_len > buf_len) {
buf_len = name_len + data_len;
if (is_vmalloc_addr(buf)) {
vfree(buf);
buf = NULL;
} else {
char *tmp = krealloc(buf, buf_len,
GFP_KERNEL | __GFP_NOWARN);
if (!tmp)
kfree(buf);
buf = tmp;
}
if (!buf) {
buf = kvmalloc(buf_len, GFP_KERNEL);
if (!buf) {
ret = -ENOMEM;
goto out;
}
}
}
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:
kvfree(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 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 &&
found_key.type != BTRFS_INODE_EXTREF_KEY)) {
ret = -ENOENT;
goto out;
}
ret = iterate_inode_ref(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;
/* data offset in the file extent item */
u64 data_offset;
/* 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)(uintptr_t)key;
struct clone_root *cr = (struct clone_root *)elt;
if (root < cr->root->root_key.objectid)
return -1;
if (root > cr->root->root_key.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->root_key.objectid < cr2->root->root_key.objectid)
return -1;
if (cr1->root->root_key.objectid > cr2->root->root_key.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;
/* First check if the root is in the list of accepted clone sources */
found = bsearch((void *)(uintptr_t)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;
}
/*
* 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;
}
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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
int extent_type;
u64 logical;
u64 disk_byte;
u64 num_bytes;
u64 extent_item_pos;
u64 flags = 0;
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;
/* We only use this path under the commit sem */
tmp_path->need_commit_sem = 0;
backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_KERNEL);
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);
down_read(&fs_info->commit_root_sem);
ret = extent_from_logical(fs_info, disk_byte, tmp_path,
&found_key, &flags);
up_read(&fs_info->commit_root_sem);
btrfs_release_path(tmp_path);
if (ret < 0)
goto out;
if (flags & 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;
/*
* For non-compressed extents iterate_extent_inodes() gives us extent
* offsets that already take into account the data offset, but not for
* compressed extents, since the offset is logical and not relative to
* the physical extent locations. We must take this into account to
* avoid sending clone offsets that go beyond the source file's size,
* which would result in the clone ioctl failing with -EINVAL on the
* receiving end.
*/
if (compressed == BTRFS_COMPRESS_NONE)
backref_ctx->data_offset = 0;
else
backref_ctx->data_offset = btrfs_file_extent_offset(eb, fi);
/*
* 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;
ret = iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, 1, __iterate_backrefs,
backref_ctx, false);
if (ret < 0)
goto out;
if (!backref_ctx->found_itself) {
/* found a bug in backref code? */
ret = -EIO;
btrfs_err(fs_info,
"did not find backref in send_root. inode=%llu, offset=%llu, disk_byte=%llu found extent=%llu",
ino, data_offset, disk_byte, found_key.objectid);
goto out;
}
btrfs_debug(fs_info,
"find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu",
data_offset, ino, num_bytes, logical);
if (!backref_ctx->found)
btrfs_debug(fs_info, "no clones found");
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 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;
if (ret) {
/*
* An empty symlink inode. Can happen in rare error paths when
* creating a symlink (transaction committed before the inode
* eviction handler removed the symlink inode items and a crash
* happened in between or the subvol was snapshoted in between).
* Print an informative message to dmesg/syslog so that the user
* can delete the symlink.
*/
btrfs_err(root->fs_info,
"Found empty symlink inode %llu at root %llu",
ino, root->root_key.objectid);
ret = -EIO;
goto out;
}
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_ram_bytes(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), "o%llu-%llu-%llu",
ino, gen, idx);
ASSERT(len < sizeof(tmp));
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;
if (ino == BTRFS_FIRST_FREE_OBJECTID)
return 1;
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 (IS_ERR_OR_NULL(di)) {
ret = di ? PTR_ERR(di) : -ENOENT;
goto out;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
if (key.type == BTRFS_ROOT_ITEM_KEY) {
ret = -ENOENT;
goto out;
}
*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 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;
int len;
u64 parent_dir;
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 != ino ||
(found_key.type != BTRFS_INODE_REF_KEY &&
found_key.type != BTRFS_INODE_EXTREF_KEY)) {
ret = -ENOENT;
goto out;
}
if (found_key.type == BTRFS_INODE_REF_KEY) {
struct btrfs_inode_ref *iref;
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);
parent_dir = found_key.offset;
} else {
struct btrfs_inode_extref *extref;
extref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_extref);
len = btrfs_inode_extref_name_len(path->nodes[0], extref);
ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
(unsigned long)&extref->name, len);
parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref);
}
if (ret < 0)
goto out;
btrfs_release_path(path);
if (dir_gen) {
ret = get_inode_info(root, parent_dir, NULL, dir_gen, NULL,
NULL, NULL, NULL);
if (ret < 0)
goto out;
}
*dir = parent_dir;
out:
btrfs_free_path(path);
return ret;
}
static int is_first_ref(struct btrfs_root *root,
u64 ino, u64 dir,
const char *name, int name_len)
{
int ret;
struct fs_path *tmp_name;
u64 tmp_dir;
tmp_name = fs_path_alloc();
if (!tmp_name)
return -ENOMEM;
ret = get_first_ref(root, ino, &tmp_dir, NULL, 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(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, u64 *who_mode)
{
int ret = 0;
u64 gen;
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;
/*
* If we have a parent root we need to verify that the parent dir was
* not deleted and then re-created, if it was then we have no overwrite
* and we can just unlink this entry.
*/
if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) {
ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL,
NULL, NULL, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
ret = 0;
goto out;
}
if (gen != dir_gen)
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 ||
is_waiting_for_move(sctx, other_inode)) {
ret = get_inode_info(sctx->parent_root, other_inode, NULL,
who_gen, who_mode, 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;
if (dir != BTRFS_FIRST_FREE_OBJECTID) {
ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL,
NULL, NULL, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
ret = 0;
goto out;
}
if (gen != dir_gen)
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.
* The current inode being processed might have been the one that caused
* inode 'ino' to be orphanized, therefore check if ow_inode matches
* the current inode being processed.
*/
if ((ow_inode < sctx->send_progress) ||
(ino != sctx->cur_ino && ow_inode == sctx->cur_ino &&
gen == sctx->cur_inode_gen))
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();
if (!name)
return -ENOMEM;
ret = get_first_ref(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(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_KERNEL);
if (!nce_head) {
kfree(nce);
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);
if (!nce_head) {
btrfs_err(sctx->send_root->fs_info,
"name_cache_delete lookup failed ino %llu cache size %d, leaking memory",
nce->ino, sctx->name_cache_size);
}
list_del(&nce->radix_list);
list_del(&nce->list);
sctx->name_cache_size--;
/*
* We may not get to the final release of nce_head if the lookup fails
*/
if (nce_head && 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 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;
}
}
/*
* 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->send_root, ino,
parent_ino, parent_gen, dest);
else
ret = get_first_ref(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_KERNEL);
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:
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 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();
if (!name) {
ret = -ENOMEM;
goto out;
}
dest->reversed = 1;
fs_path_reset(dest);
while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
struct waiting_dir_move *wdm;
fs_path_reset(name);
if (is_waiting_for_rm(sctx, ino)) {
ret = gen_unique_name(sctx, ino, gen, name);
if (ret < 0)
goto out;
ret = fs_path_add_path(dest, name);
break;
}
wdm = get_waiting_dir_move(sctx, ino);
if (wdm && wdm->orphanized) {
ret = gen_unique_name(sctx, ino, gen, name);
stop = 1;
} else if (wdm) {
ret = get_first_ref(sctx->parent_root, ino,
&parent_inode, &parent_gen, name);
} else {
ret = __get_cur_name_and_parent(sctx, ino, gen,
&parent_inode,
&parent_gen, name);
if (ret)
stop = 1;
}
if (ret < 0)
goto out;
ret = fs_path_add_path(dest, name);
if (ret < 0)
goto out;
ino = parent_inode;
gen = parent_gen;
}
out:
fs_path_free(name);
if (!ret)
fs_path_unreverse(dest);
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 = btrfs_alloc_path();
if (!path)
return -ENOMEM;
name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL);
if (!name) {
btrfs_free_path(path);
return -ENOMEM;
}
key.objectid = send_root->root_key.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->root_key.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);
if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid))
TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
sctx->send_root->root_item.received_uuid);
else
TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
sctx->send_root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
le64_to_cpu(sctx->send_root->root_item.ctransid));
if (parent_root) {
if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid))
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
parent_root->root_item.received_uuid);
else
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
parent_root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
le64_to_cpu(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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size);
p = fs_path_alloc();
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(p);
return ret;
}
static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode);
p = fs_path_alloc();
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(p);
return ret;
}
static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu",
ino, uid, gid);
p = fs_path_alloc();
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(p);
return ret;
}
static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
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;
btrfs_debug(fs_info, "send_utimes %llu", ino);
p = fs_path_alloc();
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)
ret = -ENOENT;
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, &ii->atime);
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime);
