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e2fd83064a
During fiemap, when checking if a data extent is shared we are doing the backref walking even if we already know the leaf is shared, which is a waste of time since if the leaf shared then the data extent is also shared. So skip the backref walking when we know we are in a shared leaf. The following test was measures the gains for a case where all leaves are shared due to a snapshot: $ cat test.sh #!/bin/bash DEV=/dev/sdj MNT=/mnt/sdj umount $DEV &> /dev/null mkfs.btrfs -f $DEV # Use compression to quickly create files with a lot of extents # (each with a size of 128K). mount -o compress=lzo $DEV $MNT # 40G gives 327680 extents, each with a size of 128K. xfs_io -f -c "pwrite -S 0xab -b 1M 0 40G" $MNT/foobar # Add some more files to increase the size of the fs and extent # trees (in the real world there's a lot of files and extents # from other files). xfs_io -f -c "pwrite -S 0xcd -b 1M 0 20G" $MNT/file1 xfs_io -f -c "pwrite -S 0xef -b 1M 0 20G" $MNT/file2 xfs_io -f -c "pwrite -S 0x73 -b 1M 0 20G" $MNT/file3 # Create a snapshot so all the extents become indirectly shared # through subtrees, with a generation less than or equals to the # generation used to create the snapshot. btrfs subvolume snapshot -r $MNT $MNT/snap1 # Unmount and mount again to clear cached metadata. umount $MNT mount -o compress=lzo $DEV $MNT start=$(date +%s%N) # The filefrag tool uses the fiemap ioctl. filefrag $MNT/foobar end=$(date +%s%N) dur=$(( (end - start) / 1000000 )) echo "fiemap took $dur milliseconds (metadata not cached)" echo start=$(date +%s%N) filefrag $MNT/foobar end=$(date +%s%N) dur=$(( (end - start) / 1000000 )) echo "fiemap took $dur milliseconds (metadata cached)" umount $MNT The results were the following on a non-debug kernel (Debian's default kernel config). Before this patch: (...) /mnt/sdi/foobar: 327680 extents found fiemap took 1821 milliseconds (metadata not cached) /mnt/sdi/foobar: 327680 extents found fiemap took 399 milliseconds (metadata cached) After this patch: (...) /mnt/sdi/foobar: 327680 extents found fiemap took 591 milliseconds (metadata not cached) /mnt/sdi/foobar: 327680 extents found fiemap took 123 milliseconds (metadata cached) That's a speedup of 3.1x and 3.2x. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
3608 lines
98 KiB
C
3608 lines
98 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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#include "misc.h"
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#include "tree-mod-log.h"
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#include "fs.h"
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#include "accessors.h"
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#include "extent-tree.h"
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#include "relocation.h"
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#include "tree-checker.h"
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/* Just arbitrary numbers so we can be sure one of these happened. */
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#define BACKREF_FOUND_SHARED 6
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#define BACKREF_FOUND_NOT_SHARED 7
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struct extent_inode_elem {
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u64 inum;
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u64 offset;
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u64 num_bytes;
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struct extent_inode_elem *next;
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};
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static int check_extent_in_eb(struct btrfs_backref_walk_ctx *ctx,
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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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struct extent_inode_elem **eie)
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{
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const u64 data_len = btrfs_file_extent_num_bytes(eb, fi);
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u64 offset = key->offset;
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struct extent_inode_elem *e;
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const u64 *root_ids;
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int root_count;
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bool cached;
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if (!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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data_offset = btrfs_file_extent_offset(eb, fi);
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if (ctx->extent_item_pos < data_offset ||
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ctx->extent_item_pos >= data_offset + data_len)
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return 1;
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offset += ctx->extent_item_pos - data_offset;
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}
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if (!ctx->indirect_ref_iterator || !ctx->cache_lookup)
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goto add_inode_elem;
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cached = ctx->cache_lookup(eb->start, ctx->user_ctx, &root_ids,
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&root_count);
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if (!cached)
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goto add_inode_elem;
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for (int i = 0; i < root_count; i++) {
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int ret;
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ret = ctx->indirect_ref_iterator(key->objectid, offset,
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data_len, root_ids[i],
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ctx->user_ctx);
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if (ret)
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return ret;
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}
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add_inode_elem:
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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 = offset;
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e->num_bytes = data_len;
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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(struct btrfs_backref_walk_ctx *ctx,
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const struct extent_buffer *eb,
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struct extent_inode_elem **eie)
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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 != ctx->bytenr)
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continue;
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ret = check_extent_in_eb(ctx, &key, eb, fi, eie);
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if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || 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_cached root;
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unsigned int count;
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};
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#define PREFTREE_INIT { .root = RB_ROOT_CACHED, .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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struct btrfs_backref_share_check_ctx *ctx;
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struct btrfs_root *root;
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u64 inum;
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u64 data_bytenr;
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u64 data_extent_gen;
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/*
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* Counts number of inodes that refer to an extent (different inodes in
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* the same root or different roots) that we could find. The sharedness
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* check typically stops once this counter gets greater than 1, so it
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* may not reflect the total number of inodes.
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*/
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int share_count;
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/*
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* The number of times we found our inode refers to the data extent we
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* are determining the sharedness. In other words, how many file extent
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* items we could find for our inode that point to our target data
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* extent. The value we get here after finishing the extent sharedness
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* check may be smaller than reality, but if it ends up being greater
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* than 1, then we know for sure the inode has multiple file extent
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* items that point to our inode, and we can safely assume it's useful
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* to cache the sharedness check result.
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*/
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int self_ref_count;
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bool have_delayed_delete_refs;
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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, struct prelim_ref *newref)
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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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if (newref->root_id == sc->root->root_key.objectid &&
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newref->wanted_disk_byte == sc->data_bytenr &&
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newref->key_for_search.objectid == sc->inum)
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sc->self_ref_count += newref->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_cached *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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bool leftmost = true;
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root = &preftree->root;
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p = &root->rb_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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leftmost = false;
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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, newref);
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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, newref);
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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_cached(&newref->rbnode, root, leftmost);
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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,
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&preftree->root.rb_root, rbnode) {
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free_inode_elem_list(ref->inode_list);
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free_pref(ref);
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}
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preftree->root = RB_ROOT_CACHED;
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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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else
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memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
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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 is_shared_data_backref(struct preftrees *preftrees, u64 bytenr)
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{
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struct rb_node **p = &preftrees->direct.root.rb_root.rb_node;
|
|
struct rb_node *parent = NULL;
|
|
struct prelim_ref *ref = NULL;
|
|
struct prelim_ref target = {};
|
|
int result;
|
|
|
|
target.parent = bytenr;
|
|
|
|
while (*p) {
|
|
parent = *p;
|
|
ref = rb_entry(parent, struct prelim_ref, rbnode);
|
|
result = prelim_ref_compare(ref, &target);
|
|
|
|
if (result < 0)
|
|
p = &(*p)->rb_left;
|
|
else if (result > 0)
|
|
p = &(*p)->rb_right;
|
|
else
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int add_all_parents(struct btrfs_backref_walk_ctx *ctx,
|
|
struct btrfs_root *root, struct btrfs_path *path,
|
|
struct ulist *parents,
|
|
struct preftrees *preftrees, struct prelim_ref *ref,
|
|
int level)
|
|
{
|
|
int ret = 0;
|
|
int slot;
|
|
struct extent_buffer *eb;
|
|
struct btrfs_key key;
|
|
struct btrfs_key *key_for_search = &ref->key_for_search;
|
|
struct btrfs_file_extent_item *fi;
|
|
struct extent_inode_elem *eie = NULL, *old = NULL;
|
|
u64 disk_byte;
|
|
u64 wanted_disk_byte = ref->wanted_disk_byte;
|
|
u64 count = 0;
|
|
u64 data_offset;
|
|
u8 type;
|
|
|
|
if (level != 0) {
|
|
eb = path->nodes[level];
|
|
ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
|
|
if (ret < 0)
|
|
return ret;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 1. We normally enter this function with the path already pointing to
|
|
* the first item to check. But sometimes, we may enter it with
|
|
* slot == nritems.
|
|
* 2. We are searching for normal backref but bytenr of this leaf
|
|
* matches shared data backref
|
|
* 3. The leaf owner is not equal to the root we are searching
|
|
*
|
|
* For these cases, go to the next leaf before we continue.
