![Misono Tomohiro](/assets/img/avatar_default.png)
Use ERR_CAST() instead of void * to make meaning clear. Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2250 lines
59 KiB
C
2250 lines
59 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2011 STRATO. All rights reserved.
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*/
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#include <linux/mm.h>
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#include <linux/rbtree.h>
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#include <trace/events/btrfs.h>
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#include "ctree.h"
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#include "disk-io.h"
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#include "backref.h"
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#include "ulist.h"
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#include "transaction.h"
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#include "delayed-ref.h"
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#include "locking.h"
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/* Just an arbitrary number so we can be sure this happened */
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#define BACKREF_FOUND_SHARED 6
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struct extent_inode_elem {
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u64 inum;
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u64 offset;
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struct extent_inode_elem *next;
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};
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static int check_extent_in_eb(const struct btrfs_key *key,
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const struct extent_buffer *eb,
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const struct btrfs_file_extent_item *fi,
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u64 extent_item_pos,
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struct extent_inode_elem **eie,
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bool ignore_offset)
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{
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u64 offset = 0;
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struct extent_inode_elem *e;
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if (!ignore_offset &&
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!btrfs_file_extent_compression(eb, fi) &&
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!btrfs_file_extent_encryption(eb, fi) &&
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!btrfs_file_extent_other_encoding(eb, fi)) {
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u64 data_offset;
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u64 data_len;
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data_offset = btrfs_file_extent_offset(eb, fi);
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data_len = btrfs_file_extent_num_bytes(eb, fi);
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if (extent_item_pos < data_offset ||
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extent_item_pos >= data_offset + data_len)
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return 1;
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offset = extent_item_pos - data_offset;
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}
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e = kmalloc(sizeof(*e), GFP_NOFS);
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if (!e)
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return -ENOMEM;
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e->next = *eie;
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e->inum = key->objectid;
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e->offset = key->offset + offset;
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*eie = e;
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return 0;
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}
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static void free_inode_elem_list(struct extent_inode_elem *eie)
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{
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struct extent_inode_elem *eie_next;
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for (; eie; eie = eie_next) {
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eie_next = eie->next;
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kfree(eie);
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}
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}
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static int find_extent_in_eb(const struct extent_buffer *eb,
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u64 wanted_disk_byte, u64 extent_item_pos,
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struct extent_inode_elem **eie,
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bool ignore_offset)
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{
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u64 disk_byte;
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struct btrfs_key key;
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struct btrfs_file_extent_item *fi;
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int slot;
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int nritems;
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int extent_type;
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int ret;
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/*
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* from the shared data ref, we only have the leaf but we need
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* the key. thus, we must look into all items and see that we
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* find one (some) with a reference to our extent item.
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*/
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nritems = btrfs_header_nritems(eb);
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for (slot = 0; slot < nritems; ++slot) {
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btrfs_item_key_to_cpu(eb, &key, slot);
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if (key.type != BTRFS_EXTENT_DATA_KEY)
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continue;
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fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
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extent_type = btrfs_file_extent_type(eb, fi);
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if (extent_type == BTRFS_FILE_EXTENT_INLINE)
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continue;
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/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
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disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
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if (disk_byte != wanted_disk_byte)
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continue;
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ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie, ignore_offset);
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if (ret < 0)
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return ret;
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}
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return 0;
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}
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struct preftree {
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struct rb_root root;
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unsigned int count;
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};
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#define PREFTREE_INIT { .root = RB_ROOT, .count = 0 }
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struct preftrees {
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struct preftree direct; /* BTRFS_SHARED_[DATA|BLOCK]_REF_KEY */
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struct preftree indirect; /* BTRFS_[TREE_BLOCK|EXTENT_DATA]_REF_KEY */
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struct preftree indirect_missing_keys;
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};
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/*
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* Checks for a shared extent during backref search.
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*
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* The share_count tracks prelim_refs (direct and indirect) having a
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* ref->count >0:
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* - incremented when a ref->count transitions to >0
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* - decremented when a ref->count transitions to <1
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*/
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struct share_check {
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u64 root_objectid;
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u64 inum;
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int share_count;
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};
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static inline int extent_is_shared(struct share_check *sc)
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{
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return (sc && sc->share_count > 1) ? BACKREF_FOUND_SHARED : 0;
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}
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static struct kmem_cache *btrfs_prelim_ref_cache;
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int __init btrfs_prelim_ref_init(void)
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{
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btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
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sizeof(struct prelim_ref),
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0,
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SLAB_MEM_SPREAD,
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NULL);
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if (!btrfs_prelim_ref_cache)
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return -ENOMEM;
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return 0;
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}
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void __cold btrfs_prelim_ref_exit(void)
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{
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kmem_cache_destroy(btrfs_prelim_ref_cache);
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}
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static void free_pref(struct prelim_ref *ref)
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{
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kmem_cache_free(btrfs_prelim_ref_cache, ref);
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}
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/*
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* Return 0 when both refs are for the same block (and can be merged).
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* A -1 return indicates ref1 is a 'lower' block than ref2, while 1
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* indicates a 'higher' block.
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*/
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static int prelim_ref_compare(struct prelim_ref *ref1,
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struct prelim_ref *ref2)
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{
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if (ref1->level < ref2->level)
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return -1;
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if (ref1->level > ref2->level)
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return 1;
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if (ref1->root_id < ref2->root_id)
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return -1;
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if (ref1->root_id > ref2->root_id)
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return 1;
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if (ref1->key_for_search.type < ref2->key_for_search.type)
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return -1;
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if (ref1->key_for_search.type > ref2->key_for_search.type)
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return 1;
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if (ref1->key_for_search.objectid < ref2->key_for_search.objectid)
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return -1;
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if (ref1->key_for_search.objectid > ref2->key_for_search.objectid)
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return 1;
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if (ref1->key_for_search.offset < ref2->key_for_search.offset)
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return -1;
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if (ref1->key_for_search.offset > ref2->key_for_search.offset)
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return 1;
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if (ref1->parent < ref2->parent)
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return -1;
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if (ref1->parent > ref2->parent)
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return 1;
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return 0;
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}
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static void update_share_count(struct share_check *sc, int oldcount,
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int newcount)
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{
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if ((!sc) || (oldcount == 0 && newcount < 1))
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return;
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if (oldcount > 0 && newcount < 1)
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sc->share_count--;
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else if (oldcount < 1 && newcount > 0)
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sc->share_count++;
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}
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/*
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* Add @newref to the @root rbtree, merging identical refs.
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*
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* Callers should assume that newref has been freed after calling.
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*/
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static void prelim_ref_insert(const struct btrfs_fs_info *fs_info,
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struct preftree *preftree,
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struct prelim_ref *newref,
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struct share_check *sc)
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{
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struct rb_root *root;
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struct rb_node **p;
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struct rb_node *parent = NULL;
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struct prelim_ref *ref;
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int result;
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root = &preftree->root;
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p = &root->rb_node;
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while (*p) {
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parent = *p;
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ref = rb_entry(parent, struct prelim_ref, rbnode);
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result = prelim_ref_compare(ref, newref);
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if (result < 0) {
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p = &(*p)->rb_left;
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} else if (result > 0) {
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p = &(*p)->rb_right;
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} else {
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/* Identical refs, merge them and free @newref */
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struct extent_inode_elem *eie = ref->inode_list;
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while (eie && eie->next)
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eie = eie->next;
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if (!eie)
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ref->inode_list = newref->inode_list;
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else
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eie->next = newref->inode_list;
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trace_btrfs_prelim_ref_merge(fs_info, ref, newref,
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preftree->count);
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/*
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* A delayed ref can have newref->count < 0.
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* The ref->count is updated to follow any
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* BTRFS_[ADD|DROP]_DELAYED_REF actions.
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*/
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update_share_count(sc, ref->count,
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ref->count + newref->count);
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ref->count += newref->count;
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free_pref(newref);
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return;
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}
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}
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update_share_count(sc, 0, newref->count);
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preftree->count++;
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trace_btrfs_prelim_ref_insert(fs_info, newref, NULL, preftree->count);
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rb_link_node(&newref->rbnode, parent, p);
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rb_insert_color(&newref->rbnode, root);
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}
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/*
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* Release the entire tree. We don't care about internal consistency so
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* just free everything and then reset the tree root.
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*/
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static void prelim_release(struct preftree *preftree)
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{
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struct prelim_ref *ref, *next_ref;
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rbtree_postorder_for_each_entry_safe(ref, next_ref, &preftree->root,
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rbnode)
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free_pref(ref);
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preftree->root = RB_ROOT;
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preftree->count = 0;
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}
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/*
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* the rules for all callers of this function are:
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* - obtaining the parent is the goal
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* - if you add a key, you must know that it is a correct key
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* - if you cannot add the parent or a correct key, then we will look into the
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* block later to set a correct key
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*
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* delayed refs
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* ============
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* backref type | shared | indirect | shared | indirect
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* information | tree | tree | data | data
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* --------------------+--------+----------+--------+----------
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* parent logical | y | - | - | -
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* key to resolve | - | y | y | y
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* tree block logical | - | - | - | -
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* root for resolving | y | y | y | y
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*
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* - column 1: we've the parent -> done
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* - column 2, 3, 4: we use the key to find the parent
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*
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* on disk refs (inline or keyed)
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* ==============================
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* backref type | shared | indirect | shared | indirect
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* information | tree | tree | data | data
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* --------------------+--------+----------+--------+----------
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* parent logical | y | - | y | -
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* key to resolve | - | - | - | y
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* tree block logical | y | y | y | y
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* root for resolving | - | y | y | y
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*
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* - column 1, 3: we've the parent -> done
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* - column 2: we take the first key from the block to find the parent
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* (see add_missing_keys)
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* - column 4: we use the key to find the parent
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*
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* additional information that's available but not required to find the parent
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* block might help in merging entries to gain some speed.