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime);
/* TODO Add otime support when the otime patches get into upstream */
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
int cmd;
u64 gen;
u64 mode;
u64 rdev;
btrfs_debug(fs_info, "send_create_inode %llu", ino);
p = fs_path_alloc();
if (!p)
return -ENOMEM;
if (ino != sctx->cur_ino) {
ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode,
NULL, NULL, &rdev);
if (ret < 0)
goto out;
} else {
gen = sctx->cur_inode_gen;
mode = sctx->cur_inode_mode;
rdev = sctx->cur_inode_rdev;
}
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 {
btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o",
(int)(mode & S_IFMT));
ret = -EOPNOTSUPP;
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->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, new_encode_dev(rdev));
TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode);
}
ret = send_cmd(sctx);
if (ret < 0)
goto out;
tlv_put_failure:
out:
fs_path_free(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;
ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(sctx->send_root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (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.type != BTRFS_ROOT_ITEM_KEY &&
di_key.objectid < sctx->send_progress) {
ret = 1;
goto out;
}
path->slots[0]++;
}
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 *name;
struct fs_path *full_path;
u64 dir;
u64 dir_gen;
int name_len;
};
static void set_ref_path(struct recorded_ref *ref, struct fs_path *path)
{
ref->full_path = path;
ref->name = (char *)kbasename(ref->full_path->start);
ref->name_len = ref->full_path->end - ref->name;
}
/*
* 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;
ref = kmalloc(sizeof(*ref), GFP_KERNEL);
if (!ref)
return -ENOMEM;
ref->dir = dir;
ref->dir_gen = dir_gen;
set_ref_path(ref, path);
list_add_tail(&ref->list, head);
return 0;
}
static int dup_ref(struct recorded_ref *ref, struct list_head *list)
{
struct recorded_ref *new;
new = kmalloc(sizeof(*ref), GFP_KERNEL);
if (!new)
return -ENOMEM;
new->dir = ref->dir;
new->dir_gen = ref->dir_gen;
new->full_path = NULL;
INIT_LIST_HEAD(&new->list);
list_add_tail(&new->list, list);
return 0;
}
static void __free_recorded_refs(struct list_head *head)
{
struct recorded_ref *cur;
while (!list_empty(head)) {
cur = list_entry(head->next, struct recorded_ref, list);
fs_path_free(cur->full_path);
list_del(&cur->list);
kfree(cur);
}
}
static void free_recorded_refs(struct send_ctx *sctx)
{
__free_recorded_refs(&sctx->new_refs);
__free_recorded_refs(&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();
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(orphan);
return ret;
}
static struct orphan_dir_info *
add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino)
{
struct rb_node **p = &sctx->orphan_dirs.rb_node;
struct rb_node *parent = NULL;
struct orphan_dir_info *entry, *odi;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct orphan_dir_info, node);
if (dir_ino < entry->ino) {
p = &(*p)->rb_left;
} else if (dir_ino > entry->ino) {
p = &(*p)->rb_right;
} else {
return entry;
}
}
odi = kmalloc(sizeof(*odi), GFP_KERNEL);
if (!odi)
return ERR_PTR(-ENOMEM);
odi->ino = dir_ino;
odi->gen = 0;
odi->last_dir_index_offset = 0;
rb_link_node(&odi->node, parent, p);
rb_insert_color(&odi->node, &sctx->orphan_dirs);
return odi;
}
static struct orphan_dir_info *
get_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino)
{
struct rb_node *n = sctx->orphan_dirs.rb_node;
struct orphan_dir_info *entry;
while (n) {
entry = rb_entry(n, struct orphan_dir_info, node);
if (dir_ino < entry->ino)
n = n->rb_left;
else if (dir_ino > entry->ino)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino)
{
struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino);
return odi != NULL;
}
static void free_orphan_dir_info(struct send_ctx *sctx,
struct orphan_dir_info *odi)
{
if (!odi)
return;
rb_erase(&odi->node, &sctx->orphan_dirs);
kfree(odi);
}
/*
* 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 dir_gen,
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;
struct orphan_dir_info *odi = NULL;
/*
* 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;
odi = get_orphan_dir_info(sctx, dir);
if (odi)
key.offset = odi->last_dir_index_offset;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
struct waiting_dir_move *dm;
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (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);
dm = get_waiting_dir_move(sctx, loc.objectid);
if (dm) {
odi = add_orphan_dir_info(sctx, dir);
if (IS_ERR(odi)) {
ret = PTR_ERR(odi);
goto out;
}
odi->gen = dir_gen;
odi->last_dir_index_offset = found_key.offset;
dm->rmdir_ino = dir;
ret = 0;
goto out;
}
if (loc.objectid > send_progress) {
odi = add_orphan_dir_info(sctx, dir);
if (IS_ERR(odi)) {
ret = PTR_ERR(odi);
goto out;
}
odi->gen = dir_gen;
odi->last_dir_index_offset = found_key.offset;
ret = 0;
goto out;
}
path->slots[0]++;
}
free_orphan_dir_info(sctx, odi);
ret = 1;
out:
btrfs_free_path(path);
return ret;
}
static int is_waiting_for_move(struct send_ctx *sctx, u64 ino)
{
struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino);
return entry != NULL;
}
static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized)
{
struct rb_node **p = &sctx->waiting_dir_moves.rb_node;
struct rb_node *parent = NULL;
struct waiting_dir_move *entry, *dm;
dm = kmalloc(sizeof(*dm), GFP_KERNEL);
if (!dm)
return -ENOMEM;
dm->ino = ino;
dm->rmdir_ino = 0;
dm->orphanized = orphanized;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct waiting_dir_move, node);
if (ino < entry->ino) {
p = &(*p)->rb_left;
} else if (ino > entry->ino) {
p = &(*p)->rb_right;
} else {
kfree(dm);
return -EEXIST;
}
}
rb_link_node(&dm->node, parent, p);
rb_insert_color(&dm->node, &sctx->waiting_dir_moves);
return 0;
}
static struct waiting_dir_move *
get_waiting_dir_move(struct send_ctx *sctx, u64 ino)
{
struct rb_node *n = sctx->waiting_dir_moves.rb_node;
struct waiting_dir_move *entry;
while (n) {
entry = rb_entry(n, struct waiting_dir_move, node);
if (ino < entry->ino)
n = n->rb_left;
else if (ino > entry->ino)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static void free_waiting_dir_move(struct send_ctx *sctx,
struct waiting_dir_move *dm)
{
if (!dm)
return;
rb_erase(&dm->node, &sctx->waiting_dir_moves);
kfree(dm);
}
static int add_pending_dir_move(struct send_ctx *sctx,
u64 ino,
u64 ino_gen,
u64 parent_ino,
struct list_head *new_refs,
struct list_head *deleted_refs,
const bool is_orphan)
{
struct rb_node **p = &sctx->pending_dir_moves.rb_node;
struct rb_node *parent = NULL;
struct pending_dir_move *entry = NULL, *pm;
struct recorded_ref *cur;
int exists = 0;
int ret;
pm = kmalloc(sizeof(*pm), GFP_KERNEL);
if (!pm)
return -ENOMEM;
pm->parent_ino = parent_ino;
pm->ino = ino;
pm->gen = ino_gen;
INIT_LIST_HEAD(&pm->list);
INIT_LIST_HEAD(&pm->update_refs);
RB_CLEAR_NODE(&pm->node);
while (*p) {
parent = *p;
entry = rb_entry(parent, struct pending_dir_move, node);
if (parent_ino < entry->parent_ino) {
p = &(*p)->rb_left;
} else if (parent_ino > entry->parent_ino) {
p = &(*p)->rb_right;
} else {
exists = 1;
break;
}
}
list_for_each_entry(cur, deleted_refs, list) {
ret = dup_ref(cur, &pm->update_refs);
if (ret < 0)
goto out;
}
list_for_each_entry(cur, new_refs, list) {
ret = dup_ref(cur, &pm->update_refs);
if (ret < 0)
goto out;
}
ret = add_waiting_dir_move(sctx, pm->ino, is_orphan);
if (ret)
goto out;
if (exists) {
list_add_tail(&pm->list, &entry->list);
} else {
rb_link_node(&pm->node, parent, p);
rb_insert_color(&pm->node, &sctx->pending_dir_moves);
}
ret = 0;
out:
if (ret) {
__free_recorded_refs(&pm->update_refs);
kfree(pm);
}
return ret;
}
static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx,
u64 parent_ino)
{
struct rb_node *n = sctx->pending_dir_moves.rb_node;
struct pending_dir_move *entry;
while (n) {
entry = rb_entry(n, struct pending_dir_move, node);
if (parent_ino < entry->parent_ino)
n = n->rb_left;
else if (parent_ino > entry->parent_ino)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static int path_loop(struct send_ctx *sctx, struct fs_path *name,
u64 ino, u64 gen, u64 *ancestor_ino)
{
int ret = 0;
u64 parent_inode = 0;
u64 parent_gen = 0;
u64 start_ino = ino;
*ancestor_ino = 0;
while (ino != BTRFS_FIRST_FREE_OBJECTID) {
fs_path_reset(name);
if (is_waiting_for_rm(sctx, ino))
break;
if (is_waiting_for_move(sctx, ino)) {
if (*ancestor_ino == 0)
*ancestor_ino = ino;
ret = get_first_ref(sctx->parent_root, ino,
&parent_inode, &parent_gen, name);
} else {
ret = __get_cur_name_and_parent(sctx, ino, gen,
&parent_inode,
&parent_gen, name);
if (ret > 0) {
ret = 0;
break;
}
}
if (ret < 0)
break;
if (parent_inode == start_ino) {
ret = 1;
if (*ancestor_ino == 0)
*ancestor_ino = ino;
break;
}
ino = parent_inode;
gen = parent_gen;
}
return ret;
}
static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
{
struct fs_path *from_path = NULL;
struct fs_path *to_path = NULL;
struct fs_path *name = NULL;
u64 orig_progress = sctx->send_progress;
struct recorded_ref *cur;
u64 parent_ino, parent_gen;
struct waiting_dir_move *dm = NULL;
u64 rmdir_ino = 0;
u64 ancestor;
bool is_orphan;
int ret;
name = fs_path_alloc();
from_path = fs_path_alloc();
if (!name || !from_path) {
ret = -ENOMEM;
goto out;
}
dm = get_waiting_dir_move(sctx, pm->ino);
ASSERT(dm);
rmdir_ino = dm->rmdir_ino;
is_orphan = dm->orphanized;
free_waiting_dir_move(sctx, dm);
if (is_orphan) {
ret = gen_unique_name(sctx, pm->ino,
pm->gen, from_path);
} else {
ret = get_first_ref(sctx->parent_root, pm->ino,
&parent_ino, &parent_gen, name);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, parent_ino, parent_gen,
from_path);
if (ret < 0)
goto out;
ret = fs_path_add_path(from_path, name);
}
if (ret < 0)
goto out;
sctx->send_progress = sctx->cur_ino + 1;
ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor);
if (ret < 0)
goto out;
if (ret) {
LIST_HEAD(deleted_refs);
ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID);
ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor,
&pm->update_refs, &deleted_refs,
is_orphan);
if (ret < 0)
goto out;
if (rmdir_ino) {
dm = get_waiting_dir_move(sctx, pm->ino);
ASSERT(dm);
dm->rmdir_ino = rmdir_ino;
}
goto out;
}
fs_path_reset(name);
to_path = name;
name = NULL;
ret = get_cur_path(sctx, pm->ino, pm->gen, to_path);
if (ret < 0)
goto out;
ret = send_rename(sctx, from_path, to_path);
if (ret < 0)
goto out;
if (rmdir_ino) {
struct orphan_dir_info *odi;
u64 gen;
odi = get_orphan_dir_info(sctx, rmdir_ino);
if (!odi) {
/* already deleted */
goto finish;
}
gen = odi->gen;
ret = can_rmdir(sctx, rmdir_ino, gen, sctx->cur_ino);
if (ret < 0)
goto out;
if (!ret)
goto finish;
name = fs_path_alloc();
if (!name) {
ret = -ENOMEM;
goto out;
}
ret = get_cur_path(sctx, rmdir_ino, gen, name);
if (ret < 0)
goto out;
ret = send_rmdir(sctx, name);
if (ret < 0)
goto out;
}
finish:
ret = send_utimes(sctx, pm->ino, pm->gen);
if (ret < 0)
goto out;
/*
* After rename/move, need to update the utimes of both new parent(s)
* and old parent(s).
