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-rw-r--r--fs/btrfs/send.c4695
1 files changed, 4695 insertions, 0 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
new file mode 100644
index 00000000000..321b7fb4e44
--- /dev/null
+++ b/fs/btrfs/send.c
@@ -0,0 +1,4695 @@
+/*
+ * Copyright (C) 2012 Alexander Block. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/bsearch.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/sort.h>
+#include <linux/mount.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/radix-tree.h>
+#include <linux/crc32c.h>
+#include <linux/vmalloc.h>
+
+#include "send.h"
+#include "backref.h"
+#include "locking.h"
+#include "disk-io.h"
+#include "btrfs_inode.h"
+#include "transaction.h"
+
+static int g_verbose = 0;
+
+#define verbose_printk(...) if (g_verbose) printk(__VA_ARGS__)
+
+/*
+ * A fs_path is a helper to dynamically build path names with unknown size.
+ * It reallocates the internal buffer on demand.
+ * It allows fast adding of path elements on the right side (normal path) and
+ * fast adding to the left side (reversed path). A reversed path can also be
+ * unreversed if needed.
+ */
+struct fs_path {
+ union {
+ struct {
+ char *start;
+ char *end;
+ char *prepared;
+
+ char *buf;
+ int buf_len;
+ int reversed:1;
+ int virtual_mem:1;
+ char inline_buf[];
+ };
+ char pad[PAGE_SIZE];
+ };
+};
+#define FS_PATH_INLINE_SIZE \
+ (sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf))
+
+
+/* reused for each extent */
+struct clone_root {
+ struct btrfs_root *root;
+ u64 ino;
+ u64 offset;
+
+ u64 found_refs;
+};
+
+#define SEND_CTX_MAX_NAME_CACHE_SIZE 128
+#define SEND_CTX_NAME_CACHE_CLEAN_SIZE (SEND_CTX_MAX_NAME_CACHE_SIZE * 2)
+
+struct send_ctx {
+ struct file *send_filp;
+ loff_t send_off;
+ char *send_buf;
+ u32 send_size;
+ u32 send_max_size;
+ u64 total_send_size;
+ u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
+
+ struct vfsmount *mnt;
+
+ struct btrfs_root *send_root;
+ struct btrfs_root *parent_root;
+ struct clone_root *clone_roots;
+ int clone_roots_cnt;
+
+ /* current state of the compare_tree call */
+ struct btrfs_path *left_path;
+ struct btrfs_path *right_path;
+ struct btrfs_key *cmp_key;
+
+ /*
+ * infos of the currently processed inode. In case of deleted inodes,
+ * these are the values from the deleted inode.
+ */
+ u64 cur_ino;
+ u64 cur_inode_gen;
+ int cur_inode_new;
+ int cur_inode_new_gen;
+ int cur_inode_deleted;
+ u64 cur_inode_size;
+ u64 cur_inode_mode;
+
+ u64 send_progress;
+
+ struct list_head new_refs;
+ struct list_head deleted_refs;
+
+ struct radix_tree_root name_cache;
+ struct list_head name_cache_list;
+ int name_cache_size;
+
+ struct file *cur_inode_filp;
+ char *read_buf;
+};
+
+struct name_cache_entry {
+ struct list_head list;
+ /*
+ * radix_tree has only 32bit entries but we need to handle 64bit inums.
+ * We use the lower 32bit of the 64bit inum to store it in the tree. If
+ * more then one inum would fall into the same entry, we use radix_list
+ * to store the additional entries. radix_list is also used to store
+ * entries where two entries have the same inum but different
+ * generations.
+ */
+ struct list_head radix_list;
+ u64 ino;
+ u64 gen;
+ u64 parent_ino;
+ u64 parent_gen;
+ int ret;
+ int need_later_update;
+ int name_len;
+ char name[];
+};
+
+static void fs_path_reset(struct fs_path *p)
+{
+ if (p->reversed) {
+ p->start = p->buf + p->buf_len - 1;
+ p->end = p->start;
+ *p->start = 0;
+ } else {
+ p->start = p->buf;
+ p->end = p->start;
+ *p->start = 0;
+ }
+}
+
+static struct fs_path *fs_path_alloc(struct send_ctx *sctx)
+{
+ struct fs_path *p;
+
+ p = kmalloc(sizeof(*p), GFP_NOFS);
+ if (!p)
+ return NULL;
+ p->reversed = 0;
+ p->virtual_mem = 0;
+ p->buf = p->inline_buf;
+ p->buf_len = FS_PATH_INLINE_SIZE;
+ fs_path_reset(p);
+ return p;
+}
+
+static struct fs_path *fs_path_alloc_reversed(struct send_ctx *sctx)
+{
+ struct fs_path *p;
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return NULL;
+ p->reversed = 1;
+ fs_path_reset(p);
+ return p;
+}
+
+static void fs_path_free(struct send_ctx *sctx, struct fs_path *p)
+{
+ if (!p)
+ return;
+ if (p->buf != p->inline_buf) {
+ if (p->virtual_mem)
+ vfree(p->buf);
+ else
+ kfree(p->buf);
+ }
+ kfree(p);
+}
+
+static int fs_path_len(struct fs_path *p)
+{
+ return p->end - p->start;
+}
+
+static int fs_path_ensure_buf(struct fs_path *p, int len)
+{
+ char *tmp_buf;
+ int path_len;
+ int old_buf_len;
+
+ len++;
+
+ if (p->buf_len >= len)
+ return 0;
+
+ path_len = p->end - p->start;
+ old_buf_len = p->buf_len;
+ len = PAGE_ALIGN(len);
+
+ if (p->buf == p->inline_buf) {
+ tmp_buf = kmalloc(len, GFP_NOFS);
+ if (!tmp_buf) {
+ tmp_buf = vmalloc(len);
+ if (!tmp_buf)
+ return -ENOMEM;
+ p->virtual_mem = 1;
+ }
+ memcpy(tmp_buf, p->buf, p->buf_len);
+ p->buf = tmp_buf;
+ p->buf_len = len;
+ } else {
+ if (p->virtual_mem) {
+ tmp_buf = vmalloc(len);
+ if (!tmp_buf)
+ return -ENOMEM;
+ memcpy(tmp_buf, p->buf, p->buf_len);
+ vfree(p->buf);
+ } else {
+ tmp_buf = krealloc(p->buf, len, GFP_NOFS);
+ if (!tmp_buf) {
+ tmp_buf = vmalloc(len);
+ if (!tmp_buf)
+ return -ENOMEM;
+ memcpy(tmp_buf, p->buf, p->buf_len);
+ kfree(p->buf);
+ p->virtual_mem = 1;
+ }
+ }
+ p->buf = tmp_buf;
+ p->buf_len = len;
+ }
+ if (p->reversed) {
+ tmp_buf = p->buf + old_buf_len - path_len - 1;
+ p->end = p->buf + p->buf_len - 1;
+ p->start = p->end - path_len;
+ memmove(p->start, tmp_buf, path_len + 1);
+ } else {
+ p->start = p->buf;
+ p->end = p->start + path_len;
+ }
+ return 0;
+}
+
+static int fs_path_prepare_for_add(struct fs_path *p, int name_len)
+{
+ int ret;
+ int new_len;
+
+ new_len = p->end - p->start + name_len;
+ if (p->start != p->end)
+ new_len++;
+ ret = fs_path_ensure_buf(p, new_len);
+ if (ret < 0)
+ goto out;
+
+ if (p->reversed) {
+ if (p->start != p->end)
+ *--p->start = '/';
+ p->start -= name_len;
+ p->prepared = p->start;
+ } else {
+ if (p->start != p->end)
+ *p->end++ = '/';
+ p->prepared = p->end;
+ p->end += name_len;
+ *p->end = 0;
+ }
+
+out:
+ return ret;
+}
+
+static int fs_path_add(struct fs_path *p, const char *name, int name_len)
+{
+ int ret;
+
+ ret = fs_path_prepare_for_add(p, name_len);
+ if (ret < 0)
+ goto out;
+ memcpy(p->prepared, name, name_len);
+ p->prepared = NULL;
+
+out:
+ return ret;
+}
+
+static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
+{
+ int ret;
+
+ ret = fs_path_prepare_for_add(p, p2->end - p2->start);
+ if (ret < 0)
+ goto out;
+ memcpy(p->prepared, p2->start, p2->end - p2->start);
+ p->prepared = NULL;
+
+out:
+ return ret;
+}
+
+static int fs_path_add_from_extent_buffer(struct fs_path *p,
+ struct extent_buffer *eb,
+ unsigned long off, int len)
+{
+ int ret;
+
+ ret = fs_path_prepare_for_add(p, len);
+ if (ret < 0)
+ goto out;
+
+ read_extent_buffer(eb, p->prepared, off, len);
+ p->prepared = NULL;
+
+out:
+ return ret;
+}
+
+#if 0
+static void fs_path_remove(struct fs_path *p)
+{
+ BUG_ON(p->reversed);
+ while (p->start != p->end && *p->end != '/')
+ p->end--;
+ *p->end = 0;
+}
+#endif
+
+static int fs_path_copy(struct fs_path *p, struct fs_path *from)
+{
+ int ret;
+
+ p->reversed = from->reversed;
+ fs_path_reset(p);
+
+ ret = fs_path_add_path(p, from);
+
+ return ret;
+}
+
+
+static void fs_path_unreverse(struct fs_path *p)
+{
+ char *tmp;
+ int len;
+
+ if (!p->reversed)
+ return;
+
+ tmp = p->start;
+ len = p->end - p->start;
+ p->start = p->buf;
+ p->end = p->start + len;
+ memmove(p->start, tmp, len + 1);
+ p->reversed = 0;
+}
+
+static struct btrfs_path *alloc_path_for_send(void)
+{
+ struct btrfs_path *path;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return NULL;
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+ return path;
+}
+
+int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off)
+{
+ int ret;
+ mm_segment_t old_fs;
+ u32 pos = 0;
+
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+
+ while (pos < len) {
+ ret = vfs_write(filp, (char *)buf + pos, len - pos, off);
+ /* TODO handle that correctly */
+ /*if (ret == -ERESTARTSYS) {
+ continue;
+ }*/
+ if (ret < 0)
+ goto out;
+ if (ret == 0) {
+ ret = -EIO;
+ goto out;
+ }
+ pos += ret;
+ }
+
+ ret = 0;
+
+out:
+ set_fs(old_fs);
+ return ret;
+}
+
+static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
+{
+ struct btrfs_tlv_header *hdr;
+ int total_len = sizeof(*hdr) + len;
+ int left = sctx->send_max_size - sctx->send_size;
+
+ if (unlikely(left < total_len))
+ return -EOVERFLOW;
+
+ hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size);
+ hdr->tlv_type = cpu_to_le16(attr);
+ hdr->tlv_len = cpu_to_le16(len);
+ memcpy(hdr + 1, data, len);
+ sctx->send_size += total_len;
+
+ return 0;
+}
+
+#if 0
+static int tlv_put_u8(struct send_ctx *sctx, u16 attr, u8 value)
+{
+ return tlv_put(sctx, attr, &value, sizeof(value));
+}
+
+static int tlv_put_u16(struct send_ctx *sctx, u16 attr, u16 value)
+{
+ __le16 tmp = cpu_to_le16(value);
+ return tlv_put(sctx, attr, &tmp, sizeof(tmp));
+}
+
+static int tlv_put_u32(struct send_ctx *sctx, u16 attr, u32 value)
+{
+ __le32 tmp = cpu_to_le32(value);
+ return tlv_put(sctx, attr, &tmp, sizeof(tmp));
+}
+#endif
+
+static int tlv_put_u64(struct send_ctx *sctx, u16 attr, u64 value)
+{
+ __le64 tmp = cpu_to_le64(value);
+ return tlv_put(sctx, attr, &tmp, sizeof(tmp));
+}
+
+static int tlv_put_string(struct send_ctx *sctx, u16 attr,
+ const char *str, int len)
+{
+ if (len == -1)
+ len = strlen(str);
+ return tlv_put(sctx, attr, str, len);
+}
+
+static int tlv_put_uuid(struct send_ctx *sctx, u16 attr,
+ const u8 *uuid)
+{
+ return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE);
+}
+
+#if 0
+static int tlv_put_timespec(struct send_ctx *sctx, u16 attr,
+ struct timespec *ts)
+{
+ struct btrfs_timespec bts;
+ bts.sec = cpu_to_le64(ts->tv_sec);
+ bts.nsec = cpu_to_le32(ts->tv_nsec);
+ return tlv_put(sctx, attr, &bts, sizeof(bts));
+}
+#endif
+
+static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr,
+ struct extent_buffer *eb,
+ struct btrfs_timespec *ts)
+{
+ struct btrfs_timespec bts;
+ read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts));
+ return tlv_put(sctx, attr, &bts, sizeof(bts));
+}
+
+
+#define TLV_PUT(sctx, attrtype, attrlen, data) \
+ do { \
+ ret = tlv_put(sctx, attrtype, attrlen, data); \
+ if (ret < 0) \
+ goto tlv_put_failure; \
+ } while (0)
+
+#define TLV_PUT_INT(sctx, attrtype, bits, value) \
+ do { \
+ ret = tlv_put_u##bits(sctx, attrtype, value); \
+ if (ret < 0) \
+ goto tlv_put_failure; \
+ } while (0)
+
+#define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data)
+#define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data)
+#define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data)
+#define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data)
+#define TLV_PUT_STRING(sctx, attrtype, str, len) \
+ do { \
+ ret = tlv_put_string(sctx, attrtype, str, len); \
+ if (ret < 0) \
+ goto tlv_put_failure; \
+ } while (0)
+#define TLV_PUT_PATH(sctx, attrtype, p) \
+ do { \
+ ret = tlv_put_string(sctx, attrtype, p->start, \
+ p->end - p->start); \
+ if (ret < 0) \
+ goto tlv_put_failure; \
+ } while(0)
+#define TLV_PUT_UUID(sctx, attrtype, uuid) \
+ do { \
+ ret = tlv_put_uuid(sctx, attrtype, uuid); \
+ if (ret < 0) \
+ goto tlv_put_failure; \
+ } while (0)
+#define TLV_PUT_TIMESPEC(sctx, attrtype, ts) \
+ do { \
+ ret = tlv_put_timespec(sctx, attrtype, ts); \
+ if (ret < 0) \
+ goto tlv_put_failure; \
+ } while (0)
+#define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \
+ do { \
+ ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \
+ if (ret < 0) \
+ goto tlv_put_failure; \
+ } while (0)
+
+static int send_header(struct send_ctx *sctx)
+{
+ struct btrfs_stream_header hdr;
+
+ strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
+ hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION);
+
+ return write_buf(sctx->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 (!sctx->send_buf) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ BUG_ON(sctx->send_size);
+
+ sctx->send_size += sizeof(*hdr);
+ hdr = (struct btrfs_cmd_header *)sctx->send_buf;
+ hdr->cmd = cpu_to_le16(cmd);
+
+ return 0;
+}
+
+static int send_cmd(struct send_ctx *sctx)
+{
+ int ret;
+ struct btrfs_cmd_header *hdr;
+ u32 crc;
+
+ hdr = (struct btrfs_cmd_header *)sctx->send_buf;
+ hdr->len = cpu_to_le32(sctx->send_size - sizeof(*hdr));
+ hdr->crc = 0;
+
+ crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
+ hdr->crc = cpu_to_le32(crc);
+
+ ret = write_buf(sctx->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)
+{
+ int ret;
+
+verbose_printk("btrfs: send_rename %s -> %s\n", from->start, to->start);
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from);
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ return ret;
+}
+
+/*
+ * Sends a link instruction to user space
+ */
+static int send_link(struct send_ctx *sctx,
+ struct fs_path *path, struct fs_path *lnk)
+{
+ int ret;
+
+verbose_printk("btrfs: send_link %s -> %s\n", path->start, lnk->start);
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_LINK);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ return ret;
+}
+
+/*
+ * Sends an unlink instruction to user space
+ */
+static int send_unlink(struct send_ctx *sctx, struct fs_path *path)
+{
+ int ret;
+
+verbose_printk("btrfs: send_unlink %s\n", path->start);
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ return ret;
+}
+
+/*
+ * Sends a rmdir instruction to user space
+ */
+static int send_rmdir(struct send_ctx *sctx, struct fs_path *path)
+{
+ int ret;
+
+verbose_printk("btrfs: send_rmdir %s\n", path->start);
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ return ret;
+}
+
+/*
+ * Helper function to retrieve some fields from an inode item.