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*/
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static int add_prelim_ref(const struct btrfs_fs_info *fs_info,
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struct preftree *preftree, u64 root_id,
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const struct btrfs_key *key, int level, u64 parent,
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u64 wanted_disk_byte, int count,
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struct share_check *sc, gfp_t gfp_mask)
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{
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struct prelim_ref *ref;
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if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
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return 0;
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ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
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if (!ref)
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return -ENOMEM;
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ref->root_id = root_id;
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if (key) {
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ref->key_for_search = *key;
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/*
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* We can often find data backrefs with an offset that is too
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* large (>= LLONG_MAX, maximum allowed file offset) due to
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* underflows when subtracting a file's offset with the data
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* offset of its corresponding extent data item. This can
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* happen for example in the clone ioctl.
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* So if we detect such case we set the search key's offset to
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* zero to make sure we will find the matching file extent item
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* at add_all_parents(), otherwise we will miss it because the
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* offset taken form the backref is much larger then the offset
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* of the file extent item. This can make us scan a very large
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* number of file extent items, but at least it will not make
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* us miss any.
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* This is an ugly workaround for a behaviour that should have
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* never existed, but it does and a fix for the clone ioctl
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* would touch a lot of places, cause backwards incompatibility
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* and would not fix the problem for extents cloned with older
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* kernels.
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*/
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if (ref->key_for_search.type == BTRFS_EXTENT_DATA_KEY &&
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ref->key_for_search.offset >= LLONG_MAX)
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ref->key_for_search.offset = 0;
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} else {
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memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
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}
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ref->inode_list = NULL;
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ref->level = level;
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ref->count = count;
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ref->parent = parent;
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ref->wanted_disk_byte = wanted_disk_byte;
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prelim_ref_insert(fs_info, preftree, ref, sc);
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return extent_is_shared(sc);
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}
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/* direct refs use root == 0, key == NULL */
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static int add_direct_ref(const struct btrfs_fs_info *fs_info,
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struct preftrees *preftrees, int level, u64 parent,
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u64 wanted_disk_byte, int count,
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struct share_check *sc, gfp_t gfp_mask)
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{
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return add_prelim_ref(fs_info, &preftrees->direct, 0, NULL, level,
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parent, wanted_disk_byte, count, sc, gfp_mask);
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}
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/* indirect refs use parent == 0 */
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static int add_indirect_ref(const struct btrfs_fs_info *fs_info,
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struct preftrees *preftrees, u64 root_id,
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const struct btrfs_key *key, int level,
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u64 wanted_disk_byte, int count,
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struct share_check *sc, gfp_t gfp_mask)
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{
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struct preftree *tree = &preftrees->indirect;
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if (!key)
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tree = &preftrees->indirect_missing_keys;
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return add_prelim_ref(fs_info, tree, root_id, key, level, 0,
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wanted_disk_byte, count, sc, gfp_mask);
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}
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static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
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struct ulist *parents, struct prelim_ref *ref,
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int level, u64 time_seq, const u64 *extent_item_pos,
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u64 total_refs, bool ignore_offset)
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{
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int ret = 0;
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int slot;
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struct extent_buffer *eb;
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struct btrfs_key key;
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struct btrfs_key *key_for_search = &ref->key_for_search;
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struct btrfs_file_extent_item *fi;
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struct extent_inode_elem *eie = NULL, *old = NULL;
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u64 disk_byte;
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u64 wanted_disk_byte = ref->wanted_disk_byte;
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u64 count = 0;
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if (level != 0) {
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eb = path->nodes[level];
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ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
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if (ret < 0)
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return ret;
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return 0;
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}
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/*
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* We normally enter this function with the path already pointing to
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* the first item to check. But sometimes, we may enter it with
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* slot==nritems. In that case, go to the next leaf before we continue.
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*/
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if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
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if (time_seq == SEQ_LAST)
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ret = btrfs_next_leaf(root, path);
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else
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ret = btrfs_next_old_leaf(root, path, time_seq);
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}
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while (!ret && count < total_refs) {
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eb = path->nodes[0];
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slot = path->slots[0];
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btrfs_item_key_to_cpu(eb, &key, slot);
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if (key.objectid != key_for_search->objectid ||
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key.type != BTRFS_EXTENT_DATA_KEY)
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break;
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fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
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disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
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if (disk_byte == wanted_disk_byte) {
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eie = NULL;
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old = NULL;
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count++;
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if (extent_item_pos) {
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ret = check_extent_in_eb(&key, eb, fi,
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*extent_item_pos,
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&eie, ignore_offset);
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if (ret < 0)
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break;
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}
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if (ret > 0)
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goto next;
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ret = ulist_add_merge_ptr(parents, eb->start,
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eie, (void **)&old, GFP_NOFS);
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if (ret < 0)
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break;
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if (!ret && extent_item_pos) {
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while (old->next)
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old = old->next;
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old->next = eie;
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}
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eie = NULL;
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}
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next:
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if (time_seq == SEQ_LAST)
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ret = btrfs_next_item(root, path);
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else
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ret = btrfs_next_old_item(root, path, time_seq);
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}
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if (ret > 0)
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ret = 0;
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else if (ret < 0)
|
|
free_inode_elem_list(eie);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* resolve an indirect backref in the form (root_id, key, level)
|
|
* to a logical address
|
|
*/
|
|
static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path, u64 time_seq,
|
|
struct prelim_ref *ref, struct ulist *parents,
|
|
const u64 *extent_item_pos, u64 total_refs,
|
|
bool ignore_offset)
|
|
{
|
|
struct btrfs_root *root;
|
|
struct btrfs_key root_key;
|
|
struct extent_buffer *eb;
|
|
int ret = 0;
|
|
int root_level;
|
|
int level = ref->level;
|
|
int index;
|
|
|
|
root_key.objectid = ref->root_id;
|
|
root_key.type = BTRFS_ROOT_ITEM_KEY;
|
|
root_key.offset = (u64)-1;
|
|
|
|
index = srcu_read_lock(&fs_info->subvol_srcu);
|
|
|
|
root = btrfs_get_fs_root(fs_info, &root_key, false);
|
|
if (IS_ERR(root)) {
|
|
srcu_read_unlock(&fs_info->subvol_srcu, index);
|
|
ret = PTR_ERR(root);
|
|
goto out;
|
|
}
|
|
|
|
if (btrfs_is_testing(fs_info)) {
|
|
srcu_read_unlock(&fs_info->subvol_srcu, index);
|
|
ret = -ENOENT;
|
|
goto out;
|
|
}
|
|
|
|
if (path->search_commit_root)
|
|
root_level = btrfs_header_level(root->commit_root);
|
|
else if (time_seq == SEQ_LAST)
|
|
root_level = btrfs_header_level(root->node);
|
|
else
|
|
root_level = btrfs_old_root_level(root, time_seq);
|
|
|
|
if (root_level + 1 == level) {
|
|
srcu_read_unlock(&fs_info->subvol_srcu, index);
|
|
goto out;
|
|
}
|
|
|
|
path->lowest_level = level;
|
|
if (time_seq == SEQ_LAST)
|
|
ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path,
|
|
0, 0);
|
|
else
|
|
ret = btrfs_search_old_slot(root, &ref->key_for_search, path,
|
|
time_seq);
|
|
|
|
/* root node has been locked, we can release @subvol_srcu safely here */
|
|
srcu_read_unlock(&fs_info->subvol_srcu, index);
|
|
|
|
btrfs_debug(fs_info,
|
|
"search slot in root %llu (level %d, ref count %d) returned %d for key (%llu %u %llu)",
|
|
ref->root_id, level, ref->count, ret,
|
|
ref->key_for_search.objectid, ref->key_for_search.type,
|
|
ref->key_for_search.offset);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
eb = path->nodes[level];
|
|
while (!eb) {
|
|
if (WARN_ON(!level)) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
level--;
|
|
eb = path->nodes[level];
|
|
}
|
|
|
|
ret = add_all_parents(root, path, parents, ref, level, time_seq,
|
|
extent_item_pos, total_refs, ignore_offset);
|
|
out:
|
|
path->lowest_level = 0;
|
|
btrfs_release_path(path);
|
|
return ret;
|
|
}
|
|
|
|
static struct extent_inode_elem *
|
|
unode_aux_to_inode_list(struct ulist_node *node)
|
|
{
|
|
if (!node)
|
|
return NULL;
|
|
return (struct extent_inode_elem *)(uintptr_t)node->aux;
|
|
}
|
|
|
|
/*
|
|
* We maintain three seperate rbtrees: one for direct refs, one for
|
|
* indirect refs which have a key, and one for indirect refs which do not
|
|
* have a key. Each tree does merge on insertion.
|
|
*
|
|
* Once all of the references are located, we iterate over the tree of
|
|
* indirect refs with missing keys. An appropriate key is located and
|
|
* the ref is moved onto the tree for indirect refs. After all missing
|
|
* keys are thus located, we iterate over the indirect ref tree, resolve
|
|
* each reference, and then insert the resolved reference onto the
|
|
* direct tree (merging there too).
