/* * 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 #include #include #include #include #include #include #include #include #include #include #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; unsigned int reversed:1; unsigned 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]; u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */ 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; 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(void) { 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(void) { struct fs_path *p; p = fs_path_alloc(); if (!p) return NULL; p->reversed = 1; fs_path_reset(p); return p; } static void fs_path_free(struct fs_path *p) { if (!p) return; if (p->buf != p->inline_buf) { 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 | __GFP_NOWARN); if (!tmp_buf) { tmp_buf = vmalloc(len); if (!tmp_buf) return -ENOMEM; p->virtual_mem = 1; } memcpy(tmp_buf, p->buf, p->buf_len); p->buf = tmp_buf; p->buf_len = len; } else { if (p->virtual_mem) { tmp_buf = vmalloc(len); if (!tmp_buf) return -ENOMEM; memcpy(tmp_buf, p->buf, p->buf_len); vfree(p->buf); } else { tmp_buf = krealloc(p->buf, len, GFP_NOFS); if (!tmp_buf) { tmp_buf = vmalloc(len); if (!tmp_buf) return -ENOMEM; memcpy(tmp_buf, p->buf, p->buf_len); kfree(p->buf); p->virtual_mem = 1; } } p->buf = tmp_buf; p->buf_len = len; } if (p->reversed) { tmp_buf = p->buf + old_buf_len - path_len - 1; p->end = p->buf + p->buf_len - 1; p->start = p->end - path_len; memmove(p->start, tmp_buf, path_len + 1); } else { p->start = p->buf; p->end = p->start + path_len; } return 0; } static int fs_path_prepare_for_add(struct fs_path *p, int name_len) { int ret; int new_len; new_len = p->end - p->start + name_len; if (p->start != p->end) new_len++; ret = fs_path_ensure_buf(p, new_len); if (ret < 0) goto out; if (p->reversed) { if (p->start != p->end) *--p->start = '/'; p->start -= name_len; p->prepared = p->start; } else { if (p->start != p->end) *p->end++ = '/'; p->prepared = p->end; p->end += name_len; *p->end = 0; } out: return ret; } static int fs_path_add(struct fs_path *p, const char *name, int name_len) { int ret; ret = fs_path_prepare_for_add(p, name_len); if (ret < 0) goto out; memcpy(p->prepared, name, name_len); p->prepared = NULL; out: return ret; } static int fs_path_add_path(struct fs_path *p, struct fs_path *p2) { int ret; ret = fs_path_prepare_for_add(p, p2->end - p2->start); if (ret < 0) goto out; memcpy(p->prepared, p2->start, p2->end - p2->start); p->prepared = NULL; out: return ret; } static int fs_path_add_from_extent_buffer(struct fs_path *p, struct extent_buffer *eb, unsigned long off, int len) { int ret; ret = fs_path_prepare_for_add(p, len); if (ret < 0) goto out; read_extent_buffer(eb, p->prepared, off, len); p->prepared = NULL; out: return ret; } #if 0 static void fs_path_remove(struct fs_path *p) { BUG_ON(p->reversed); while (p->start != p->end && *p->end != '/') p->end--; *p->end = 0; } #endif static int fs_path_copy(struct fs_path *p, struct fs_path *from) { int ret; p->reversed = from->reversed; fs_path_reset(p); ret = fs_path_add_path(p, from); return ret; } static void fs_path_unreverse(struct fs_path *p) { char *tmp; int len; if (!p->reversed) return; tmp = p->start; len = p->end - p->start; p->start = p->buf; p->end = p->start + len; memmove(p->start, tmp, len + 1); p->reversed = 0; } static struct btrfs_path *alloc_path_for_send(void) { struct btrfs_path *path; path = btrfs_alloc_path(); if (!path) return NULL; path->search_commit_root = 1; path->skip_locking = 1; return path; } static int write_buf(struct 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 btrfs_root *root, struct btrfs_path *path, struct btrfs_key *found_key, int resolve, iterate_inode_ref_t iterate, void *ctx) { struct extent_buffer *eb = path->nodes[0]; struct btrfs_item *item; struct btrfs_inode_ref *iref; struct btrfs_inode_extref *extref; struct btrfs_path *tmp_path; struct fs_path *p; u32 cur = 0; u32 total; int slot = path->slots[0]; u32 name_len; char *start; int ret = 0; int num = 0; int index; u64 dir; unsigned long name_off; unsigned long elem_size; unsigned long ptr; p = fs_path_alloc_reversed(); if (!p) return -ENOMEM; tmp_path = alloc_path_for_send(); if (!tmp_path) { fs_path_free(p); return -ENOMEM; } if (found_key->type == BTRFS_INODE_REF_KEY) { ptr = (unsigned long)btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); item = btrfs_item_nr(slot); total = btrfs_item_size(eb, item); elem_size = sizeof(*iref); } else { ptr = btrfs_item_ptr_offset(eb, slot); total = btrfs_item_size_nr(eb, slot); elem_size = sizeof(*extref); } while (cur < total) { fs_path_reset(p); if (found_key->type == BTRFS_INODE_REF_KEY) { iref = (struct btrfs_inode_ref *)(ptr + cur); name_len = btrfs_inode_ref_name_len(eb, iref); name_off = (unsigned long)(iref + 1); index = btrfs_inode_ref_index(eb, iref); dir = found_key->offset; } else { extref = (struct btrfs_inode_extref *)(ptr + cur); name_len = btrfs_inode_extref_name_len(eb, extref); name_off = (unsigned long)&extref->name; index = btrfs_inode_extref_index(eb, extref); dir = btrfs_inode_extref_parent(eb, extref); } if (resolve) { start = btrfs_ref_to_path(root, tmp_path, name_len, name_off, eb, dir, p->buf, p->buf_len); if (IS_ERR(start)) { ret = PTR_ERR(start); goto out; } if (start < p->buf) { /* overflow , try again with larger buffer */ ret = fs_path_ensure_buf(p, p->buf_len + p->buf - start); if (ret < 0) goto out; start = btrfs_ref_to_path(root, tmp_path, name_len, name_off, eb, dir, p->buf, p->buf_len); if (IS_ERR(start)) { ret = PTR_ERR(start); goto out; } BUG_ON(start < p->buf); } p->start = start; } else { ret = fs_path_add_from_extent_buffer(p, eb, name_off, name_len); if (ret < 0) goto out; } cur += elem_size + name_len; ret = iterate(num, dir, index, p, ctx); if (ret) goto out; num++; } out: btrfs_free_path(tmp_path); fs_path_free(p); return ret; } typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx); /* * Helper function to iterate the entries in ONE btrfs_dir_item. * The iterate callback may return a non zero value to stop iteration. This can * be a negative value for error codes or 1 to simply stop it. * * path must point to the dir item when called. */ static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, 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(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 btrfs_root *root, u64 ino, struct fs_path *path) { int ret; struct btrfs_key key, found_key; struct btrfs_path *p; p = alloc_path_for_send(); if (!p) return -ENOMEM; fs_path_reset(path); key.objectid = ino; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(root, &key, p, 1, 0); if (ret < 0) goto out; if (ret) { ret = 1; goto out; } btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]); if (found_key.objectid != ino || (found_key.type != BTRFS_INODE_REF_KEY && found_key.type != BTRFS_INODE_EXTREF_KEY)) { ret = -ENOENT; goto out; } ret = iterate_inode_ref(root, p, &found_key, 1, __copy_first_ref, path); if (ret < 0) goto out; ret = 0; out: btrfs_free_path(p); return ret; } struct backref_ctx { struct send_ctx *sctx; /* number of total found references */ u64 found; /* * used for clones found in send_root. clones found behind cur_objectid * and cur_offset are not considered as allowed clones. */ u64 cur_objectid; u64 cur_offset; /* may be truncated in case it's the last extent in a file */ u64 extent_len; /* 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 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 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 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(); if (!tmp_name) return -ENOMEM; ret = get_first_ref(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(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 gen; u64 other_inode = 0; u8 other_type = 0; if (!sctx->parent_root) goto out; ret = is_inode_existent(sctx, dir, dir_gen); if (ret <= 0) goto out; /* * If we have a parent root we need to verify that the parent dir was * not delted and then re-created, if it was then we have no overwrite * and we can just unlink this entry. */ if (sctx->parent_root) { ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL, NULL, NULL, NULL); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { ret = 0; goto out; } if (gen != dir_gen) goto out; } ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len, &other_inode, &other_type); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { ret = 0; goto out; } /* * Check if the overwritten ref was already processed. If yes, the ref * was already unlinked/moved, so we can safely assume that we will not * overwrite anything at this point in time. */ if (other_inode > sctx->send_progress) { 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(); if (!name) return -ENOMEM; ret = get_first_ref(sctx->parent_root, ino, &dir, &dir_gen, name); if (ret < 0) goto out; ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen, name->start, fs_path_len(name)); out: fs_path_free(name); return ret; } /* * Insert a name cache entry. On 32bit kernels the radix tree index is 32bit, * so we need to do some special handling in case we have clashes. This function * takes care of this with the help of name_cache_entry::radix_list. * In case of error, nce is kfreed. */ static int name_cache_insert(struct send_ctx *sctx, struct name_cache_entry *nce) { int ret = 0; struct list_head *nce_head; nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)nce->ino); if (!nce_head) { nce_head = kmalloc(sizeof(*nce_head), GFP_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->send_root, ino, parent_ino, parent_gen, dest); else ret = get_first_ref(sctx->parent_root, ino, parent_ino, parent_gen, dest); if (ret < 0) goto out; /* * Check if the ref was overwritten by an inode's ref that was processed * earlier. If yes, treat as orphan and return 1. */ ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen, dest->start, dest->end - dest->start); if (ret < 0) goto out; if (ret) { fs_path_reset(dest); ret = gen_unique_name(sctx, ino, gen, dest); if (ret < 0) goto out; ret = 1; } out_cache: /* * Store the result of the lookup in the name cache. */ nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_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(); 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(name); if (!ret) fs_path_unreverse(dest); return ret; } /* * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace */ static int send_subvol_begin(struct send_ctx *sctx) { int ret; struct btrfs_root *send_root = sctx->send_root; struct btrfs_root *parent_root = sctx->parent_root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_root_ref *ref; struct extent_buffer *leaf; char *name = NULL; int namelen; path = 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(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode) { int ret = 0; struct fs_path *p; verbose_printk("btrfs: send_chmod %llu mode=%llu\n", ino, mode); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid) { 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(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid); TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen) { 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(); 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(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(); 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->send_root, ino, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p); } else if (S_ISCHR(mode) || S_ISBLK(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev)); TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode); } ret = send_cmd(sctx); if (ret < 0) goto out; tlv_put_failure: out: fs_path_free(p); return ret; } /* * We need some special handling for inodes that get processed before the parent * directory got created. See process_recorded_refs for details. * This function does the check if we already created the dir out of order. */ static int did_create_dir(struct send_ctx *sctx, u64 dir) { int ret = 0; struct btrfs_path *path = NULL; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_key di_key; struct extent_buffer *eb; struct btrfs_dir_item *di; int slot; path = alloc_path_for_send(); if (!path) { ret = -ENOMEM; goto out; } key.objectid = dir; key.type = BTRFS_DIR_INDEX_KEY; key.offset = 0; 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.type != BTRFS_ROOT_ITEM_KEY && 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; ref = kmalloc(sizeof(*ref), GFP_NOFS); if (!ref) return -ENOMEM; ref->dir = dir; ref->dir_gen = dir_gen; ref->full_path = path; ref->name = (char *)kbasename(ref->full_path->start); ref->name_len = ref->full_path->end - ref->name; ref->dir_path = ref->full_path->start; if (ref->name == ref->full_path->start) ref->dir_path_len = 0; else 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 int dup_ref(struct recorded_ref *ref, struct list_head *list) { struct recorded_ref *new; new = kmalloc(sizeof(*ref), GFP_NOFS); if (!new) return -ENOMEM; new->dir = ref->dir; new->dir_gen = ref->dir_gen; new->full_path = NULL; INIT_LIST_HEAD(&new->list); list_add_tail(&new->list, list); return 0; } static void __free_recorded_refs(struct list_head *head) { struct recorded_ref *cur; while (!list_empty(head)) { cur = list_entry(head->next, struct recorded_ref, list); fs_path_free(cur->full_path); list_del(&cur->list); kfree(cur); } } static void free_recorded_refs(struct send_ctx *sctx) { __free_recorded_refs(&sctx->new_refs); __free_recorded_refs(&sctx->deleted_refs); } /* * Renames/moves a file/dir to its orphan name. Used when the first * ref of an unprocessed inode gets overwritten and for all non empty * directories. */ static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen, struct fs_path *path) { int ret; struct fs_path *orphan; orphan = fs_path_alloc(); if (!orphan) return -ENOMEM; ret = gen_unique_name(sctx, ino, gen, orphan); if (ret < 0) goto out; ret = send_rename(sctx, path, orphan); out: fs_path_free(orphan); return ret; } /* * 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 list_head check_dirs; 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); INIT_LIST_HEAD(&check_dirs); valid_path = fs_path_alloc(); if (!valid_path) { ret = -ENOMEM; goto out; } /* * First, check if the first ref of the current inode was overwritten * before. If yes, we know that the current inode was already orphanized * and thus use the orphan name. If not, we can use get_cur_path to * get the path of the first ref as it would like while receiving at * this point in time. * New inodes are always orphan at the beginning, so force to use the * orphan name in this case. * The first ref is stored in valid_path and will be updated if it * gets moved around. */ if (!sctx->cur_inode_new) { ret = did_overwrite_first_ref(sctx, sctx->cur_ino, sctx->cur_inode_gen); if (ret < 0) goto out; if (ret) did_overwrite = 1; } if (sctx->cur_inode_new || did_overwrite) { ret = gen_unique_name(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; is_orphan = 1; } else { ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; } list_for_each_entry(cur, &sctx->new_refs, list) { /* * We may have refs where the parent directory does not exist * yet. This happens if the parent directories inum is higher * 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->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 = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) { /* * Check if we can already rmdir the directory. If not, * orphanize it. For every dir item inside that gets deleted * later, we do this check again and rmdir it then if possible. * See the use of check_dirs for more details. */ ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_ino); if (ret < 0) goto out; if (ret) { ret = send_rmdir(sctx, valid_path); if (ret < 0) goto out; } else if (!is_orphan) { ret = orphanize_inode(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; is_orphan = 1; } list_for_each_entry(cur, &sctx->deleted_refs, list) { ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } } else if (S_ISDIR(sctx->cur_inode_mode) && !list_empty(&sctx->deleted_refs)) { /* * We have a moved dir. Add the old parent to check_dirs */ cur = list_entry(sctx->deleted_refs.next, struct recorded_ref, list); ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } else if (!S_ISDIR(sctx->cur_inode_mode)) { /* * We have a non dir inode. Go through all deleted refs and * unlink them if they were not already overwritten by other * inodes. */ list_for_each_entry(cur, &sctx->deleted_refs, list) { ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen, sctx->cur_ino, sctx->cur_inode_gen, cur->name, cur->name_len); if (ret < 0) goto out; if (!ret) { ret = send_unlink(sctx, cur->full_path); if (ret < 0) goto out; } ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } /* * If the inode is still orphan, unlink the orphan. This may * happen when a previous inode did overwrite the first ref * of this inode and no new refs were added for the current * inode. Unlinking does not mean that the inode is deleted in * all cases. There may still be links to this inode in other * places. */ if (is_orphan) { ret = send_unlink(sctx, valid_path); if (ret < 0) goto out; } } /* * We did collect all parent dirs where cur_inode was once located. We * now go through all these dirs and check if they are pending for * deletion and if it's finally possible to perform the rmdir now. * We also update the inode stats of the parent dirs here. */ list_for_each_entry(cur, &check_dirs, list) { /* * In case we had refs into dirs that were not processed yet, * we don't need to do the utime and rmdir logic for these dirs. * The dir will be processed