+ */
+static int get_inode_info(struct btrfs_root *root,
+ u64 ino, u64 *size, u64 *gen,
+ u64 *mode, u64 *uid, u64 *gid,
+ u64 *rdev)
+{
+ int ret;
+ struct btrfs_inode_item *ii;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = ino;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_inode_item);
+ if (size)
+ *size = btrfs_inode_size(path->nodes[0], ii);
+ if (gen)
+ *gen = btrfs_inode_generation(path->nodes[0], ii);
+ if (mode)
+ *mode = btrfs_inode_mode(path->nodes[0], ii);
+ if (uid)
+ *uid = btrfs_inode_uid(path->nodes[0], ii);
+ if (gid)
+ *gid = btrfs_inode_gid(path->nodes[0], ii);
+ if (rdev)
+ *rdev = btrfs_inode_rdev(path->nodes[0], ii);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index,
+ struct fs_path *p,
+ void *ctx);
+
+/*
+ * Helper function to iterate the entries in ONE btrfs_inode_ref 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 send_ctx *sctx,
+ struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_key *found_key, int resolve,
+ iterate_inode_ref_t iterate, void *ctx)
+{
+ struct extent_buffer *eb = 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(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ tmp_path = alloc_path_for_send();
+ if (!tmp_path) {
+ fs_path_free(sctx, 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(eb, 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(sctx, p);
+ return ret;
+}
+
+typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key,
+ const char *name, int name_len,
+ const char *data, int data_len,
+ u8 type, void *ctx);
+
+/*
+ * Helper function to iterate the entries in ONE btrfs_dir_item.
+ * The iterate callback may return a non zero value to stop iteration. This can
+ * be a negative value for error codes or 1 to simply stop it.
+ *
+ * path must point to the dir item when called.
+ */
+static int iterate_dir_item(struct send_ctx *sctx,
+ struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_key *found_key,
+ iterate_dir_item_t iterate, void *ctx)
+{
+ int ret = 0;
+ struct extent_buffer *eb;
+ struct btrfs_item *item;
+ struct btrfs_dir_item *di;
+ struct btrfs_key di_key;
+ char *buf = NULL;
+ char *buf2 = NULL;
+ int buf_len;
+ int buf_virtual = 0;
+ u32 name_len;
+ u32 data_len;
+ u32 cur;
+ u32 len;
+ u32 total;
+ int slot;
+ int num;
+ u8 type;
+
+ buf_len = PAGE_SIZE;
+ buf = kmalloc(buf_len, GFP_NOFS);
+ if (!buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ item = btrfs_item_nr(eb, slot);
+ di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
+ cur = 0;
+ len = 0;
+ total = btrfs_item_size(eb, item);
+
+ num = 0;
+ while (cur < total) {
+ name_len = btrfs_dir_name_len(eb, di);
+ data_len = btrfs_dir_data_len(eb, di);
+ type = btrfs_dir_type(eb, di);
+ btrfs_dir_item_key_to_cpu(eb, di, &di_key);
+
+ if (name_len + data_len > buf_len) {
+ buf_len = PAGE_ALIGN(name_len + data_len);
+ if (buf_virtual) {
+ buf2 = vmalloc(buf_len);
+ if (!buf2) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ vfree(buf);
+ } else {
+ buf2 = krealloc(buf, buf_len, GFP_NOFS);
+ if (!buf2) {
+ buf2 = vmalloc(buf_len);
+ if (!buf2) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ kfree(buf);
+ buf_virtual = 1;
+ }
+ }
+
+ buf = buf2;
+ buf2 = NULL;
+ }
+
+ read_extent_buffer(eb, buf, (unsigned long)(di + 1),
+ name_len + data_len);
+
+ len = sizeof(*di) + name_len + data_len;
+ di = (struct btrfs_dir_item *)((char *)di + len);
+ cur += len;
+
+ ret = iterate(num, &di_key, buf, name_len, buf + name_len,
+ data_len, type, ctx);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+
+ num++;
+ }
+
+out:
+ if (buf_virtual)
+ vfree(buf);
+ else
+ kfree(buf);
+ return ret;
+}
+
+static int __copy_first_ref(int num, u64 dir, int index,
+ struct fs_path *p, void *ctx)
+{
+ int ret;
+ struct fs_path *pt = ctx;
+
+ ret = fs_path_copy(pt, p);
+ if (ret < 0)
+ return ret;
+
+ /* we want the first only */
+ return 1;
+}
+
+/*
+ * Retrieve the first path of an inode. If an inode has more then one
+ * ref/hardlink, this is ignored.
+ */
+static int get_inode_path(struct send_ctx *sctx, struct btrfs_root *root,
+ u64 ino, struct fs_path *path)
+{
+ int ret;
+ struct btrfs_key key, found_key;
+ struct btrfs_path *p;
+
+ p = alloc_path_for_send();
+ if (!p)
+ return -ENOMEM;
+
+ fs_path_reset(path);
+
+ key.objectid = ino;
+ key.type = BTRFS_INODE_REF_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot_for_read(root, &key, p, 1, 0);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 1;
+ goto out;
+ }
+ btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]);
+ if (found_key.objectid != ino ||
+ (found_key.type != BTRFS_INODE_REF_KEY &&
+ found_key.type != BTRFS_INODE_EXTREF_KEY)) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ ret = iterate_inode_ref(sctx, root, p, &found_key, 1,
+ __copy_first_ref, path);
+ if (ret < 0)
+ goto out;
+ ret = 0;
+
+out:
+ btrfs_free_path(p);
+ return ret;
+}
+
+struct backref_ctx {
+ struct send_ctx *sctx;
+
+ /* number of total found references */
+ u64 found;
+
+ /*
+ * used for clones found in send_root. clones found behind cur_objectid
+ * and cur_offset are not considered as allowed clones.
+ */
+ u64 cur_objectid;
+ u64 cur_offset;
+
+ /* may be truncated in case it's the last extent in a file */
+ u64 extent_len;
+
+ /* Just to check for bugs in backref resolving */
+ int found_itself;
+};
+
+static int __clone_root_cmp_bsearch(const void *key, const void *elt)
+{
+ u64 root = (u64)(uintptr_t)key;
+ struct clone_root *cr = (struct clone_root *)elt;
+
+ if (root < cr->root->objectid)
+ return -1;
+ if (root > cr->root->objectid)
+ return 1;
+ return 0;
+}
+
+static int __clone_root_cmp_sort(const void *e1, const void *e2)
+{
+ struct clone_root *cr1 = (struct clone_root *)e1;
+ struct clone_root *cr2 = (struct clone_root *)e2;
+
+ if (cr1->root->objectid < cr2->root->objectid)
+ return -1;
+ if (cr1->root->objectid > cr2->root->objectid)
+ return 1;
+ return 0;
+}
+
+/*
+ * Called for every backref that is found for the current extent.
+ * Results are collected in sctx->clone_roots->ino/offset/found_refs
+ */
+static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
+{
+ struct backref_ctx *bctx = ctx_;
+ struct clone_root *found;
+ int ret;
+ u64 i_size;
+
+ /* First check if the root is in the list of accepted clone sources */
+ found = bsearch((void *)(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;
+ }
+
+ /*
+ * There are inodes that have extents that lie behind its i_size. Don't
+ * accept clones from these extents.
+ */
+ ret = get_inode_info(found->root, ino, &i_size, NULL, NULL, NULL, NULL,
+ NULL);
+ if (ret < 0)
+ return ret;
+
+ if (offset + bctx->extent_len > i_size)
+ return 0;
+
+ /*
+ * Make sure we don't consider clones from send_root that are
+ * behind the current inode/offset.
+ */
+ if (found->root == bctx->sctx->send_root) {
+ /*
+ * TODO for the moment we don't accept clones from the inode
+ * that is currently send. We may change this when
+ * BTRFS_IOC_CLONE_RANGE supports cloning from and to the same
+ * file.
+ */
+ if (ino >= bctx->cur_objectid)
+ return 0;
+#if 0
+ if (ino > bctx->cur_objectid)
+ return 0;
+ if (offset + bctx->extent_len > bctx->cur_offset)
+ return 0;
+#endif
+ }
+
+ bctx->found++;
+ found->found_refs++;
+ if (ino < found->ino) {
+ found->ino = ino;
+ found->offset = offset;
+ } else if (found->ino == ino) {
+ /*
+ * same extent found more then once in the same file.
+ */
+ if (found->offset > offset + bctx->extent_len)
+ found->offset = offset;
+ }
+
+ return 0;
+}
+
+/*
+ * Given an inode, offset and extent item, it finds a good clone for a clone
+ * instruction. Returns -ENOENT when none could be found. The function makes
+ * sure that the returned clone is usable at the point where sending is at the
+ * moment. This means, that no clones are accepted which lie behind the current
+ * inode+offset.
+ *
+ * path must point to the extent item when called.
+ */
+static int find_extent_clone(struct send_ctx *sctx,
+ struct btrfs_path *path,
+ u64 ino, u64 data_offset,
+ u64 ino_size,
+ struct clone_root **found)
+{
+ int ret;
+ int extent_type;
+ u64 logical;
+ u64 disk_byte;
+ u64 num_bytes;
+ u64 extent_item_pos;
+ 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;
+
+ backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_NOFS);
+ if (!backref_ctx) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (data_offset >= ino_size) {
+ /*
+ * There may be extents that lie behind the file's size.
+ * I at least had this in combination with snapshotting while
+ * writing large files.
+ */
+ ret = 0;
+ goto out;
+ }
+
+ fi = btrfs_item_ptr(eb, path->slots[0],
+ struct btrfs_file_extent_item);
+ extent_type = btrfs_file_extent_type(eb, fi);
+ if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+ ret = -ENOENT;
+ goto out;
+ }
+ compressed = btrfs_file_extent_compression(eb, fi);
+
+ num_bytes = btrfs_file_extent_num_bytes(eb, fi);
+ disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
+ if (disk_byte == 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+ logical = disk_byte + btrfs_file_extent_offset(eb, fi);
+
+ ret = extent_from_logical(sctx->send_root->fs_info, disk_byte, tmp_path,
+ &found_key, &flags);
+ 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;
+
+ /*
+ * The last extent of a file may be too large due to page alignment.
+ * We need to adjust extent_len in this case so that the checks in
+ * __iterate_backrefs work.
+ */
+ if (data_offset + num_bytes >= ino_size)
+ backref_ctx->extent_len = ino_size - data_offset;
+
+ /*
+ * Now collect all backrefs.