|
|
*/
|
|
eb = path->nodes[0];
|
|
if (path->slots[0] >= btrfs_header_nritems(eb) ||
|
|
is_shared_data_backref(preftrees, eb->start) ||
|
|
ref->root_id != btrfs_header_owner(eb)) {
|
|
if (ctx->time_seq == BTRFS_SEQ_LAST)
|
|
ret = btrfs_next_leaf(root, path);
|
|
else
|
|
ret = btrfs_next_old_leaf(root, path, ctx->time_seq);
|
|
}
|
|
|
|
while (!ret && count < ref->count) {
|
|
eb = path->nodes[0];
|
|
slot = path->slots[0];
|
|
|
|
btrfs_item_key_to_cpu(eb, &key, slot);
|
|
|
|
if (key.objectid != key_for_search->objectid ||
|
|
key.type != BTRFS_EXTENT_DATA_KEY)
|
|
break;
|
|
|
|
/*
|
|
* We are searching for normal backref but bytenr of this leaf
|
|
* matches shared data backref, OR
|
|
* the leaf owner is not equal to the root we are searching for
|
|
*/
|
|
if (slot == 0 &&
|
|
(is_shared_data_backref(preftrees, eb->start) ||
|
|
ref->root_id != btrfs_header_owner(eb))) {
|
|
if (ctx->time_seq == BTRFS_SEQ_LAST)
|
|
ret = btrfs_next_leaf(root, path);
|
|
else
|
|
ret = btrfs_next_old_leaf(root, path, ctx->time_seq);
|
|
continue;
|
|
}
|
|
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
|
|
type = btrfs_file_extent_type(eb, fi);
|
|
if (type == BTRFS_FILE_EXTENT_INLINE)
|
|
goto next;
|
|
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
|
|
data_offset = btrfs_file_extent_offset(eb, fi);
|
|
|
|
if (disk_byte == wanted_disk_byte) {
|
|
eie = NULL;
|
|
old = NULL;
|
|
if (ref->key_for_search.offset == key.offset - data_offset)
|
|
count++;
|
|
else
|
|
goto next;
|
|
if (!ctx->ignore_extent_item_pos) {
|
|
ret = check_extent_in_eb(ctx, &key, eb, fi, &eie);
|
|
if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP ||
|
|
ret < 0)
|
|
break;
|
|
}
|
|
if (ret > 0)
|
|
goto next;
|
|
ret = ulist_add_merge_ptr(parents, eb->start,
|
|
eie, (void **)&old, GFP_NOFS);
|
|
if (ret < 0)
|
|
break;
|
|
if (!ret && !ctx->ignore_extent_item_pos) {
|
|
while (old->next)
|
|
old = old->next;
|
|
old->next = eie;
|
|
}
|
|
eie = NULL;
|
|
}
|
|
next:
|
|
if (ctx->time_seq == BTRFS_SEQ_LAST)
|
|
ret = btrfs_next_item(root, path);
|
|
else
|
|
ret = btrfs_next_old_item(root, path, ctx->time_seq);
|
|
}
|
|
|
|
if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || ret < 0)
|
|
free_inode_elem_list(eie);
|
|
else if (ret > 0)
|
|
ret = 0;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* resolve an indirect backref in the form (root_id, key, level)
|
|
* to a logical address
|
|
*/
|
|
static int resolve_indirect_ref(struct btrfs_backref_walk_ctx *ctx,
|
|
struct btrfs_path *path,
|
|
struct preftrees *preftrees,
|
|
struct prelim_ref *ref, struct ulist *parents)
|
|
{
|
|
struct btrfs_root *root;
|
|
struct extent_buffer *eb;
|
|
int ret = 0;
|
|
int root_level;
|
|
int level = ref->level;
|
|
struct btrfs_key search_key = ref->key_for_search;
|
|
|
|
/*
|
|
* If we're search_commit_root we could possibly be holding locks on
|
|
* other tree nodes. This happens when qgroups does backref walks when
|
|
* adding new delayed refs. To deal with this we need to look in cache
|
|
* for the root, and if we don't find it then we need to search the
|
|
* tree_root's commit root, thus the btrfs_get_fs_root_commit_root usage
|
|
* here.
|
|
*/
|
|
if (path->search_commit_root)
|
|
root = btrfs_get_fs_root_commit_root(ctx->fs_info, path, ref->root_id);
|
|
else
|
|
root = btrfs_get_fs_root(ctx->fs_info, ref->root_id, false);
|
|
if (IS_ERR(root)) {
|
|
ret = PTR_ERR(root);
|
|
goto out_free;
|
|
}
|
|
|
|
if (!path->search_commit_root &&
|
|
test_bit(BTRFS_ROOT_DELETING, &root->state)) {
|
|
ret = -ENOENT;
|
|
goto out;
|
|
}
|
|
|
|
if (btrfs_is_testing(ctx->fs_info)) {
|
|
ret = -ENOENT;
|
|
goto out;
|
|
}
|
|
|
|
if (path->search_commit_root)
|
|
root_level = btrfs_header_level(root->commit_root);
|
|
else if (ctx->time_seq == BTRFS_SEQ_LAST)
|
|
root_level = btrfs_header_level(root->node);
|
|
else
|
|
root_level = btrfs_old_root_level(root, ctx->time_seq);
|
|
|
|
if (root_level + 1 == level)
|
|
goto out;
|
|
|
|
/*
|
|
* We can often find data backrefs with an offset that is too large
|
|
* (>= LLONG_MAX, maximum allowed file offset) due to underflows when
|
|
* subtracting a file's offset with the data offset of its
|
|
* corresponding extent data item. This can happen for example in the
|
|
* clone ioctl.
|
|
*
|
|
* So if we detect such case we set the search key's offset to zero to
|
|
* make sure we will find the matching file extent item at
|
|
* add_all_parents(), otherwise we will miss it because the offset
|
|
* taken form the backref is much larger then the offset of the file
|
|
* extent item. This can make us scan a very large number of file
|
|
* extent items, but at least it will not make us miss any.
|
|
*
|
|
* This is an ugly workaround for a behaviour that should have never
|
|
* existed, but it does and a fix for the clone ioctl would touch a lot
|
|
* of places, cause backwards incompatibility and would not fix the
|
|
* problem for extents cloned with older kernels.
|
|
*/
|
|
if (search_key.type == BTRFS_EXTENT_DATA_KEY &&
|
|
search_key.offset >= LLONG_MAX)
|
|
search_key.offset = 0;
|
|
path->lowest_level = level;
|
|
if (ctx->time_seq == BTRFS_SEQ_LAST)
|
|
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
|
|
else
|
|
ret = btrfs_search_old_slot(root, &search_key, path, ctx->time_seq);
|
|
|
|
btrfs_debug(ctx->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(ctx, root, path, parents, preftrees, ref, level);
|
|
out:
|
|
btrfs_put_root(root);
|
|
out_free:
|
|
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;
|
|
}
|
|
|
|
static void free_leaf_list(struct ulist *ulist)
|
|
{
|
|
struct ulist_node *node;
|
|
struct ulist_iterator uiter;
|
|
|
|
ULIST_ITER_INIT(&uiter);
|
|
while ((node = ulist_next(ulist, &uiter)))
|
|
free_inode_elem_list(unode_aux_to_inode_list(node));
|
|
|
|
ulist_free(ulist);
|
|
}
|
|
|
|
/*
|
|
* We maintain three separate 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_backref_walk_ctx *ctx,
|
|
struct btrfs_path *path,
|
|
struct preftrees *preftrees,
|
|
struct share_check *sc)
|
|
{
|
|
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_cached(&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_cached(&ref->rbnode, &preftrees->indirect.root);
|
|
preftrees->indirect.count--;
|
|
|
|
if (ref->count == 0) {
|
|
free_pref(ref);
|
|
continue;
|
|
}
|
|
|
|
if (sc && ref->root_id != sc->root->root_key.objectid) {
|
|
free_pref(ref);
|
|
ret = BACKREF_FOUND_SHARED;
|
|
goto out;
|
|
}
|
|
err = resolve_indirect_ref(ctx, path, preftrees, ref, parents);
|
|
/*
|
|
* we can only tolerate ENOENT,otherwise,we should catch error
|
|
* and return directly.
|
|
*/
|
|
if (err == -ENOENT) {
|
|
prelim_ref_insert(ctx->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(ctx->fs_info, &preftrees->direct,
|
|
new_ref, NULL);
|
|
}
|
|
|
|
/*
|
|
* Now it's a direct ref, put it in the direct tree. We must
|
|
* do this last because the ref could be merged/freed here.
|
|
*/
|
|
prelim_ref_insert(ctx->fs_info, &preftrees->direct, ref, NULL);
|
|
|
|
ulist_reinit(parents);
|
|
cond_resched();
|
|
}
|
|
out:
|
|
/*
|
|
* We may have inode lists attached to refs in the parents ulist, so we
|
|
* must free them before freeing the ulist and its refs.
|
|
*/
|
|
free_leaf_list(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, bool lock)
|
|
{
|
|
struct prelim_ref *ref;
|
|
struct extent_buffer *eb;
|
|
struct preftree *tree = &preftrees->indirect_missing_keys;
|
|
struct rb_node *node;
|
|
|
|
while ((node = rb_first_cached(&tree->root))) {
|
|
struct btrfs_tree_parent_check check = { 0 };
|
|
|
|
ref = rb_entry(node, struct prelim_ref, rbnode);
|
|
rb_erase_cached(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);
|
|
|
|
check.level = ref->level - 1;
|
|
check.owner_root = ref->root_id;
|
|
|
|
eb = read_tree_block(fs_info, ref->wanted_disk_byte, &check);
|
|
if (IS_ERR(eb)) {
|
|
free_pref(ref);
|
|
return PTR_ERR(eb);
|
|
}
|
|
if (!extent_buffer_uptodate(eb)) {
|
|
free_pref(ref);
|
|
free_extent_buffer(eb);
|
|
return -EIO;
|
|
}
|
|
|
|
if (lock)
|
|
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);
|
|
if (lock)
|
|
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, struct share_check *sc)
|
|
{
|
|
struct btrfs_delayed_ref_node *node;
|
|
struct btrfs_key key;
|
|
struct rb_node *n;
|
|
int count;
|
|
int ret = 0;
|
|
|
|
spin_lock(&head->lock);
|
|
for (n = rb_first_cached(&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();
|
|
}
|
|
switch (node->type) {
|
|
case BTRFS_TREE_BLOCK_REF_KEY: {
|
|
/* NORMAL INDIRECT METADATA backref */
|
|
struct btrfs_delayed_tree_ref *ref;
|
|
struct btrfs_key *key_ptr = NULL;
|
|
|
|
if (head->extent_op && head->extent_op->update_key) {
|
|
btrfs_disk_key_to_cpu(&key, &head->extent_op->key);
|
|
key_ptr = &key;
|
|
}
|
|
|
|
ref = btrfs_delayed_node_to_tree_ref(node);
|
|
ret = add_indirect_ref(fs_info, preftrees, ref->root,
|
|
key_ptr, 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;
|
|
|
|
/*
|
|
* If we have a share check context and a reference for
|
|
* another inode, we can't exit immediately. This is
|
|
* because even if this is a BTRFS_ADD_DELAYED_REF
|
|
* reference we may find next a BTRFS_DROP_DELAYED_REF
|
|
* which cancels out this ADD reference.