|
|
*
|
|
* New backrefs (i.e., for parent nodes) are added to the appropriate
|
|
* rbtree as they are encountered. The new backrefs are subsequently
|
|
* resolved as above.
|
|
*/
|
|
static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path, u64 time_seq,
|
|
struct preftrees *preftrees,
|
|
const u64 *extent_item_pos, u64 total_refs,
|
|
struct share_check *sc, bool ignore_offset)
|
|
{
|
|
int err;
|
|
int ret = 0;
|
|
struct ulist *parents;
|
|
struct ulist_node *node;
|
|
struct ulist_iterator uiter;
|
|
struct rb_node *rnode;
|
|
|
|
parents = ulist_alloc(GFP_NOFS);
|
|
if (!parents)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* We could trade memory usage for performance here by iterating
|
|
* the tree, allocating new refs for each insertion, and then
|
|
* freeing the entire indirect tree when we're done. In some test
|
|
* cases, the tree can grow quite large (~200k objects).
|
|
*/
|
|
while ((rnode = rb_first(&preftrees->indirect.root))) {
|
|
struct prelim_ref *ref;
|
|
|
|
ref = rb_entry(rnode, struct prelim_ref, rbnode);
|
|
if (WARN(ref->parent,
|
|
"BUG: direct ref found in indirect tree")) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
rb_erase(&ref->rbnode, &preftrees->indirect.root);
|
|
preftrees->indirect.count--;
|
|
|
|
if (ref->count == 0) {
|
|
free_pref(ref);
|
|
continue;
|
|
}
|
|
|
|
if (sc && sc->root_objectid &&
|
|
ref->root_id != sc->root_objectid) {
|
|
free_pref(ref);
|
|
ret = BACKREF_FOUND_SHARED;
|
|
goto out;
|
|
}
|
|
err = resolve_indirect_ref(fs_info, path, time_seq, ref,
|
|
parents, extent_item_pos,
|
|
total_refs, ignore_offset);
|
|
/*
|
|
* we can only tolerate ENOENT,otherwise,we should catch error
|
|
* and return directly.
|
|
*/
|
|
if (err == -ENOENT) {
|
|
prelim_ref_insert(fs_info, &preftrees->direct, ref,
|
|
NULL);
|
|
continue;
|
|
} else if (err) {
|
|
free_pref(ref);
|
|
ret = err;
|
|
goto out;
|
|
}
|
|
|
|
/* we put the first parent into the ref at hand */
|
|
ULIST_ITER_INIT(&uiter);
|
|
node = ulist_next(parents, &uiter);
|
|
ref->parent = node ? node->val : 0;
|
|
ref->inode_list = unode_aux_to_inode_list(node);
|
|
|
|
/* Add a prelim_ref(s) for any other parent(s). */
|
|
while ((node = ulist_next(parents, &uiter))) {
|
|
struct prelim_ref *new_ref;
|
|
|
|
new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
|
|
GFP_NOFS);
|
|
if (!new_ref) {
|
|
free_pref(ref);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
memcpy(new_ref, ref, sizeof(*ref));
|
|
new_ref->parent = node->val;
|
|
new_ref->inode_list = unode_aux_to_inode_list(node);
|
|
prelim_ref_insert(fs_info, &preftrees->direct,
|
|
new_ref, NULL);
|
|
}
|
|
|
|
/*
|
|
* Now it's a direct ref, put it in the the direct tree. We must
|
|
* do this last because the ref could be merged/freed here.
|
|
*/
|
|
prelim_ref_insert(fs_info, &preftrees->direct, ref, NULL);
|
|
|
|
ulist_reinit(parents);
|
|
cond_resched();
|
|
}
|
|
out:
|
|
ulist_free(parents);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* read tree blocks and add keys where required.
|
|
*/
|
|
static int add_missing_keys(struct btrfs_fs_info *fs_info,
|
|
struct preftrees *preftrees)
|
|
{
|
|
struct prelim_ref *ref;
|
|
struct extent_buffer *eb;
|
|
struct preftree *tree = &preftrees->indirect_missing_keys;
|
|
struct rb_node *node;
|
|
|
|
while ((node = rb_first(&tree->root))) {
|
|
ref = rb_entry(node, struct prelim_ref, rbnode);
|
|
rb_erase(node, &tree->root);
|
|
|
|
BUG_ON(ref->parent); /* should not be a direct ref */
|
|
BUG_ON(ref->key_for_search.type);
|
|
BUG_ON(!ref->wanted_disk_byte);
|
|
|
|
eb = read_tree_block(fs_info, ref->wanted_disk_byte, 0,
|
|
ref->level - 1, NULL);
|
|
if (IS_ERR(eb)) {
|
|
free_pref(ref);
|
|
return PTR_ERR(eb);
|
|
} else if (!extent_buffer_uptodate(eb)) {
|
|
free_pref(ref);
|
|
free_extent_buffer(eb);
|
|
return -EIO;
|
|
}
|
|
btrfs_tree_read_lock(eb);
|
|
if (btrfs_header_level(eb) == 0)
|
|
btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
|
|
else
|
|
btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
|
|
btrfs_tree_read_unlock(eb);
|
|
free_extent_buffer(eb);
|
|
prelim_ref_insert(fs_info, &preftrees->indirect, ref, NULL);
|
|
cond_resched();
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* add all currently queued delayed refs from this head whose seq nr is
|
|
* smaller or equal that seq to the list
|
|
*/
|
|
static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
|
|
struct btrfs_delayed_ref_head *head, u64 seq,
|
|
struct preftrees *preftrees, u64 *total_refs,
|
|
struct share_check *sc)
|
|
{
|
|
struct btrfs_delayed_ref_node *node;
|
|
struct btrfs_delayed_extent_op *extent_op = head->extent_op;
|
|
struct btrfs_key key;
|
|
struct btrfs_key tmp_op_key;
|
|
struct rb_node *n;
|
|
int count;
|
|
int ret = 0;
|
|
|
|
if (extent_op && extent_op->update_key)
|
|
btrfs_disk_key_to_cpu(&tmp_op_key, &extent_op->key);
|
|
|
|
spin_lock(&head->lock);
|
|
for (n = rb_first(&head->ref_tree); n; n = rb_next(n)) {
|
|
node = rb_entry(n, struct btrfs_delayed_ref_node,
|
|
ref_node);
|
|
if (node->seq > seq)
|
|
continue;
|
|
|
|
switch (node->action) {
|
|
case BTRFS_ADD_DELAYED_EXTENT:
|
|
case BTRFS_UPDATE_DELAYED_HEAD:
|
|
WARN_ON(1);
|
|
continue;
|
|
case BTRFS_ADD_DELAYED_REF:
|
|
count = node->ref_mod;
|
|
break;
|
|
case BTRFS_DROP_DELAYED_REF:
|
|
count = node->ref_mod * -1;
|
|
break;
|
|
default:
|
|
BUG_ON(1);
|
|
}
|
|
*total_refs += count;
|
|
switch (node->type) {
|
|
case BTRFS_TREE_BLOCK_REF_KEY: {
|
|
/* NORMAL INDIRECT METADATA backref */
|
|
struct btrfs_delayed_tree_ref *ref;
|
|
|
|
ref = btrfs_delayed_node_to_tree_ref(node);
|
|
ret = add_indirect_ref(fs_info, preftrees, ref->root,
|
|
&tmp_op_key, ref->level + 1,
|
|
node->bytenr, count, sc,
|
|
GFP_ATOMIC);
|
|
break;
|
|
}
|
|
case BTRFS_SHARED_BLOCK_REF_KEY: {
|
|
/* SHARED DIRECT METADATA backref */
|
|
struct btrfs_delayed_tree_ref *ref;
|
|
|
|
ref = btrfs_delayed_node_to_tree_ref(node);
|
|
|
|
ret = add_direct_ref(fs_info, preftrees, ref->level + 1,
|
|
ref->parent, node->bytenr, count,
|
|
sc, GFP_ATOMIC);
|
|
break;
|
|
}
|
|
case BTRFS_EXTENT_DATA_REF_KEY: {
|
|
/* NORMAL INDIRECT DATA backref */
|
|
struct btrfs_delayed_data_ref *ref;
|
|
ref = btrfs_delayed_node_to_data_ref(node);
|
|
|
|
key.objectid = ref->objectid;
|
|
key.type = BTRFS_EXTENT_DATA_KEY;
|
|
key.offset = ref->offset;
|
|
|
|
/*
|
|
* Found a inum that doesn't match our known inum, we
|
|
* know it's shared.
|
|
*/
|
|
if (sc && sc->inum && ref->objectid != sc->inum) {
|
|
ret = BACKREF_FOUND_SHARED;
|
|
goto out;
|
|
}
|
|
|
|
ret = add_indirect_ref(fs_info, preftrees, ref->root,
|
|
&key, 0, node->bytenr, count, sc,
|
|
GFP_ATOMIC);
|
|
break;
|
|
}
|
|
case BTRFS_SHARED_DATA_REF_KEY: {
|
|
/* SHARED DIRECT FULL backref */
|
|
struct btrfs_delayed_data_ref *ref;
|
|
|
|
ref = btrfs_delayed_node_to_data_ref(node);
|
|
|
|
ret = add_direct_ref(fs_info, preftrees, 0, ref->parent,
|
|
node->bytenr, count, sc,
|
|
GFP_ATOMIC);
|
|
break;
|
|
}
|
|
default:
|
|
WARN_ON(1);
|
|
}
|
|
/*
|
|
* We must ignore BACKREF_FOUND_SHARED until all delayed
|
|
* refs have been checked.