+ */
+ if (compressed == BTRFS_COMPRESS_NONE)
+ extent_item_pos = logical - found_key.objectid;
+ else
+ extent_item_pos = 0;
+
+ extent_item_pos = logical - found_key.objectid;
+ ret = iterate_extent_inodes(sctx->send_root->fs_info,
+ found_key.objectid, extent_item_pos, 1,
+ __iterate_backrefs, backref_ctx);
+
+ if (ret < 0)
+ goto out;
+
+ if (!backref_ctx->found_itself) {
+ /* found a bug in backref code? */
+ ret = -EIO;
+ printk(KERN_ERR "btrfs: ERROR did not find backref in "
+ "send_root. inode=%llu, offset=%llu, "
+ "disk_byte=%llu found extent=%llu\n",
+ ino, data_offset, disk_byte, found_key.objectid);
+ goto out;
+ }
+
+verbose_printk(KERN_DEBUG "btrfs: find_extent_clone: data_offset=%llu, "
+ "ino=%llu, "
+ "num_bytes=%llu, logical=%llu\n",
+ data_offset, ino, num_bytes, logical);
+
+ if (!backref_ctx->found)
+ verbose_printk("btrfs: no clones found\n");
+
+ cur_clone_root = NULL;
+ for (i = 0; i < sctx->clone_roots_cnt; i++) {
+ if (sctx->clone_roots[i].found_refs) {
+ if (!cur_clone_root)
+ cur_clone_root = sctx->clone_roots + i;
+ else if (sctx->clone_roots[i].root == sctx->send_root)
+ /* prefer clones from send_root over others */
+ cur_clone_root = sctx->clone_roots + i;
+ }
+
+ }
+
+ if (cur_clone_root) {
+ *found = cur_clone_root;
+ ret = 0;
+ } else {
+ ret = -ENOENT;
+ }
+
+out:
+ btrfs_free_path(tmp_path);
+ kfree(backref_ctx);
+ return ret;
+}
+
+static int read_symlink(struct send_ctx *sctx,
+ struct btrfs_root *root,
+ u64 ino,
+ struct fs_path *dest)
+{
+ int ret;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_file_extent_item *ei;
+ u8 type;
+ u8 compression;
+ unsigned long off;
+ int len;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = 0;
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret);
+
+ ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_file_extent_item);
+ type = btrfs_file_extent_type(path->nodes[0], ei);
+ compression = btrfs_file_extent_compression(path->nodes[0], ei);
+ BUG_ON(type != BTRFS_FILE_EXTENT_INLINE);
+ BUG_ON(compression);
+
+ off = btrfs_file_extent_inline_start(ei);
+ len = btrfs_file_extent_inline_len(path->nodes[0], ei);
+
+ ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * Helper function to generate a file name that is unique in the root of
+ * send_root and parent_root. This is used to generate names for orphan inodes.
+ */
+static int gen_unique_name(struct send_ctx *sctx,
+ u64 ino, u64 gen,
+ struct fs_path *dest)
+{
+ int ret = 0;
+ struct btrfs_path *path;
+ struct btrfs_dir_item *di;
+ char tmp[64];
+ int len;
+ u64 idx = 0;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ while (1) {
+ len = snprintf(tmp, sizeof(tmp) - 1, "o%llu-%llu-%llu",
+ ino, gen, idx);
+ if (len >= sizeof(tmp)) {
+ /* should really not happen */
+ ret = -EOVERFLOW;
+ goto out;
+ }
+
+ di = btrfs_lookup_dir_item(NULL, sctx->send_root,
+ path, BTRFS_FIRST_FREE_OBJECTID,
+ tmp, strlen(tmp), 0);
+ btrfs_release_path(path);
+ if (IS_ERR(di)) {
+ ret = PTR_ERR(di);
+ goto out;
+ }
+ if (di) {
+ /* not unique, try again */
+ idx++;
+ continue;
+ }
+
+ if (!sctx->parent_root) {
+ /* unique */
+ ret = 0;
+ break;
+ }
+
+ di = btrfs_lookup_dir_item(NULL, sctx->parent_root,
+ path, BTRFS_FIRST_FREE_OBJECTID,
+ tmp, strlen(tmp), 0);
+ btrfs_release_path(path);
+ if (IS_ERR(di)) {
+ ret = PTR_ERR(di);
+ goto out;
+ }
+ if (di) {
+ /* not unique, try again */
+ idx++;
+ continue;
+ }
+ /* unique */
+ break;
+ }
+
+ ret = fs_path_add(dest, tmp, strlen(tmp));
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+enum inode_state {
+ inode_state_no_change,
+ inode_state_will_create,
+ inode_state_did_create,
+ inode_state_will_delete,
+ inode_state_did_delete,
+};
+
+static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen)
+{
+ int ret;
+ int left_ret;
+ int right_ret;
+ u64 left_gen;
+ u64 right_gen;
+
+ ret = get_inode_info(sctx->send_root, ino, NULL, &left_gen, NULL, NULL,
+ NULL, NULL);
+ if (ret < 0 && ret != -ENOENT)
+ goto out;
+ left_ret = ret;
+
+ if (!sctx->parent_root) {
+ right_ret = -ENOENT;
+ } else {
+ ret = get_inode_info(sctx->parent_root, ino, NULL, &right_gen,
+ NULL, NULL, NULL, NULL);
+ if (ret < 0 && ret != -ENOENT)
+ goto out;
+ right_ret = ret;
+ }
+
+ if (!left_ret && !right_ret) {
+ if (left_gen == gen && right_gen == gen) {
+ ret = inode_state_no_change;
+ } else if (left_gen == gen) {
+ if (ino < sctx->send_progress)
+ ret = inode_state_did_create;
+ else
+ ret = inode_state_will_create;
+ } else if (right_gen == gen) {
+ if (ino < sctx->send_progress)
+ ret = inode_state_did_delete;
+ else
+ ret = inode_state_will_delete;
+ } else {
+ ret = -ENOENT;
+ }
+ } else if (!left_ret) {
+ if (left_gen == gen) {
+ if (ino < sctx->send_progress)
+ ret = inode_state_did_create;
+ else
+ ret = inode_state_will_create;
+ } else {
+ ret = -ENOENT;
+ }
+ } else if (!right_ret) {
+ if (right_gen == gen) {
+ if (ino < sctx->send_progress)
+ ret = inode_state_did_delete;
+ else
+ ret = inode_state_will_delete;
+ } else {
+ ret = -ENOENT;
+ }
+ } else {
+ ret = -ENOENT;
+ }
+
+out:
+ return ret;
+}
+
+static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen)
+{
+ int ret;
+
+ ret = get_cur_inode_state(sctx, ino, gen);
+ if (ret < 0)
+ goto out;
+
+ if (ret == inode_state_no_change ||
+ ret == inode_state_did_create ||
+ ret == inode_state_will_delete)
+ ret = 1;
+ else
+ ret = 0;
+
+out:
+ return ret;
+}
+
+/*
+ * Helper function to lookup a dir item in a dir.
+ */
+static int lookup_dir_item_inode(struct btrfs_root *root,
+ u64 dir, const char *name, int name_len,
+ u64 *found_inode,
+ u8 *found_type)
+{
+ int ret = 0;
+ struct btrfs_dir_item *di;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ di = btrfs_lookup_dir_item(NULL, root, path,
+ dir, name, name_len, 0);
+ if (!di) {
+ ret = -ENOENT;
+ goto out;
+ }
+ if (IS_ERR(di)) {
+ ret = PTR_ERR(di);
+ goto out;
+ }
+ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
+ *found_inode = key.objectid;
+ *found_type = btrfs_dir_type(path->nodes[0], di);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir,
+ * generation of the parent dir and the name of the dir entry.
+ */
+static int get_first_ref(struct send_ctx *sctx,
+ struct btrfs_root *root, u64 ino,
+ u64 *dir, u64 *dir_gen, struct fs_path *name)
+{
+ int ret;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct btrfs_path *path;
+ 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 (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);
+
+ 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 send_ctx *sctx,
+ struct btrfs_root *root,
+ u64 ino, u64 dir,
+ const char *name, int name_len)
+{
+ int ret;
+ struct fs_path *tmp_name;
+ u64 tmp_dir;
+ u64 tmp_dir_gen;
+
+ tmp_name = fs_path_alloc(sctx);
+ if (!tmp_name)
+ return -ENOMEM;
+
+ ret = get_first_ref(sctx, root, ino, &tmp_dir, &tmp_dir_gen, tmp_name);
+ if (ret < 0)
+ goto out;
+
+ if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) {
+ ret = 0;
+ goto out;
+ }
+
+ ret = !memcmp(tmp_name->start, name, name_len);
+
+out:
+ fs_path_free(sctx, tmp_name);
+ return ret;
+}
+
+/*
+ * Used by process_recorded_refs to determine if a new ref would overwrite an
+ * already existing ref. In case it detects an overwrite, it returns the
+ * inode/gen in who_ino/who_gen.
+ * When an overwrite is detected, process_recorded_refs does proper orphanizing
+ * to make sure later references to the overwritten inode are possible.
+ * Orphanizing is however only required for the first ref of an inode.
+ * process_recorded_refs does an additional is_first_ref check to see if
+ * orphanizing is really required.
+ */
+static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
+ const char *name, int name_len,
+ u64 *who_ino, u64 *who_gen)
+{
+ int ret = 0;
+ u64 other_inode = 0;
+ u8 other_type = 0;
+
+ if (!sctx->parent_root)
+ goto out;
+
+ ret = is_inode_existent(sctx, dir, dir_gen);
+ if (ret <= 0)
+ goto out;
+
+ ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
+ &other_inode, &other_type);
+ if (ret < 0 && ret != -ENOENT)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * Check if the overwritten ref was already processed. If yes, the ref
+ * was already unlinked/moved, so we can safely assume that we will not
+ * overwrite anything at this point in time.
+ */
+ if (other_inode > sctx->send_progress) {
+ ret = get_inode_info(sctx->parent_root, other_inode, NULL,
+ who_gen, NULL, NULL, NULL, NULL);
+ if (ret < 0)
+ goto out;
+
+ ret = 1;
+ *who_ino = other_inode;
+ } else {
+ ret = 0;
+ }
+
+out:
+ return ret;
+}
+
+/*
+ * Checks if the ref was overwritten by an already processed inode. This is
+ * used by __get_cur_name_and_parent to find out if the ref was orphanized and
+ * thus the orphan name needs be used.
+ * process_recorded_refs also uses it to avoid unlinking of refs that were
+ * overwritten.
+ */
+static int did_overwrite_ref(struct send_ctx *sctx,
+ u64 dir, u64 dir_gen,
+ u64 ino, u64 ino_gen,
+ const char *name, int name_len)
+{
+ int ret = 0;
+ u64 gen;
+ u64 ow_inode;
+ u8 other_type;
+
+ if (!sctx->parent_root)
+ goto out;
+
+ ret = is_inode_existent(sctx, dir, dir_gen);
+ if (ret <= 0)
+ goto out;
+
+ /* check if the ref was overwritten by another ref */
+ ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
+ &ow_inode, &other_type);
+ if (ret < 0 && ret != -ENOENT)
+ goto out;
+ if (ret) {
+ /* was never and will never be overwritten */
+ ret = 0;
+ goto out;
+ }
+
+ ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL,
+ NULL, NULL);
+ if (ret < 0)
+ goto out;
+
+ if (ow_inode == ino && gen == ino_gen) {
+ ret = 0;
+ goto out;
+ }
+
+ /* we know that it is or will be overwritten. check this now */
+ if (ow_inode < sctx->send_progress)
+ ret = 1;
+ else
+ ret = 0;
+
+out:
+ return ret;
+}
+
+/*
+ * Same as did_overwrite_ref, but also checks if it is the first ref of an inode
+ * that got overwritten. This is used by process_recorded_refs to determine
+ * if it has to use the path as returned by get_cur_path or the orphan name.
+ */
+static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen)
+{
+ int ret = 0;
+ struct fs_path *name = NULL;
+ u64 dir;
+ u64 dir_gen;
+
+ if (!sctx->parent_root)
+ goto out;
+
+ name = fs_path_alloc(sctx);
+ if (!name)
+ return -ENOMEM;
+
+ ret = get_first_ref(sctx, sctx->parent_root, ino, &dir, &dir_gen, name);
+ if (ret < 0)
+ goto out;
+
+ ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen,
+ name->start, fs_path_len(name));
+
+out:
+ fs_path_free(sctx, name);
+ return ret;
+}
+
+/*
+ * Insert a name cache entry. On 32bit kernels the radix tree index is 32bit,
+ * so we need to do some special handling in case we have clashes. This function
+ * takes care of this with the help of name_cache_entry::radix_list.
+ * In case of error, nce is kfreed.
+ */
+static int name_cache_insert(struct send_ctx *sctx,
+ struct name_cache_entry *nce)
+{
+ int ret = 0;
+ struct list_head *nce_head;
+
+ nce_head = radix_tree_lookup(&sctx->name_cache,
+ (unsigned long)nce->ino);
+ if (!nce_head) {
+ nce_head = kmalloc(sizeof(*nce_head), GFP_NOFS);
+ if (!nce_head) {
+ 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);
+ BUG_ON(!nce_head);
+
+ list_del(&nce->radix_list);
+ list_del(&nce->list);
+ sctx->name_cache_size--;
+
+ if (list_empty(nce_head)) {
+ radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino);
+ kfree(nce_head);
+ }
+}
+
+static struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
+ u64 ino, u64 gen)
+{
+ struct list_head *nce_head;
+ struct name_cache_entry *cur;
+
+ nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino);
+ if (!nce_head)
+ return NULL;
+
+ list_for_each_entry(cur, nce_head, radix_list) {
+ if (cur->ino == ino && cur->gen == gen)
+ return cur;
+ }
+ return NULL;
+}
+
+/*
+ * Removes the entry from the list and adds it back to the end. This marks the
+ * entry as recently used so that name_cache_clean_unused does not remove it.