|
|
*
|
|
* If this is a DROP reference and there was no previous
|
|
* ADD reference, then we need to signal that when we
|
|
* process references from the extent tree (through
|
|
* add_inline_refs() and add_keyed_refs()), we should
|
|
* not exit early if we find a reference for another
|
|
* inode, because one of the delayed DROP references
|
|
* may cancel that reference in the extent tree.
|
|
*/
|
|
if (sc && count < 0)
|
|
sc->have_delayed_delete_refs = true;
|
|
|
|
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);
|
|
|
|
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(struct btrfs_backref_walk_ctx *ctx,
|
|
struct btrfs_path *path,
|
|
int *info_level, struct preftrees *preftrees,
|
|
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(leaf, slot);
|
|
BUG_ON(item_size < sizeof(*ei));
|
|
|
|
ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
|
|
|
|
if (ctx->check_extent_item) {
|
|
ret = ctx->check_extent_item(ctx->bytenr, ei, leaf, ctx->user_ctx);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
flags = btrfs_extent_flags(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(ctx->fs_info, preftrees,
|
|
*info_level + 1, offset,
|
|
ctx->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(ctx->fs_info, preftrees, 0, offset,
|
|
ctx->bytenr, count, sc, GFP_NOFS);
|
|
break;
|
|
}
|
|
case BTRFS_TREE_BLOCK_REF_KEY:
|
|
ret = add_indirect_ref(ctx->fs_info, preftrees, offset,
|
|
NULL, *info_level + 1,
|
|
ctx->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 && key.objectid != sc->inum &&
|
|
!sc->have_delayed_delete_refs) {
|
|
ret = BACKREF_FOUND_SHARED;
|
|
break;
|
|
}
|
|
|
|
root = btrfs_extent_data_ref_root(leaf, dref);
|
|
|
|
if (!ctx->skip_data_ref ||
|
|
!ctx->skip_data_ref(root, key.objectid, key.offset,
|
|
ctx->user_ctx))
|
|
ret = add_indirect_ref(ctx->fs_info, preftrees,
|
|
root, &key, 0, ctx->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_backref_walk_ctx *ctx,
|
|
struct btrfs_root *extent_root,
|
|
struct btrfs_path *path,
|
|
int info_level, struct preftrees *preftrees,
|
|
struct share_check *sc)
|
|
{
|
|
struct btrfs_fs_info *fs_info = extent_root->fs_info;
|
|
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 != ctx->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,
|
|
ctx->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, ctx->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, ctx->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 && key.objectid != sc->inum &&
|
|
!sc->have_delayed_delete_refs) {
|
|
ret = BACKREF_FOUND_SHARED;
|
|
break;
|
|
}
|
|
|
|
root = btrfs_extent_data_ref_root(leaf, dref);
|
|
|
|
if (!ctx->skip_data_ref ||
|
|
!ctx->skip_data_ref(root, key.objectid, key.offset,
|
|
ctx->user_ctx))
|
|
ret = add_indirect_ref(fs_info, preftrees, root,
|
|
&key, 0, ctx->bytenr,
|
|
count, sc, GFP_NOFS);
|
|
break;
|
|
}
|
|
default:
|
|
WARN_ON(1);
|
|
}
|
|
if (ret)
|
|
return ret;
|
|
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* The caller has joined a transaction or is holding a read lock on the
|
|
* fs_info->commit_root_sem semaphore, so no need to worry about the root's last
|
|
* snapshot field changing while updating or checking the cache.
|
|
*/
|
|
static bool lookup_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx,
|
|
struct btrfs_root *root,
|
|
u64 bytenr, int level, bool *is_shared)
|
|
{
|
|
const struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_backref_shared_cache_entry *entry;
|
|
|
|
if (!current->journal_info)
|
|
lockdep_assert_held(&fs_info->commit_root_sem);
|
|
|
|
if (!ctx->use_path_cache)
|
|
return false;
|
|
|
|
if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL))
|
|
return false;
|
|
|
|
/*
|
|
* Level -1 is used for the data extent, which is not reliable to cache
|
|
* because its reference count can increase or decrease without us
|
|
* realizing. We cache results only for extent buffers that lead from
|
|
* the root node down to the leaf with the file extent item.
|
|
*/
|
|
ASSERT(level >= 0);
|
|
|
|
entry = &ctx->path_cache_entries[level];
|
|
|
|
/* Unused cache entry or being used for some other extent buffer. */
|
|
if (entry->bytenr != bytenr)
|
|
return false;
|
|
|
|
/*
|
|
* We cached a false result, but the last snapshot generation of the
|
|
* root changed, so we now have a snapshot. Don't trust the result.
|
|
*/
|
|
if (!entry->is_shared &&
|
|
entry->gen != btrfs_root_last_snapshot(&root->root_item))
|
|
return false;
|
|
|
|
/*
|
|
* If we cached a true result and the last generation used for dropping
|
|
* a root changed, we can not trust the result, because the dropped root
|
|
* could be a snapshot sharing this extent buffer.
|
|
*/
|
|
if (entry->is_shared &&
|
|
entry->gen != btrfs_get_last_root_drop_gen(fs_info))
|
|
return false;
|
|
|
|
*is_shared = entry->is_shared;
|
|
/*
|
|
* If the node at this level is shared, than all nodes below are also
|
|
* shared. Currently some of the nodes below may be marked as not shared
|
|
* because we have just switched from one leaf to another, and switched
|
|
* also other nodes above the leaf and below the current level, so mark
|
|
* them as shared.
|
|
*/
|
|
if (*is_shared) {
|
|
for (int i = 0; i < level; i++) {
|
|
ctx->path_cache_entries[i].is_shared = true;
|
|
ctx->path_cache_entries[i].gen = entry->gen;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* The caller has joined a transaction or is holding a read lock on the
|
|
* fs_info->commit_root_sem semaphore, so no need to worry about the root's last
|
|
* snapshot field changing while updating or checking the cache.
|
|
*/
|
|
static void store_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx,
|
|
struct btrfs_root *root,
|
|
u64 bytenr, int level, bool is_shared)
|
|
{
|
|
const struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_backref_shared_cache_entry *entry;
|
|
u64 gen;
|
|
|
|
if (!current->journal_info)
|
|
lockdep_assert_held(&fs_info->commit_root_sem);
|
|
|
|
if (!ctx->use_path_cache)
|
|
return;
|
|
|
|
if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL))
|
|
return;
|
|
|
|
/*
|
|
* Level -1 is used for the data extent, which is not reliable to cache
|
|
* because its reference count can increase or decrease without us
|
|
* realizing. We cache results only for extent buffers that lead from
|
|
* the root node down to the leaf with the file extent item.
|
|
*/
|
|
ASSERT(level >= 0);
|
|
|
|
if (is_shared)
|
|
gen = btrfs_get_last_root_drop_gen(fs_info);
|
|
else
|
|
gen = btrfs_root_last_snapshot(&root->root_item);
|
|
|
|
entry = &ctx->path_cache_entries[level];
|
|
entry->bytenr = bytenr;
|
|
entry->is_shared = is_shared;
|
|
entry->gen = gen;
|
|
|
|
/*
|
|
* If we found an extent buffer is shared, set the cache result for all
|
|
* extent buffers below it to true. As nodes in the path are COWed,
|
|
* their sharedness is moved to their children, and if a leaf is COWed,
|
|
* then the sharedness of a data extent becomes direct, the refcount of
|
|
* data extent is increased in the extent item at the extent tree.
|
|
*/
|
|
if (is_shared) {
|
|
for (int i = 0; i < level; i++) {
|
|
entry = &ctx->path_cache_entries[i];
|
|
entry->is_shared = is_shared;
|
|
entry->gen = gen;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
*
|
|
* @ctx: Backref walking context object, must be not NULL.
|
|
* @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.
|
|
*
|
|
* FIXME some caching might speed things up
|
|
*/
|
|
static int find_parent_nodes(struct btrfs_backref_walk_ctx *ctx,
|
|
struct share_check *sc)
|
|
{
|
|
struct btrfs_root *root = btrfs_extent_root(ctx->fs_info, ctx->bytenr);
|
|
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;
|
|
struct preftrees preftrees = {
|
|
.direct = PREFTREE_INIT,
|
|
.indirect = PREFTREE_INIT,
|
|
.indirect_missing_keys = PREFTREE_INIT
|
|
};
|
|
|
|
/* Roots ulist is not needed when using a sharedness check context. */
|
|
if (sc)
|
|
ASSERT(ctx->roots == NULL);
|
|
|
|
key.objectid = ctx->bytenr;
|
|
key.offset = (u64)-1;
|
|
if (btrfs_fs_incompat(ctx->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 (!ctx->trans) {
|
|
path->search_commit_root = 1;
|
|
path->skip_locking = 1;
|
|
}
|
|
|
|
if (ctx->time_seq == BTRFS_SEQ_LAST)
|
|
path->skip_locking = 1;
|
|
|
|
again:
|
|
head = NULL;
|
|
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
goto out;
|
|
if (ret == 0) {
|
|
/* This shouldn't happen, indicates a bug or fs corruption. */
|
|
ASSERT(ret != 0);
|
|
ret = -EUCLEAN;
|
|
goto out;
|
|
}
|
|
|
|
if (ctx->trans && likely(ctx->trans->type != __TRANS_DUMMY) &&
|
|
ctx->time_seq != BTRFS_SEQ_LAST) {
|
|
/*
|
|
* We have a specific time_seq we care about and trans which
|
|
* means we have the path lock, we need to grab the ref head and
|
|
* lock it so we have a consistent view of the refs at the given
|
|
* time.