later. */ if (cur->dir > sctx->cur_ino) continue; ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; if (ret == inode_state_did_create || ret == inode_state_no_change) { /* TODO delayed utimes */ ret = send_utimes(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; } else if (ret == inode_state_did_delete) { ret = can_rmdir(sctx, cur->dir, sctx->cur_ino); if (ret < 0) goto out; if (ret) { ret = get_cur_path(sctx, cur->dir, cur->dir_gen, valid_path); if (ret < 0) goto out; ret = send_rmdir(sctx, valid_path); if (ret < 0) goto out; } } } ret = 0; out: __free_recorded_refs(&check_dirs); free_recorded_refs(sctx); fs_path_free(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(); 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(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(); 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(p); return ret; } static int record_new_ref(struct send_ctx *sctx) { int ret; ret = iterate_inode_ref(sctx->send_root, sctx->left_path, sctx->cmp_key, 0, __record_new_ref, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } static int record_deleted_ref(struct send_ctx *sctx) { int ret; ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, sctx->cmp_key, 0, __record_deleted_ref, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } struct find_ref_ctx { u64 dir; u64 dir_gen; struct btrfs_root *root; struct fs_path *name; int found_idx; }; static int __find_iref(int num, u64 dir, int index, struct fs_path *name, void *ctx_) { struct find_ref_ctx *ctx = ctx_; u64 dir_gen; int ret; if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) && strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) { /* * To avoid doing extra lookups we'll only do this if everything * else matches. */ ret = get_inode_info(ctx->root, dir, NULL, &dir_gen, NULL, NULL, NULL, NULL); if (ret) return ret; if (dir_gen != ctx->dir_gen) return 0; ctx->found_idx = num; return 1; } return 0; } static int find_iref(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *key, u64 dir, u64 dir_gen, struct fs_path *name) { int ret; struct find_ref_ctx ctx; ctx.dir = dir; ctx.name = name; ctx.dir_gen = dir_gen; ctx.found_idx = -1; ctx.root = root; ret = iterate_inode_ref(root, path, key, 0, __find_iref, &ctx); if (ret < 0) return ret; if (ctx.found_idx == -1) return -ENOENT; return ctx.found_idx; } static int __record_changed_new_ref(int num, u64 dir, int index, struct fs_path *name, void *ctx) { u64 dir_gen; int ret; struct send_ctx *sctx = ctx; ret = get_inode_info(sctx->send_root, dir, NULL, &dir_gen, NULL, NULL, NULL, NULL); if (ret) return ret; ret = find_iref(sctx->parent_root, sctx->right_path, sctx->cmp_key, dir, dir_gen, name); if (ret == -ENOENT) ret = __record_new_ref(num, dir, index, name, sctx); else if (ret > 0) ret = 0; return ret; } static int __record_changed_deleted_ref(int num, u64 dir, int index, struct fs_path *name, void *ctx) { u64 dir_gen; int ret; struct send_ctx *sctx = ctx; ret = get_inode_info(sctx->parent_root, dir, NULL, &dir_gen, NULL, NULL, NULL, NULL); if (ret) return ret; ret = find_iref(sctx->send_root, sctx->left_path, sctx->cmp_key, dir, dir_gen, name); if (ret == -ENOENT) ret = __record_deleted_ref(num, dir, index, name, sctx); else if (ret > 0) ret = 0; return ret; } static int record_changed_ref(struct send_ctx *sctx) { int ret = 0; ret = iterate_inode_ref(sctx->send_root, sctx->left_path, sctx->cmp_key, 0, __record_changed_new_ref, sctx); if (ret < 0) goto out; ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, sctx->cmp_key, 0, __record_changed_deleted_ref, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } /* * Record and process all refs at once. Needed when an inode changes the * generation number, which means that it was deleted and recreated. */ static int process_all_refs(struct send_ctx *sctx, enum btrfs_compare_tree_result cmd) { int ret; struct btrfs_root *root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; struct extent_buffer *eb; int slot; iterate_inode_ref_t cb; 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(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(); 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(p); return ret; } static int __process_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx) { int ret; struct send_ctx *sctx = ctx; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; ret = send_remove_xattr(sctx, p, name, name_len); out: fs_path_free(p); return ret; } static int process_new_xattr(struct send_ctx *sctx) { int ret = 0; ret = iterate_dir_item(sctx->send_root, sctx->left_path, 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->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 = kmemdup(data, data_len, GFP_NOFS); if (!ctx->found_data) return -ENOMEM; return 1; } return 0; } static int find_xattr(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *key, const char *name, int name_len, char **data, int *data_len) { int ret; struct find_xattr_ctx ctx; ctx.name = name; ctx.name_len = name_len; ctx.found_idx = -1; ctx.found_data = NULL; ctx.found_data_len = 0; ret = iterate_dir_item(root, path, 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; ret = find_xattr(sctx->parent_root, sctx->right_path, sctx->cmp_key, name, name_len, &found_data, &found_data_len); if (ret == -ENOENT) { ret = __process_new_xattr(num, di_key, name, name_len, data, data_len, type, ctx); } else if (ret >= 0) { if (data_len != found_data_len || memcmp(data, found_data, data_len)) { ret = __process_new_xattr(num, di_key, name, name_len, data, data_len, type, ctx); } else { ret = 0; } } kfree(found_data); return ret; } static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx) { int ret; struct send_ctx *sctx = ctx; ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key, name, name_len, NULL, NULL); if (ret == -ENOENT) ret = __process_deleted_xattr(num, di_key, name, name_len, data, data_len, type, ctx); else if (ret >= 0) ret = 0; return ret; } static int process_changed_xattr(struct send_ctx *sctx) { int ret = 0; ret = iterate_dir_item(sctx->send_root, sctx->left_path, sctx->cmp_key, __process_changed_new_xattr, sctx); if (ret < 0) goto out; ret = iterate_dir_item(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(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; } static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len) { struct btrfs_root *root = sctx->send_root; struct btrfs_fs_info *fs_info = root->fs_info; struct inode *inode; struct page *page; char *addr; struct btrfs_key key; pgoff_t index = offset >> PAGE_CACHE_SHIFT; pgoff_t last_index; unsigned pg_offset = offset & ~PAGE_CACHE_MASK; ssize_t ret = 0; key.objectid = sctx->cur_ino; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; inode = btrfs_iget(fs_info->sb, &key, root, NULL); if (IS_ERR(inode)) return PTR_ERR(inode); if (offset + len > i_size_read(inode)) { if (offset > i_size_read(inode)) len = 0; else len = offset - i_size_read(inode); } if (len == 0) goto out; last_index = (offset + len - 1) >> PAGE_CACHE_SHIFT; while (index <= last_index) { unsigned cur_len = min_t(unsigned, len, PAGE_CACHE_SIZE - pg_offset); page = find_or_create_page(inode->i_mapping, index, GFP_NOFS); if (!page) { ret = -ENOMEM; break; } if (!PageUptodate(page)) { btrfs_readpage(NULL, page); lock_page(page); if (!PageUptodate(page)) { unlock_page(page); page_cache_release(page); ret = -EIO; break; } } addr = kmap(page); memcpy(sctx->read_buf + ret, addr + pg_offset, cur_len); kunmap(page); unlock_page(page); page_cache_release(page); index++; pg_offset = 0; len -= cur_len; ret += cur_len; } out: iput(inode); return ret; } /* * Read some bytes from the current inode/file and send a write command to * user space. */ static int send_write(struct send_ctx *sctx, u64 offset, u32 len) { int ret = 0; struct fs_path *p; ssize_t num_read = 0; p = fs_path_alloc(); if (!p) return -ENOMEM; verbose_printk("btrfs: send_write offset=%llu, len=%d\n", offset, len); num_read = fill_read_buf(sctx, offset, len); if (num_read <= 0) { if (num_read < 0) ret = num_read; goto out; } ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); if (ret < 0) return ret; return num_read; } /* * Send a clone command to user space. */ static int send_clone(struct send_ctx *sctx, u64 offset, u32 len, struct clone_root *clone_root) { int ret = 0; struct fs_path *p; u64 gen; 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(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); if (clone_root->root == sctx->send_root) { ret = get_inode_info(sctx->send_root, clone_root->ino, NULL, &gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; ret = get_cur_path(sctx, clone_root->ino, gen, p); } else { ret = get_inode_path(clone_root->root, clone_root->ino, p); } if (ret < 0) goto out; 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(p); return ret; } /* * Send an update