*/
list_for_each_entry(cur, &pm->update_refs, list) {
/*
* The parent inode might have been deleted in the send snapshot
*/
ret = get_inode_info(sctx->send_root, cur->dir, NULL,
NULL, NULL, NULL, NULL, NULL);
if (ret == -ENOENT) {
ret = 0;
continue;
}
if (ret < 0)
goto out;
ret = send_utimes(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
}
out:
fs_path_free(name);
fs_path_free(from_path);
fs_path_free(to_path);
sctx->send_progress = orig_progress;
return ret;
}
static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m)
{
if (!list_empty(&m->list))
list_del(&m->list);
if (!RB_EMPTY_NODE(&m->node))
rb_erase(&m->node, &sctx->pending_dir_moves);
__free_recorded_refs(&m->update_refs);
kfree(m);
}
static void tail_append_pending_moves(struct send_ctx *sctx,
struct pending_dir_move *moves,
struct list_head *stack)
{
if (list_empty(&moves->list)) {
list_add_tail(&moves->list, stack);
} else {
LIST_HEAD(list);
list_splice_init(&moves->list, &list);
list_add_tail(&moves->list, stack);
list_splice_tail(&list, stack);
}
if (!RB_EMPTY_NODE(&moves->node)) {
rb_erase(&moves->node, &sctx->pending_dir_moves);
RB_CLEAR_NODE(&moves->node);
}
}
static int apply_children_dir_moves(struct send_ctx *sctx)
{
struct pending_dir_move *pm;
struct list_head stack;
u64 parent_ino = sctx->cur_ino;
int ret = 0;
pm = get_pending_dir_moves(sctx, parent_ino);
if (!pm)
return 0;
INIT_LIST_HEAD(&stack);
tail_append_pending_moves(sctx, pm, &stack);
while (!list_empty(&stack)) {
pm = list_first_entry(&stack, struct pending_dir_move, list);
parent_ino = pm->ino;
ret = apply_dir_move(sctx, pm);
free_pending_move(sctx, pm);
if (ret)
goto out;
pm = get_pending_dir_moves(sctx, parent_ino);
if (pm)
tail_append_pending_moves(sctx, pm, &stack);
}
return 0;
out:
while (!list_empty(&stack)) {
pm = list_first_entry(&stack, struct pending_dir_move, list);
free_pending_move(sctx, pm);
}
return ret;
}
/*
* We might need to delay a directory rename even when no ancestor directory
* (in the send root) with a higher inode number than ours (sctx->cur_ino) was
* renamed. This happens when we rename a directory to the old name (the name
* in the parent root) of some other unrelated directory that got its rename
* delayed due to some ancestor with higher number that got renamed.
*
* Example:
*
* Parent snapshot:
* . (ino 256)
* |---- a/ (ino 257)
* | |---- file (ino 260)
* |
* |---- b/ (ino 258)
* |---- c/ (ino 259)
*
* Send snapshot:
* . (ino 256)
* |---- a/ (ino 258)
* |---- x/ (ino 259)
* |---- y/ (ino 257)
* |----- file (ino 260)
*
* Here we can not rename 258 from 'b' to 'a' without the rename of inode 257
* from 'a' to 'x/y' happening first, which in turn depends on the rename of
* inode 259 from 'c' to 'x'. So the order of rename commands the send stream
* must issue is:
*
* 1 - rename 259 from 'c' to 'x'
* 2 - rename 257 from 'a' to 'x/y'
* 3 - rename 258 from 'b' to 'a'
*
* Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can
* be done right away and < 0 on error.
*/
static int wait_for_dest_dir_move(struct send_ctx *sctx,
struct recorded_ref *parent_ref,
const bool is_orphan)
{
struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key di_key;
struct btrfs_dir_item *di;
u64 left_gen;
u64 right_gen;
int ret = 0;
struct waiting_dir_move *wdm;
if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves))
return 0;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = parent_ref->dir;
key.type = BTRFS_DIR_ITEM_KEY;
key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len);
ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
goto out;
}
di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name,
parent_ref->name_len);
if (!di) {
ret = 0;
goto out;
}
/*
* di_key.objectid has the number of the inode that has a dentry in the
* parent directory with the same name that sctx->cur_ino is being
* renamed to. We need to check if that inode is in the send root as
* well and if it is currently marked as an inode with a pending rename,
* if it is, we need to delay the rename of sctx->cur_ino as well, so
* that it happens after that other inode is renamed.
*/
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key);
if (di_key.type != BTRFS_INODE_ITEM_KEY) {
ret = 0;
goto out;
}
ret = get_inode_info(sctx->parent_root, di_key.objectid, NULL,
&left_gen, NULL, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = get_inode_info(sctx->send_root, di_key.objectid, NULL,
&right_gen, NULL, NULL, NULL, NULL);
if (ret < 0) {
if (ret == -ENOENT)
ret = 0;
goto out;
}
/* Different inode, no need to delay the rename of sctx->cur_ino */
if (right_gen != left_gen) {
ret = 0;
goto out;
}
wdm = get_waiting_dir_move(sctx, di_key.objectid);
if (wdm && !wdm->orphanized) {
ret = add_pending_dir_move(sctx,
sctx->cur_ino,
sctx->cur_inode_gen,
di_key.objectid,
&sctx->new_refs,
&sctx->deleted_refs,
is_orphan);
if (!ret)
ret = 1;
}
out:
btrfs_free_path(path);
return ret;
}
/*
* Check if inode ino2, or any of its ancestors, is inode ino1.
* Return 1 if true, 0 if false and < 0 on error.
*/
static int check_ino_in_path(struct btrfs_root *root,
const u64 ino1,
const u64 ino1_gen,
const u64 ino2,
const u64 ino2_gen,
struct fs_path *fs_path)
{
u64 ino = ino2;
if (ino1 == ino2)
return ino1_gen == ino2_gen;
while (ino > BTRFS_FIRST_FREE_OBJECTID) {
u64 parent;
u64 parent_gen;
int ret;
fs_path_reset(fs_path);
ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path);
if (ret < 0)
return ret;
if (parent == ino1)
return parent_gen == ino1_gen;
ino = parent;
}
return 0;
}
/*
* Check if ino ino1 is an ancestor of inode ino2 in the given root for any
* possible path (in case ino2 is not a directory and has multiple hard links).
* Return 1 if true, 0 if false and < 0 on error.
*/
static int is_ancestor(struct btrfs_root *root,
const u64 ino1,
const u64 ino1_gen,
const u64 ino2,
struct fs_path *fs_path)
{
bool free_fs_path = false;
int ret = 0;
struct btrfs_path *path = NULL;
struct btrfs_key key;
if (!fs_path) {
fs_path = fs_path_alloc();
if (!fs_path)
return -ENOMEM;
free_fs_path = true;
}
path = alloc_path_for_send();
if (!path) {
ret = -ENOMEM;
goto out;
}
key.objectid = ino2;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (true) {
struct extent_buffer *leaf = path->nodes[0];
int slot = path->slots[0];
u32 cur_offset = 0;
u32 item_size;
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != ino2)
break;
if (key.type != BTRFS_INODE_REF_KEY &&
key.type != BTRFS_INODE_EXTREF_KEY)
break;
item_size = btrfs_item_size_nr(leaf, slot);
while (cur_offset < item_size) {
u64 parent;
u64 parent_gen;
if (key.type == BTRFS_INODE_EXTREF_KEY) {
unsigned long ptr;
struct btrfs_inode_extref *extref;
ptr = btrfs_item_ptr_offset(leaf, slot);
extref = (struct btrfs_inode_extref *)
(ptr + cur_offset);
parent = btrfs_inode_extref_parent(leaf,
extref);
cur_offset += sizeof(*extref);
cur_offset += btrfs_inode_extref_name_len(leaf,
extref);
} else {
parent = key.offset;
cur_offset = item_size;
}
ret = get_inode_info(root, parent, NULL, &parent_gen,
NULL, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = check_ino_in_path(root, ino1, ino1_gen,
parent, parent_gen, fs_path);
if (ret)
goto out;
}
path->slots[0]++;
}
ret = 0;
out:
btrfs_free_path(path);
if (free_fs_path)
fs_path_free(fs_path);
return ret;
}
static int wait_for_parent_move(struct send_ctx *sctx,
struct recorded_ref *parent_ref,
const bool is_orphan)
{
int ret = 0;
u64 ino = parent_ref->dir;
u64 ino_gen = parent_ref->dir_gen;
u64 parent_ino_before, parent_ino_after;
struct fs_path *path_before = NULL;
struct fs_path *path_after = NULL;
int len1, len2;
path_after = fs_path_alloc();
path_before = fs_path_alloc();
if (!path_after || !path_before) {
ret = -ENOMEM;
goto out;
}
/*
* Our current directory inode may not yet be renamed/moved because some
* ancestor (immediate or not) has to be renamed/moved first. So find if
* such ancestor exists and make sure our own rename/move happens after
* that ancestor is processed to avoid path build infinite loops (done
* at get_cur_path()).