+ */
+static void name_cache_used(struct send_ctx *sctx, struct name_cache_entry *nce)
+{
+ list_del(&nce->list);
+ list_add_tail(&nce->list, &sctx->name_cache_list);
+}
+
+/*
+ * Remove some entries from the beginning of name_cache_list.
+ */
+static void name_cache_clean_unused(struct send_ctx *sctx)
+{
+ struct name_cache_entry *nce;
+
+ if (sctx->name_cache_size < SEND_CTX_NAME_CACHE_CLEAN_SIZE)
+ return;
+
+ while (sctx->name_cache_size > SEND_CTX_MAX_NAME_CACHE_SIZE) {
+ nce = list_entry(sctx->name_cache_list.next,
+ struct name_cache_entry, list);
+ name_cache_delete(sctx, nce);
+ kfree(nce);
+ }
+}
+
+static void name_cache_free(struct send_ctx *sctx)
+{
+ struct name_cache_entry *nce;
+
+ while (!list_empty(&sctx->name_cache_list)) {
+ nce = list_entry(sctx->name_cache_list.next,
+ struct name_cache_entry, list);
+ name_cache_delete(sctx, nce);
+ kfree(nce);
+ }
+}
+
+/*
+ * Used by get_cur_path for each ref up to the root.
+ * Returns 0 if it succeeded.
+ * Returns 1 if the inode is not existent or got overwritten. In that case, the
+ * name is an orphan name. This instructs get_cur_path to stop iterating. If 1
+ * is returned, parent_ino/parent_gen are not guaranteed to be valid.
+ * Returns <0 in case of error.
+ */
+static int __get_cur_name_and_parent(struct send_ctx *sctx,
+ u64 ino, u64 gen,
+ u64 *parent_ino,
+ u64 *parent_gen,
+ struct fs_path *dest)
+{
+ int ret;
+ int nce_ret;
+ struct btrfs_path *path = NULL;
+ struct name_cache_entry *nce = NULL;
+
+ /*
+ * First check if we already did a call to this function with the same
+ * ino/gen. If yes, check if the cache entry is still up-to-date. If yes
+ * return the cached result.
+ */
+ nce = name_cache_search(sctx, ino, gen);
+ if (nce) {
+ if (ino < sctx->send_progress && nce->need_later_update) {
+ name_cache_delete(sctx, nce);
+ kfree(nce);
+ nce = NULL;
+ } else {
+ name_cache_used(sctx, nce);
+ *parent_ino = nce->parent_ino;
+ *parent_gen = nce->parent_gen;
+ ret = fs_path_add(dest, nce->name, nce->name_len);
+ if (ret < 0)
+ goto out;
+ ret = nce->ret;
+ goto out;
+ }
+ }
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ /*
+ * If the inode is not existent yet, add the orphan name and return 1.
+ * This should only happen for the parent dir that we determine in
+ * __record_new_ref
+ */
+ ret = is_inode_existent(sctx, ino, gen);
+ if (ret < 0)
+ goto out;
+
+ if (!ret) {
+ ret = gen_unique_name(sctx, ino, gen, dest);
+ if (ret < 0)
+ goto out;
+ ret = 1;
+ goto out_cache;
+ }
+
+ /*
+ * Depending on whether the inode was already processed or not, use
+ * send_root or parent_root for ref lookup.
+ */
+ if (ino < sctx->send_progress)
+ ret = get_first_ref(sctx, sctx->send_root, ino,
+ parent_ino, parent_gen, dest);
+ else
+ ret = get_first_ref(sctx, sctx->parent_root, ino,
+ parent_ino, parent_gen, dest);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * Check if the ref was overwritten by an inode's ref that was processed
+ * earlier. If yes, treat as orphan and return 1.
+ */
+ ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen,
+ dest->start, dest->end - dest->start);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ fs_path_reset(dest);
+ ret = gen_unique_name(sctx, ino, gen, dest);
+ if (ret < 0)
+ goto out;
+ ret = 1;
+ }
+
+out_cache:
+ /*
+ * Store the result of the lookup in the name cache.
+ */
+ nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_NOFS);
+ if (!nce) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ nce->ino = ino;
+ nce->gen = gen;
+ nce->parent_ino = *parent_ino;
+ nce->parent_gen = *parent_gen;
+ nce->name_len = fs_path_len(dest);
+ nce->ret = ret;
+ strcpy(nce->name, dest->start);
+
+ if (ino < sctx->send_progress)
+ nce->need_later_update = 0;
+ else
+ nce->need_later_update = 1;
+
+ nce_ret = name_cache_insert(sctx, nce);
+ if (nce_ret < 0)
+ ret = nce_ret;
+ name_cache_clean_unused(sctx);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * Magic happens here. This function returns the first ref to an inode as it
+ * would look like while receiving the stream at this point in time.
+ * We walk the path up to the root. For every inode in between, we check if it
+ * was already processed/sent. If yes, we continue with the parent as found
+ * in send_root. If not, we continue with the parent as found in parent_root.
+ * If we encounter an inode that was deleted at this point in time, we use the
+ * inodes "orphan" name instead of the real name and stop. Same with new inodes
+ * that were not created yet and overwritten inodes/refs.
+ *
+ * When do we have have orphan inodes:
+ * 1. When an inode is freshly created and thus no valid refs are available yet
+ * 2. When a directory lost all it's refs (deleted) but still has dir items
+ * inside which were not processed yet (pending for move/delete). If anyone
+ * tried to get the path to the dir items, it would get a path inside that
+ * orphan directory.
+ * 3. When an inode is moved around or gets new links, it may overwrite the ref
+ * of an unprocessed inode. If in that case the first ref would be
+ * overwritten, the overwritten inode gets "orphanized". Later when we
+ * process this overwritten inode, it is restored at a new place by moving
+ * the orphan inode.
+ *
+ * sctx->send_progress tells this function at which point in time receiving
+ * would be.
+ */
+static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
+ struct fs_path *dest)
+{
+ int ret = 0;
+ struct fs_path *name = NULL;
+ u64 parent_inode = 0;
+ u64 parent_gen = 0;
+ int stop = 0;
+
+ name = fs_path_alloc(sctx);
+ if (!name) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ dest->reversed = 1;
+ fs_path_reset(dest);
+
+ while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
+ fs_path_reset(name);
+
+ ret = __get_cur_name_and_parent(sctx, ino, gen,
+ &parent_inode, &parent_gen, name);
+ if (ret < 0)
+ goto out;
+ if (ret)
+ stop = 1;
+
+ ret = fs_path_add_path(dest, name);
+ if (ret < 0)
+ goto out;
+
+ ino = parent_inode;
+ gen = parent_gen;
+ }
+
+out:
+ fs_path_free(sctx, name);
+ if (!ret)
+ fs_path_unreverse(dest);
+ return ret;
+}
+
+/*
+ * Called for regular files when sending extents data. Opens a struct file
+ * to read from the file.
+ */
+static int open_cur_inode_file(struct send_ctx *sctx)
+{
+ int ret = 0;
+ struct btrfs_key key;
+ struct path path;
+ struct inode *inode;
+ struct dentry *dentry;
+ struct file *filp;
+ int new = 0;
+
+ if (sctx->cur_inode_filp)
+ goto out;
+
+ key.objectid = sctx->cur_ino;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+
+ inode = btrfs_iget(sctx->send_root->fs_info->sb, &key, sctx->send_root,
+ &new);
+ if (IS_ERR(inode)) {
+ ret = PTR_ERR(inode);
+ goto out;
+ }
+
+ dentry = d_obtain_alias(inode);
+ inode = NULL;
+ if (IS_ERR(dentry)) {
+ ret = PTR_ERR(dentry);
+ goto out;
+ }
+
+ path.mnt = sctx->mnt;
+ path.dentry = dentry;
+ filp = dentry_open(&path, O_RDONLY | O_LARGEFILE, current_cred());
+ dput(dentry);
+ dentry = NULL;
+ if (IS_ERR(filp)) {
+ ret = PTR_ERR(filp);
+ goto out;
+ }
+ sctx->cur_inode_filp = filp;
+
+out:
+ /*
+ * no xxxput required here as every vfs op
+ * does it by itself on failure
+ */
+ return ret;
+}
+
+/*
+ * Closes the struct file that was created in open_cur_inode_file
+ */
+static int close_cur_inode_file(struct send_ctx *sctx)
+{
+ int ret = 0;
+
+ if (!sctx->cur_inode_filp)
+ goto out;
+
+ ret = filp_close(sctx->cur_inode_filp, NULL);
+ sctx->cur_inode_filp = NULL;
+
+out:
+ return ret;
+}
+
+/*
+ * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace
+ */
+static int send_subvol_begin(struct send_ctx *sctx)
+{
+ int ret;
+ struct btrfs_root *send_root = sctx->send_root;
+ struct btrfs_root *parent_root = sctx->parent_root;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_root_ref *ref;
+ struct extent_buffer *leaf;
+ char *name = NULL;
+ int namelen;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_NOFS);
+ if (!name) {
+ btrfs_free_path(path);
+ return -ENOMEM;
+ }
+
+ key.objectid = send_root->objectid;
+ key.type = BTRFS_ROOT_BACKREF_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root,
+ &key, path, 1, 0);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.type != BTRFS_ROOT_BACKREF_KEY ||
+ key.objectid != send_root->objectid) {
+ ret = -ENOENT;
+ goto out;
+ }
+ ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
+ namelen = btrfs_root_ref_name_len(leaf, ref);
+ read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen);
+ btrfs_release_path(path);
+
+ if (parent_root) {
+ ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT);
+ if (ret < 0)
+ goto out;
+ } else {
+ ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL);
+ if (ret < 0)
+ goto out;
+ }
+
+ TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen);
+ TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
+ sctx->send_root->root_item.uuid);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
+ sctx->send_root->root_item.ctransid);
+ if (parent_root) {
+ TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
+ sctx->parent_root->root_item.uuid);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
+ sctx->parent_root->root_item.ctransid);
+ }
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ btrfs_free_path(path);
+ kfree(name);
+ return ret;
+}
+
+static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size)
+{
+ int ret = 0;
+ struct fs_path *p;
+
+verbose_printk("btrfs: send_truncate %llu size=%llu\n", ino, size);
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, ino, gen, p);
+ if (ret < 0)
+ goto out;
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
+{
+ int ret = 0;
+ struct fs_path *p;
+
+verbose_printk("btrfs: send_chmod %llu mode=%llu\n", ino, mode);
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, ino, gen, p);
+ if (ret < 0)
+ goto out;
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
+{
+ int ret = 0;
+ struct fs_path *p;
+
+verbose_printk("btrfs: send_chown %llu uid=%llu, gid=%llu\n", ino, uid, gid);
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, ino, gen, p);
+ if (ret < 0)
+ goto out;
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
+{
+ int ret = 0;
+ struct fs_path *p = NULL;
+ struct btrfs_inode_item *ii;
+ struct btrfs_path *path = NULL;
+ struct extent_buffer *eb;
+ struct btrfs_key key;
+ int slot;
+
+verbose_printk("btrfs: send_utimes %llu\n", ino);
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ path = alloc_path_for_send();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ key.objectid = ino;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+ ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, ino, gen, p);
+ if (ret < 0)
+ goto out;
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+ TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb,
+ btrfs_inode_atime(ii));
+ TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb,
+ btrfs_inode_mtime(ii));
+ TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb,
+ btrfs_inode_ctime(ii));
+ /* TODO Add otime support when the otime patches get into upstream */
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ fs_path_free(sctx, p);
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have
+ * a valid path yet because we did not process the refs yet. So, the inode
+ * is created as orphan.
+ */
+static int send_create_inode(struct send_ctx *sctx, u64 ino)
+{
+ int ret = 0;
+ struct fs_path *p;
+ int cmd;
+ u64 gen;
+ u64 mode;
+ u64 rdev;
+
+verbose_printk("btrfs: send_create_inode %llu\n", ino);
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode, NULL,
+ NULL, &rdev);
+ if (ret < 0)
+ goto out;
+
+ if (S_ISREG(mode)) {
+ cmd = BTRFS_SEND_C_MKFILE;
+ } else if (S_ISDIR(mode)) {
+ cmd = BTRFS_SEND_C_MKDIR;
+ } else if (S_ISLNK(mode)) {
+ cmd = BTRFS_SEND_C_SYMLINK;
+ } else if (S_ISCHR(mode) || S_ISBLK(mode)) {
+ cmd = BTRFS_SEND_C_MKNOD;
+ } else if (S_ISFIFO(mode)) {
+ cmd = BTRFS_SEND_C_MKFIFO;
+ } else if (S_ISSOCK(mode)) {
+ cmd = BTRFS_SEND_C_MKSOCK;
+ } else {
+ printk(KERN_WARNING "btrfs: unexpected inode type %o",
+ (int)(mode & S_IFMT));
+ ret = -ENOTSUPP;
+ goto out;
+ }
+
+ ret = begin_cmd(sctx, cmd);
+ if (ret < 0)
+ goto out;
+
+ ret = gen_unique_name(sctx, ino, gen, p);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino);
+
+ if (S_ISLNK(mode)) {
+ fs_path_reset(p);
+ ret = read_symlink(sctx, sctx->send_root, ino, p);
+ if (ret < 0)
+ goto out;
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p);
+ } else if (S_ISCHR(mode) || S_ISBLK(mode) ||
+ S_ISFIFO(mode) || S_ISSOCK(mode)) {
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, 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(sctx, p);
+ return ret;
+}
+
+/*
+ * We need some special handling for inodes that get processed before the parent
+ * directory got created. See process_recorded_refs for details.
+ * This function does the check if we already created the dir out of order.