|
|
*/
|
|
if (ret && (ret != BACKREF_FOUND_SHARED))
|
|
break;
|
|
}
|
|
if (!ret)
|
|
ret = extent_is_shared(sc);
|
|
out:
|
|
spin_unlock(&head->lock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* add all inline backrefs for bytenr to the list
|
|
*
|
|
* Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED.
|
|
*/
|
|
static int add_inline_refs(const struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path, u64 bytenr,
|
|
int *info_level, struct preftrees *preftrees,
|
|
u64 *total_refs, struct share_check *sc)
|
|
{
|
|
int ret = 0;
|
|
int slot;
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_key key;
|
|
struct btrfs_key found_key;
|
|
unsigned long ptr;
|
|
unsigned long end;
|
|
struct btrfs_extent_item *ei;
|
|
u64 flags;
|
|
u64 item_size;
|
|
|
|
/*
|
|
* enumerate all inline refs
|
|
*/
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0];
|
|
|
|
item_size = btrfs_item_size_nr(leaf, slot);
|
|
BUG_ON(item_size < sizeof(*ei));
|
|
|
|
ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
|
|
flags = btrfs_extent_flags(leaf, ei);
|
|
*total_refs += btrfs_extent_refs(leaf, ei);
|
|
btrfs_item_key_to_cpu(leaf, &found_key, slot);
|
|
|
|
ptr = (unsigned long)(ei + 1);
|
|
end = (unsigned long)ei + item_size;
|
|
|
|
if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
|
|
flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
|
|
struct btrfs_tree_block_info *info;
|
|
|
|
info = (struct btrfs_tree_block_info *)ptr;
|
|
*info_level = btrfs_tree_block_level(leaf, info);
|
|
ptr += sizeof(struct btrfs_tree_block_info);
|
|
BUG_ON(ptr > end);
|
|
} else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
|
|
*info_level = found_key.offset;
|
|
} else {
|
|
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
|
|
}
|
|
|
|
while (ptr < end) {
|
|
struct btrfs_extent_inline_ref *iref;
|
|
u64 offset;
|
|
int type;
|
|
|
|
iref = (struct btrfs_extent_inline_ref *)ptr;
|
|
type = btrfs_get_extent_inline_ref_type(leaf, iref,
|
|
BTRFS_REF_TYPE_ANY);
|
|
if (type == BTRFS_REF_TYPE_INVALID)
|
|
return -EUCLEAN;
|
|
|
|
offset = btrfs_extent_inline_ref_offset(leaf, iref);
|
|
|
|
switch (type) {
|
|
case BTRFS_SHARED_BLOCK_REF_KEY:
|
|
ret = add_direct_ref(fs_info, preftrees,
|
|
*info_level + 1, offset,
|
|
bytenr, 1, NULL, GFP_NOFS);
|
|
break;
|
|
case BTRFS_SHARED_DATA_REF_KEY: {
|
|
struct btrfs_shared_data_ref *sdref;
|
|
int count;
|
|
|
|
sdref = (struct btrfs_shared_data_ref *)(iref + 1);
|
|
count = btrfs_shared_data_ref_count(leaf, sdref);
|
|
|
|
ret = add_direct_ref(fs_info, preftrees, 0, offset,
|
|
bytenr, count, sc, GFP_NOFS);
|
|
break;
|
|
}
|
|
case BTRFS_TREE_BLOCK_REF_KEY:
|
|
ret = add_indirect_ref(fs_info, preftrees, offset,
|
|
NULL, *info_level + 1,
|
|
bytenr, 1, NULL, GFP_NOFS);
|
|
break;
|
|
case BTRFS_EXTENT_DATA_REF_KEY: {
|
|
struct btrfs_extent_data_ref *dref;
|
|
int count;
|
|
u64 root;
|
|
|
|
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
|
|
count = btrfs_extent_data_ref_count(leaf, dref);
|
|
key.objectid = btrfs_extent_data_ref_objectid(leaf,
|
|
dref);
|
|
key.type = BTRFS_EXTENT_DATA_KEY;
|
|
key.offset = btrfs_extent_data_ref_offset(leaf, dref);
|
|
|
|
if (sc && sc->inum && key.objectid != sc->inum) {
|
|
ret = BACKREF_FOUND_SHARED;
|
|
break;
|
|
}
|
|
|
|
root = btrfs_extent_data_ref_root(leaf, dref);
|
|
|
|
ret = add_indirect_ref(fs_info, preftrees, root,
|
|
&key, 0, bytenr, count,
|
|
sc, GFP_NOFS);
|
|
break;
|
|
}
|
|
default:
|
|
WARN_ON(1);
|
|
}
|
|
if (ret)
|
|
return ret;
|
|
ptr += btrfs_extent_inline_ref_size(type);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* add all non-inline backrefs for bytenr to the list
|
|
*
|
|
* Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED.
|
|
*/
|
|
static int add_keyed_refs(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path, u64 bytenr,
|
|
int info_level, struct preftrees *preftrees,
|
|
struct share_check *sc)
|
|
{
|
|
struct btrfs_root *extent_root = fs_info->extent_root;
|
|
int ret;
|
|
int slot;
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_key key;
|
|
|
|
while (1) {
|
|
ret = btrfs_next_item(extent_root, path);
|
|
if (ret < 0)
|
|
break;
|
|
if (ret) {
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
slot = path->slots[0];
|
|
leaf = path->nodes[0];
|
|
btrfs_item_key_to_cpu(leaf, &key, slot);
|
|
|
|
if (key.objectid != bytenr)
|
|
break;
|
|
if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
|
|
continue;
|
|
if (key.type > BTRFS_SHARED_DATA_REF_KEY)
|
|
break;
|
|
|
|
switch (key.type) {
|
|
case BTRFS_SHARED_BLOCK_REF_KEY:
|
|
/* SHARED DIRECT METADATA backref */
|
|
ret = add_direct_ref(fs_info, preftrees,
|
|
info_level + 1, key.offset,
|
|
bytenr, 1, NULL, GFP_NOFS);
|
|
break;
|
|
case BTRFS_SHARED_DATA_REF_KEY: {
|
|
/* SHARED DIRECT FULL backref */
|
|
struct btrfs_shared_data_ref *sdref;
|
|
int count;
|
|
|
|
sdref = btrfs_item_ptr(leaf, slot,
|
|
struct btrfs_shared_data_ref);
|
|
count = btrfs_shared_data_ref_count(leaf, sdref);
|
|
ret = add_direct_ref(fs_info, preftrees, 0,
|
|
key.offset, bytenr, count,
|
|
sc, GFP_NOFS);
|
|
break;
|
|
}
|
|
case BTRFS_TREE_BLOCK_REF_KEY:
|
|
/* NORMAL INDIRECT METADATA backref */
|
|
ret = add_indirect_ref(fs_info, preftrees, key.offset,
|
|
NULL, info_level + 1, bytenr,
|
|
1, NULL, GFP_NOFS);
|
|
break;
|
|
case BTRFS_EXTENT_DATA_REF_KEY: {
|
|
/* NORMAL INDIRECT DATA backref */
|
|
struct btrfs_extent_data_ref *dref;
|
|
int count;
|
|
u64 root;
|
|
|
|
dref = btrfs_item_ptr(leaf, slot,
|
|
struct btrfs_extent_data_ref);
|
|
count = btrfs_extent_data_ref_count(leaf, dref);
|
|
key.objectid = btrfs_extent_data_ref_objectid(leaf,
|
|
dref);
|
|
key.type = BTRFS_EXTENT_DATA_KEY;
|
|
key.offset = btrfs_extent_data_ref_offset(leaf, dref);
|
|
|
|
if (sc && sc->inum && key.objectid != sc->inum) {
|
|
ret = BACKREF_FOUND_SHARED;
|
|
break;
|
|
}
|
|
|
|
root = btrfs_extent_data_ref_root(leaf, dref);
|
|
ret = add_indirect_ref(fs_info, preftrees, root,
|
|
&key, 0, bytenr, count,
|
|
sc, GFP_NOFS);
|
|
break;
|
|
}
|
|
default:
|
|
WARN_ON(1);
|
|
}
|
|
if (ret)
|
|
return ret;
|
|
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* this adds all existing backrefs (inline backrefs, backrefs and delayed
|
|
* refs) for the given bytenr to the refs list, merges duplicates and resolves
|
|
* indirect refs to their parent bytenr.
|
|
* When roots are found, they're added to the roots list
|
|
*
|
|
* If time_seq is set to SEQ_LAST, it will not search delayed_refs, and behave
|
|
* much like trans == NULL case, the difference only lies in it will not
|
|
* commit root.
|
|
* The special case is for qgroup to search roots in commit_transaction().
|
|
*
|
|
* @sc - if !NULL, then immediately return BACKREF_FOUND_SHARED when a
|
|
* shared extent is detected.
|
|
*
|
|
* Otherwise this returns 0 for success and <0 for an error.
|
|
*
|
|
* If ignore_offset is set to false, only extent refs whose offsets match
|
|
* extent_item_pos are returned. If true, every extent ref is returned
|
|
* and extent_item_pos is ignored.