*/
while (ino > BTRFS_FIRST_FREE_OBJECTID) {
u64 parent_ino_after_gen;
if (is_waiting_for_move(sctx, ino)) {
/*
* If the current inode is an ancestor of ino in the
* parent root, we need to delay the rename of the
* current inode, otherwise don't delayed the rename
* because we can end up with a circular dependency
* of renames, resulting in some directories never
* getting the respective rename operations issued in
* the send stream or getting into infinite path build
* loops.
*/
ret = is_ancestor(sctx->parent_root,
sctx->cur_ino, sctx->cur_inode_gen,
ino, path_before);
if (ret)
break;
}
fs_path_reset(path_before);
fs_path_reset(path_after);
ret = get_first_ref(sctx->send_root, ino, &parent_ino_after,
&parent_ino_after_gen, path_after);
if (ret < 0)
goto out;
ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before,
NULL, path_before);
if (ret < 0 && ret != -ENOENT) {
goto out;
} else if (ret == -ENOENT) {
ret = 0;
break;
}
len1 = fs_path_len(path_before);
len2 = fs_path_len(path_after);
if (ino > sctx->cur_ino &&
(parent_ino_before != parent_ino_after || len1 != len2 ||
memcmp(path_before->start, path_after->start, len1))) {
u64 parent_ino_gen;
ret = get_inode_info(sctx->parent_root, ino, NULL,
&parent_ino_gen, NULL, NULL, NULL,
NULL);
if (ret < 0)
goto out;
if (ino_gen == parent_ino_gen) {
ret = 1;
break;
}
}
ino = parent_ino_after;
ino_gen = parent_ino_after_gen;
}
out:
fs_path_free(path_before);
fs_path_free(path_after);
if (ret == 1) {
ret = add_pending_dir_move(sctx,
sctx->cur_ino,
sctx->cur_inode_gen,
ino,
&sctx->new_refs,
&sctx->deleted_refs,
is_orphan);
if (!ret)
ret = 1;
}
return ret;
}
static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
{
int ret;
struct fs_path *new_path;
/*
* Our reference's name member points to its full_path member string, so
* we use here a new path.
*/
new_path = fs_path_alloc();
if (!new_path)
return -ENOMEM;
ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path);
if (ret < 0) {
fs_path_free(new_path);
return ret;
}
ret = fs_path_add(new_path, ref->name, ref->name_len);
if (ret < 0) {
fs_path_free(new_path);
return ret;
}
fs_path_free(ref->full_path);
set_ref_path(ref, new_path);
return 0;
}
/*
* This does all the move/link/unlink/rmdir magic.
*/
static int process_recorded_refs(struct send_ctx *sctx, int *pending_move)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct recorded_ref *cur;
struct recorded_ref *cur2;
struct list_head check_dirs;
struct fs_path *valid_path = NULL;
u64 ow_inode = 0;
u64 ow_gen;
u64 ow_mode;
int did_overwrite = 0;
int is_orphan = 0;
u64 last_dir_ino_rm = 0;
bool can_rename = true;
bool orphanized_dir = false;
bool orphanized_ancestor = false;
btrfs_debug(fs_info, "process_recorded_refs %llu", 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);
INIT_LIST_HEAD(&check_dirs);
valid_path = fs_path_alloc();
if (!valid_path) {
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
* than 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, &ow_mode);
if (ret < 0)
goto out;
if (ret) {
ret = is_first_ref(sctx->parent_root,
ow_inode, cur->dir, cur->name,
cur->name_len);
if (ret < 0)
goto out;
if (ret) {
struct name_cache_entry *nce;
struct waiting_dir_move *wdm;
ret = orphanize_inode(sctx, ow_inode, ow_gen,
cur->full_path);
if (ret < 0)
goto out;
if (S_ISDIR(ow_mode))
orphanized_dir = true;
/*
* If ow_inode has its rename operation delayed
* make sure that its orphanized name is used in
* the source path when performing its rename
* operation.
*/
if (is_waiting_for_move(sctx, ow_inode)) {
wdm = get_waiting_dir_move(sctx,
ow_inode);
ASSERT(wdm);
wdm->orphanized = true;
}
/*
* Make sure we clear our orphanized inode's
* name from the name cache. This is because the
* inode ow_inode might be an ancestor of some
* other inode that will be orphanized as well
* later and has an inode number greater than
* sctx->send_progress. We need to prevent
* future name lookups from using the old name
* and get instead the orphan name.
*/
nce = name_cache_search(sctx, ow_inode, ow_gen);
if (nce) {
name_cache_delete(sctx, nce);
kfree(nce);
}
/*
* ow_inode might currently be an ancestor of
* cur_ino, therefore compute valid_path (the
* current path of cur_ino) again because it
* might contain the pre-orphanization name of
* ow_inode, which is no longer valid.
*/
ret = is_ancestor(sctx->parent_root,
ow_inode, ow_gen,
sctx->cur_ino, NULL);
if (ret > 0) {
orphanized_ancestor = true;
fs_path_reset(valid_path);
ret = get_cur_path(sctx, sctx->cur_ino,
sctx->cur_inode_gen,
valid_path);
}
if (ret < 0)
goto out;
} else {
ret = send_unlink(sctx, cur->full_path);
if (ret < 0)
goto out;
}
}
if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) {
ret = wait_for_dest_dir_move(sctx, cur, is_orphan);
if (ret < 0)
goto out;
if (ret == 1) {
can_rename = false;
*pending_move = 1;
}
}
if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root &&
can_rename) {
ret = wait_for_parent_move(sctx, cur, is_orphan);
if (ret < 0)
goto out;
if (ret == 1) {
can_rename = false;
*pending_move = 1;
}
}
/*
* 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 && can_rename) {
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 (can_rename) {
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)
ret = fs_path_copy(valid_path,
cur->full_path);
if (ret < 0)
goto out;
} else {
/*
* We might have previously orphanized an inode
* which is an ancestor of our current inode,
* so our reference's full path, which was
* computed before any such orphanizations, must
* be updated.
*/
if (orphanized_dir) {
ret = update_ref_path(sctx, cur);
if (ret < 0)
goto out;
}
ret = send_link(sctx, cur->full_path,
valid_path);
if (ret < 0)
goto out;
}
}
ret = dup_ref(cur, &check_dirs);
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_inode_gen,
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 = dup_ref(cur, &check_dirs);
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 = dup_ref(cur, &check_dirs);
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) {
/*
* If we orphanized any ancestor before, we need
* to recompute the full path for deleted names,
* since any such path was computed before we
* processed any references and orphanized any
* ancestor inode.
*/
if (orphanized_ancestor) {
ret = update_ref_path(sctx, cur);
if (ret < 0)
goto out;
}
ret = send_unlink(sctx, cur->full_path);
if (ret < 0)
goto out;
}
ret = dup_ref(cur, &check_dirs);
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.
*/
list_for_each_entry(cur, &check_dirs, list) {
/*
* 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 (cur->dir > sctx->cur_ino)
continue;
ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
if (ret == inode_state_did_create ||
ret == inode_state_no_change) {
/* TODO delayed utimes */
ret = send_utimes(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
} else if (ret == inode_state_did_delete &&
cur->dir != last_dir_ino_rm) {
ret = can_rmdir(sctx, cur->dir, cur->dir_gen,
sctx->cur_ino);
if (ret < 0)
goto out;
if (ret) {
ret = get_cur_path(sctx, cur->dir,
cur->dir_gen, valid_path);
if (ret < 0)
goto out;
ret = send_rmdir(sctx, valid_path);
if (ret < 0)
goto out;
last_dir_ino_rm = cur->dir;
}
}
}
ret = 0;
out:
__free_recorded_refs(&check_dirs);
free_recorded_refs(sctx);
fs_path_free(valid_path);
return ret;
}
static int record_ref(struct btrfs_root *root, u64 dir, struct fs_path *name,
void *ctx, struct list_head *refs)
{
int ret = 0;
struct send_ctx *sctx = ctx;
struct fs_path *p;
u64 gen;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
ret = get_inode_info(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(refs, dir, gen, p);
out:
if (ret)
fs_path_free(p);
return ret;
}
static int __record_new_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
struct send_ctx *sctx = ctx;
return record_ref(sctx->send_root, dir, name, ctx, &sctx->new_refs);
}
static int __record_deleted_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
struct send_ctx *sctx = ctx;
return record_ref(sctx->parent_root, dir, name, ctx,
&sctx->deleted_refs);
}
static int record_new_ref(struct send_ctx *sctx)
{
int ret;
ret = iterate_inode_ref(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->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;
u64 dir_gen;
struct btrfs_root *root;
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_;
u64 dir_gen;
int ret;
if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) &&
strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) {
/*
* To avoid doing extra lookups we'll only do this if everything
* else matches.