|
|
*/
|
|
delayed_refs = &ctx->trans->transaction->delayed_refs;
|
|
spin_lock(&delayed_refs->lock);
|
|
head = btrfs_find_delayed_ref_head(delayed_refs, ctx->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(ctx->fs_info, head, ctx->time_seq,
|
|
&preftrees, 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 == ctx->bytenr &&
|
|
(key.type == BTRFS_EXTENT_ITEM_KEY ||
|
|
key.type == BTRFS_METADATA_ITEM_KEY)) {
|
|
ret = add_inline_refs(ctx, path, &info_level,
|
|
&preftrees, sc);
|
|
if (ret)
|
|
goto out;
|
|
ret = add_keyed_refs(ctx, root, path, info_level,
|
|
&preftrees, sc);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we have a share context and we reached here, it means the extent
|
|
* is not directly shared (no multiple reference items for it),
|
|
* otherwise we would have exited earlier with a return value of
|
|
* BACKREF_FOUND_SHARED after processing delayed references or while
|
|
* processing inline or keyed references from the extent tree.
|
|
* The extent may however be indirectly shared through shared subtrees
|
|
* as a result from creating snapshots, so we determine below what is
|
|
* its parent node, in case we are dealing with a metadata extent, or
|
|
* what's the leaf (or leaves), from a fs tree, that has a file extent
|
|
* item pointing to it in case we are dealing with a data extent.
|
|
*/
|
|
ASSERT(extent_is_shared(sc) == 0);
|
|
|
|
/*
|
|
* If we are here for a data extent and we have a share_check structure
|
|
* it means the data extent is not directly shared (does not have
|
|
* multiple reference items), so we have to check if a path in the fs
|
|
* tree (going from the root node down to the leaf that has the file
|
|
* extent item pointing to the data extent) is shared, that is, if any
|
|
* of the extent buffers in the path is referenced by other trees.
|
|
*/
|
|
if (sc && ctx->bytenr == sc->data_bytenr) {
|
|
/*
|
|
* If our data extent is from a generation more recent than the
|
|
* last generation used to snapshot the root, then we know that
|
|
* it can not be shared through subtrees, so we can skip
|
|
* resolving indirect references, there's no point in
|
|
* determining the extent buffers for the path from the fs tree
|
|
* root node down to the leaf that has the file extent item that
|
|
* points to the data extent.
|
|
*/
|
|
if (sc->data_extent_gen >
|
|
btrfs_root_last_snapshot(&sc->root->root_item)) {
|
|
ret = BACKREF_FOUND_NOT_SHARED;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* If we are only determining if a data extent is shared or not
|
|
* and the corresponding file extent item is located in the same
|
|
* leaf as the previous file extent item, we can skip resolving
|
|
* indirect references for a data extent, since the fs tree path
|
|
* is the same (same leaf, so same path). We skip as long as the
|
|
* cached result for the leaf is valid and only if there's only
|
|
* one file extent item pointing to the data extent, because in
|
|
* the case of multiple file extent items, they may be located
|
|
* in different leaves and therefore we have multiple paths.
|
|
*/
|
|
if (sc->ctx->curr_leaf_bytenr == sc->ctx->prev_leaf_bytenr &&
|
|
sc->self_ref_count == 1) {
|
|
bool cached;
|
|
bool is_shared;
|
|
|
|
cached = lookup_backref_shared_cache(sc->ctx, sc->root,
|
|
sc->ctx->curr_leaf_bytenr,
|
|
0, &is_shared);
|
|
if (cached) {
|
|
if (is_shared)
|
|
ret = BACKREF_FOUND_SHARED;
|
|
else
|
|
ret = BACKREF_FOUND_NOT_SHARED;
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
ret = add_missing_keys(ctx->fs_info, &preftrees, path->skip_locking == 0);
|
|
if (ret)
|
|
goto out;
|
|
|
|
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect_missing_keys.root.rb_root));
|
|
|
|
ret = resolve_indirect_refs(ctx, path, &preftrees, sc);
|
|
if (ret)
|
|
goto out;
|
|
|
|
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect.root.rb_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_cached(&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 (ctx->roots && ref->count && ref->root_id && ref->parent == 0) {
|
|
/* no parent == root of tree */
|
|
ret = ulist_add(ctx->roots, ref->root_id, 0, GFP_NOFS);
|
|
if (ret < 0)
|
|
goto out;
|
|
}
|
|
if (ref->count && ref->parent) {
|
|
if (!ctx->ignore_extent_item_pos && !ref->inode_list &&
|
|
ref->level == 0) {
|
|
struct btrfs_tree_parent_check check = { 0 };
|
|
struct extent_buffer *eb;
|
|
|
|
check.level = ref->level;
|
|
|
|
eb = read_tree_block(ctx->fs_info, ref->parent,
|
|
&check);
|
|
if (IS_ERR(eb)) {
|
|
ret = PTR_ERR(eb);
|
|
goto out;
|
|
}
|
|
if (!extent_buffer_uptodate(eb)) {
|
|
free_extent_buffer(eb);
|
|
ret = -EIO;
|
|
goto out;
|
|
}
|
|
|
|
if (!path->skip_locking)
|
|
btrfs_tree_read_lock(eb);
|
|
ret = find_extent_in_eb(ctx, eb, &eie);
|
|
if (!path->skip_locking)
|
|
btrfs_tree_read_unlock(eb);
|
|
free_extent_buffer(eb);
|
|
if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP ||
|
|
ret < 0)
|
|
goto out;
|
|
ref->inode_list = eie;
|
|
/*
|
|
* We transferred the list ownership to the ref,
|
|
* so set to NULL to avoid a double free in case
|
|
* an error happens after this.
|
|
*/
|
|
eie = NULL;
|
|
}
|
|
ret = ulist_add_merge_ptr(ctx->refs, ref->parent,
|
|
ref->inode_list,
|
|
(void **)&eie, GFP_NOFS);
|
|
if (ret < 0)
|
|
goto out;
|
|
if (!ret && !ctx->ignore_extent_item_pos) {
|
|
/*
|
|
* We've recorded that parent, so we must extend
|
|
* its inode list here.
|
|
*
|
|
* However if there was corruption we may not
|
|
* have found an eie, return an error in this
|
|
* case.
|
|
*/
|
|
ASSERT(eie);
|
|
if (!eie) {
|
|
ret = -EUCLEAN;
|
|
goto out;
|
|
}
|
|
while (eie->next)
|
|
eie = eie->next;
|
|
eie->next = ref->inode_list;
|
|
}
|
|
eie = NULL;
|
|
/*
|
|
* We have transferred the inode list ownership from
|
|
* this ref to the ref we added to the 'refs' ulist.
|
|
* So set this ref's inode list to NULL to avoid
|
|
* use-after-free when our caller uses it or double
|
|
* frees in case an error happens before we return.
|
|
*/
|
|
ref->inode_list = NULL;
|
|
}
|
|
cond_resched();
|
|
}
|
|
|
|
out:
|
|
btrfs_free_path(path);
|
|
|
|
prelim_release(&preftrees.direct);
|
|
prelim_release(&preftrees.indirect);
|
|
prelim_release(&preftrees.indirect_missing_keys);
|
|
|
|
if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || ret < 0)
|
|
free_inode_elem_list(eie);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Finds all leaves with a reference to the specified combination of
|
|
* @ctx->bytenr and @ctx->extent_item_pos. The bytenr of the found leaves are
|
|
* added to the ulist at @ctx->refs, and that ulist is allocated by this
|
|
* function. The caller should free the ulist with free_leaf_list() if
|
|
* @ctx->ignore_extent_item_pos is false, otherwise a fimple ulist_free() is
|
|
* enough.
|
|
*
|
|
* Returns 0 on success and < 0 on error. On error @ctx->refs is not allocated.
|
|
*/
|
|
int btrfs_find_all_leafs(struct btrfs_backref_walk_ctx *ctx)
|
|
{
|
|
int ret;
|
|
|
|
ASSERT(ctx->refs == NULL);
|
|
|
|
ctx->refs = ulist_alloc(GFP_NOFS);
|
|
if (!ctx->refs)
|
|
return -ENOMEM;
|
|
|
|
ret = find_parent_nodes(ctx, NULL);
|
|
if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP ||
|
|
(ret < 0 && ret != -ENOENT)) {
|
|
free_leaf_list(ctx->refs);
|
|
ctx->refs = NULL;
|
|
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 @ctx->roots, which is allocated by this function if
|
|
* it points to NULL, in which case the caller is responsible for freeing it
|
|
* after it's not needed anymore.
|
|
* This function requires @ctx->refs to be NULL, as it uses it for allocating a
|
|
* ulist to do temporary work, and frees it before returning.