|
|
*
|
|
* FIXME some caching might speed things up
|
|
*/
|
|
static int find_parent_nodes(struct btrfs_trans_handle *trans,
|
|
struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 time_seq, struct ulist *refs,
|
|
struct ulist *roots, const u64 *extent_item_pos,
|
|
struct share_check *sc, bool ignore_offset)
|
|
{
|
|
struct btrfs_key key;
|
|
struct btrfs_path *path;
|
|
struct btrfs_delayed_ref_root *delayed_refs = NULL;
|
|
struct btrfs_delayed_ref_head *head;
|
|
int info_level = 0;
|
|
int ret;
|
|
struct prelim_ref *ref;
|
|
struct rb_node *node;
|
|
struct extent_inode_elem *eie = NULL;
|
|
/* total of both direct AND indirect refs! */
|
|
u64 total_refs = 0;
|
|
struct preftrees preftrees = {
|
|
.direct = PREFTREE_INIT,
|
|
.indirect = PREFTREE_INIT,
|
|
.indirect_missing_keys = PREFTREE_INIT
|
|
};
|
|
|
|
key.objectid = bytenr;
|
|
key.offset = (u64)-1;
|
|
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
|
|
key.type = BTRFS_METADATA_ITEM_KEY;
|
|
else
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
|
|
path = btrfs_alloc_path();
|
|
if (!path)
|
|
return -ENOMEM;
|
|
if (!trans) {
|
|
path->search_commit_root = 1;
|
|
path->skip_locking = 1;
|
|
}
|
|
|
|
if (time_seq == SEQ_LAST)
|
|
path->skip_locking = 1;
|
|
|
|
/*
|
|
* grab both a lock on the path and a lock on the delayed ref head.
|
|
* We need both to get a consistent picture of how the refs look
|
|
* at a specified point in time
|
|
*/
|
|
again:
|
|
head = NULL;
|
|
|
|
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
goto out;
|
|
BUG_ON(ret == 0);
|
|
|
|
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
|
|
if (trans && likely(trans->type != __TRANS_DUMMY) &&
|
|
time_seq != SEQ_LAST) {
|
|
#else
|
|
if (trans && time_seq != SEQ_LAST) {
|
|
#endif
|
|
/*
|
|
* look if there are updates for this ref queued and lock the
|
|
* head
|
|
*/
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
spin_lock(&delayed_refs->lock);
|
|
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
|
|
if (head) {
|
|
if (!mutex_trylock(&head->mutex)) {
|
|
refcount_inc(&head->refs);
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
btrfs_release_path(path);
|
|
|
|
/*
|
|
* Mutex was contended, block until it's
|
|
* released and try again
|
|
*/
|
|
mutex_lock(&head->mutex);
|
|
mutex_unlock(&head->mutex);
|
|
btrfs_put_delayed_ref_head(head);
|
|
goto again;
|
|
}
|
|
spin_unlock(&delayed_refs->lock);
|
|
ret = add_delayed_refs(fs_info, head, time_seq,
|
|
&preftrees, &total_refs, sc);
|
|
mutex_unlock(&head->mutex);
|
|
if (ret)
|
|
goto out;
|
|
} else {
|
|
spin_unlock(&delayed_refs->lock);
|
|
}
|
|
}
|
|
|
|
if (path->slots[0]) {
|
|
struct extent_buffer *leaf;
|
|
int slot;
|
|
|
|
path->slots[0]--;
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0];
|
|
btrfs_item_key_to_cpu(leaf, &key, slot);
|
|
if (key.objectid == bytenr &&
|
|
(key.type == BTRFS_EXTENT_ITEM_KEY ||
|
|
key.type == BTRFS_METADATA_ITEM_KEY)) {
|
|
ret = add_inline_refs(fs_info, path, bytenr,
|
|
&info_level, &preftrees,
|
|
&total_refs, sc);
|
|
if (ret)
|
|
goto out;
|
|
ret = add_keyed_refs(fs_info, path, bytenr, info_level,
|
|
&preftrees, sc);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
ret = add_missing_keys(fs_info, &preftrees);
|
|
if (ret)
|
|
goto out;
|
|
|
|
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect_missing_keys.root));
|
|
|
|
ret = resolve_indirect_refs(fs_info, path, time_seq, &preftrees,
|
|
extent_item_pos, total_refs, sc, ignore_offset);
|
|
if (ret)
|
|
goto out;
|
|
|
|
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect.root));
|
|
|
|
/*
|
|
* This walks the tree of merged and resolved refs. Tree blocks are
|
|
* read in as needed. Unique entries are added to the ulist, and
|
|
* the list of found roots is updated.
|
|
*
|
|
* We release the entire tree in one go before returning.
|
|
*/
|
|
node = rb_first(&preftrees.direct.root);
|
|
while (node) {
|
|
ref = rb_entry(node, struct prelim_ref, rbnode);
|
|
node = rb_next(&ref->rbnode);
|
|
/*
|
|
* ref->count < 0 can happen here if there are delayed
|
|
* refs with a node->action of BTRFS_DROP_DELAYED_REF.
|
|
* prelim_ref_insert() relies on this when merging
|
|
* identical refs to keep the overall count correct.
|
|
* prelim_ref_insert() will merge only those refs
|
|
* which compare identically. Any refs having
|
|
* e.g. different offsets would not be merged,
|
|
* and would retain their original ref->count < 0.
|
|
*/
|
|
if (roots && ref->count && ref->root_id && ref->parent == 0) {
|
|
if (sc && sc->root_objectid &&
|
|
ref->root_id != sc->root_objectid) {
|
|
ret = BACKREF_FOUND_SHARED;
|
|
goto out;
|
|
}
|
|
|
|
/* no parent == root of tree */
|
|
ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
|
|
if (ret < 0)
|
|
goto out;
|
|
}
|
|
if (ref->count && ref->parent) {
|
|
if (extent_item_pos && !ref->inode_list &&
|
|
ref->level == 0) {
|
|
struct extent_buffer *eb;
|
|
|
|
eb = read_tree_block(fs_info, ref->parent, 0,
|
|
ref->level, NULL);
|
|
if (IS_ERR(eb)) {
|
|
ret = PTR_ERR(eb);
|
|
goto out;
|
|
} else if (!extent_buffer_uptodate(eb)) {
|
|
free_extent_buffer(eb);
|
|
ret = -EIO;
|
|
goto out;
|
|
}
|
|
btrfs_tree_read_lock(eb);
|
|
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
|
|
ret = find_extent_in_eb(eb, bytenr,
|
|
*extent_item_pos, &eie, ignore_offset);
|
|
btrfs_tree_read_unlock_blocking(eb);
|
|
free_extent_buffer(eb);
|
|
if (ret < 0)
|
|
goto out;
|
|
ref->inode_list = eie;
|
|
}
|
|
ret = ulist_add_merge_ptr(refs, ref->parent,
|
|
ref->inode_list,
|
|
(void **)&eie, GFP_NOFS);
|
|
if (ret < 0)
|
|
goto out;
|
|
if (!ret && extent_item_pos) {
|
|
/*
|
|
* we've recorded that parent, so we must extend
|
|
* its inode list here
|
|
*/
|
|
BUG_ON(!eie);
|
|
while (eie->next)
|
|
eie = eie->next;
|
|
eie->next = ref->inode_list;
|
|
}
|
|
eie = NULL;
|
|
}
|
|
cond_resched();
|
|
}
|
|
|
|
out:
|
|
btrfs_free_path(path);
|
|
|
|
prelim_release(&preftrees.direct);
|
|
prelim_release(&preftrees.indirect);
|
|
prelim_release(&preftrees.indirect_missing_keys);
|
|
|
|
if (ret < 0)
|
|
free_inode_elem_list(eie);
|
|
return ret;
|
|
}
|
|
|
|
static void free_leaf_list(struct ulist *blocks)
|
|
{
|
|
struct ulist_node *node = NULL;
|
|
struct extent_inode_elem *eie;
|
|
struct ulist_iterator uiter;
|
|
|
|
ULIST_ITER_INIT(&uiter);
|
|
while ((node = ulist_next(blocks, &uiter))) {
|
|
if (!node->aux)
|
|
continue;
|
|
eie = unode_aux_to_inode_list(node);
|
|
free_inode_elem_list(eie);
|
|
node->aux = 0;
|
|
}
|
|
|
|
ulist_free(blocks);
|
|
}
|
|
|
|
/*
|
|
* Finds all leafs with a reference to the specified combination of bytenr and
|
|
* offset. key_list_head will point to a list of corresponding keys (caller must
|
|
* free each list element). The leafs will be stored in the leafs ulist, which
|
|
* must be freed with ulist_free.
|
|
*
|
|
* returns 0 on success, <0 on error
|
|
*/
|
|
static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
|
|
struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 time_seq, struct ulist **leafs,
|
|
const u64 *extent_item_pos, bool ignore_offset)
|
|
{
|
|
int ret;
|
|
|
|
*leafs = ulist_alloc(GFP_NOFS);
|
|
if (!*leafs)
|
|
return -ENOMEM;
|
|
|
|
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
|
|
*leafs, NULL, extent_item_pos, NULL, ignore_offset);
|
|
if (ret < 0 && ret != -ENOENT) {
|
|
free_leaf_list(*leafs);
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* walk all backrefs for a given extent to find all roots that reference this
|
|
* extent. Walking a backref means finding all extents that reference this
|
|
* extent and in turn walk the backrefs of those, too. Naturally this is a
|
|
* recursive process, but here it is implemented in an iterative fashion: We
|
|
* find all referencing extents for the extent in question and put them on a
|
|
* list. In turn, we find all referencing extents for those, further appending
|
|
* to the list. The way we iterate the list allows adding more elements after
|
|
* the current while iterating. The process stops when we reach the end of the
|
|
* list. Found roots are added to the roots list.