*/
ret = get_inode_info(ctx->root, dir, NULL, &dir_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
if (dir_gen != ctx->dir_gen)
return 0;
ctx->found_idx = num;
return 1;
}
return 0;
}
static int find_iref(struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *key,
u64 dir, u64 dir_gen, struct fs_path *name)
{
int ret;
struct find_ref_ctx ctx;
ctx.dir = dir;
ctx.name = name;
ctx.dir_gen = dir_gen;
ctx.found_idx = -1;
ctx.root = root;
ret = iterate_inode_ref(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)
{
u64 dir_gen;
int ret;
struct send_ctx *sctx = ctx;
ret = get_inode_info(sctx->send_root, dir, NULL, &dir_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
ret = find_iref(sctx->parent_root, sctx->right_path,
sctx->cmp_key, dir, dir_gen, 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)
{
u64 dir_gen;
int ret;
struct send_ctx *sctx = ctx;
ret = get_inode_info(sctx->parent_root, dir, NULL, &dir_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
ret = find_iref(sctx->send_root, sctx->left_path, sctx->cmp_key,
dir, dir_gen, 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->send_root, sctx->left_path,
sctx->cmp_key, 0, __record_changed_new_ref, sctx);
if (ret < 0)
goto out;
ret = iterate_inode_ref(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;
int pending_move = 0;
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 {
btrfs_err(sctx->send_root->fs_info,
"Wrong command %d in process_all_refs", cmd);
ret = -EINVAL;
goto out;
}
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
(found_key.type != BTRFS_INODE_REF_KEY &&
found_key.type != BTRFS_INODE_EXTREF_KEY))
break;
ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx);
if (ret < 0)
goto out;
path->slots[0]++;
}
btrfs_release_path(path);
/*
* We don't actually care about pending_move as we are simply
* re-creating this inode and will be rename'ing it into place once we
* rename the parent directory.
*/
ret = process_recorded_refs(sctx, &pending_move);
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;
struct posix_acl_xattr_header dummy_acl;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
/*
* This hack is needed because empty acls are stored as zero byte
* data in xattrs. Problem with that is, that receiving these zero byte
* acls 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(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();
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(p);
return ret;
}
static int process_new_xattr(struct send_ctx *sctx)
{
int ret = 0;
ret = iterate_dir_item(sctx->send_root, sctx->left_path,
__process_new_xattr, sctx);
return ret;
}
static int process_deleted_xattr(struct send_ctx *sctx)
{
return iterate_dir_item(sctx->parent_root, sctx->right_path,
__process_deleted_xattr, sctx);
}
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 = kmemdup(data, data_len, GFP_KERNEL);
if (!ctx->found_data)
return -ENOMEM;
return 1;
}
return 0;
}
static int find_xattr(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(root, path, __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;
ret = find_xattr(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);
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->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->send_root, sctx->left_path,
__process_changed_new_xattr, sctx);
if (ret < 0)
goto out;
ret = iterate_dir_item(sctx->parent_root, sctx->right_path,
__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;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
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(root, path, __process_new_xattr, sctx);
if (ret < 0)
goto out;
path->slots[0]++;
}
out:
btrfs_free_path(path);
return ret;
}
static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
{
struct btrfs_root *root = sctx->send_root;
struct btrfs_fs_info *fs_info = root->fs_info;
struct inode *inode;
struct page *page;
char *addr;
struct btrfs_key key;
pgoff_t index = offset >> PAGE_SHIFT;
pgoff_t last_index;
unsigned pg_offset = offset_in_page(offset);
ssize_t ret = 0;
key.objectid = sctx->cur_ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
inode = btrfs_iget(fs_info->sb, &key, root, NULL);
if (IS_ERR(inode))
return PTR_ERR(inode);
if (offset + len > i_size_read(inode)) {
if (offset > i_size_read(inode))
len = 0;
else
len = offset - i_size_read(inode);
}
if (len == 0)
goto out;
last_index = (offset + len - 1) >> PAGE_SHIFT;
/* initial readahead */
memset(&sctx->ra, 0, sizeof(struct file_ra_state));
file_ra_state_init(&sctx->ra, inode->i_mapping);
while (index <= last_index) {
unsigned cur_len = min_t(unsigned, len,
PAGE_SIZE - pg_offset);
page = find_lock_page(inode->i_mapping, index);
if (!page) {
page_cache_sync_readahead(inode->i_mapping, &sctx->ra,
NULL, index, last_index + 1 - index);
page = find_or_create_page(inode->i_mapping, index,
GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
break;
}
}
if (PageReadahead(page)) {
page_cache_async_readahead(inode->i_mapping, &sctx->ra,
NULL, page, index, last_index + 1 - index);
}
if (!PageUptodate(page)) {
btrfs_readpage(NULL, page);
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
put_page(page);
ret = -EIO;
break;
}
}
addr = kmap(page);
memcpy(sctx->read_buf + ret, addr + pg_offset, cur_len);
kunmap(page);
unlock_page(page);
put_page(page);
index++;
pg_offset = 0;
len -= cur_len;
ret += cur_len;
}
out:
iput(inode);
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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
ssize_t num_read = 0;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
num_read = fill_read_buf(sctx, offset, len);
if (num_read <= 0) {
if (num_read < 0)
ret = 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(p);
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;
btrfs_debug(sctx->send_root->fs_info,
"send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu",
offset, len, clone_root->root->root_key.objectid,
clone_root->ino, clone_root->offset);
p = fs_path_alloc();
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(clone_root->root, clone_root->ino, p);
}
if (ret < 0)
goto out;
/*
* If the parent we're using has a received_uuid set then use that as
* our clone source as that is what we will look for when doing a
* receive.
*
* This covers the case that we create a snapshot off of a received
* subvolume and then use that as the parent and try to receive on a
* different host.
*/
if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid))
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
clone_root->root->root_item.received_uuid);
else
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
clone_root->root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
le64_to_cpu(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(p);
return ret;
}
/*
* Send an update extent command to user space.
*/
static int send_update_extent(struct send_ctx *sctx,
u64 offset, u32 len)
{
int ret = 0;
struct fs_path *p;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
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_U64(sctx, BTRFS_SEND_A_SIZE, len);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(p);
return ret;
}
static int send_hole(struct send_ctx *sctx, u64 end)
{
struct fs_path *p = NULL;
u64 offset = sctx->cur_inode_last_extent;
u64 len;
int ret = 0;
/*
* A hole that starts at EOF or beyond it. Since we do not yet support
* fallocate (for extent preallocation and hole punching), sending a
* write of zeroes starting at EOF or beyond would later require issuing
* a truncate operation which would undo the write and achieve nothing.
*/
if (offset >= sctx->cur_inode_size)
return 0;
/*
* Don't go beyond the inode's i_size due to prealloc extents that start
* after the i_size.
*/
end = min_t(u64, end, sctx->cur_inode_size);
if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
return send_update_extent(sctx, offset, end - offset);
p = fs_path_alloc();
if (!p)
return -ENOMEM;
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto tlv_put_failure;
memset(sctx->read_buf, 0, BTRFS_SEND_READ_SIZE);
while (offset < end) {
len = min_t(u64, end - offset, BTRFS_SEND_READ_SIZE);
ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
if (ret < 0)
break;
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, len);
ret = send_cmd(sctx);
if (ret < 0)
break;
offset += len;
}
sctx->cur_inode_next_write_offset = offset;
tlv_put_failure:
fs_path_free(p);
return ret;
}
static int send_extent_data(struct send_ctx *sctx,
const u64 offset,
const u64 len)
{
u64 sent = 0;
if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
return send_update_extent(sctx, offset, len);
while (sent < len) {
u64 size = len - sent;
int ret;
if (size > BTRFS_SEND_READ_SIZE)
size = BTRFS_SEND_READ_SIZE;
ret = send_write(sctx, offset + sent, size);
if (ret < 0)
return ret;
if (!ret)
break;
sent += ret;
}
return 0;
}
static int clone_range(struct send_ctx *sctx,
struct clone_root *clone_root,
const u64 disk_byte,
u64 data_offset,
u64 offset,
u64 len)
{
struct btrfs_path *path;
struct btrfs_key key;
int ret;
u64 clone_src_i_size;
/*
* Prevent cloning from a zero offset with a length matching the sector
* size because in some scenarios this will make the receiver fail.
*
* For example, if in the source filesystem the extent at offset 0
* has a length of sectorsize and it was written using direct IO, then
* it can never be an inline extent (even if compression is enabled).
* Then this extent can be cloned in the original filesystem to a non
* zero file offset, but it may not be possible to clone in the
* destination filesystem because it can be inlined due to compression
* on the destination filesystem (as the receiver's write operations are
* always done using buffered IO). The same happens when the original
* filesystem does not have compression enabled but the destination
* filesystem has.
*/
if (clone_root->offset == 0 &&
len == sctx->send_root->fs_info->sectorsize)
return send_extent_data(sctx, offset, len);
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
/*
* There are inodes that have extents that lie behind its i_size. Don't
* accept clones from these extents.
*/
ret = __get_inode_info(clone_root->root, path, clone_root->ino,
&clone_src_i_size, NULL, NULL, NULL, NULL, NULL);
btrfs_release_path(path);
if (ret < 0)
goto out;
/*
* We can't send a clone operation for the entire range if we find
* extent items in the respective range in the source file that
* refer to different extents or if we find holes.
* So check for that and do a mix of clone and regular write/copy
* operations if needed.
*
* Example:
*
* mkfs.btrfs -f /dev/sda
* mount /dev/sda /mnt
* xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo
* cp --reflink=always /mnt/foo /mnt/bar
* xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo
* btrfs subvolume snapshot -r /mnt /mnt/snap
*
* If when we send the snapshot and we are processing file bar (which
* has a higher inode number than foo) we blindly send a clone operation
* for the [0, 100K[ range from foo to bar, the receiver ends up getting
* a file bar that matches the content of file foo - iow, doesn't match
* the content from bar in the original filesystem.
*/
key.objectid = clone_root->ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = clone_root->offset;
ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0 && path->slots[0] > 0) {
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
if (key.objectid == clone_root->ino &&
key.type == BTRFS_EXTENT_DATA_KEY)
path->slots[0]--;
}
while (true) {
struct extent_buffer *leaf = path->nodes[0];
int slot = path->slots[0];
struct btrfs_file_extent_item *ei;
u8 type;
u64 ext_len;
u64 clone_len;
u64 clone_data_offset;
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(clone_root->root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(leaf, &key, slot);
/*
* We might have an implicit trailing hole (NO_HOLES feature
* enabled). We deal with it after leaving this loop.