|
|
*
|
|
* Returns 0 on success, < 0 on error.
|
|
*/
|
|
static int btrfs_find_all_roots_safe(struct btrfs_backref_walk_ctx *ctx)
|
|
{
|
|
const u64 orig_bytenr = ctx->bytenr;
|
|
const bool orig_ignore_extent_item_pos = ctx->ignore_extent_item_pos;
|
|
bool roots_ulist_allocated = false;
|
|
struct ulist_iterator uiter;
|
|
int ret = 0;
|
|
|
|
ASSERT(ctx->refs == NULL);
|
|
|
|
ctx->refs = ulist_alloc(GFP_NOFS);
|
|
if (!ctx->refs)
|
|
return -ENOMEM;
|
|
|
|
if (!ctx->roots) {
|
|
ctx->roots = ulist_alloc(GFP_NOFS);
|
|
if (!ctx->roots) {
|
|
ulist_free(ctx->refs);
|
|
ctx->refs = NULL;
|
|
return -ENOMEM;
|
|
}
|
|
roots_ulist_allocated = true;
|
|
}
|
|
|
|
ctx->ignore_extent_item_pos = true;
|
|
|
|
ULIST_ITER_INIT(&uiter);
|
|
while (1) {
|
|
struct ulist_node *node;
|
|
|
|
ret = find_parent_nodes(ctx, NULL);
|
|
if (ret < 0 && ret != -ENOENT) {
|
|
if (roots_ulist_allocated) {
|
|
ulist_free(ctx->roots);
|
|
ctx->roots = NULL;
|
|
}
|
|
break;
|
|
}
|
|
ret = 0;
|
|
node = ulist_next(ctx->refs, &uiter);
|
|
if (!node)
|
|
break;
|
|
ctx->bytenr = node->val;
|
|
cond_resched();
|
|
}
|
|
|
|
ulist_free(ctx->refs);
|
|
ctx->refs = NULL;
|
|
ctx->bytenr = orig_bytenr;
|
|
ctx->ignore_extent_item_pos = orig_ignore_extent_item_pos;
|
|
|
|
return ret;
|
|
}
|
|
|
|
int btrfs_find_all_roots(struct btrfs_backref_walk_ctx *ctx,
|
|
bool skip_commit_root_sem)
|
|
{
|
|
int ret;
|
|
|
|
if (!ctx->trans && !skip_commit_root_sem)
|
|
down_read(&ctx->fs_info->commit_root_sem);
|
|
ret = btrfs_find_all_roots_safe(ctx);
|
|
if (!ctx->trans && !skip_commit_root_sem)
|
|
up_read(&ctx->fs_info->commit_root_sem);
|
|
return ret;
|
|
}
|
|
|
|
struct btrfs_backref_share_check_ctx *btrfs_alloc_backref_share_check_ctx(void)
|
|
{
|
|
struct btrfs_backref_share_check_ctx *ctx;
|
|
|
|
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
|
|
if (!ctx)
|
|
return NULL;
|
|
|
|
ulist_init(&ctx->refs);
|
|
|
|
return ctx;
|
|
}
|
|
|
|
void btrfs_free_backref_share_ctx(struct btrfs_backref_share_check_ctx *ctx)
|
|
{
|
|
if (!ctx)
|
|
return;
|
|
|
|
ulist_release(&ctx->refs);
|
|
kfree(ctx);
|
|
}
|
|
|
|
/*
|
|
* Check if a data extent is shared or not.
|
|
*
|
|
* @inode: The inode whose extent we are checking.
|
|
* @bytenr: Logical bytenr of the extent we are checking.
|
|
* @extent_gen: Generation of the extent (file extent item) or 0 if it is
|
|
* not known.
|
|
* @ctx: A backref sharedness check context.
|
|
*
|
|
* btrfs_is_data_extent_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 attach to the running transaction in order to account for
|
|
* delayed refs, but continues on even when no running transaction exists.
|
|
*
|
|
* Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
|
|
*/
|
|
int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
|
|
u64 extent_gen,
|
|
struct btrfs_backref_share_check_ctx *ctx)
|
|
{
|
|
struct btrfs_backref_walk_ctx walk_ctx = { 0 };
|
|
struct btrfs_root *root = inode->root;
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_trans_handle *trans;
|
|
struct ulist_iterator uiter;
|
|
struct ulist_node *node;
|
|
struct btrfs_seq_list elem = BTRFS_SEQ_LIST_INIT(elem);
|
|
int ret = 0;
|
|
struct share_check shared = {
|
|
.ctx = ctx,
|
|
.root = root,
|
|
.inum = btrfs_ino(inode),
|
|
.data_bytenr = bytenr,
|
|
.data_extent_gen = extent_gen,
|
|
.share_count = 0,
|
|
.self_ref_count = 0,
|
|
.have_delayed_delete_refs = false,
|
|
};
|
|
int level;
|
|
bool leaf_cached;
|
|
bool leaf_is_shared;
|
|
|
|
for (int i = 0; i < BTRFS_BACKREF_CTX_PREV_EXTENTS_SIZE; i++) {
|
|
if (ctx->prev_extents_cache[i].bytenr == bytenr)
|
|
return ctx->prev_extents_cache[i].is_shared;
|
|
}
|
|
|
|
ulist_init(&ctx->refs);
|
|
|
|
trans = btrfs_join_transaction_nostart(root);
|
|
if (IS_ERR(trans)) {
|
|
if (PTR_ERR(trans) != -ENOENT && PTR_ERR(trans) != -EROFS) {
|
|
ret = PTR_ERR(trans);
|
|
goto out;
|
|
}
|
|
trans = NULL;
|
|
down_read(&fs_info->commit_root_sem);
|
|
} else {
|
|
btrfs_get_tree_mod_seq(fs_info, &elem);
|
|
walk_ctx.time_seq = elem.seq;
|
|
}
|
|
|
|
ctx->use_path_cache = true;
|
|
|
|
/*
|
|
* We may have previously determined that the current leaf is shared.
|
|
* If it is, then we have a data extent that is shared due to a shared
|
|
* subtree (caused by snapshotting) and we don't need to check for data
|
|
* backrefs. If the leaf is not shared, then we must do backref walking
|
|
* to determine if the data extent is shared through reflinks.
|
|
*/
|
|
leaf_cached = lookup_backref_shared_cache(ctx, root,
|
|
ctx->curr_leaf_bytenr, 0,
|
|
&leaf_is_shared);
|
|
if (leaf_cached && leaf_is_shared) {
|
|
ret = 1;
|
|
goto out_trans;
|
|
}
|
|
|
|
walk_ctx.ignore_extent_item_pos = true;
|
|
walk_ctx.trans = trans;
|
|
walk_ctx.fs_info = fs_info;
|
|
walk_ctx.refs = &ctx->refs;
|
|
|
|
/* -1 means we are in the bytenr of the data extent. */
|
|
level = -1;
|
|
ULIST_ITER_INIT(&uiter);
|
|
while (1) {
|
|
bool is_shared;
|
|
bool cached;
|
|
|
|
walk_ctx.bytenr = bytenr;
|
|
ret = find_parent_nodes(&walk_ctx, &shared);
|
|
if (ret == BACKREF_FOUND_SHARED ||
|
|
ret == BACKREF_FOUND_NOT_SHARED) {
|
|
/* If shared must return 1, otherwise return 0. */
|
|
ret = (ret == BACKREF_FOUND_SHARED) ? 1 : 0;
|
|
if (level >= 0)
|
|
store_backref_shared_cache(ctx, root, bytenr,
|
|
level, ret == 1);
|
|
break;
|
|
}
|
|
if (ret < 0 && ret != -ENOENT)
|
|
break;
|
|
ret = 0;
|
|
|
|
/*
|
|
* If our data extent was not directly shared (without multiple
|
|
* reference items), than it might have a single reference item
|
|
* with a count > 1 for the same offset, which means there are 2
|
|
* (or more) file extent items that point to the data extent -
|
|
* this happens when a file extent item needs to be split and
|
|
* then one item gets moved to another leaf due to a b+tree leaf
|
|
* split when inserting some item. In this case the file extent
|
|
* items may be located in different leaves and therefore some
|
|
* of the leaves may be referenced through shared subtrees while
|
|
* others are not. Since our extent buffer cache only works for
|
|
* a single path (by far the most common case and simpler to
|
|
* deal with), we can not use it if we have multiple leaves
|
|
* (which implies multiple paths).
|
|
*/
|
|
if (level == -1 && ctx->refs.nnodes > 1)
|
|
ctx->use_path_cache = false;
|
|
|
|
if (level >= 0)
|
|
store_backref_shared_cache(ctx, root, bytenr,
|
|
level, false);
|
|
node = ulist_next(&ctx->refs, &uiter);
|
|
if (!node)
|
|
break;
|
|
bytenr = node->val;
|
|
level++;
|
|
cached = lookup_backref_shared_cache(ctx, root, bytenr, level,
|
|
&is_shared);
|
|
if (cached) {
|
|
ret = (is_shared ? 1 : 0);
|
|
break;
|
|
}
|
|
shared.share_count = 0;
|
|
shared.have_delayed_delete_refs = false;
|
|
cond_resched();
|
|
}
|
|
|
|
/*
|
|
* Cache the sharedness result for the data extent if we know our inode
|
|
* has more than 1 file extent item that refers to the data extent.