|
|
*
|
|
* returns 0 on success, < 0 on error.
|
|
*/
|
|
static int btrfs_find_all_roots_safe(struct btrfs_trans_handle *trans,
|
|
struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 time_seq, struct ulist **roots,
|
|
bool ignore_offset)
|
|
{
|
|
struct ulist *tmp;
|
|
struct ulist_node *node = NULL;
|
|
struct ulist_iterator uiter;
|
|
int ret;
|
|
|
|
tmp = ulist_alloc(GFP_NOFS);
|
|
if (!tmp)
|
|
return -ENOMEM;
|
|
*roots = ulist_alloc(GFP_NOFS);
|
|
if (!*roots) {
|
|
ulist_free(tmp);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ULIST_ITER_INIT(&uiter);
|
|
while (1) {
|
|
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
|
|
tmp, *roots, NULL, NULL, ignore_offset);
|
|
if (ret < 0 && ret != -ENOENT) {
|
|
ulist_free(tmp);
|
|
ulist_free(*roots);
|
|
return ret;
|
|
}
|
|
node = ulist_next(tmp, &uiter);
|
|
if (!node)
|
|
break;
|
|
bytenr = node->val;
|
|
cond_resched();
|
|
}
|
|
|
|
ulist_free(tmp);
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
|
|
struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 time_seq, struct ulist **roots,
|
|
bool ignore_offset)
|
|
{
|
|
int ret;
|
|
|
|
if (!trans)
|
|
down_read(&fs_info->commit_root_sem);
|
|
ret = btrfs_find_all_roots_safe(trans, fs_info, bytenr,
|
|
time_seq, roots, ignore_offset);
|
|
if (!trans)
|
|
up_read(&fs_info->commit_root_sem);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* btrfs_check_shared - tell us whether an extent is shared
|
|
*
|
|
* btrfs_check_shared uses the backref walking code but will short
|
|
* circuit as soon as it finds a root or inode that doesn't match the
|
|
* one passed in. This provides a significant performance benefit for
|
|
* callers (such as fiemap) which want to know whether the extent is
|
|
* shared but do not need a ref count.
|
|
*
|
|
* This attempts to allocate a transaction in order to account for
|
|
* delayed refs, but continues on even when the alloc fails.
|
|
*
|
|
* Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
|
|
*/
|
|
int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_trans_handle *trans;
|
|
struct ulist *tmp = NULL;
|
|
struct ulist *roots = NULL;
|
|
struct ulist_iterator uiter;
|
|
struct ulist_node *node;
|
|
struct seq_list elem = SEQ_LIST_INIT(elem);
|
|
int ret = 0;
|
|
struct share_check shared = {
|
|
.root_objectid = root->objectid,
|
|
.inum = inum,
|
|
.share_count = 0,
|
|
};
|
|
|
|
tmp = ulist_alloc(GFP_NOFS);
|
|
roots = ulist_alloc(GFP_NOFS);
|
|
if (!tmp || !roots) {
|
|
ulist_free(tmp);
|
|
ulist_free(roots);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
trans = btrfs_join_transaction(root);
|
|
if (IS_ERR(trans)) {
|
|
trans = NULL;
|
|
down_read(&fs_info->commit_root_sem);
|
|
} else {
|
|
btrfs_get_tree_mod_seq(fs_info, &elem);
|
|
}
|
|
|
|
ULIST_ITER_INIT(&uiter);
|
|
while (1) {
|
|
ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
|
|
roots, NULL, &shared, false);
|
|
if (ret == BACKREF_FOUND_SHARED) {
|
|
/* this is the only condition under which we return 1 */
|
|
ret = 1;
|
|
break;
|
|
}
|
|
if (ret < 0 && ret != -ENOENT)
|
|
break;
|
|
ret = 0;
|
|
node = ulist_next(tmp, &uiter);
|
|
if (!node)
|
|
break;
|
|
bytenr = node->val;
|
|
shared.share_count = 0;
|
|
cond_resched();
|
|
}
|
|
|
|
if (trans) {
|
|
btrfs_put_tree_mod_seq(fs_info, &elem);
|
|
btrfs_end_transaction(trans);
|
|
} else {
|
|
up_read(&fs_info->commit_root_sem);
|
|
}
|
|
ulist_free(tmp);
|
|
ulist_free(roots);
|
|
return ret;
|
|
}
|
|
|
|
int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
|
|
u64 start_off, struct btrfs_path *path,
|
|
struct btrfs_inode_extref **ret_extref,
|
|
u64 *found_off)
|
|
{
|
|
int ret, slot;
|
|
struct btrfs_key key;
|
|
struct btrfs_key found_key;
|
|
struct btrfs_inode_extref *extref;
|
|
const struct extent_buffer *leaf;
|
|
unsigned long ptr;
|
|
|
|
key.objectid = inode_objectid;
|
|
key.type = BTRFS_INODE_EXTREF_KEY;
|
|
key.offset = start_off;
|
|
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
while (1) {
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0];
|
|
if (slot >= btrfs_header_nritems(leaf)) {
|
|
/*
|
|
* If the item at offset is not found,
|
|
* btrfs_search_slot will point us to the slot
|
|
* where it should be inserted. In our case
|
|
* that will be the slot directly before the
|
|
* next INODE_REF_KEY_V2 item. In the case
|
|
* that we're pointing to the last slot in a
|
|
* leaf, we must move one leaf over.
|
|
*/
|
|
ret = btrfs_next_leaf(root, path);
|
|
if (ret) {
|
|
if (ret >= 1)
|
|
ret = -ENOENT;
|
|
break;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, slot);
|
|
|
|
/*
|
|
* Check that we're still looking at an extended ref key for
|
|
* this particular objectid. If we have different
|
|
* objectid or type then there are no more to be found
|
|
* in the tree and we can exit.
|
|
*/
|
|
ret = -ENOENT;
|
|
if (found_key.objectid != inode_objectid)
|
|
break;
|
|
if (found_key.type != BTRFS_INODE_EXTREF_KEY)
|
|
break;
|
|
|
|
ret = 0;
|
|
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
|
|
extref = (struct btrfs_inode_extref *)ptr;
|
|
*ret_extref = extref;
|
|
if (found_off)
|
|
*found_off = found_key.offset;
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* this iterates to turn a name (from iref/extref) into a full filesystem path.
|
|
* Elements of the path are separated by '/' and the path is guaranteed to be
|
|
* 0-terminated. the path is only given within the current file system.
|
|
* Therefore, it never starts with a '/'. the caller is responsible to provide
|
|
* "size" bytes in "dest". the dest buffer will be filled backwards. finally,
|
|
* the start point of the resulting string is returned. this pointer is within
|
|
* dest, normally.
|
|
* in case the path buffer would overflow, the pointer is decremented further
|
|
* as if output was written to the buffer, though no more output is actually
|
|
* generated. that way, the caller can determine how much space would be
|
|
* required for the path to fit into the buffer. in that case, the returned
|
|
* value will be smaller than dest. callers must check this!
|
|
*/
|
|
char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
|
|
u32 name_len, unsigned long name_off,
|
|
struct extent_buffer *eb_in, u64 parent,
|
|
char *dest, u32 size)
|
|
{
|
|
int slot;
|
|
u64 next_inum;
|
|
int ret;
|
|
s64 bytes_left = ((s64)size) - 1;
|
|
struct extent_buffer *eb = eb_in;
|
|
struct btrfs_key found_key;
|
|
int leave_spinning = path->leave_spinning;
|
|
struct btrfs_inode_ref *iref;
|
|
|
|
if (bytes_left >= 0)
|
|
dest[bytes_left] = '\0';
|
|
|
|
path->leave_spinning = 1;
|
|
while (1) {
|
|
bytes_left -= name_len;
|
|
if (bytes_left >= 0)
|
|
read_extent_buffer(eb, dest + bytes_left,
|
|
name_off, name_len);
|
|
if (eb != eb_in) {
|
|
if (!path->skip_locking)
|
|
btrfs_tree_read_unlock_blocking(eb);
|
|
free_extent_buffer(eb);
|
|
}
|
|
ret = btrfs_find_item(fs_root, path, parent, 0,
|
|
BTRFS_INODE_REF_KEY, &found_key);
|
|
if (ret > 0)
|
|
ret = -ENOENT;
|
|
if (ret)
|
|
break;
|
|
|
|
next_inum = found_key.offset;
|
|
|
|
/* regular exit ahead */
|
|
if (parent == next_inum)
|
|
break;
|
|
|
|
slot = path->slots[0];
|
|
eb = path->nodes[0];
|
|
/* make sure we can use eb after releasing the path */
|
|
if (eb != eb_in) {
|
|
if (!path->skip_locking)
|
|
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
|
|
path->nodes[0] = NULL;
|
|
path->locks[0] = 0;
|
|
}
|
|
btrfs_release_path(path);
|
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
|
|
|
|
name_len = btrfs_inode_ref_name_len(eb, iref);
|
|
name_off = (unsigned long)(iref + 1);
|
|
|
|
parent = next_inum;
|
|
--bytes_left;
|
|
if (bytes_left >= 0)
|
|
dest[bytes_left] = '/';
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
path->leave_spinning = leave_spinning;
|
|
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
return dest + bytes_left;
|
|
}
|
|
|
|
/*
|
|
* this makes the path point to (logical EXTENT_ITEM *)
|
|
* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
|
|
* tree blocks and <0 on error.