*/
if (key.objectid != clone_root->ino ||
key.type != BTRFS_EXTENT_DATA_KEY)
break;
ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
type = btrfs_file_extent_type(leaf, ei);
if (type == BTRFS_FILE_EXTENT_INLINE) {
ext_len = btrfs_file_extent_ram_bytes(leaf, ei);
ext_len = PAGE_ALIGN(ext_len);
} else {
ext_len = btrfs_file_extent_num_bytes(leaf, ei);
}
if (key.offset + ext_len <= clone_root->offset)
goto next;
if (key.offset > clone_root->offset) {
/* Implicit hole, NO_HOLES feature enabled. */
u64 hole_len = key.offset - clone_root->offset;
if (hole_len > len)
hole_len = len;
ret = send_extent_data(sctx, offset, hole_len);
if (ret < 0)
goto out;
len -= hole_len;
if (len == 0)
break;
offset += hole_len;
clone_root->offset += hole_len;
data_offset += hole_len;
}
if (key.offset >= clone_root->offset + len)
break;
if (key.offset >= clone_src_i_size)
break;
if (key.offset + ext_len > clone_src_i_size)
ext_len = clone_src_i_size - key.offset;
clone_data_offset = btrfs_file_extent_offset(leaf, ei);
if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) {
clone_root->offset = key.offset;
if (clone_data_offset < data_offset &&
clone_data_offset + ext_len > data_offset) {
u64 extent_offset;
extent_offset = data_offset - clone_data_offset;
ext_len -= extent_offset;
clone_data_offset += extent_offset;
clone_root->offset += extent_offset;
}
}
clone_len = min_t(u64, ext_len, len);
if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte &&
clone_data_offset == data_offset) {
const u64 src_end = clone_root->offset + clone_len;
const u64 sectorsize = SZ_64K;
/*
* We can't clone the last block, when its size is not
* sector size aligned, into the middle of a file. If we
* do so, the receiver will get a failure (-EINVAL) when
* trying to clone or will silently corrupt the data in
* the destination file if it's on a kernel without the
* fix introduced by commit ac765f83f1397646
* ("Btrfs: fix data corruption due to cloning of eof
* block).
*
* So issue a clone of the aligned down range plus a
* regular write for the eof block, if we hit that case.
*
* Also, we use the maximum possible sector size, 64K,
* because we don't know what's the sector size of the
* filesystem that receives the stream, so we have to
* assume the largest possible sector size.
*/
if (src_end == clone_src_i_size &&
!IS_ALIGNED(src_end, sectorsize) &&
offset + clone_len < sctx->cur_inode_size) {
u64 slen;
slen = ALIGN_DOWN(src_end - clone_root->offset,
sectorsize);
if (slen > 0) {
ret = send_clone(sctx, offset, slen,
clone_root);
if (ret < 0)
goto out;
}
ret = send_extent_data(sctx, offset + slen,
clone_len - slen);
} else {
ret = send_clone(sctx, offset, clone_len,
clone_root);
}
} else {
ret = send_extent_data(sctx, offset, clone_len);
}
if (ret < 0)
goto out;
len -= clone_len;
if (len == 0)
break;
offset += clone_len;
clone_root->offset += clone_len;
data_offset += clone_len;
next:
path->slots[0]++;
}
if (len > 0)
ret = send_extent_data(sctx, offset, len);
else
ret = 0;
out:
btrfs_free_path(path);
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 len;
u8 type;
u64 bs = sctx->send_root->fs_info->sb->s_blocksize;
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_ram_bytes(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_ALIGN(len);
} else {
len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
}
if (offset >= sctx->cur_inode_size) {
ret = 0;
goto out;
}
if (offset + len > sctx->cur_inode_size)
len = sctx->cur_inode_size - offset;
if (len == 0) {
ret = 0;
goto out;
}
if (clone_root && IS_ALIGNED(offset + len, bs)) {
u64 disk_byte;
u64 data_offset;
disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei);
data_offset = btrfs_file_extent_offset(path->nodes[0], ei);
ret = clone_range(sctx, clone_root, disk_byte, data_offset,
offset, len);
} else {
ret = send_extent_data(sctx, offset, len);
}
sctx->cur_inode_next_write_offset = offset + len;
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) {
/* If we're a hole then just pretend nothing changed */
ret = (left_disknr) ? 0 : 1;
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);
if (right_type != BTRFS_FILE_EXTENT_REG &&
right_type != BTRFS_FILE_EXTENT_INLINE) {
ret = 0;
goto out;
}
if (right_type == BTRFS_FILE_EXTENT_INLINE) {
right_len = btrfs_file_extent_ram_bytes(eb, ei);
right_len = PAGE_ALIGN(right_len);
} else {
right_len = btrfs_file_extent_num_bytes(eb, ei);
}
/*
* 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) {
/* If we're a hole just pretend nothing changed */
ret = (left_disknr) ? 0 : 1;
goto out;
}
/*
* We just wanted to see if when we have an inline extent, what
* follows it is a regular extent (wanted to check the above
* condition for inline extents too). This should normally not
* happen but it's possible for example when we have an inline
* compressed extent representing data with a size matching
* the page size (currently the same as sector size).
*/
if (right_type == BTRFS_FILE_EXTENT_INLINE) {
ret = 0;
goto out;
}
right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
right_offset = btrfs_file_extent_offset(eb, ei);
right_gen = btrfs_file_extent_generation(eb, ei);
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;
}
if (found_key.offset != key.offset + right_len) {
ret = 0;
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 get_last_extent(struct send_ctx *sctx, u64 offset)
{
struct btrfs_path *path;
struct btrfs_root *root = sctx->send_root;
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
u64 extent_end;
u8 type;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
sctx->cur_inode_last_extent = 0;
key.objectid = sctx->cur_ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = offset;
ret = btrfs_search_slot_for_read(root, &key, path, 0, 1);
if (ret < 0)
goto out;
ret = 0;
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY)
goto out;
fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
type = btrfs_file_extent_type(path->nodes[0], fi);
if (type == BTRFS_FILE_EXTENT_INLINE) {
u64 size = btrfs_file_extent_ram_bytes(path->nodes[0], fi);
extent_end = ALIGN(key.offset + size,
sctx->send_root->fs_info->sectorsize);
} else {
extent_end = key.offset +
btrfs_file_extent_num_bytes(path->nodes[0], fi);
}
sctx->cur_inode_last_extent = extent_end;
out:
btrfs_free_path(path);
return ret;
}
static int range_is_hole_in_parent(struct send_ctx *sctx,
const u64 start,
const u64 end)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_root *root = sctx->parent_root;
u64 search_start = start;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = sctx->cur_ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = search_start;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0 && path->slots[0] > 0)
path->slots[0]--;
while (search_start < end) {
struct extent_buffer *leaf = path->nodes[0];
int slot = path->slots[0];
struct btrfs_file_extent_item *fi;
u64 extent_end;
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid < sctx->cur_ino ||
key.type < BTRFS_EXTENT_DATA_KEY)
goto next;
if (key.objectid > sctx->cur_ino ||
key.type > BTRFS_EXTENT_DATA_KEY ||
key.offset >= end)
break;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) ==
BTRFS_FILE_EXTENT_INLINE) {
u64 size = btrfs_file_extent_ram_bytes(leaf, fi);
extent_end = ALIGN(key.offset + size,
root->fs_info->sectorsize);
} else {
extent_end = key.offset +
btrfs_file_extent_num_bytes(leaf, fi);
}
if (extent_end <= start)
goto next;
if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
search_start = extent_end;
goto next;
}
ret = 0;
goto out;
next:
path->slots[0]++;
}
ret = 1;
out:
btrfs_free_path(path);
return ret;
}
static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path,
struct btrfs_key *key)
{
struct btrfs_file_extent_item *fi;
u64 extent_end;
u8 type;
int ret = 0;
if (sctx->cur_ino != key->objectid || !need_send_hole(sctx))
return 0;
if (sctx->cur_inode_last_extent == (u64)-1) {
ret = get_last_extent(sctx, key->offset - 1);
if (ret)
return ret;
}
fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
type = btrfs_file_extent_type(path->nodes[0], fi);
if (type == BTRFS_FILE_EXTENT_INLINE) {
u64 size = btrfs_file_extent_ram_bytes(path->nodes[0], fi);
extent_end = ALIGN(key->offset + size,
sctx->send_root->fs_info->sectorsize);
} else {
extent_end = key->offset +
btrfs_file_extent_num_bytes(path->nodes[0], fi);
}
if (path->slots[0] == 0 &&
sctx->cur_inode_last_extent < key->offset) {
/*
* We might have skipped entire leafs that contained only
* file extent items for our current inode. These leafs have
* a generation number smaller (older) than the one in the
* current leaf and the leaf our last extent came from, and
* are located between these 2 leafs.
*/
ret = get_last_extent(sctx, key->offset - 1);
if (ret)
return ret;
}
if (sctx->cur_inode_last_extent < key->offset) {
ret = range_is_hole_in_parent(sctx,
sctx->cur_inode_last_extent,
key->offset);
if (ret < 0)
return ret;
else if (ret == 0)
ret = send_hole(sctx, key->offset);
else
ret = 0;
}
sctx->cur_inode_last_extent = extent_end;
return ret;
}
static int process_extent(struct send_ctx *sctx,
struct btrfs_path *path,
struct btrfs_key *key)
{
struct clone_root *found_clone = NULL;
int ret = 0;
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_hole;
}
} else {
struct btrfs_file_extent_item *ei;
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_PREALLOC ||
type == BTRFS_FILE_EXTENT_REG) {
/*
* The send spec does not have a prealloc command yet,
* so just leave a hole for prealloc'ed extents until
* we have enough commands queued up to justify rev'ing
* the send spec.