+ */
+static int did_create_dir(struct send_ctx *sctx, u64 dir)
+{
+ int ret = 0;
+ struct btrfs_path *path = NULL;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct btrfs_key di_key;
+ struct extent_buffer *eb;
+ struct btrfs_dir_item *di;
+ int slot;
+
+ path = alloc_path_for_send();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ key.objectid = dir;
+ key.type = BTRFS_DIR_INDEX_KEY;
+ key.offset = 0;
+ while (1) {
+ ret = btrfs_search_slot_for_read(sctx->send_root, &key, path,
+ 1, 0);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+ }
+ if (ret || found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ ret = 0;
+ goto out;
+ }
+
+ di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
+ btrfs_dir_item_key_to_cpu(eb, di, &di_key);
+
+ if (di_key.objectid < sctx->send_progress) {
+ ret = 1;
+ goto out;
+ }
+
+ key.offset = found_key.offset + 1;
+ btrfs_release_path(path);
+ }
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * Only creates the inode if it is:
+ * 1. Not a directory
+ * 2. Or a directory which was not created already due to out of order
+ * directories. See did_create_dir and process_recorded_refs for details.
+ */
+static int send_create_inode_if_needed(struct send_ctx *sctx)
+{
+ int ret;
+
+ if (S_ISDIR(sctx->cur_inode_mode)) {
+ ret = did_create_dir(sctx, sctx->cur_ino);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+ }
+
+ ret = send_create_inode(sctx, sctx->cur_ino);
+ if (ret < 0)
+ goto out;
+
+out:
+ return ret;
+}
+
+struct recorded_ref {
+ struct list_head list;
+ char *dir_path;
+ char *name;
+ struct fs_path *full_path;
+ u64 dir;
+ u64 dir_gen;
+ int dir_path_len;
+ int name_len;
+};
+
+/*
+ * We need to process new refs before deleted refs, but compare_tree gives us
+ * everything mixed. So we first record all refs and later process them.
+ * This function is a helper to record one ref.
+ */
+static int record_ref(struct list_head *head, u64 dir,
+ u64 dir_gen, struct fs_path *path)
+{
+ struct recorded_ref *ref;
+ char *tmp;
+
+ ref = kmalloc(sizeof(*ref), GFP_NOFS);
+ if (!ref)
+ return -ENOMEM;
+
+ ref->dir = dir;
+ ref->dir_gen = dir_gen;
+ ref->full_path = path;
+
+ tmp = strrchr(ref->full_path->start, '/');
+ if (!tmp) {
+ ref->name_len = ref->full_path->end - ref->full_path->start;
+ ref->name = ref->full_path->start;
+ ref->dir_path_len = 0;
+ ref->dir_path = ref->full_path->start;
+ } else {
+ tmp++;
+ ref->name_len = ref->full_path->end - tmp;
+ ref->name = tmp;
+ ref->dir_path = ref->full_path->start;
+ ref->dir_path_len = ref->full_path->end -
+ ref->full_path->start - 1 - ref->name_len;
+ }
+
+ list_add_tail(&ref->list, head);
+ return 0;
+}
+
+static void __free_recorded_refs(struct send_ctx *sctx, struct list_head *head)
+{
+ struct recorded_ref *cur;
+
+ while (!list_empty(head)) {
+ cur = list_entry(head->next, struct recorded_ref, list);
+ fs_path_free(sctx, cur->full_path);
+ list_del(&cur->list);
+ kfree(cur);
+ }
+}
+
+static void free_recorded_refs(struct send_ctx *sctx)
+{
+ __free_recorded_refs(sctx, &sctx->new_refs);
+ __free_recorded_refs(sctx, &sctx->deleted_refs);
+}
+
+/*
+ * Renames/moves a file/dir to its orphan name. Used when the first
+ * ref of an unprocessed inode gets overwritten and for all non empty
+ * directories.
+ */
+static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen,
+ struct fs_path *path)
+{
+ int ret;
+ struct fs_path *orphan;
+
+ orphan = fs_path_alloc(sctx);
+ if (!orphan)
+ return -ENOMEM;
+
+ ret = gen_unique_name(sctx, ino, gen, orphan);
+ if (ret < 0)
+ goto out;
+
+ ret = send_rename(sctx, path, orphan);
+
+out:
+ fs_path_free(sctx, orphan);
+ return ret;
+}
+
+/*
+ * Returns 1 if a directory can be removed at this point in time.
+ * We check this by iterating all dir items and checking if the inode behind
+ * the dir item was already processed.
+ */
+static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 send_progress)
+{
+ int ret = 0;
+ struct btrfs_root *root = sctx->parent_root;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct btrfs_key loc;
+ struct btrfs_dir_item *di;
+
+ /*
+ * Don't try to rmdir the top/root subvolume dir.
+ */
+ if (dir == BTRFS_FIRST_FREE_OBJECTID)
+ return 0;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = dir;
+ key.type = BTRFS_DIR_INDEX_KEY;
+ key.offset = 0;
+
+ while (1) {
+ ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+ path->slots[0]);
+ }
+ if (ret || found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ break;
+ }
+
+ di = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_dir_item);
+ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc);
+
+ if (loc.objectid > send_progress) {
+ ret = 0;
+ goto out;
+ }
+
+ btrfs_release_path(path);
+ key.offset = found_key.offset + 1;
+ }
+
+ ret = 1;
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * This does all the move/link/unlink/rmdir magic.
+ */
+static int process_recorded_refs(struct send_ctx *sctx)
+{
+ int ret = 0;
+ struct recorded_ref *cur;
+ struct recorded_ref *cur2;
+ struct ulist *check_dirs = NULL;
+ struct ulist_iterator uit;
+ struct ulist_node *un;
+ struct fs_path *valid_path = NULL;
+ u64 ow_inode = 0;
+ u64 ow_gen;
+ int did_overwrite = 0;
+ int is_orphan = 0;
+
+verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
+
+ /*
+ * This should never happen as the root dir always has the same ref
+ * which is always '..'
+ */
+ BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID);
+
+ valid_path = fs_path_alloc(sctx);
+ if (!valid_path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ check_dirs = ulist_alloc(GFP_NOFS);
+ if (!check_dirs) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * First, check if the first ref of the current inode was overwritten
+ * before. If yes, we know that the current inode was already orphanized
+ * and thus use the orphan name. If not, we can use get_cur_path to
+ * get the path of the first ref as it would like while receiving at
+ * this point in time.
+ * New inodes are always orphan at the beginning, so force to use the
+ * orphan name in this case.
+ * The first ref is stored in valid_path and will be updated if it
+ * gets moved around.
+ */
+ if (!sctx->cur_inode_new) {
+ ret = did_overwrite_first_ref(sctx, sctx->cur_ino,
+ sctx->cur_inode_gen);
+ if (ret < 0)
+ goto out;
+ if (ret)
+ did_overwrite = 1;
+ }
+ if (sctx->cur_inode_new || did_overwrite) {
+ ret = gen_unique_name(sctx, sctx->cur_ino,
+ sctx->cur_inode_gen, valid_path);
+ if (ret < 0)
+ goto out;
+ is_orphan = 1;
+ } else {
+ ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen,
+ valid_path);
+ if (ret < 0)
+ goto out;
+ }
+
+ list_for_each_entry(cur, &sctx->new_refs, list) {
+ /*
+ * We may have refs where the parent directory does not exist
+ * yet. This happens if the parent directories inum is higher
+ * the the current inum. To handle this case, we create the
+ * parent directory out of order. But we need to check if this
+ * did already happen before due to other refs in the same dir.
+ */
+ ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
+ if (ret < 0)
+ goto out;
+ if (ret == inode_state_will_create) {
+ ret = 0;
+ /*
+ * First check if any of the current inodes refs did
+ * already create the dir.
+ */
+ list_for_each_entry(cur2, &sctx->new_refs, list) {
+ if (cur == cur2)
+ break;
+ if (cur2->dir == cur->dir) {
+ ret = 1;
+ break;
+ }
+ }
+
+ /*
+ * If that did not happen, check if a previous inode
+ * did already create the dir.
+ */
+ if (!ret)
+ ret = did_create_dir(sctx, cur->dir);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = send_create_inode(sctx, cur->dir);
+ if (ret < 0)
+ goto out;
+ }
+ }
+
+ /*
+ * Check if this new ref would overwrite the first ref of
+ * another unprocessed inode. If yes, orphanize the
+ * overwritten inode. If we find an overwritten ref that is
+ * not the first ref, simply unlink it.
+ */
+ ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen,
+ cur->name, cur->name_len,
+ &ow_inode, &ow_gen);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = is_first_ref(sctx, sctx->parent_root,
+ ow_inode, cur->dir, cur->name,
+ cur->name_len);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = orphanize_inode(sctx, ow_inode, ow_gen,
+ cur->full_path);
+ if (ret < 0)
+ goto out;
+ } else {
+ ret = send_unlink(sctx, cur->full_path);
+ if (ret < 0)
+ goto out;
+ }
+ }
+
+ /*
+ * link/move the ref to the new place. If we have an orphan
+ * inode, move it and update valid_path. If not, link or move
+ * it depending on the inode mode.
+ */
+ if (is_orphan) {
+ ret = send_rename(sctx, valid_path, cur->full_path);
+ if (ret < 0)
+ goto out;
+ is_orphan = 0;
+ ret = fs_path_copy(valid_path, cur->full_path);
+ if (ret < 0)
+ goto out;
+ } else {
+ if (S_ISDIR(sctx->cur_inode_mode)) {
+ /*
+ * Dirs can't be linked, so move it. For moved
+ * dirs, we always have one new and one deleted
+ * ref. The deleted ref is ignored later.
+ */
+ ret = send_rename(sctx, valid_path,
+ cur->full_path);
+ if (ret < 0)
+ goto out;
+ ret = fs_path_copy(valid_path, cur->full_path);
+ if (ret < 0)
+ goto out;
+ } else {
+ ret = send_link(sctx, cur->full_path,
+ valid_path);
+ if (ret < 0)
+ goto out;
+ }
+ }
+ ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
+ GFP_NOFS);
+ if (ret < 0)
+ goto out;
+ }
+
+ if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) {
+ /*
+ * Check if we can already rmdir the directory. If not,
+ * orphanize it. For every dir item inside that gets deleted
+ * later, we do this check again and rmdir it then if possible.
+ * See the use of check_dirs for more details.
+ */
+ ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_ino);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = send_rmdir(sctx, valid_path);
+ if (ret < 0)
+ goto out;
+ } else if (!is_orphan) {
+ ret = orphanize_inode(sctx, sctx->cur_ino,
+ sctx->cur_inode_gen, valid_path);
+ if (ret < 0)
+ goto out;
+ is_orphan = 1;
+ }
+
+ list_for_each_entry(cur, &sctx->deleted_refs, list) {
+ ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
+ GFP_NOFS);
+ if (ret < 0)
+ goto out;
+ }
+ } else if (S_ISDIR(sctx->cur_inode_mode) &&
+ !list_empty(&sctx->deleted_refs)) {
+ /*
+ * We have a moved dir. Add the old parent to check_dirs
+ */
+ cur = list_entry(sctx->deleted_refs.next, struct recorded_ref,
+ list);
+ ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
+ GFP_NOFS);
+ if (ret < 0)
+ goto out;
+ } else if (!S_ISDIR(sctx->cur_inode_mode)) {
+ /*
+ * We have a non dir inode. Go through all deleted refs and
+ * unlink them if they were not already overwritten by other
+ * inodes.
+ */
+ list_for_each_entry(cur, &sctx->deleted_refs, list) {
+ ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen,
+ sctx->cur_ino, sctx->cur_inode_gen,
+ cur->name, cur->name_len);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = send_unlink(sctx, cur->full_path);
+ if (ret < 0)
+ goto out;
+ }
+ ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
+ GFP_NOFS);
+ if (ret < 0)
+ goto out;
+ }
+
+ /*
+ * If the inode is still orphan, unlink the orphan. This may
+ * happen when a previous inode did overwrite the first ref
+ * of this inode and no new refs were added for the current
+ * inode. Unlinking does not mean that the inode is deleted in
+ * all cases. There may still be links to this inode in other
+ * places.
+ */
+ if (is_orphan) {
+ ret = send_unlink(sctx, valid_path);
+ if (ret < 0)
+ goto out;
+ }
+ }
+
+ /*
+ * We did collect all parent dirs where cur_inode was once located. We
+ * now go through all these dirs and check if they are pending for
+ * deletion and if it's finally possible to perform the rmdir now.
+ * We also update the inode stats of the parent dirs here.
+ */
+ ULIST_ITER_INIT(&uit);
+ while ((un = ulist_next(check_dirs, &uit))) {
+ /*
+ * In case we had refs into dirs that were not processed yet,
+ * we don't need to do the utime and rmdir logic for these dirs.
+ * The dir will be processed later.