|
|
*/
|
|
if (ret >= 0 && shared.self_ref_count > 1) {
|
|
int slot = ctx->prev_extents_cache_slot;
|
|
|
|
ctx->prev_extents_cache[slot].bytenr = shared.data_bytenr;
|
|
ctx->prev_extents_cache[slot].is_shared = (ret == 1);
|
|
|
|
slot = (slot + 1) % BTRFS_BACKREF_CTX_PREV_EXTENTS_SIZE;
|
|
ctx->prev_extents_cache_slot = slot;
|
|
}
|
|
|
|
out_trans:
|
|
if (trans) {
|
|
btrfs_put_tree_mod_seq(fs_info, &elem);
|
|
btrfs_end_transaction(trans);
|
|
} else {
|
|
up_read(&fs_info->commit_root_sem);
|
|
}
|
|
out:
|
|
ulist_release(&ctx->refs);
|
|
ctx->prev_leaf_bytenr = ctx->curr_leaf_bytenr;
|
|
|
|
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;
|
|
struct btrfs_inode_ref *iref;
|
|
|
|
if (bytes_left >= 0)
|
|
dest[bytes_left] = '\0';
|
|
|
|
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(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) {
|
|
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);
|
|
|
|
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)
|
|
{
|
|
struct btrfs_root *extent_root = btrfs_extent_root(fs_info, logical);
|
|
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, extent_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ret = btrfs_previous_extent_item(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(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();
|
|
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, eie->num_bytes, 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_backref_walk_ctx *ctx,
|
|
bool search_commit_root,
|
|
iterate_extent_inodes_t *iterate, void *user_ctx)
|
|
{
|
|
int ret;
|
|
struct ulist *refs;
|
|
struct ulist_node *ref_node;
|
|
struct btrfs_seq_list seq_elem = BTRFS_SEQ_LIST_INIT(seq_elem);
|
|
struct ulist_iterator ref_uiter;
|
|
|
|
btrfs_debug(ctx->fs_info, "resolving all inodes for extent %llu",
|
|
ctx->bytenr);
|
|
|
|
ASSERT(ctx->trans == NULL);
|
|
ASSERT(ctx->roots == NULL);
|
|
|
|
if (!search_commit_root) {
|
|
struct btrfs_trans_handle *trans;
|
|
|
|
trans = btrfs_attach_transaction(ctx->fs_info->tree_root);
|
|
if (IS_ERR(trans)) {
|
|
if (PTR_ERR(trans) != -ENOENT &&
|
|
PTR_ERR(trans) != -EROFS)
|
|
return PTR_ERR(trans);
|
|
trans = NULL;
|
|
}
|
|
ctx->trans = trans;
|
|
}
|
|
|
|
if (ctx->trans) {
|
|
btrfs_get_tree_mod_seq(ctx->fs_info, &seq_elem);
|
|
ctx->time_seq = seq_elem.seq;
|
|
} else {
|
|
down_read(&ctx->fs_info->commit_root_sem);
|
|
}
|
|
|
|
ret = btrfs_find_all_leafs(ctx);
|
|
if (ret)
|
|
goto out;
|
|
refs = ctx->refs;
|
|
ctx->refs = NULL;
|
|
|
|
ULIST_ITER_INIT(&ref_uiter);
|
|
while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
|
|
const u64 leaf_bytenr = ref_node->val;
|
|
struct ulist_node *root_node;
|
|
struct ulist_iterator root_uiter;
|
|
struct extent_inode_elem *inode_list;
|
|
|
|
inode_list = (struct extent_inode_elem *)(uintptr_t)ref_node->aux;
|
|
|
|
if (ctx->cache_lookup) {
|
|
const u64 *root_ids;
|
|
int root_count;
|
|
bool cached;
|
|
|
|
cached = ctx->cache_lookup(leaf_bytenr, ctx->user_ctx,
|
|
&root_ids, &root_count);
|
|
if (cached) {
|
|
for (int i = 0; i < root_count; i++) {
|
|
ret = iterate_leaf_refs(ctx->fs_info,
|
|
inode_list,
|
|
root_ids[i],
|
|
leaf_bytenr,
|
|
iterate,
|
|
user_ctx);
|
|
if (ret)
|
|
break;
|
|
}
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (!ctx->roots) {
|
|
ctx->roots = ulist_alloc(GFP_NOFS);
|
|
if (!ctx->roots) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
}
|
|
|
|
ctx->bytenr = leaf_bytenr;
|
|
ret = btrfs_find_all_roots_safe(ctx);
|
|
if (ret)
|
|
break;
|
|
|
|
if (ctx->cache_store)
|
|
ctx->cache_store(leaf_bytenr, ctx->roots, ctx->user_ctx);
|
|
|
|
ULIST_ITER_INIT(&root_uiter);
|
|
while (!ret && (root_node = ulist_next(ctx->roots, &root_uiter))) {
|
|
btrfs_debug(ctx->fs_info,
|
|
"root %llu references leaf %llu, data list %#llx",
|
|
root_node->val, ref_node->val,
|
|
ref_node->aux);
|
|
ret = iterate_leaf_refs(ctx->fs_info, inode_list,
|
|
root_node->val, ctx->bytenr,
|
|
iterate, user_ctx);
|
|
}
|
|
ulist_reinit(ctx->roots);
|
|
}
|
|
|
|
free_leaf_list(refs);
|
|
out:
|
|
if (ctx->trans) {
|
|
btrfs_put_tree_mod_seq(ctx->fs_info, &seq_elem);
|
|
btrfs_end_transaction(ctx->trans);
|
|
ctx->trans = NULL;
|
|
} else {
|
|
up_read(&ctx->fs_info->commit_root_sem);
|
|
}
|
|
|
|
ulist_free(ctx->roots);
|
|
ctx->roots = NULL;
|
|
|
|
if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP)
|
|
ret = 0;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int build_ino_list(u64 inum, u64 offset, u64 num_bytes, u64 root, void *ctx)
|
|
{
|
|
struct btrfs_data_container *inodes = ctx;
|
|
const size_t c = 3 * sizeof(u64);
|
|
|
|
if (inodes->bytes_left >= c) {
|
|
inodes->bytes_left -= c;
|
|
inodes->val[inodes->elem_cnt] = inum;
|
|
inodes->val[inodes->elem_cnt + 1] = offset;
|
|
inodes->val[inodes->elem_cnt + 2] = root;
|
|
inodes->elem_cnt += 3;
|
|
} else {
|
|
inodes->bytes_missing += c - inodes->bytes_left;
|
|
inodes->bytes_left = 0;
|
|
inodes->elem_missed += 3;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
void *ctx, bool ignore_offset)
|
|
{
|
|
struct btrfs_backref_walk_ctx walk_ctx = { 0 };
|
|
int ret;
|
|
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;
|
|
|
|
walk_ctx.bytenr = found_key.objectid;
|
|
if (ignore_offset)
|
|
walk_ctx.ignore_extent_item_pos = true;
|
|
else
|
|
walk_ctx.extent_item_pos = logical - found_key.objectid;
|
|
walk_ctx.fs_info = fs_info;
|
|
|
|
return iterate_extent_inodes(&walk_ctx, search_commit_root,
|
|
build_ino_list, ctx);
|
|
}
|
|
|
|
static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
|
|
struct extent_buffer *eb, struct inode_fs_paths *ipath);
|
|
|
|
static int iterate_inode_refs(u64 inum, struct inode_fs_paths *ipath)
|
|
{
|
|
int ret = 0;
|
|
int slot;
|
|
u32 cur;
|
|
u32 len;
|
|
u32 name_len;
|
|
u64 parent = 0;
|
|
int found = 0;
|
|
struct btrfs_root *fs_root = ipath->fs_root;
|
|
struct btrfs_path *path = ipath->btrfs_path;
|
|
struct extent_buffer *eb;
|
|
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;
|
|
}
|
|
btrfs_release_path(path);
|
|
|
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
|
|
|
|
for (cur = 0; cur < btrfs_item_size(eb, slot); 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->root_key.objectid);
|
|
ret = inode_to_path(parent, name_len,
|
|
(unsigned long)(iref + 1), eb, ipath);
|
|
if (ret)
|
|
break;
|
|
len = sizeof(*iref) + name_len;
|
|
iref = (struct btrfs_inode_ref *)((char *)iref + len);
|
|
}
|
|
free_extent_buffer(eb);
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int iterate_inode_extrefs(u64 inum, struct inode_fs_paths *ipath)
|
|
{
|
|
int ret;
|
|
int slot;
|
|
u64 offset = 0;
|
|
u64 parent;
|
|
int found = 0;
|
|
struct btrfs_root *fs_root = ipath->fs_root;
|
|
struct btrfs_path *path = ipath->btrfs_path;
|
|
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;
|
|
}
|
|
btrfs_release_path(path);
|
|
|
|
item_size = btrfs_item_size(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 = inode_to_path(parent, name_len,
|
|
(unsigned long)&extref->name, eb, ipath);
|
|
if (ret)
|
|
break;
|
|
|
|
cur_offset += btrfs_inode_extref_name_len(eb, extref);
|
|
cur_offset += sizeof(*extref);
|
|
}
|
|
free_extent_buffer(eb);
|
|
|
|
offset++;
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
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, struct inode_fs_paths *ipath)
|
|
{
|
|
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)
|
|
{
|
|
int ret;
|
|
int found_refs = 0;
|
|
|
|
ret = iterate_inode_refs(inum, ipath);
|
|
if (!ret)
|
|
++found_refs;
|
|
else if (ret != -ENOENT)
|
|
return ret;
|
|
|
|
ret = iterate_inode_extrefs(inum, ipath);
|
|
if (ret == -ENOENT && found_refs)
|
|
return 0;
|
|
|
|
return ret;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
struct btrfs_backref_iter *btrfs_backref_iter_alloc(struct btrfs_fs_info *fs_info)
|
|
{
|
|
struct btrfs_backref_iter *ret;
|
|
|
|
ret = kzalloc(sizeof(*ret), GFP_NOFS);
|
|
if (!ret)
|
|
return NULL;
|
|
|
|
ret->path = btrfs_alloc_path();
|
|
if (!ret->path) {
|
|
kfree(ret);
|
|
return NULL;
|
|
}
|
|
|
|
/* Current backref iterator only supports iteration in commit root */
|
|
ret->path->search_commit_root = 1;
|
|
ret->path->skip_locking = 1;
|
|
ret->fs_info = fs_info;
|
|
|
|
return ret;
|
|
}
|
|
|
|
int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr)
|
|
{
|
|
struct btrfs_fs_info *fs_info = iter->fs_info;
|
|
struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bytenr);
|
|
struct btrfs_path *path = iter->path;
|
|
struct btrfs_extent_item *ei;
|
|
struct btrfs_key key;
|
|
int ret;
|
|
|
|
key.objectid = bytenr;
|
|
key.type = BTRFS_METADATA_ITEM_KEY;
|
|
key.offset = (u64)-1;
|
|
iter->bytenr = bytenr;
|
|
|
|
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret == 0) {
|
|
ret = -EUCLEAN;
|
|
goto release;
|
|
}
|
|
if (path->slots[0] == 0) {
|
|
WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
|
|
ret = -EUCLEAN;
|
|
goto release;
|
|
}
|
|
path->slots[0]--;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
|
|
if ((key.type != BTRFS_EXTENT_ITEM_KEY &&
|
|
key.type != BTRFS_METADATA_ITEM_KEY) || key.objectid != bytenr) {
|
|
ret = -ENOENT;
|
|
goto release;
|
|
}
|
|
memcpy(&iter->cur_key, &key, sizeof(key));
|
|
iter->item_ptr = (u32)btrfs_item_ptr_offset(path->nodes[0],
|
|
path->slots[0]);
|
|
iter->end_ptr = (u32)(iter->item_ptr +
|
|
btrfs_item_size(path->nodes[0], path->slots[0]));
|
|
ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
|
|
struct btrfs_extent_item);
|
|
|
|
/*
|
|
* Only support iteration on tree backref yet.