extent command to user space. */ static int send_update_extent(struct send_ctx *sctx, u64 offset, u32 len) { int ret = 0; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_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) { ret = send_clone(sctx, offset, len, clone_root); } else if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) { ret = send_update_extent(sctx, offset, len); } else { 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; } out: return ret; } static int is_extent_unchanged(struct send_ctx *sctx, struct btrfs_path *left_path, struct btrfs_key *ekey) { int ret = 0; struct btrfs_key key; struct btrfs_path *path = NULL; struct extent_buffer *eb; int slot; struct btrfs_key found_key; struct btrfs_file_extent_item *ei; u64 left_disknr; u64 right_disknr; u64 left_offset; u64 right_offset; u64 left_offset_fixed; u64 left_len; u64 right_len; u64 left_gen; u64 right_gen; u8 left_type; u8 right_type; path = alloc_path_for_send(); if (!path) return -ENOMEM; eb = left_path->nodes[0]; slot = left_path->slots[0]; ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); left_type = btrfs_file_extent_type(eb, ei); if (left_type != BTRFS_FILE_EXTENT_REG) { ret = 0; goto out; } left_disknr = btrfs_file_extent_disk_bytenr(eb, ei); left_len = btrfs_file_extent_num_bytes(eb, ei); left_offset = btrfs_file_extent_offset(eb, ei); left_gen = btrfs_file_extent_generation(eb, ei); /* * Following comments will refer to these graphics. L is the left * extents which we are checking at the moment. 1-8 are the right * extents that we iterate. * * |-----L-----| * |-1-|-2a-|-3-|-4-|-5-|-6-| * * |-----L-----| * |--1--|-2b-|...(same as above) * * Alternative situation. Happens on files where extents got split. * |-----L-----| * |-----------7-----------|-6-| * * Alternative situation. Happens on files which got larger. * |-----L-----| * |-8-| * Nothing follows after 8. */ key.objectid = ekey->objectid; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = ekey->offset; ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0); if (ret < 0) goto out; if (ret) { ret = 0; goto out; } /* * Handle special case where the right side has no extents at all. */ eb = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || found_key.type != key.type) { /* If we're a hole then just pretend nothing changed */ ret = (left_disknr) ? 0 : 1; goto out; } /* * We're now on 2a, 2b or 7. */ key = found_key; while (key.offset < ekey->offset + left_len) { ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); right_type = btrfs_file_extent_type(eb, ei); 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) { /* If we're a hole just pretend nothing changed */ ret = (left_disknr) ? 0 : 1; 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; } if (found_key.offset != key.offset + right_len) { ret = 0; goto out; } key = found_key; } /* * We're now behind the left extent (treat as unchanged) or at the end * of the right side (treat as changed). */ if (key.offset >= ekey->offset + left_len) ret = 1; else ret = 0; out: btrfs_free_path(path); return ret; } static int process_extent(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { struct clone_root *found_clone = NULL; int ret = 0; if (S_ISLNK(sctx->cur_inode_mode)) return 0; if (sctx->parent_root && !sctx->cur_inode_new) { ret = is_extent_unchanged(sctx, path, key); if (ret < 0) goto out; if (ret) { ret = 0; goto out; } } else { struct btrfs_file_extent_item *ei; u8 type; ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_file_extent_item); type = btrfs_file_extent_type(path->nodes[0], ei); if (type == BTRFS_FILE_EXTENT_PREALLOC || type == BTRFS_FILE_EXTENT_REG) { /* * The send spec does not have a prealloc command yet, * so just leave a hole for prealloc'ed extents until * we have enough commands queued up to justify rev'ing * the send spec. */ if (type == BTRFS_FILE_EXTENT_PREALLOC) { ret = 0; goto out; } /* Have a hole, just skip it. */ if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) { ret = 0; goto out; } } } ret = find_extent_clone(sctx, path, key->objectid, key->offset, sctx->cur_inode_size, &found_clone); if (ret != -ENOENT && ret < 0) goto out; ret = send_write_or_clone(sctx, path, key, found_clone); 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; 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; } static int dir_changed(struct send_ctx *sctx, u64 dir) { u64 orig_gen, new_gen; int ret; ret = get_inode_info(sctx->send_root, dir, NULL, &new_gen, NULL, NULL, NULL, NULL); if (ret) return ret; ret = get_inode_info(sctx->parent_root, dir, NULL, &orig_gen, NULL, NULL, NULL, NULL); if (ret) return ret; return (orig_gen != new_gen) ? 