+ */
+ if (un->val > sctx->cur_ino)
+ continue;
+
+ ret = get_cur_inode_state(sctx, un->val, un->aux);
+ if (ret < 0)
+ goto out;
+
+ if (ret == inode_state_did_create ||
+ ret == inode_state_no_change) {
+ /* TODO delayed utimes */
+ ret = send_utimes(sctx, un->val, un->aux);
+ if (ret < 0)
+ goto out;
+ } else if (ret == inode_state_did_delete) {
+ ret = can_rmdir(sctx, un->val, sctx->cur_ino);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = get_cur_path(sctx, un->val, un->aux,
+ valid_path);
+ if (ret < 0)
+ goto out;
+ ret = send_rmdir(sctx, valid_path);
+ if (ret < 0)
+ goto out;
+ }
+ }
+ }
+
+ ret = 0;
+
+out:
+ free_recorded_refs(sctx);
+ ulist_free(check_dirs);
+ fs_path_free(sctx, valid_path);
+ return ret;
+}
+
+static int __record_new_ref(int num, u64 dir, int index,
+ struct fs_path *name,
+ void *ctx)
+{
+ int ret = 0;
+ struct send_ctx *sctx = ctx;
+ struct fs_path *p;
+ u64 gen;
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL, NULL,
+ NULL, NULL);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, dir, gen, p);
+ if (ret < 0)
+ goto out;
+ ret = fs_path_add_path(p, name);
+ if (ret < 0)
+ goto out;
+
+ ret = record_ref(&sctx->new_refs, dir, gen, p);
+
+out:
+ if (ret)
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int __record_deleted_ref(int num, u64 dir, int index,
+ struct fs_path *name,
+ void *ctx)
+{
+ int ret = 0;
+ struct send_ctx *sctx = ctx;
+ struct fs_path *p;
+ u64 gen;
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL, NULL,
+ NULL, NULL);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, dir, gen, p);
+ if (ret < 0)
+ goto out;
+ ret = fs_path_add_path(p, name);
+ if (ret < 0)
+ goto out;
+
+ ret = record_ref(&sctx->deleted_refs, dir, gen, p);
+
+out:
+ if (ret)
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int record_new_ref(struct send_ctx *sctx)
+{
+ int ret;
+
+ ret = iterate_inode_ref(sctx, sctx->send_root, sctx->left_path,
+ sctx->cmp_key, 0, __record_new_ref, sctx);
+ if (ret < 0)
+ goto out;
+ ret = 0;
+
+out:
+ return ret;
+}
+
+static int record_deleted_ref(struct send_ctx *sctx)
+{
+ int ret;
+
+ ret = iterate_inode_ref(sctx, sctx->parent_root, sctx->right_path,
+ sctx->cmp_key, 0, __record_deleted_ref, sctx);
+ if (ret < 0)
+ goto out;
+ ret = 0;
+
+out:
+ return ret;
+}
+
+struct find_ref_ctx {
+ u64 dir;
+ struct fs_path *name;
+ int found_idx;
+};
+
+static int __find_iref(int num, u64 dir, int index,
+ struct fs_path *name,
+ void *ctx_)
+{
+ struct find_ref_ctx *ctx = ctx_;
+
+ if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) &&
+ strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) {
+ ctx->found_idx = num;
+ return 1;
+ }
+ return 0;
+}
+
+static int find_iref(struct send_ctx *sctx,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *key,
+ u64 dir, struct fs_path *name)
+{
+ int ret;
+ struct find_ref_ctx ctx;
+
+ ctx.dir = dir;
+ ctx.name = name;
+ ctx.found_idx = -1;
+
+ ret = iterate_inode_ref(sctx, root, path, key, 0, __find_iref, &ctx);
+ if (ret < 0)
+ return ret;
+
+ if (ctx.found_idx == -1)
+ return -ENOENT;
+
+ return ctx.found_idx;
+}
+
+static int __record_changed_new_ref(int num, u64 dir, int index,
+ struct fs_path *name,
+ void *ctx)
+{
+ int ret;
+ struct send_ctx *sctx = ctx;
+
+ ret = find_iref(sctx, sctx->parent_root, sctx->right_path,
+ sctx->cmp_key, dir, name);
+ if (ret == -ENOENT)
+ ret = __record_new_ref(num, dir, index, name, sctx);
+ else if (ret > 0)
+ ret = 0;
+
+ return ret;
+}
+
+static int __record_changed_deleted_ref(int num, u64 dir, int index,
+ struct fs_path *name,
+ void *ctx)
+{
+ int ret;
+ struct send_ctx *sctx = ctx;
+
+ ret = find_iref(sctx, sctx->send_root, sctx->left_path, sctx->cmp_key,
+ dir, name);
+ if (ret == -ENOENT)
+ ret = __record_deleted_ref(num, dir, index, name, sctx);
+ else if (ret > 0)
+ ret = 0;
+
+ return ret;
+}
+
+static int record_changed_ref(struct send_ctx *sctx)
+{
+ int ret = 0;
+
+ ret = iterate_inode_ref(sctx, sctx->send_root, sctx->left_path,
+ sctx->cmp_key, 0, __record_changed_new_ref, sctx);
+ if (ret < 0)
+ goto out;
+ ret = iterate_inode_ref(sctx, sctx->parent_root, sctx->right_path,
+ sctx->cmp_key, 0, __record_changed_deleted_ref, sctx);
+ if (ret < 0)
+ goto out;
+ ret = 0;
+
+out:
+ return ret;
+}
+
+/*
+ * Record and process all refs at once. Needed when an inode changes the
+ * generation number, which means that it was deleted and recreated.
+ */
+static int process_all_refs(struct send_ctx *sctx,
+ enum btrfs_compare_tree_result cmd)
+{
+ int ret;
+ struct btrfs_root *root;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct extent_buffer *eb;
+ int slot;
+ iterate_inode_ref_t cb;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ if (cmd == BTRFS_COMPARE_TREE_NEW) {
+ root = sctx->send_root;
+ cb = __record_new_ref;
+ } else if (cmd == BTRFS_COMPARE_TREE_DELETED) {
+ root = sctx->parent_root;
+ cb = __record_deleted_ref;
+ } else {
+ BUG();
+ }
+
+ key.objectid = sctx->cmp_key->objectid;
+ key.type = BTRFS_INODE_REF_KEY;
+ key.offset = 0;
+ while (1) {
+ ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
+ if (ret < 0)
+ goto out;
+ if (ret)
+ break;
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+
+ if (found_key.objectid != key.objectid ||
+ (found_key.type != BTRFS_INODE_REF_KEY &&
+ found_key.type != BTRFS_INODE_EXTREF_KEY))
+ break;
+
+ ret = iterate_inode_ref(sctx, root, path, &found_key, 0, cb,
+ sctx);
+ btrfs_release_path(path);
+ if (ret < 0)
+ goto out;
+
+ key.offset = found_key.offset + 1;
+ }
+ btrfs_release_path(path);
+
+ ret = process_recorded_refs(sctx);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int send_set_xattr(struct send_ctx *sctx,
+ struct fs_path *path,
+ const char *name, int name_len,
+ const char *data, int data_len)
+{
+ int ret = 0;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
+ TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
+ TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ return ret;
+}
+
+static int send_remove_xattr(struct send_ctx *sctx,
+ struct fs_path *path,
+ const char *name, int name_len)
+{
+ int ret = 0;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
+ TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ return ret;
+}
+
+static int __process_new_xattr(int num, struct btrfs_key *di_key,
+ const char *name, int name_len,
+ const char *data, int data_len,
+ u8 type, void *ctx)
+{
+ int ret;
+ struct send_ctx *sctx = ctx;
+ struct fs_path *p;
+ posix_acl_xattr_header dummy_acl;
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ /*
+ * This hack is needed because empty acl's are stored as zero byte
+ * data in xattrs. Problem with that is, that receiving these zero byte
+ * acl's will fail later. To fix this, we send a dummy acl list that
+ * only contains the version number and no entries.
+ */
+ if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) ||
+ !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) {
+ if (data_len == 0) {
+ dummy_acl.a_version =
+ cpu_to_le32(POSIX_ACL_XATTR_VERSION);
+ data = (char *)&dummy_acl;
+ data_len = sizeof(dummy_acl);
+ }
+ }
+
+ ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+ if (ret < 0)
+ goto out;
+
+ ret = send_set_xattr(sctx, p, name, name_len, data, data_len);
+
+out:
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int __process_deleted_xattr(int num, struct btrfs_key *di_key,
+ const char *name, int name_len,
+ const char *data, int data_len,
+ u8 type, void *ctx)
+{
+ int ret;
+ struct send_ctx *sctx = ctx;
+ struct fs_path *p;
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+ if (ret < 0)
+ goto out;
+
+ ret = send_remove_xattr(sctx, p, name, name_len);
+
+out:
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int process_new_xattr(struct send_ctx *sctx)
+{
+ int ret = 0;
+
+ ret = iterate_dir_item(sctx, sctx->send_root, sctx->left_path,
+ sctx->cmp_key, __process_new_xattr, sctx);
+
+ return ret;
+}
+
+static int process_deleted_xattr(struct send_ctx *sctx)
+{
+ int ret;
+
+ ret = iterate_dir_item(sctx, sctx->parent_root, sctx->right_path,
+ sctx->cmp_key, __process_deleted_xattr, sctx);
+
+ return ret;
+}
+
+struct find_xattr_ctx {
+ const char *name;
+ int name_len;
+ int found_idx;
+ char *found_data;
+ int found_data_len;
+};
+
+static int __find_xattr(int num, struct btrfs_key *di_key,
+ const char *name, int name_len,
+ const char *data, int data_len,
+ u8 type, void *vctx)
+{
+ struct find_xattr_ctx *ctx = vctx;
+
+ if (name_len == ctx->name_len &&
+ strncmp(name, ctx->name, name_len) == 0) {
+ ctx->found_idx = num;
+ ctx->found_data_len = data_len;
+ ctx->found_data = kmalloc(data_len, GFP_NOFS);
+ if (!ctx->found_data)
+ return -ENOMEM;
+ memcpy(ctx->found_data, data, data_len);
+ return 1;
+ }
+ return 0;
+}
+
+static int find_xattr(struct send_ctx *sctx,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *key,
+ const char *name, int name_len,
+ char **data, int *data_len)
+{
+ int ret;
+ struct find_xattr_ctx ctx;
+
+ ctx.name = name;
+ ctx.name_len = name_len;
+ ctx.found_idx = -1;
+ ctx.found_data = NULL;
+ ctx.found_data_len = 0;
+
+ ret = iterate_dir_item(sctx, root, path, key, __find_xattr, &ctx);
+ if (ret < 0)
+ return ret;
+
+ if (ctx.found_idx == -1)
+ return -ENOENT;
+ if (data) {
+ *data = ctx.found_data;
+ *data_len = ctx.found_data_len;
+ } else {
+ kfree(ctx.found_data);
+ }
+ return ctx.found_idx;
+}
+
+
+static int __process_changed_new_xattr(int num, struct btrfs_key *di_key,
+ const char *name, int name_len,
+ const char *data, int data_len,
+ u8 type, void *ctx)
+{
+ int ret;
+ struct send_ctx *sctx = ctx;
+ char *found_data = NULL;
+ int found_data_len = 0;
+ struct fs_path *p = NULL;
+
+ ret = find_xattr(sctx, sctx->parent_root, sctx->right_path,
+ sctx->cmp_key, name, name_len, &found_data,
+ &found_data_len);
+ if (ret == -ENOENT) {
+ ret = __process_new_xattr(num, di_key, name, name_len, data,
+ data_len, type, ctx);
+ } else if (ret >= 0) {
+ if (data_len != found_data_len ||
+ memcmp(data, found_data, data_len)) {
+ ret = __process_new_xattr(num, di_key, name, name_len,
+ data, data_len, type, ctx);
+ } else {
+ ret = 0;
+ }
+ }
+
+ kfree(found_data);
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key,
+ const char *name, int name_len,
+ const char *data, int data_len,
+ u8 type, void *ctx)
+{
+ int ret;
+ struct send_ctx *sctx = ctx;
+
+ ret = find_xattr(sctx, sctx->send_root, sctx->left_path, sctx->cmp_key,
+ name, name_len, NULL, NULL);
+ if (ret == -ENOENT)
+ ret = __process_deleted_xattr(num, di_key, name, name_len, data,
+ data_len, type, ctx);
+ else if (ret >= 0)
+ ret = 0;
+
+ return ret;
+}
+
+static int process_changed_xattr(struct send_ctx *sctx)
+{
+ int ret = 0;
+
+ ret = iterate_dir_item(sctx, sctx->send_root, sctx->left_path,
+ sctx->cmp_key, __process_changed_new_xattr, sctx);
+ if (ret < 0)
+ goto out;
+ ret = iterate_dir_item(sctx, sctx->parent_root, sctx->right_path,
+ sctx->cmp_key, __process_changed_deleted_xattr, sctx);
+
+out:
+ return ret;
+}
+
+static int process_all_new_xattrs(struct send_ctx *sctx)
+{
+ int ret;
+ struct btrfs_root *root;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct extent_buffer *eb;
+ int slot;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ root = sctx->send_root;
+
+ key.objectid = sctx->cmp_key->objectid;
+ key.type = BTRFS_XATTR_ITEM_KEY;
+ key.offset = 0;
+ while (1) {
+ ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+
+ if (found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ ret = 0;
+ goto out;
+ }
+
+ ret = iterate_dir_item(sctx, root, path, &found_key,
+ __process_new_xattr, sctx);
+ if (ret < 0)
+ goto out;
+
+ btrfs_release_path(path);
+ key.offset = found_key.offset + 1;
+ }
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * Read some bytes from the current inode/file and send a write command to
+ * user space.
+ */
+static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
+{
+ int ret = 0;
+ struct fs_path *p;
+ loff_t pos = offset;
+ int num_read = 0;
+ mm_segment_t old_fs;
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ /*
+ * vfs normally only accepts user space buffers for security reasons.
+ * we only read from the file and also only provide the read_buf buffer
+ * to vfs. As this buffer does not come from a user space call, it's
+ * ok to temporary allow kernel space buffers.
+ */
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+
+verbose_printk("btrfs: send_write offset=%llu, len=%d\n", offset, len);
+
+ ret = open_cur_inode_file(sctx);
+ if (ret < 0)
+ goto out;
+
+ ret = vfs_read(sctx->cur_inode_filp, sctx->read_buf, len, &pos);
+ if (ret < 0)
+ goto out;
+ num_read = ret;
+ if (!num_read)
+ goto out;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+ TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ fs_path_free(sctx, p);
+ set_fs(old_fs);
+ if (ret < 0)
+ return ret;
+ return num_read;
+}
+
+/*
+ * Send a clone command to user space.