*/
if (type == BTRFS_FILE_EXTENT_PREALLOC) {
ret = 0;
goto out;
}
/* Have a hole, just skip it. */
if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) {
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);
if (ret)
goto out;
out_hole:
ret = maybe_send_hole(sctx, path, key);
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;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
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;
path->slots[0]++;
}
out:
btrfs_free_path(path);
return ret;
}
static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end,
int *pending_move,
int *refs_processed)
{
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_EXTREF_KEY)
goto out;
if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
goto out;
ret = process_recorded_refs(sctx, pending_move);
if (ret < 0)
goto out;
*refs_processed = 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;
int need_truncate = 1;
int pending_move = 0;
int refs_processed = 0;
if (sctx->ignore_cur_inode)
return 0;
ret = process_recorded_refs_if_needed(sctx, at_end, &pending_move,
&refs_processed);
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.
*
* On the other hand, if our current inode is a directory and couldn't
* be moved/renamed because its parent was renamed/moved too and it has
* a higher inode number, we can only move/rename our current inode
* after we moved/renamed its parent. Therefore in this case operate on
* the old path (pre move/rename) of our current inode, and the
* move/rename will be performed later.
*/
if (refs_processed && !pending_move)
sctx->send_progress = sctx->cur_ino + 1;
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 (!sctx->parent_root || sctx->cur_inode_new) {
need_chown = 1;
if (!S_ISLNK(sctx->cur_inode_mode))
need_chmod = 1;
if (sctx->cur_inode_next_write_offset == sctx->cur_inode_size)
need_truncate = 0;
} else {
u64 old_size;
ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
&old_size, 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 (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode)
need_chmod = 1;
if ((old_size == sctx->cur_inode_size) ||
(sctx->cur_inode_size > old_size &&
sctx->cur_inode_next_write_offset == sctx->cur_inode_size))
need_truncate = 0;
}
if (S_ISREG(sctx->cur_inode_mode)) {
if (need_send_hole(sctx)) {
if (sctx->cur_inode_last_extent == (u64)-1 ||
sctx->cur_inode_last_extent <
sctx->cur_inode_size) {
ret = get_last_extent(sctx, (u64)-1);
if (ret)
goto out;
}
if (sctx->cur_inode_last_extent <
sctx->cur_inode_size) {
ret = send_hole(sctx, sctx->cur_inode_size);
if (ret)
goto out;
}
}
if (need_truncate) {
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;
}
/*
* If other directory inodes depended on our current directory
* inode's move/rename, now do their move/rename operations.
*/
if (!is_waiting_for_move(sctx, sctx->cur_ino)) {
ret = apply_children_dir_moves(sctx);
if (ret)
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. If our inode is a directory and it's
* waiting to be moved/renamed, we will send its utimes when
* it's moved/renamed, therefore we don't need to do it here.
*/
sctx->send_progress = sctx->cur_ino + 1;
ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
if (ret < 0)
goto out;
}
out:
return ret;
}
struct parent_paths_ctx {
struct list_head *refs;
struct send_ctx *sctx;
};
static int record_parent_ref(int num, u64 dir, int index, struct fs_path *name,
void *ctx)
{
struct parent_paths_ctx *ppctx = ctx;
return record_ref(ppctx->sctx->parent_root, dir, name, ppctx->sctx,
ppctx->refs);
}
/*
* Issue unlink operations for all paths of the current inode found in the
* parent snapshot.
*/
static int btrfs_unlink_all_paths(struct send_ctx *sctx)
{
LIST_HEAD(deleted_refs);
struct btrfs_path *path;
struct btrfs_key key;
struct parent_paths_ctx ctx;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = sctx->cur_ino;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
ctx.refs = &deleted_refs;
ctx.sctx = sctx;
while (true) {
struct extent_buffer *eb = path->nodes[0];
int slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(sctx->parent_root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(eb, &key, slot);
if (key.objectid != sctx->cur_ino)
break;
if (key.type != BTRFS_INODE_REF_KEY &&
key.type != BTRFS_INODE_EXTREF_KEY)
break;
ret = iterate_inode_ref(sctx->parent_root, path, &key, 1,
record_parent_ref, &ctx);
if (ret < 0)
goto out;
path->slots[0]++;
}
while (!list_empty(&deleted_refs)) {
struct recorded_ref *ref;
ref = list_first_entry(&deleted_refs, struct recorded_ref, list);
ret = send_unlink(sctx, ref->full_path);
if (ret < 0)
goto out;
fs_path_free(ref->full_path);
list_del(&ref->list);
kfree(ref);
}
ret = 0;
out:
btrfs_free_path(path);
if (ret)
__free_recorded_refs(&deleted_refs);
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;
sctx->cur_ino = key->objectid;
sctx->cur_inode_new_gen = 0;
sctx->cur_inode_last_extent = (u64)-1;
sctx->cur_inode_next_write_offset = 0;
sctx->ignore_cur_inode = false;
/*
* 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;
}
/*
* Normally we do not find inodes with a link count of zero (orphans)
* because the most common case is to create a snapshot and use it
* for a send operation. However other less common use cases involve
* using a subvolume and send it after turning it to RO mode just
* after deleting all hard links of a file while holding an open
* file descriptor against it or turning a RO snapshot into RW mode,
* keep an open file descriptor against a file, delete it and then
* turn the snapshot back to RO mode before using it for a send
* operation. So if we find such cases, ignore the inode and all its
* items completely if it's a new inode, or if it's a changed inode
* make sure all its previous paths (from the parent snapshot) are all
* unlinked and all other the inode items are ignored.
*/
if (result == BTRFS_COMPARE_TREE_NEW ||
result == BTRFS_COMPARE_TREE_CHANGED) {
u32 nlinks;
nlinks = btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii);
if (nlinks == 0) {
sctx->ignore_cur_inode = true;
if (result == BTRFS_COMPARE_TREE_CHANGED)
ret = btrfs_unlink_all_paths(sctx);
goto out;
}
}
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);
sctx->cur_inode_rdev = btrfs_inode_rdev(
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);
sctx->cur_inode_rdev = btrfs_inode_rdev(
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;
if (sctx->cur_ino != sctx->cmp_key->objectid) {
inconsistent_snapshot_error(sctx, result, "reference");
return -EIO;
}
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;
if (sctx->cur_ino != sctx->cmp_key->objectid) {
inconsistent_snapshot_error(sctx, result, "xattr");
return -EIO;
}
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;
/*
* We have found an extent item that changed without the inode item
* having changed. This can happen either after relocation (where the
* disk_bytenr of an extent item is replaced at
* relocation.c:replace_file_extents()) or after deduplication into a
* file in both the parent and send snapshots (where an extent item can
* get modified or replaced with a new one). Note that deduplication
* updates the inode item, but it only changes the iversion (sequence
* field in the inode item) of the inode, so if a file is deduplicated
* the same amount of times in both the parent and send snapshots, its
* iversion becames the same in both snapshots, whence the inode item is
* the same on both snapshots.
*/
if (sctx->cur_ino != sctx->cmp_key->objectid)
return 0;
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;
}
static int dir_changed(struct send_ctx *sctx, u64 dir)
{
u64 orig_gen, new_gen;
int ret;
ret = get_inode_info(sctx->send_root, dir, NULL, &new_gen, NULL, NULL,
NULL, NULL);
if (ret)
return ret;
ret = get_inode_info(sctx->parent_root, dir, NULL, &orig_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
return (orig_gen != new_gen) ? 1 : 0;
}
static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path,
struct btrfs_key *key)
{
struct btrfs_inode_extref *extref;
struct extent_buffer *leaf;
u64 dirid = 0, last_dirid = 0;
unsigned long ptr;
u32 item_size;
u32 cur_offset = 0;
int ref_name_len;
int ret = 0;
/* Easy case, just check this one dirid */
if (key->type == BTRFS_INODE_REF_KEY) {
dirid = key->offset;
ret = dir_changed(sctx, dirid);
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
while (cur_offset < item_size) {
extref = (struct btrfs_inode_extref *)(ptr +
cur_offset);
dirid = btrfs_inode_extref_parent(leaf, extref);
ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
cur_offset += ref_name_len + sizeof(*extref);
if (dirid == last_dirid)
continue;
ret = dir_changed(sctx, dirid);
if (ret)
break;
last_dirid = dirid;
}
out:
return ret;
}
/*
* Updates compare related fields in sctx and simply forwards to the actual
* changed_xxx functions.
*/
static int changed_cb(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;
if (result == BTRFS_COMPARE_TREE_SAME) {
if (key->type == BTRFS_INODE_REF_KEY ||
key->type == BTRFS_INODE_EXTREF_KEY) {
ret = compare_refs(sctx, left_path, key);
if (!ret)
return 0;
if (ret < 0)
return ret;
} else if (key->type == BTRFS_EXTENT_DATA_KEY) {
return maybe_send_hole(sctx, left_path, key);
} else {
return 0;
}
result = BTRFS_COMPARE_TREE_CHANGED;
ret = 0;
}
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 (!sctx->ignore_cur_inode) {
if (key->type == BTRFS_INODE_REF_KEY ||
key->type == BTRFS_INODE_EXTREF_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_root *send_root = sctx->send_root;
struct btrfs_key key;
struct btrfs_path *path;
struct extent_buffer *eb;
int slot;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret)
goto out_finish;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &key, slot);
ret = changed_cb(path, NULL, &key,
BTRFS_COMPARE_TREE_NEW, sctx);
if (ret < 0)
goto out;
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);
return ret;
}
static int send_subvol(struct send_ctx *sctx)
{
int ret;
if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) {
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:
free_recorded_refs(sctx);
return ret;
}
/*
* If orphan cleanup did remove any orphans from a root, it means the tree
* was modified and therefore the commit root is not the same as the current
* root anymore. This is a problem, because send uses the commit root and
* therefore can see inode items that don't exist in the current root anymore,
* and for example make calls to btrfs_iget, which will do tree lookups based
* on the current root and not on the commit root. Those lookups will fail,
* returning a -ESTALE error, and making send fail with that error. So make
* sure a send does not see any orphans we have just removed, and that it will
* see the same inodes regardless of whether a transaction commit happened
* before it started (meaning that the commit root will be the same as the
* current root) or not.