1 : 0; } static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { struct btrfs_inode_extref *extref; struct extent_buffer *leaf; u64 dirid = 0, last_dirid = 0; unsigned long ptr; u32 item_size; u32 cur_offset = 0; int ref_name_len; int ret = 0; /* Easy case, just check this one dirid */ if (key->type == BTRFS_INODE_REF_KEY) { dirid = key->offset; ret = dir_changed(sctx, dirid); goto out; } leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, path->slots[0]); ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); while (cur_offset < item_size) { extref = (struct btrfs_inode_extref *)(ptr + cur_offset); dirid = btrfs_inode_extref_parent(leaf, extref); ref_name_len = btrfs_inode_extref_name_len(leaf, extref); cur_offset += ref_name_len + sizeof(*extref); if (dirid == last_dirid) continue; ret = dir_changed(sctx, dirid); if (ret) break; last_dirid = dirid; } out: return ret; } /* * Updates compare related fields in sctx and simply forwards to the actual * changed_xxx functions. */ static int changed_cb(struct btrfs_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; if (result == BTRFS_COMPARE_TREE_SAME) { if (key->type != BTRFS_INODE_REF_KEY && key->type != BTRFS_INODE_EXTREF_KEY) return 0; ret = compare_refs(sctx, left_path, key); if (!ret) return 0; if (ret < 0) return ret; result = BTRFS_COMPARE_TREE_CHANGED; ret = 0; } sctx->left_path = left_path; sctx->right_path = right_path; sctx->cmp_key = key; ret = finish_inode_if_needed(sctx, 0); if (ret < 0) goto out; /* Ignore non-FS objects */ if (key->objectid == BTRFS_FREE_INO_OBJECTID || key->objectid == BTRFS_FREE_SPACE_OBJECTID) goto out; if (key->type == BTRFS_INODE_ITEM_KEY) ret = changed_inode(sctx, result); else if (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; if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) { ret = send_header(sctx); if (ret < 0) goto out; } ret = send_subvol_begin(sctx); if (ret < 0) goto out; if (sctx->parent_root) { ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root, changed_cb, sctx); if (ret < 0) goto out; ret = finish_inode_if_needed(sctx, 1); if (ret < 0) goto out; } else { ret = full_send_tree(sctx); if (ret < 0) goto out; } out: free_recorded_refs(sctx); return ret; } 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 send_ctx *sctx = NULL; u32 i; u64 *clone_sources_tmp = NULL; if (!capable(CAP_SYS_ADMIN)) return -EPERM; send_root = BTRFS_I(file_inode(mnt_file))->root; fs_info = send_root->fs_info; /* * This is done when we lookup the root, it should already be complete * by the time we get here. */ WARN_ON(send_root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE); /* * If we just created this root we need to make sure that the orphan * cleanup has been done and committed since we search the commit root, * so check its commit root transid with our otransid and if they match * commit the transaction to make sure everything is updated. */ down_read(&send_root->fs_info->extent_commit_sem); if (btrfs_header_generation(send_root->commit_root) == btrfs_root_otransid(&send_root->root_item)) { struct btrfs_trans_handle *trans; up_read(&send_root->fs_info->extent_commit_sem); trans = btrfs_attach_transaction_barrier(send_root); if (IS_ERR(trans)) { if (PTR_ERR(trans) != -ENOENT) { ret = PTR_ERR(trans); goto out; } /* ENOENT means theres no transaction */ } else { ret = btrfs_commit_transaction(trans, send_root); if (ret) goto out; } } else { up_read(&send_root->fs_info->extent_commit_sem); } 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; } if (arg->flags & ~BTRFS_SEND_FLAG_MASK) { ret = -EINVAL; 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->flags = arg->flags; sctx->send_filp = fget(arg->send_fd); if (!sctx->send_filp) { ret = -EBADF; 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 (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 (IS_ERR(sctx->parent_root)) { ret = PTR_ERR(sctx->parent_root); 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; if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) { ret = begin_cmd(sctx, BTRFS_SEND_C_END); if (ret < 0) goto out; ret = send_cmd(sctx); if (ret < 0) goto out; } out: 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; }