+ */
+static int send_clone(struct send_ctx *sctx,
+ u64 offset, u32 len,
+ struct clone_root *clone_root)
+{
+ int ret = 0;
+ struct fs_path *p;
+ u64 gen;
+
+verbose_printk("btrfs: send_clone offset=%llu, len=%d, clone_root=%llu, "
+ "clone_inode=%llu, clone_offset=%llu\n", offset, len,
+ clone_root->root->objectid, clone_root->ino,
+ clone_root->offset);
+
+ p = fs_path_alloc(sctx);
+ if (!p)
+ return -ENOMEM;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE);
+ if (ret < 0)
+ goto out;
+
+ ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len);
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+
+ if (clone_root->root == sctx->send_root) {
+ ret = get_inode_info(sctx->send_root, clone_root->ino, NULL,
+ &gen, NULL, NULL, NULL, NULL);
+ if (ret < 0)
+ goto out;
+ ret = get_cur_path(sctx, clone_root->ino, gen, p);
+ } else {
+ ret = get_inode_path(sctx, clone_root->root,
+ clone_root->ino, p);
+ }
+ if (ret < 0)
+ goto out;
+
+ TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
+ clone_root->root->root_item.uuid);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
+ clone_root->root->root_item.ctransid);
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET,
+ clone_root->offset);
+
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ fs_path_free(sctx, p);
+ return ret;
+}
+
+static int send_write_or_clone(struct send_ctx *sctx,
+ struct btrfs_path *path,
+ struct btrfs_key *key,
+ struct clone_root *clone_root)
+{
+ int ret = 0;
+ struct btrfs_file_extent_item *ei;
+ u64 offset = key->offset;
+ u64 pos = 0;
+ u64 len;
+ u32 l;
+ u8 type;
+
+ ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_file_extent_item);
+ type = btrfs_file_extent_type(path->nodes[0], ei);
+ if (type == BTRFS_FILE_EXTENT_INLINE) {
+ len = btrfs_file_extent_inline_len(path->nodes[0], ei);
+ /*
+ * it is possible the inline item won't cover the whole page,
+ * but there may be items after this page. Make
+ * sure to send the whole thing
+ */
+ len = PAGE_CACHE_ALIGN(len);
+ } else {
+ len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
+ }
+
+ if (offset + len > sctx->cur_inode_size)
+ len = sctx->cur_inode_size - offset;
+ if (len == 0) {
+ ret = 0;
+ goto out;
+ }
+
+ if (!clone_root) {
+ while (pos < len) {
+ l = len - pos;
+ if (l > BTRFS_SEND_READ_SIZE)
+ l = BTRFS_SEND_READ_SIZE;
+ ret = send_write(sctx, pos + offset, l);
+ if (ret < 0)
+ goto out;
+ if (!ret)
+ break;
+ pos += ret;
+ }
+ ret = 0;
+ } else {
+ ret = send_clone(sctx, offset, len, clone_root);
+ }
+
+out:
+ return ret;
+}
+
+static int is_extent_unchanged(struct send_ctx *sctx,
+ struct btrfs_path *left_path,
+ struct btrfs_key *ekey)
+{
+ int ret = 0;
+ struct btrfs_key key;
+ struct btrfs_path *path = NULL;
+ struct extent_buffer *eb;
+ int slot;
+ struct btrfs_key found_key;
+ struct btrfs_file_extent_item *ei;
+ u64 left_disknr;
+ u64 right_disknr;
+ u64 left_offset;
+ u64 right_offset;
+ u64 left_offset_fixed;
+ u64 left_len;
+ u64 right_len;
+ u64 left_gen;
+ u64 right_gen;
+ u8 left_type;
+ u8 right_type;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ eb = left_path->nodes[0];
+ slot = left_path->slots[0];
+ ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
+ left_type = btrfs_file_extent_type(eb, ei);
+
+ if (left_type != BTRFS_FILE_EXTENT_REG) {
+ ret = 0;
+ goto out;
+ }
+ left_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
+ left_len = btrfs_file_extent_num_bytes(eb, ei);
+ left_offset = btrfs_file_extent_offset(eb, ei);
+ left_gen = btrfs_file_extent_generation(eb, ei);
+
+ /*
+ * Following comments will refer to these graphics. L is the left
+ * extents which we are checking at the moment. 1-8 are the right
+ * extents that we iterate.
+ *
+ * |-----L-----|
+ * |-1-|-2a-|-3-|-4-|-5-|-6-|
+ *
+ * |-----L-----|
+ * |--1--|-2b-|...(same as above)
+ *
+ * Alternative situation. Happens on files where extents got split.
+ * |-----L-----|
+ * |-----------7-----------|-6-|
+ *
+ * Alternative situation. Happens on files which got larger.
+ * |-----L-----|
+ * |-8-|
+ * Nothing follows after 8.
+ */
+
+ key.objectid = ekey->objectid;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = ekey->offset;
+ ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * Handle special case where the right side has no extents at all.
+ */
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+ if (found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * We're now on 2a, 2b or 7.
+ */
+ key = found_key;
+ while (key.offset < ekey->offset + left_len) {
+ ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
+ right_type = btrfs_file_extent_type(eb, ei);
+ right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
+ right_len = btrfs_file_extent_num_bytes(eb, ei);
+ right_offset = btrfs_file_extent_offset(eb, ei);
+ right_gen = btrfs_file_extent_generation(eb, ei);
+
+ if (right_type != BTRFS_FILE_EXTENT_REG) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * Are we at extent 8? If yes, we know the extent is changed.
+ * This may only happen on the first iteration.
+ */
+ if (found_key.offset + right_len <= ekey->offset) {
+ ret = 0;
+ goto out;
+ }
+
+ left_offset_fixed = left_offset;
+ if (key.offset < ekey->offset) {
+ /* Fix the right offset for 2a and 7. */
+ right_offset += ekey->offset - key.offset;
+ } else {
+ /* Fix the left offset for all behind 2a and 2b */
+ left_offset_fixed += key.offset - ekey->offset;
+ }
+
+ /*
+ * Check if we have the same extent.
+ */
+ if (left_disknr != right_disknr ||
+ left_offset_fixed != right_offset ||
+ left_gen != right_gen) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * Go to the next extent.
+ */
+ ret = btrfs_next_item(sctx->parent_root, path);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+ }
+ if (ret || found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ key.offset += right_len;
+ break;
+ } else {
+ if (found_key.offset != key.offset + right_len) {
+ /* Should really not happen */
+ ret = -EIO;
+ goto out;
+ }
+ }
+ key = found_key;
+ }
+
+ /*
+ * We're now behind the left extent (treat as unchanged) or at the end
+ * of the right side (treat as changed).
+ */
+ if (key.offset >= ekey->offset + left_len)
+ ret = 1;
+ else
+ ret = 0;
+
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int process_extent(struct send_ctx *sctx,
+ struct btrfs_path *path,
+ struct btrfs_key *key)
+{
+ int ret = 0;
+ struct clone_root *found_clone = NULL;
+
+ if (S_ISLNK(sctx->cur_inode_mode))
+ return 0;
+
+ if (sctx->parent_root && !sctx->cur_inode_new) {
+ ret = is_extent_unchanged(sctx, path, key);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+ }
+
+ ret = find_extent_clone(sctx, path, key->objectid, key->offset,
+ sctx->cur_inode_size, &found_clone);
+ if (ret != -ENOENT && ret < 0)
+ goto out;
+
+ ret = send_write_or_clone(sctx, path, key, found_clone);
+
+out:
+ return ret;
+}
+
+static int process_all_extents(struct send_ctx *sctx)
+{
+ int ret;
+ struct btrfs_root *root;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct extent_buffer *eb;
+ int slot;
+
+ root = sctx->send_root;
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = sctx->cmp_key->objectid;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = 0;
+ while (1) {
+ ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+
+ if (found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ ret = 0;
+ goto out;
+ }
+
+ ret = process_extent(sctx, path, &found_key);
+ if (ret < 0)
+ goto out;
+
+ btrfs_release_path(path);
+ key.offset = found_key.offset + 1;
+ }
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end)
+{
+ int ret = 0;
+
+ if (sctx->cur_ino == 0)
+ goto out;
+ if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid &&
+ sctx->cmp_key->type <= BTRFS_INODE_EXTREF_KEY)
+ goto out;
+ if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
+ goto out;
+
+ ret = process_recorded_refs(sctx);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * We have processed the refs and thus need to advance send_progress.
+ * Now, calls to get_cur_xxx will take the updated refs of the current
+ * inode into account.
+ */
+ sctx->send_progress = sctx->cur_ino + 1;
+
+out:
+ return ret;
+}
+
+static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
+{
+ int ret = 0;
+ u64 left_mode;
+ u64 left_uid;
+ u64 left_gid;
+ u64 right_mode;
+ u64 right_uid;
+ u64 right_gid;
+ int need_chmod = 0;
+ int need_chown = 0;
+
+ ret = process_recorded_refs_if_needed(sctx, at_end);
+ if (ret < 0)
+ goto out;
+
+ if (sctx->cur_ino == 0 || sctx->cur_inode_deleted)
+ goto out;
+ if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino)
+ goto out;
+
+ ret = get_inode_info(sctx->send_root, sctx->cur_ino, NULL, NULL,
+ &left_mode, &left_uid, &left_gid, NULL);
+ if (ret < 0)
+ goto out;
+
+ if (!sctx->parent_root || sctx->cur_inode_new) {
+ need_chown = 1;
+ if (!S_ISLNK(sctx->cur_inode_mode))
+ need_chmod = 1;
+ } else {
+ ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
+ NULL, NULL, &right_mode, &right_uid,
+ &right_gid, NULL);
+ if (ret < 0)
+ goto out;
+
+ if (left_uid != right_uid || left_gid != right_gid)
+ need_chown = 1;
+ if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode)
+ need_chmod = 1;
+ }
+
+ if (S_ISREG(sctx->cur_inode_mode)) {
+ ret = send_truncate(sctx, sctx->cur_ino, sctx->cur_inode_gen,
+ sctx->cur_inode_size);
+ if (ret < 0)
+ goto out;
+ }
+
+ if (need_chown) {
+ ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen,
+ left_uid, left_gid);
+ if (ret < 0)
+ goto out;
+ }
+ if (need_chmod) {
+ ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen,
+ left_mode);
+ if (ret < 0)
+ goto out;
+ }
+
+ /*
+ * Need to send that every time, no matter if it actually changed
+ * between the two trees as we have done changes to the inode before.
+ */
+ ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
+ if (ret < 0)
+ goto out;
+
+out:
+ return ret;
+}
+
+static int changed_inode(struct send_ctx *sctx,
+ enum btrfs_compare_tree_result result)
+{
+ int ret = 0;
+ struct btrfs_key *key = sctx->cmp_key;
+ struct btrfs_inode_item *left_ii = NULL;
+ struct btrfs_inode_item *right_ii = NULL;
+ u64 left_gen = 0;
+ u64 right_gen = 0;
+
+ ret = close_cur_inode_file(sctx);
+ if (ret < 0)
+ goto out;
+
+ sctx->cur_ino = key->objectid;
+ sctx->cur_inode_new_gen = 0;
+
+ /*
+ * Set send_progress to current inode. This will tell all get_cur_xxx
+ * functions that the current inode's refs are not updated yet. Later,
+ * when process_recorded_refs is finished, it is set to cur_ino + 1.
+ */
+ sctx->send_progress = sctx->cur_ino;
+
+ if (result == BTRFS_COMPARE_TREE_NEW ||
+ result == BTRFS_COMPARE_TREE_CHANGED) {
+ left_ii = btrfs_item_ptr(sctx->left_path->nodes[0],
+ sctx->left_path->slots[0],
+ struct btrfs_inode_item);
+ left_gen = btrfs_inode_generation(sctx->left_path->nodes[0],
+ left_ii);
+ } else {
+ right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
+ sctx->right_path->slots[0],
+ struct btrfs_inode_item);
+ right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
+ right_ii);
+ }
+ if (result == BTRFS_COMPARE_TREE_CHANGED) {
+ right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
+ sctx->right_path->slots[0],
+ struct btrfs_inode_item);
+
+ right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
+ right_ii);
+
+ /*
+ * The cur_ino = root dir case is special here. We can't treat
+ * the inode as deleted+reused because it would generate a
+ * stream that tries to delete/mkdir the root dir.
+ */
+ if (left_gen != right_gen &&
+ sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
+ sctx->cur_inode_new_gen = 1;
+ }
+
+ if (result == BTRFS_COMPARE_TREE_NEW) {
+ sctx->cur_inode_gen = left_gen;
+ sctx->cur_inode_new = 1;
+ sctx->cur_inode_deleted = 0;
+ sctx->cur_inode_size = btrfs_inode_size(
+ sctx->left_path->nodes[0], left_ii);
+ sctx->cur_inode_mode = btrfs_inode_mode(
+ sctx->left_path->nodes[0], left_ii);
+ if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
+ ret = send_create_inode_if_needed(sctx);
+ } else if (result == BTRFS_COMPARE_TREE_DELETED) {
+ sctx->cur_inode_gen = right_gen;
+ sctx->cur_inode_new = 0;
+ sctx->cur_inode_deleted = 1;
+ sctx->cur_inode_size = btrfs_inode_size(
+ sctx->right_path->nodes[0], right_ii);
+ sctx->cur_inode_mode = btrfs_inode_mode(
+ sctx->right_path->nodes[0], right_ii);
+ } else if (result == BTRFS_COMPARE_TREE_CHANGED) {
+ /*
+ * We need to do some special handling in case the inode was
+ * reported as changed with a changed generation number. This
+ * means that the original inode was deleted and new inode
+ * reused the same inum. So we have to treat the old inode as
+ * deleted and the new one as new.