*/
static int ensure_commit_roots_uptodate(struct send_ctx *sctx)
{
int i;
struct btrfs_trans_handle *trans = NULL;
again:
if (sctx->parent_root &&
sctx->parent_root->node != sctx->parent_root->commit_root)
goto commit_trans;
for (i = 0; i < sctx->clone_roots_cnt; i++)
if (sctx->clone_roots[i].root->node !=
sctx->clone_roots[i].root->commit_root)
goto commit_trans;
if (trans)
return btrfs_end_transaction(trans);
return 0;
commit_trans:
/* Use any root, all fs roots will get their commit roots updated. */
if (!trans) {
trans = btrfs_join_transaction(sctx->send_root);
if (IS_ERR(trans))
return PTR_ERR(trans);
goto again;
}
return btrfs_commit_transaction(trans);
}
/*
* Make sure any existing dellaloc is flushed for any root used by a send
* operation so that we do not miss any data and we do not race with writeback
* finishing and changing a tree while send is using the tree. This could
* happen if a subvolume is in RW mode, has delalloc, is turned to RO mode and
* a send operation then uses the subvolume.
* After flushing delalloc ensure_commit_roots_uptodate() must be called.
*/
static int flush_delalloc_roots(struct send_ctx *sctx)
{
struct btrfs_root *root = sctx->parent_root;
int ret;
int i;
if (root) {
ret = btrfs_start_delalloc_snapshot(root);
if (ret)
return ret;
btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX);
}
for (i = 0; i < sctx->clone_roots_cnt; i++) {
root = sctx->clone_roots[i].root;
ret = btrfs_start_delalloc_snapshot(root);
if (ret)
return ret;
btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX);
}
return 0;
}
static void btrfs_root_dec_send_in_progress(struct btrfs_root* root)
{
spin_lock(&root->root_item_lock);
root->send_in_progress--;
/*
* Not much left to do, we don't know why it's unbalanced and
* can't blindly reset it to 0.
*/
if (root->send_in_progress < 0)
btrfs_err(root->fs_info,
"send_in_progress unbalanced %d root %llu",
root->send_in_progress, root->root_key.objectid);
spin_unlock(&root->root_item_lock);
}
static void dedupe_in_progress_warn(const struct btrfs_root *root)
{
btrfs_warn_rl(root->fs_info,
"cannot use root %llu for send while deduplications on it are in progress (%d in progress)",
root->root_key.objectid, root->dedupe_in_progress);
}
long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
{
int ret = 0;
struct btrfs_root *send_root = BTRFS_I(file_inode(mnt_file))->root;
struct btrfs_fs_info *fs_info = send_root->fs_info;
struct btrfs_root *clone_root;
struct btrfs_key key;
struct send_ctx *sctx = NULL;
u32 i;
u64 *clone_sources_tmp = NULL;
int clone_sources_to_rollback = 0;
unsigned alloc_size;
int sort_clone_roots = 0;
int index;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/*
* The subvolume must remain read-only during send, protect against
* making it RW. This also protects against deletion.
*/
spin_lock(&send_root->root_item_lock);
if (btrfs_root_readonly(send_root) && send_root->dedupe_in_progress) {
dedupe_in_progress_warn(send_root);
spin_unlock(&send_root->root_item_lock);
return -EAGAIN;
}
send_root->send_in_progress++;
spin_unlock(&send_root->root_item_lock);
/*
* This is done when we lookup the root, it should already be complete
* by the time we get here.
*/
WARN_ON(send_root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE);
/*
* Userspace tools do the checks and warn the user if it's
* not RO.
*/
if (!btrfs_root_readonly(send_root)) {
ret = -EPERM;
goto out;
}
/*
* Check that we don't overflow at later allocations, we request
* clone_sources_count + 1 items, and compare to unsigned long inside
* access_ok.
*/
if (arg->clone_sources_count >
ULONG_MAX / sizeof(struct clone_root) - 1) {
ret = -EINVAL;
goto out;
}
if (!access_ok(arg->clone_sources,
sizeof(*arg->clone_sources) *
arg->clone_sources_count)) {
ret = -EFAULT;
goto out;
}
if (arg->flags & ~BTRFS_SEND_FLAG_MASK) {
ret = -EINVAL;
goto out;
}
sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL);
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_KERNEL);
INIT_LIST_HEAD(&sctx->name_cache_list);
sctx->flags = arg->flags;
sctx->send_filp = fget(arg->send_fd);
if (!sctx->send_filp) {
ret = -EBADF;
goto out;
}
sctx->send_root = send_root;
/*
* Unlikely but possible, if the subvolume is marked for deletion but
* is slow to remove the directory entry, send can still be started
*/
if (btrfs_root_dead(sctx->send_root)) {
ret = -EPERM;
goto out;
}
sctx->clone_roots_cnt = arg->clone_sources_count;
sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
if (!sctx->send_buf) {
ret = -ENOMEM;
goto out;
}
sctx->read_buf = kvmalloc(BTRFS_SEND_READ_SIZE, GFP_KERNEL);
if (!sctx->read_buf) {
ret = -ENOMEM;
goto out;
}
sctx->pending_dir_moves = RB_ROOT;
sctx->waiting_dir_moves = RB_ROOT;
sctx->orphan_dirs = RB_ROOT;
alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL);
if (!sctx->clone_roots) {
ret = -ENOMEM;
goto out;
}
alloc_size = arg->clone_sources_count * sizeof(*arg->clone_sources);
if (arg->clone_sources_count) {
clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL);
if (!clone_sources_tmp) {
ret = -ENOMEM;
goto out;
}
ret = copy_from_user(clone_sources_tmp, arg->clone_sources,
alloc_size);
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;
index = srcu_read_lock(&fs_info->subvol_srcu);
clone_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (IS_ERR(clone_root)) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = PTR_ERR(clone_root);
goto out;
}
spin_lock(&clone_root->root_item_lock);
if (!btrfs_root_readonly(clone_root) ||
btrfs_root_dead(clone_root)) {
spin_unlock(&clone_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -EPERM;
goto out;
}
if (clone_root->dedupe_in_progress) {
dedupe_in_progress_warn(clone_root);
spin_unlock(&clone_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -EAGAIN;
goto out;
}
clone_root->send_in_progress++;
spin_unlock(&clone_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
sctx->clone_roots[i].root = clone_root;
clone_sources_to_rollback = i + 1;
}
kvfree(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;
index = srcu_read_lock(&fs_info->subvol_srcu);
sctx->parent_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (IS_ERR(sctx->parent_root)) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = PTR_ERR(sctx->parent_root);
goto out;
}
spin_lock(&sctx->parent_root->root_item_lock);
sctx->parent_root->send_in_progress++;
if (!btrfs_root_readonly(sctx->parent_root) ||
btrfs_root_dead(sctx->parent_root)) {
spin_unlock(&sctx->parent_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -EPERM;
goto out;
}
if (sctx->parent_root->dedupe_in_progress) {
dedupe_in_progress_warn(sctx->parent_root);
spin_unlock(&sctx->parent_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -EAGAIN;
goto out;
}
spin_unlock(&sctx->parent_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
}
/*
* 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);
sort_clone_roots = 1;
ret = flush_delalloc_roots(sctx);
if (ret)
goto out;
ret = ensure_commit_roots_uptodate(sctx);
if (ret)
goto out;
mutex_lock(&fs_info->balance_mutex);
if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
mutex_unlock(&fs_info->balance_mutex);
btrfs_warn_rl(fs_info,
"cannot run send because a balance operation is in progress");
ret = -EAGAIN;
goto out;
}
fs_info->send_in_progress++;
mutex_unlock(&fs_info->balance_mutex);
current->journal_info = BTRFS_SEND_TRANS_STUB;
ret = send_subvol(sctx);
current->journal_info = NULL;
mutex_lock(&fs_info->balance_mutex);
fs_info->send_in_progress--;
mutex_unlock(&fs_info->balance_mutex);
if (ret < 0)
goto out;
if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) {
ret = begin_cmd(sctx, BTRFS_SEND_C_END);
if (ret < 0)
goto out;
ret = send_cmd(sctx);
if (ret < 0)
goto out;
}
out:
WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->pending_dir_moves));
while (sctx && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)) {
struct rb_node *n;
struct pending_dir_move *pm;
n = rb_first(&sctx->pending_dir_moves);
pm = rb_entry(n, struct pending_dir_move, node);
while (!list_empty(&pm->list)) {
struct pending_dir_move *pm2;
pm2 = list_first_entry(&pm->list,
struct pending_dir_move, list);
free_pending_move(sctx, pm2);
}
free_pending_move(sctx, pm);
}
WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves));
while (sctx && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) {
struct rb_node *n;
struct waiting_dir_move *dm;
n = rb_first(&sctx->waiting_dir_moves);
dm = rb_entry(n, struct waiting_dir_move, node);
rb_erase(&dm->node, &sctx->waiting_dir_moves);
kfree(dm);
}
WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->orphan_dirs));
while (sctx && !RB_EMPTY_ROOT(&sctx->orphan_dirs)) {
struct rb_node *n;
struct orphan_dir_info *odi;
n = rb_first(&sctx->orphan_dirs);
odi = rb_entry(n, struct orphan_dir_info, node);
free_orphan_dir_info(sctx, odi);
}
if (sort_clone_roots) {
for (i = 0; i < sctx->clone_roots_cnt; i++)
btrfs_root_dec_send_in_progress(
sctx->clone_roots[i].root);
} else {
for (i = 0; sctx && i < clone_sources_to_rollback; i++)
btrfs_root_dec_send_in_progress(
sctx->clone_roots[i].root);
btrfs_root_dec_send_in_progress(send_root);
}
if (sctx && !IS_ERR_OR_NULL(sctx->parent_root))
btrfs_root_dec_send_in_progress(sctx->parent_root);
kvfree(clone_sources_tmp);
if (sctx) {
if (sctx->send_filp)
fput(sctx->send_filp);
kvfree(sctx->clone_roots);
kvfree(sctx->send_buf);
kvfree(sctx->read_buf);
name_cache_free(sctx);
kfree(sctx);
}
return ret;
}
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