|
|
*
|
|
* This is an extra precaution for non skinny-metadata, where
|
|
* EXTENT_ITEM is also used for tree blocks, that we can only use
|
|
* extent flags to determine if it's a tree block.
|
|
*/
|
|
if (btrfs_extent_flags(path->nodes[0], ei) & BTRFS_EXTENT_FLAG_DATA) {
|
|
ret = -ENOTSUPP;
|
|
goto release;
|
|
}
|
|
iter->cur_ptr = (u32)(iter->item_ptr + sizeof(*ei));
|
|
|
|
/* If there is no inline backref, go search for keyed backref */
|
|
if (iter->cur_ptr >= iter->end_ptr) {
|
|
ret = btrfs_next_item(extent_root, path);
|
|
|
|
/* No inline nor keyed ref */
|
|
if (ret > 0) {
|
|
ret = -ENOENT;
|
|
goto release;
|
|
}
|
|
if (ret < 0)
|
|
goto release;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &iter->cur_key,
|
|
path->slots[0]);
|
|
if (iter->cur_key.objectid != bytenr ||
|
|
(iter->cur_key.type != BTRFS_SHARED_BLOCK_REF_KEY &&
|
|
iter->cur_key.type != BTRFS_TREE_BLOCK_REF_KEY)) {
|
|
ret = -ENOENT;
|
|
goto release;
|
|
}
|
|
iter->cur_ptr = (u32)btrfs_item_ptr_offset(path->nodes[0],
|
|
path->slots[0]);
|
|
iter->item_ptr = iter->cur_ptr;
|
|
iter->end_ptr = (u32)(iter->item_ptr + btrfs_item_size(
|
|
path->nodes[0], path->slots[0]));
|
|
}
|
|
|
|
return 0;
|
|
release:
|
|
btrfs_backref_iter_release(iter);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Go to the next backref item of current bytenr, can be either inlined or
|
|
* keyed.
|
|
*
|
|
* Caller needs to check whether it's inline ref or not by iter->cur_key.
|
|
*
|
|
* Return 0 if we get next backref without problem.
|
|
* Return >0 if there is no extra backref for this bytenr.
|
|
* Return <0 if there is something wrong happened.
|
|
*/
|
|
int btrfs_backref_iter_next(struct btrfs_backref_iter *iter)
|
|
{
|
|
struct extent_buffer *eb = btrfs_backref_get_eb(iter);
|
|
struct btrfs_root *extent_root;
|
|
struct btrfs_path *path = iter->path;
|
|
struct btrfs_extent_inline_ref *iref;
|
|
int ret;
|
|
u32 size;
|
|
|
|
if (btrfs_backref_iter_is_inline_ref(iter)) {
|
|
/* We're still inside the inline refs */
|
|
ASSERT(iter->cur_ptr < iter->end_ptr);
|
|
|
|
if (btrfs_backref_has_tree_block_info(iter)) {
|
|
/* First tree block info */
|
|
size = sizeof(struct btrfs_tree_block_info);
|
|
} else {
|
|
/* Use inline ref type to determine the size */
|
|
int type;
|
|
|
|
iref = (struct btrfs_extent_inline_ref *)
|
|
((unsigned long)iter->cur_ptr);
|
|
type = btrfs_extent_inline_ref_type(eb, iref);
|
|
|
|
size = btrfs_extent_inline_ref_size(type);
|
|
}
|
|
iter->cur_ptr += size;
|
|
if (iter->cur_ptr < iter->end_ptr)
|
|
return 0;
|
|
|
|
/* All inline items iterated, fall through */
|
|
}
|
|
|
|
/* We're at keyed items, there is no inline item, go to the next one */
|
|
extent_root = btrfs_extent_root(iter->fs_info, iter->bytenr);
|
|
ret = btrfs_next_item(extent_root, iter->path);
|
|
if (ret)
|
|
return ret;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &iter->cur_key, path->slots[0]);
|
|
if (iter->cur_key.objectid != iter->bytenr ||
|
|
(iter->cur_key.type != BTRFS_TREE_BLOCK_REF_KEY &&
|
|
iter->cur_key.type != BTRFS_SHARED_BLOCK_REF_KEY))
|
|
return 1;
|
|
iter->item_ptr = (u32)btrfs_item_ptr_offset(path->nodes[0],
|
|
path->slots[0]);
|
|
iter->cur_ptr = iter->item_ptr;
|
|
iter->end_ptr = iter->item_ptr + (u32)btrfs_item_size(path->nodes[0],
|
|
path->slots[0]);
|
|
return 0;
|
|
}
|
|
|
|
void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_backref_cache *cache, int is_reloc)
|
|
{
|
|
int i;
|
|
|
|
cache->rb_root = RB_ROOT;
|
|
for (i = 0; i < BTRFS_MAX_LEVEL; i++)
|
|
INIT_LIST_HEAD(&cache->pending[i]);
|
|
INIT_LIST_HEAD(&cache->changed);
|
|
INIT_LIST_HEAD(&cache->detached);
|
|
INIT_LIST_HEAD(&cache->leaves);
|
|
INIT_LIST_HEAD(&cache->pending_edge);
|
|
INIT_LIST_HEAD(&cache->useless_node);
|
|
cache->fs_info = fs_info;
|
|
cache->is_reloc = is_reloc;
|
|
}
|
|
|
|
struct btrfs_backref_node *btrfs_backref_alloc_node(
|
|
struct btrfs_backref_cache *cache, u64 bytenr, int level)
|
|
{
|
|
struct btrfs_backref_node *node;
|
|
|
|
ASSERT(level >= 0 && level < BTRFS_MAX_LEVEL);
|
|
node = kzalloc(sizeof(*node), GFP_NOFS);
|
|
if (!node)
|
|
return node;
|
|
|
|
INIT_LIST_HEAD(&node->list);
|
|
INIT_LIST_HEAD(&node->upper);
|
|
INIT_LIST_HEAD(&node->lower);
|
|
RB_CLEAR_NODE(&node->rb_node);
|
|
cache->nr_nodes++;
|
|
node->level = level;
|
|
node->bytenr = bytenr;
|
|
|
|
return node;
|
|
}
|
|
|
|
struct btrfs_backref_edge *btrfs_backref_alloc_edge(
|
|
struct btrfs_backref_cache *cache)
|
|
{
|
|
struct btrfs_backref_edge *edge;
|
|
|
|
edge = kzalloc(sizeof(*edge), GFP_NOFS);
|
|
if (edge)
|
|
cache->nr_edges++;
|
|
return edge;
|
|
}
|
|
|
|
/*
|
|
* Drop the backref node from cache, also cleaning up all its
|
|
* upper edges and any uncached nodes in the path.
|
|
*
|
|
* This cleanup happens bottom up, thus the node should either
|
|
* be the lowest node in the cache or a detached node.