+ */
+ if (sctx->cur_inode_new_gen) {
+ /*
+ * First, process the inode as if it was deleted.
+ */
+ sctx->cur_inode_gen = right_gen;
+ sctx->cur_inode_new = 0;
+ sctx->cur_inode_deleted = 1;
+ sctx->cur_inode_size = btrfs_inode_size(
+ sctx->right_path->nodes[0], right_ii);
+ sctx->cur_inode_mode = btrfs_inode_mode(
+ sctx->right_path->nodes[0], right_ii);
+ ret = process_all_refs(sctx,
+ BTRFS_COMPARE_TREE_DELETED);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * Now process the inode as if it was new.
+ */
+ sctx->cur_inode_gen = left_gen;
+ sctx->cur_inode_new = 1;
+ sctx->cur_inode_deleted = 0;
+ sctx->cur_inode_size = btrfs_inode_size(
+ sctx->left_path->nodes[0], left_ii);
+ sctx->cur_inode_mode = btrfs_inode_mode(
+ sctx->left_path->nodes[0], left_ii);
+ ret = send_create_inode_if_needed(sctx);
+ if (ret < 0)
+ goto out;
+
+ ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW);
+ if (ret < 0)
+ goto out;
+ /*
+ * Advance send_progress now as we did not get into
+ * process_recorded_refs_if_needed in the new_gen case.
+ */
+ sctx->send_progress = sctx->cur_ino + 1;
+
+ /*
+ * Now process all extents and xattrs of the inode as if
+ * they were all new.
+ */
+ ret = process_all_extents(sctx);
+ if (ret < 0)
+ goto out;
+ ret = process_all_new_xattrs(sctx);
+ if (ret < 0)
+ goto out;
+ } else {
+ sctx->cur_inode_gen = left_gen;
+ sctx->cur_inode_new = 0;
+ sctx->cur_inode_new_gen = 0;
+ sctx->cur_inode_deleted = 0;
+ sctx->cur_inode_size = btrfs_inode_size(
+ sctx->left_path->nodes[0], left_ii);
+ sctx->cur_inode_mode = btrfs_inode_mode(
+ sctx->left_path->nodes[0], left_ii);
+ }
+ }
+
+out:
+ return ret;
+}
+
+/*
+ * We have to process new refs before deleted refs, but compare_trees gives us
+ * the new and deleted refs mixed. To fix this, we record the new/deleted refs
+ * first and later process them in process_recorded_refs.
+ * For the cur_inode_new_gen case, we skip recording completely because
+ * changed_inode did already initiate processing of refs. The reason for this is
+ * that in this case, compare_tree actually compares the refs of 2 different
+ * inodes. To fix this, process_all_refs is used in changed_inode to handle all
+ * refs of the right tree as deleted and all refs of the left tree as new.
+ */
+static int changed_ref(struct send_ctx *sctx,
+ enum btrfs_compare_tree_result result)
+{
+ int ret = 0;
+
+ BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
+
+ if (!sctx->cur_inode_new_gen &&
+ sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) {
+ if (result == BTRFS_COMPARE_TREE_NEW)
+ ret = record_new_ref(sctx);
+ else if (result == BTRFS_COMPARE_TREE_DELETED)
+ ret = record_deleted_ref(sctx);
+ else if (result == BTRFS_COMPARE_TREE_CHANGED)
+ ret = record_changed_ref(sctx);
+ }
+
+ return ret;
+}
+
+/*
+ * Process new/deleted/changed xattrs. We skip processing in the
+ * cur_inode_new_gen case because changed_inode did already initiate processing
+ * of xattrs. The reason is the same as in changed_ref
+ */
+static int changed_xattr(struct send_ctx *sctx,
+ enum btrfs_compare_tree_result result)
+{
+ int ret = 0;
+
+ BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
+
+ if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
+ if (result == BTRFS_COMPARE_TREE_NEW)
+ ret = process_new_xattr(sctx);
+ else if (result == BTRFS_COMPARE_TREE_DELETED)
+ ret = process_deleted_xattr(sctx);
+ else if (result == BTRFS_COMPARE_TREE_CHANGED)
+ ret = process_changed_xattr(sctx);
+ }
+
+ return ret;
+}
+
+/*
+ * Process new/deleted/changed extents. We skip processing in the
+ * cur_inode_new_gen case because changed_inode did already initiate processing
+ * of extents. The reason is the same as in changed_ref
+ */
+static int changed_extent(struct send_ctx *sctx,
+ enum btrfs_compare_tree_result result)
+{
+ int ret = 0;
+
+ BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
+
+ if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
+ if (result != BTRFS_COMPARE_TREE_DELETED)
+ ret = process_extent(sctx, sctx->left_path,
+ sctx->cmp_key);
+ }
+
+ return ret;
+}
+
+/*
+ * Updates compare related fields in sctx and simply forwards to the actual
+ * changed_xxx functions.
+ */
+static int changed_cb(struct btrfs_root *left_root,
+ struct btrfs_root *right_root,
+ struct btrfs_path *left_path,
+ struct btrfs_path *right_path,
+ struct btrfs_key *key,
+ enum btrfs_compare_tree_result result,
+ void *ctx)
+{
+ int ret = 0;
+ struct send_ctx *sctx = ctx;
+
+ sctx->left_path = left_path;
+ sctx->right_path = right_path;
+ sctx->cmp_key = key;
+
+ ret = finish_inode_if_needed(sctx, 0);
+ if (ret < 0)
+ goto out;
+
+ /* Ignore non-FS objects */
+ if (key->objectid == BTRFS_FREE_INO_OBJECTID ||
+ key->objectid == BTRFS_FREE_SPACE_OBJECTID)
+ goto out;
+
+ if (key->type == BTRFS_INODE_ITEM_KEY)
+ ret = changed_inode(sctx, result);
+ else if (key->type == BTRFS_INODE_REF_KEY ||
+ 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_trans_handle *trans = NULL;
+ struct btrfs_root *send_root = sctx->send_root;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct btrfs_path *path;
+ struct extent_buffer *eb;
+ int slot;
+ u64 start_ctransid;
+ u64 ctransid;
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ spin_lock(&send_root->root_item_lock);
+ start_ctransid = btrfs_root_ctransid(&send_root->root_item);
+ spin_unlock(&send_root->root_item_lock);
+
+ key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+
+join_trans:
+ /*
+ * We need to make sure the transaction does not get committed
+ * while we do anything on commit roots. Join a transaction to prevent
+ * this.
+ */
+ trans = btrfs_join_transaction(send_root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ trans = NULL;
+ goto out;
+ }
+
+ /*
+ * Make sure the tree has not changed after re-joining. We detect this
+ * by comparing start_ctransid and ctransid. They should always match.
+ */
+ spin_lock(&send_root->root_item_lock);
+ ctransid = btrfs_root_ctransid(&send_root->root_item);
+ spin_unlock(&send_root->root_item_lock);
+
+ if (ctransid != start_ctransid) {
+ WARN(1, KERN_WARNING "btrfs: the root that you're trying to "
+ "send was modified in between. This is "
+ "probably a bug.\n");
+ ret = -EIO;
+ goto out;
+ }
+
+ ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
+ if (ret < 0)
+ goto out;
+ if (ret)
+ goto out_finish;
+
+ while (1) {
+ /*
+ * When someone want to commit while we iterate, end the
+ * joined transaction and rejoin.
+ */
+ if (btrfs_should_end_transaction(trans, send_root)) {
+ ret = btrfs_end_transaction(trans, send_root);
+ trans = NULL;
+ if (ret < 0)
+ goto out;
+ btrfs_release_path(path);
+ goto join_trans;
+ }
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+
+ ret = changed_cb(send_root, NULL, path, NULL,
+ &found_key, BTRFS_COMPARE_TREE_NEW, sctx);
+ if (ret < 0)
+ goto out;
+
+ key.objectid = found_key.objectid;
+ key.type = found_key.type;
+ key.offset = found_key.offset + 1;
+
+ ret = btrfs_next_item(send_root, path);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ break;
+ }
+ }
+
+out_finish:
+ ret = finish_inode_if_needed(sctx, 1);
+
+out:
+ btrfs_free_path(path);
+ if (trans) {
+ if (!ret)
+ ret = btrfs_end_transaction(trans, send_root);
+ else
+ btrfs_end_transaction(trans, send_root);
+ }
+ return ret;
+}
+
+static int send_subvol(struct send_ctx *sctx)
+{
+ int ret;
+
+ ret = send_header(sctx);
+ if (ret < 0)
+ goto out;
+
+ ret = send_subvol_begin(sctx);
+ if (ret < 0)
+ goto out;
+
+ if (sctx->parent_root) {
+ ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root,
+ changed_cb, sctx);
+ if (ret < 0)
+ goto out;
+ ret = finish_inode_if_needed(sctx, 1);
+ if (ret < 0)
+ goto out;
+ } else {
+ ret = full_send_tree(sctx);
+ if (ret < 0)
+ goto out;
+ }
+
+out:
+ if (!ret)
+ ret = close_cur_inode_file(sctx);
+ else
+ close_cur_inode_file(sctx);
+
+ free_recorded_refs(sctx);
+ return ret;
+}
+
+long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
+{
+ int ret = 0;
+ struct btrfs_root *send_root;
+ struct btrfs_root *clone_root;
+ struct btrfs_fs_info *fs_info;
+ struct btrfs_ioctl_send_args *arg = NULL;
+ struct btrfs_key key;
+ struct file *filp = NULL;
+ struct send_ctx *sctx = NULL;
+ u32 i;
+ u64 *clone_sources_tmp = NULL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ send_root = BTRFS_I(fdentry(mnt_file)->d_inode)->root;
+ fs_info = send_root->fs_info;
+
+ arg = memdup_user(arg_, sizeof(*arg));
+ if (IS_ERR(arg)) {
+ ret = PTR_ERR(arg);
+ arg = NULL;
+ goto out;
+ }
+
+ if (!access_ok(VERIFY_READ, arg->clone_sources,
+ sizeof(*arg->clone_sources *
+ arg->clone_sources_count))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ sctx = kzalloc(sizeof(struct send_ctx), GFP_NOFS);
+ if (!sctx) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ INIT_LIST_HEAD(&sctx->new_refs);
+ INIT_LIST_HEAD(&sctx->deleted_refs);
+ INIT_RADIX_TREE(&sctx->name_cache, GFP_NOFS);
+ INIT_LIST_HEAD(&sctx->name_cache_list);
+
+ sctx->send_filp = fget(arg->send_fd);
+ if (IS_ERR(sctx->send_filp)) {
+ ret = PTR_ERR(sctx->send_filp);
+ goto out;
+ }
+
+ sctx->mnt = mnt_file->f_path.mnt;
+
+ sctx->send_root = send_root;
+ sctx->clone_roots_cnt = arg->clone_sources_count;
+
+ sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
+ sctx->send_buf = vmalloc(sctx->send_max_size);
+ if (!sctx->send_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ sctx->read_buf = vmalloc(BTRFS_SEND_READ_SIZE);
+ if (!sctx->read_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ sctx->clone_roots = vzalloc(sizeof(struct clone_root) *
+ (arg->clone_sources_count + 1));
+ if (!sctx->clone_roots) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (arg->clone_sources_count) {
+ clone_sources_tmp = vmalloc(arg->clone_sources_count *
+ sizeof(*arg->clone_sources));
+ if (!clone_sources_tmp) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = copy_from_user(clone_sources_tmp, arg->clone_sources,
+ arg->clone_sources_count *
+ sizeof(*arg->clone_sources));
+ if (ret) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ for (i = 0; i < arg->clone_sources_count; i++) {
+ key.objectid = clone_sources_tmp[i];
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+ clone_root = btrfs_read_fs_root_no_name(fs_info, &key);
+ if (!clone_root) {
+ ret = -EINVAL;
+ goto out;
+ }
+ if (IS_ERR(clone_root)) {
+ ret = PTR_ERR(clone_root);
+ goto out;
+ }
+ sctx->clone_roots[i].root = clone_root;
+ }
+ vfree(clone_sources_tmp);
+ clone_sources_tmp = NULL;
+ }
+
+ if (arg->parent_root) {
+ key.objectid = arg->parent_root;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+ sctx->parent_root = btrfs_read_fs_root_no_name(fs_info, &key);
+ if (!sctx->parent_root) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ /*
+ * Clones from send_root are allowed, but only if the clone source
+ * is behind the current send position. This is checked while searching
+ * for possible clone sources.
+ */
+ sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root;
+
+ /* We do a bsearch later */
+ sort(sctx->clone_roots, sctx->clone_roots_cnt,
+ sizeof(*sctx->clone_roots), __clone_root_cmp_sort,
+ NULL);
+
+ ret = send_subvol(sctx);
+ if (ret < 0)
+ goto out;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_END);
+ if (ret < 0)
+ goto out;
+ ret = send_cmd(sctx);
+ if (ret < 0)
+ goto out;
+
+out:
+ if (filp)
+ fput(filp);
+ kfree(arg);
+ vfree(clone_sources_tmp);
+
+ if (sctx) {
+ if (sctx->send_filp)
+ fput(sctx->send_filp);
+
+ vfree(sctx->clone_roots);
+ vfree(sctx->send_buf);
+ vfree(sctx->read_buf);
+
+ name_cache_free(sctx);
+
+ kfree(sctx);
+ }
+
+ return ret;
+}