|
|
*/
|
|
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
|
|
struct btrfs_path *path, struct btrfs_key *found_key,
|
|
u64 *flags_ret)
|
|
{
|
|
int ret;
|
|
u64 flags;
|
|
u64 size = 0;
|
|
u32 item_size;
|
|
const struct extent_buffer *eb;
|
|
struct btrfs_extent_item *ei;
|
|
struct btrfs_key key;
|
|
|
|
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
|
|
key.type = BTRFS_METADATA_ITEM_KEY;
|
|
else
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
key.objectid = logical;
|
|
key.offset = (u64)-1;
|
|
|
|
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
|
|
if (ret) {
|
|
if (ret > 0)
|
|
ret = -ENOENT;
|
|
return ret;
|
|
}
|
|
btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
|
|
if (found_key->type == BTRFS_METADATA_ITEM_KEY)
|
|
size = fs_info->nodesize;
|
|
else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
|
|
size = found_key->offset;
|
|
|
|
if (found_key->objectid > logical ||
|
|
found_key->objectid + size <= logical) {
|
|
btrfs_debug(fs_info,
|
|
"logical %llu is not within any extent", logical);
|
|
return -ENOENT;
|
|
}
|
|
|
|
eb = path->nodes[0];
|
|
item_size = btrfs_item_size_nr(eb, path->slots[0]);
|
|
BUG_ON(item_size < sizeof(*ei));
|
|
|
|
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
|
|
flags = btrfs_extent_flags(eb, ei);
|
|
|
|
btrfs_debug(fs_info,
|
|
"logical %llu is at position %llu within the extent (%llu EXTENT_ITEM %llu) flags %#llx size %u",
|
|
logical, logical - found_key->objectid, found_key->objectid,
|
|
found_key->offset, flags, item_size);
|
|
|
|
WARN_ON(!flags_ret);
|
|
if (flags_ret) {
|
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
|
|
*flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
|
|
else if (flags & BTRFS_EXTENT_FLAG_DATA)
|
|
*flags_ret = BTRFS_EXTENT_FLAG_DATA;
|
|
else
|
|
BUG_ON(1);
|
|
return 0;
|
|
}
|
|
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* helper function to iterate extent inline refs. ptr must point to a 0 value
|
|
* for the first call and may be modified. it is used to track state.
|
|
* if more refs exist, 0 is returned and the next call to
|
|
* get_extent_inline_ref must pass the modified ptr parameter to get the
|
|
* next ref. after the last ref was processed, 1 is returned.
|
|
* returns <0 on error
|
|
*/
|
|
static int get_extent_inline_ref(unsigned long *ptr,
|
|
const struct extent_buffer *eb,
|
|
const struct btrfs_key *key,
|
|
const struct btrfs_extent_item *ei,
|
|
u32 item_size,
|
|
struct btrfs_extent_inline_ref **out_eiref,
|
|
int *out_type)
|
|
{
|
|
unsigned long end;
|
|
u64 flags;
|
|
struct btrfs_tree_block_info *info;
|
|
|
|
if (!*ptr) {
|
|
/* first call */
|
|
flags = btrfs_extent_flags(eb, ei);
|
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
|
|
if (key->type == BTRFS_METADATA_ITEM_KEY) {
|
|
/* a skinny metadata extent */
|
|
*out_eiref =
|
|
(struct btrfs_extent_inline_ref *)(ei + 1);
|
|
} else {
|
|
WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
|
|
info = (struct btrfs_tree_block_info *)(ei + 1);
|
|
*out_eiref =
|
|
(struct btrfs_extent_inline_ref *)(info + 1);
|
|
}
|
|
} else {
|
|
*out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
|
|
}
|
|
*ptr = (unsigned long)*out_eiref;
|
|
if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
|
|
return -ENOENT;
|
|
}
|
|
|
|
end = (unsigned long)ei + item_size;
|
|
*out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
|
|
*out_type = btrfs_get_extent_inline_ref_type(eb, *out_eiref,
|
|
BTRFS_REF_TYPE_ANY);
|
|
if (*out_type == BTRFS_REF_TYPE_INVALID)
|
|
return -EUCLEAN;
|
|
|
|
*ptr += btrfs_extent_inline_ref_size(*out_type);
|
|
WARN_ON(*ptr > end);
|
|
if (*ptr == end)
|
|
return 1; /* last */
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* reads the tree block backref for an extent. tree level and root are returned
|
|
* through out_level and out_root. ptr must point to a 0 value for the first
|
|
* call and may be modified (see get_extent_inline_ref comment).
|
|
* returns 0 if data was provided, 1 if there was no more data to provide or
|
|
* <0 on error.
|
|
*/
|
|
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
|
|
struct btrfs_key *key, struct btrfs_extent_item *ei,
|
|
u32 item_size, u64 *out_root, u8 *out_level)
|
|
{
|
|
int ret;
|
|
int type;
|
|
struct btrfs_extent_inline_ref *eiref;
|
|
|
|
if (*ptr == (unsigned long)-1)
|
|
return 1;
|
|
|
|
while (1) {
|
|
ret = get_extent_inline_ref(ptr, eb, key, ei, item_size,
|
|
&eiref, &type);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
|
|
type == BTRFS_SHARED_BLOCK_REF_KEY)
|
|
break;
|
|
|
|
if (ret == 1)
|
|
return 1;
|
|
}
|
|
|
|
/* we can treat both ref types equally here */
|
|
*out_root = btrfs_extent_inline_ref_offset(eb, eiref);
|
|
|
|
if (key->type == BTRFS_EXTENT_ITEM_KEY) {
|
|
struct btrfs_tree_block_info *info;
|
|
|
|
info = (struct btrfs_tree_block_info *)(ei + 1);
|
|
*out_level = btrfs_tree_block_level(eb, info);
|
|
} else {
|
|
ASSERT(key->type == BTRFS_METADATA_ITEM_KEY);
|
|
*out_level = (u8)key->offset;
|
|
}
|
|
|
|
if (ret == 1)
|
|
*ptr = (unsigned long)-1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int iterate_leaf_refs(struct btrfs_fs_info *fs_info,
|
|
struct extent_inode_elem *inode_list,
|
|
u64 root, u64 extent_item_objectid,
|
|
iterate_extent_inodes_t *iterate, void *ctx)
|
|
{
|
|
struct extent_inode_elem *eie;
|
|
int ret = 0;
|
|
|
|
for (eie = inode_list; eie; eie = eie->next) {
|
|
btrfs_debug(fs_info,
|
|
"ref for %llu resolved, key (%llu EXTEND_DATA %llu), root %llu",
|
|
extent_item_objectid, eie->inum,
|
|
eie->offset, root);
|
|
ret = iterate(eie->inum, eie->offset, root, ctx);
|
|
if (ret) {
|
|
btrfs_debug(fs_info,
|
|
"stopping iteration for %llu due to ret=%d",
|
|
extent_item_objectid, ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* calls iterate() for every inode that references the extent identified by
|
|
* the given parameters.
|
|
* when the iterator function returns a non-zero value, iteration stops.
|
|
*/
|
|
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
|
|
u64 extent_item_objectid, u64 extent_item_pos,
|
|
int search_commit_root,
|
|
iterate_extent_inodes_t *iterate, void *ctx,
|
|
bool ignore_offset)
|
|
{
|
|
int ret;
|
|
struct btrfs_trans_handle *trans = NULL;
|
|
struct ulist *refs = NULL;
|
|
struct ulist *roots = NULL;
|
|
struct ulist_node *ref_node = NULL;
|
|
struct ulist_node *root_node = NULL;
|
|
struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
|
|
struct ulist_iterator ref_uiter;
|
|
struct ulist_iterator root_uiter;
|
|
|
|
btrfs_debug(fs_info, "resolving all inodes for extent %llu",
|
|
extent_item_objectid);
|
|
|
|
if (!search_commit_root) {
|
|
trans = btrfs_join_transaction(fs_info->extent_root);
|
|
if (IS_ERR(trans))
|
|
return PTR_ERR(trans);
|
|
btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
|
|
} else {
|
|
down_read(&fs_info->commit_root_sem);
|
|
}
|
|
|
|
ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
|
|
tree_mod_seq_elem.seq, &refs,
|
|
&extent_item_pos, ignore_offset);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ULIST_ITER_INIT(&ref_uiter);
|
|
while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
|
|
ret = btrfs_find_all_roots_safe(trans, fs_info, ref_node->val,
|
|
tree_mod_seq_elem.seq, &roots,
|
|
ignore_offset);
|
|
if (ret)
|
|
break;
|
|
ULIST_ITER_INIT(&root_uiter);
|
|
while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
|
|
btrfs_debug(fs_info,
|
|
"root %llu references leaf %llu, data list %#llx",
|
|
root_node->val, ref_node->val,
|
|
ref_node->aux);
|
|
ret = iterate_leaf_refs(fs_info,
|
|
(struct extent_inode_elem *)
|
|
(uintptr_t)ref_node->aux,
|
|
root_node->val,
|
|
extent_item_objectid,
|
|
iterate, ctx);
|
|
}
|
|
ulist_free(roots);
|
|
}
|
|
|
|
free_leaf_list(refs);
|
|
out:
|
|
if (!search_commit_root) {
|
|
btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
|
|
btrfs_end_transaction(trans);
|
|
} else {
|
|
up_read(&fs_info->commit_root_sem);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
iterate_extent_inodes_t *iterate, void *ctx,
|
|
bool ignore_offset)
|
|
{
|
|
int ret;
|
|
u64 extent_item_pos;
|
|
u64 flags = 0;
|
|
struct btrfs_key found_key;
|
|
int search_commit_root = path->search_commit_root;
|
|
|
|
ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
|
|
btrfs_release_path(path);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
|
|
return -EINVAL;
|
|
|
|
extent_item_pos = logical - found_key.objectid;
|
|
ret = iterate_extent_inodes(fs_info, found_key.objectid,
|
|
extent_item_pos, search_commit_root,
|
|
iterate, ctx, ignore_offset);
|
|
|
|
return ret;
|
|
}
|
|
|
|
typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
|
|
struct extent_buffer *eb, void *ctx);
|
|
|
|
static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path,
|
|
iterate_irefs_t *iterate, void *ctx)
|
|
{
|
|
int ret = 0;
|
|
int slot;
|
|
u32 cur;
|
|
u32 len;
|
|
u32 name_len;
|
|
u64 parent = 0;
|
|
int found = 0;
|
|
struct extent_buffer *eb;
|
|
struct btrfs_item *item;
|
|
struct btrfs_inode_ref *iref;
|
|
struct btrfs_key found_key;
|
|
|
|
while (!ret) {
|
|
ret = btrfs_find_item(fs_root, path, inum,
|
|
parent ? parent + 1 : 0, BTRFS_INODE_REF_KEY,
|
|
&found_key);
|
|
|
|
if (ret < 0)
|
|
break;
|
|
if (ret) {
|
|
ret = found ? 0 : -ENOENT;
|
|
break;
|
|
}
|
|
++found;
|
|
|
|
parent = found_key.offset;
|
|
slot = path->slots[0];
|
|
eb = btrfs_clone_extent_buffer(path->nodes[0]);
|
|
if (!eb) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
extent_buffer_get(eb);
|
|
btrfs_tree_read_lock(eb);
|
|
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
|
|
btrfs_release_path(path);
|
|
|
|
item = btrfs_item_nr(slot);
|
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
|
|
|
|
for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
|
|
name_len = btrfs_inode_ref_name_len(eb, iref);
|
|
/* path must be released before calling iterate()! */
|
|
btrfs_debug(fs_root->fs_info,
|
|
"following ref at offset %u for inode %llu in tree %llu",
|
|
cur, found_key.objectid, fs_root->objectid);
|
|
ret = iterate(parent, name_len,
|
|
(unsigned long)(iref + 1), eb, ctx);
|
|
if (ret)
|
|
break;
|
|
len = sizeof(*iref) + name_len;
|
|
iref = (struct btrfs_inode_ref *)((char *)iref + len);
|
|
}
|
|
btrfs_tree_read_unlock_blocking(eb);
|
|
free_extent_buffer(eb);
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path,
|
|
iterate_irefs_t *iterate, void *ctx)
|
|
{
|
|
int ret;
|
|
int slot;
|
|
u64 offset = 0;
|
|
u64 parent;
|
|
int found = 0;
|
|
struct extent_buffer *eb;
|
|
struct btrfs_inode_extref *extref;
|
|
u32 item_size;
|
|
u32 cur_offset;
|
|
unsigned long ptr;
|
|
|
|
while (1) {
|
|
ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
|
|
&offset);
|
|
if (ret < 0)
|
|
break;
|
|
if (ret) {
|
|
ret = found ? 0 : -ENOENT;
|
|
break;
|
|
}
|
|
++found;
|
|
|
|
slot = path->slots[0];
|
|
eb = btrfs_clone_extent_buffer(path->nodes[0]);
|
|
if (!eb) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
extent_buffer_get(eb);
|
|
|
|
btrfs_tree_read_lock(eb);
|
|
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
|
|
btrfs_release_path(path);
|
|
|
|
item_size = btrfs_item_size_nr(eb, slot);
|
|
ptr = btrfs_item_ptr_offset(eb, slot);
|
|
cur_offset = 0;
|
|
|
|
while (cur_offset < item_size) {
|
|
u32 name_len;
|
|
|
|
extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
|
|
parent = btrfs_inode_extref_parent(eb, extref);
|
|
name_len = btrfs_inode_extref_name_len(eb, extref);
|
|
ret = iterate(parent, name_len,
|
|
(unsigned long)&extref->name, eb, ctx);
|
|
if (ret)
|
|
break;
|
|
|
|
cur_offset += btrfs_inode_extref_name_len(eb, extref);
|
|
cur_offset += sizeof(*extref);
|
|
}
|
|
btrfs_tree_read_unlock_blocking(eb);
|
|
free_extent_buffer(eb);
|
|
|
|
offset++;
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path, iterate_irefs_t *iterate,
|
|
void *ctx)
|
|
{
|
|
int ret;
|
|
int found_refs = 0;
|
|
|
|
ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
|
|
if (!ret)
|
|
++found_refs;
|
|
else if (ret != -ENOENT)
|
|
return ret;
|
|
|
|
ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
|
|
if (ret == -ENOENT && found_refs)
|
|
return 0;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* returns 0 if the path could be dumped (probably truncated)
|
|
* returns <0 in case of an error
|
|
*/
|
|
static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
|
|
struct extent_buffer *eb, void *ctx)
|
|
{
|
|
struct inode_fs_paths *ipath = ctx;
|
|
char *fspath;
|
|
char *fspath_min;
|
|
int i = ipath->fspath->elem_cnt;
|
|
const int s_ptr = sizeof(char *);
|
|
u32 bytes_left;
|
|
|
|
bytes_left = ipath->fspath->bytes_left > s_ptr ?
|
|
ipath->fspath->bytes_left - s_ptr : 0;
|
|
|
|
fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
|
|
fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
|
|
name_off, eb, inum, fspath_min, bytes_left);
|
|
if (IS_ERR(fspath))
|
|
return PTR_ERR(fspath);
|
|
|
|
if (fspath > fspath_min) {
|
|
ipath->fspath->val[i] = (u64)(unsigned long)fspath;
|
|
++ipath->fspath->elem_cnt;
|
|
ipath->fspath->bytes_left = fspath - fspath_min;
|
|
} else {
|
|
++ipath->fspath->elem_missed;
|
|
ipath->fspath->bytes_missing += fspath_min - fspath;
|
|
ipath->fspath->bytes_left = 0;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* this dumps all file system paths to the inode into the ipath struct, provided
|
|
* is has been created large enough. each path is zero-terminated and accessed
|
|
* from ipath->fspath->val[i].
|
|
* when it returns, there are ipath->fspath->elem_cnt number of paths available
|
|
* in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
|
|
* number of missed paths is recorded in ipath->fspath->elem_missed, otherwise,
|
|
* it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
|
|
* have been needed to return all paths.
|
|
*/
|
|
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
|
|
{
|
|
return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
|
|
inode_to_path, ipath);
|
|
}
|
|
|
|
struct btrfs_data_container *init_data_container(u32 total_bytes)
|
|
{
|
|
struct btrfs_data_container *data;
|
|
size_t alloc_bytes;
|
|
|
|
alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
|
|
data = kvmalloc(alloc_bytes, GFP_KERNEL);
|
|
if (!data)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (total_bytes >= sizeof(*data)) {
|
|
data->bytes_left = total_bytes - sizeof(*data);
|
|
data->bytes_missing = 0;
|
|
} else {
|
|
data->bytes_missing = sizeof(*data) - total_bytes;
|
|
data->bytes_left = 0;
|
|
}
|
|
|
|
data->elem_cnt = 0;
|
|
data->elem_missed = 0;
|
|
|
|
return data;
|
|
}
|
|
|
|
/*
|
|
* allocates space to return multiple file system paths for an inode.
|
|
* total_bytes to allocate are passed, note that space usable for actual path
|
|
* information will be total_bytes - sizeof(struct inode_fs_paths).
|
|
* the returned pointer must be freed with free_ipath() in the end.
|
|
*/
|
|
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path)
|
|
{
|
|
struct inode_fs_paths *ifp;
|
|
struct btrfs_data_container *fspath;
|
|
|
|
fspath = init_data_container(total_bytes);
|
|
if (IS_ERR(fspath))
|
|
return ERR_CAST(fspath);
|
|
|
|
ifp = kmalloc(sizeof(*ifp), GFP_KERNEL);
|
|
if (!ifp) {
|
|
kvfree(fspath);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
ifp->btrfs_path = path;
|
|
ifp->fspath = fspath;
|
|
ifp->fs_root = fs_root;
|
|
|
|
return ifp;
|
|
}
|
|
|
|
void free_ipath(struct inode_fs_paths *ipath)
|
|
{
|
|
if (!ipath)
|
|
return;
|
|
kvfree(ipath->fspath);
|
|
kfree(ipath);
|
|
}
|