|
|
*/
|
|
void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
|
|
struct btrfs_backref_node *node)
|
|
{
|
|
struct btrfs_backref_node *upper;
|
|
struct btrfs_backref_edge *edge;
|
|
|
|
if (!node)
|
|
return;
|
|
|
|
BUG_ON(!node->lowest && !node->detached);
|
|
while (!list_empty(&node->upper)) {
|
|
edge = list_entry(node->upper.next, struct btrfs_backref_edge,
|
|
list[LOWER]);
|
|
upper = edge->node[UPPER];
|
|
list_del(&edge->list[LOWER]);
|
|
list_del(&edge->list[UPPER]);
|
|
btrfs_backref_free_edge(cache, edge);
|
|
|
|
/*
|
|
* Add the node to leaf node list if no other child block
|
|
* cached.
|
|
*/
|
|
if (list_empty(&upper->lower)) {
|
|
list_add_tail(&upper->lower, &cache->leaves);
|
|
upper->lowest = 1;
|
|
}
|
|
}
|
|
|
|
btrfs_backref_drop_node(cache, node);
|
|
}
|
|
|
|
/*
|
|
* Release all nodes/edges from current cache
|
|
*/
|
|
void btrfs_backref_release_cache(struct btrfs_backref_cache *cache)
|
|
{
|
|
struct btrfs_backref_node *node;
|
|
int i;
|
|
|
|
while (!list_empty(&cache->detached)) {
|
|
node = list_entry(cache->detached.next,
|
|
struct btrfs_backref_node, list);
|
|
btrfs_backref_cleanup_node(cache, node);
|
|
}
|
|
|
|
while (!list_empty(&cache->leaves)) {
|
|
node = list_entry(cache->leaves.next,
|
|
struct btrfs_backref_node, lower);
|
|
btrfs_backref_cleanup_node(cache, node);
|
|
}
|
|
|
|
cache->last_trans = 0;
|
|
|
|
for (i = 0; i < BTRFS_MAX_LEVEL; i++)
|
|
ASSERT(list_empty(&cache->pending[i]));
|
|
ASSERT(list_empty(&cache->pending_edge));
|
|
ASSERT(list_empty(&cache->useless_node));
|
|
ASSERT(list_empty(&cache->changed));
|
|
ASSERT(list_empty(&cache->detached));
|
|
ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
|
|
ASSERT(!cache->nr_nodes);
|
|
ASSERT(!cache->nr_edges);
|
|
}
|
|
|
|
/*
|
|
* Handle direct tree backref
|
|
*
|
|
* Direct tree backref means, the backref item shows its parent bytenr
|
|
* directly. This is for SHARED_BLOCK_REF backref (keyed or inlined).
|
|
*
|
|
* @ref_key: The converted backref key.
|
|
* For keyed backref, it's the item key.
|
|
* For inlined backref, objectid is the bytenr,
|
|
* type is btrfs_inline_ref_type, offset is
|
|
* btrfs_inline_ref_offset.
|
|
*/
|
|
static int handle_direct_tree_backref(struct btrfs_backref_cache *cache,
|
|
struct btrfs_key *ref_key,
|
|
struct btrfs_backref_node *cur)
|
|
{
|
|
struct btrfs_backref_edge *edge;
|
|
struct btrfs_backref_node *upper;
|
|
struct rb_node *rb_node;
|
|
|
|
ASSERT(ref_key->type == BTRFS_SHARED_BLOCK_REF_KEY);
|
|
|
|
/* Only reloc root uses backref pointing to itself */
|
|
if (ref_key->objectid == ref_key->offset) {
|
|
struct btrfs_root *root;
|
|
|
|
cur->is_reloc_root = 1;
|
|
/* Only reloc backref cache cares about a specific root */
|
|
if (cache->is_reloc) {
|
|
root = find_reloc_root(cache->fs_info, cur->bytenr);
|
|
if (!root)
|
|
return -ENOENT;
|
|
cur->root = root;
|
|
} else {
|
|
/*
|
|
* For generic purpose backref cache, reloc root node
|
|
* is useless.
|
|
*/
|
|
list_add(&cur->list, &cache->useless_node);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
edge = btrfs_backref_alloc_edge(cache);
|
|
if (!edge)
|
|
return -ENOMEM;
|
|
|
|
rb_node = rb_simple_search(&cache->rb_root, ref_key->offset);
|
|
if (!rb_node) {
|
|
/* Parent node not yet cached */
|
|
upper = btrfs_backref_alloc_node(cache, ref_key->offset,
|
|
cur->level + 1);
|
|
if (!upper) {
|
|
btrfs_backref_free_edge(cache, edge);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Backrefs for the upper level block isn't cached, add the
|
|
* block to pending list
|
|
*/
|
|
list_add_tail(&edge->list[UPPER], &cache->pending_edge);
|
|
} else {
|
|
/* Parent node already cached */
|
|
upper = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
|
|
ASSERT(upper->checked);
|
|
INIT_LIST_HEAD(&edge->list[UPPER]);
|
|
}
|
|
btrfs_backref_link_edge(edge, cur, upper, LINK_LOWER);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Handle indirect tree backref
|
|
*
|
|
* Indirect tree backref means, we only know which tree the node belongs to.
|
|
* We still need to do a tree search to find out the parents. This is for
|
|
* TREE_BLOCK_REF backref (keyed or inlined).
|
|
*
|
|
* @ref_key: The same as @ref_key in handle_direct_tree_backref()
|
|
* @tree_key: The first key of this tree block.
|
|
* @path: A clean (released) path, to avoid allocating path every time
|
|
* the function get called.
|
|
*/
|
|
static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
|
|
struct btrfs_path *path,
|
|
struct btrfs_key *ref_key,
|
|
struct btrfs_key *tree_key,
|
|
struct btrfs_backref_node *cur)
|
|
{
|
|
struct btrfs_fs_info *fs_info = cache->fs_info;
|
|
struct btrfs_backref_node *upper;
|
|
struct btrfs_backref_node *lower;
|
|
struct btrfs_backref_edge *edge;
|
|
struct extent_buffer *eb;
|
|
struct btrfs_root *root;
|
|
struct rb_node *rb_node;
|
|
int level;
|
|
bool need_check = true;
|
|
int ret;
|
|
|
|
root = btrfs_get_fs_root(fs_info, ref_key->offset, false);
|
|
if (IS_ERR(root))
|
|
return PTR_ERR(root);
|
|
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
|
|
cur->cowonly = 1;
|
|
|
|
if (btrfs_root_level(&root->root_item) == cur->level) {
|
|
/* Tree root */
|
|
ASSERT(btrfs_root_bytenr(&root->root_item) == cur->bytenr);
|
|
/*
|
|
* For reloc backref cache, we may ignore reloc root. But for
|
|
* general purpose backref cache, we can't rely on
|
|
* btrfs_should_ignore_reloc_root() as it may conflict with
|
|
* current running relocation and lead to missing root.
|
|
*
|
|
* For general purpose backref cache, reloc root detection is
|
|
* completely relying on direct backref (key->offset is parent
|
|
* bytenr), thus only do such check for reloc cache.
|
|
*/
|
|
if (btrfs_should_ignore_reloc_root(root) && cache->is_reloc) {
|
|
btrfs_put_root(root);
|
|
list_add(&cur->list, &cache->useless_node);
|
|
} else {
|
|
cur->root = root;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
level = cur->level + 1;
|
|
|
|
/* Search the tree to find parent blocks referring to the block */
|
|
path->search_commit_root = 1;
|
|
path->skip_locking = 1;
|
|
path->lowest_level = level;
|
|
ret = btrfs_search_slot(NULL, root, tree_key, path, 0, 0);
|
|
path->lowest_level = 0;
|
|
if (ret < 0) {
|
|
btrfs_put_root(root);
|
|
return ret;
|
|
}
|
|
if (ret > 0 && path->slots[level] > 0)
|
|
path->slots[level]--;
|
|
|
|
eb = path->nodes[level];
|
|
if (btrfs_node_blockptr(eb, path->slots[level]) != cur->bytenr) {
|
|
btrfs_err(fs_info,
|
|
"couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
|
|
cur->bytenr, level - 1, root->root_key.objectid,
|
|
tree_key->objectid, tree_key->type, tree_key->offset);
|
|
btrfs_put_root(root);
|
|
ret = -ENOENT;
|
|
goto out;
|
|
}
|
|
lower = cur;
|
|
|
|
/* Add all nodes and edges in the path */
|
|
for (; level < BTRFS_MAX_LEVEL; level++) {
|
|
if (!path->nodes[level]) {
|
|
ASSERT(btrfs_root_bytenr(&root->root_item) ==
|
|
lower->bytenr);
|
|
/* Same as previous should_ignore_reloc_root() call */
|
|
if (btrfs_should_ignore_reloc_root(root) &&
|
|
cache->is_reloc) {
|
|
btrfs_put_root(root);
|
|
list_add(&lower->list, &cache->useless_node);
|
|
} else {
|
|
lower->root = root;
|
|
}
|
|
break;
|
|
}
|
|
|
|
edge = btrfs_backref_alloc_edge(cache);
|
|
if (!edge) {
|
|
btrfs_put_root(root);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
eb = path->nodes[level];
|
|
rb_node = rb_simple_search(&cache->rb_root, eb->start);
|
|
if (!rb_node) {
|
|
upper = btrfs_backref_alloc_node(cache, eb->start,
|
|
lower->level + 1);
|
|
if (!upper) {
|
|
btrfs_put_root(root);
|
|
btrfs_backref_free_edge(cache, edge);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
upper->owner = btrfs_header_owner(eb);
|
|
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
|
|
upper->cowonly = 1;
|
|
|
|
/*
|
|
* If we know the block isn't shared we can avoid
|
|
* checking its backrefs.
|
|
*/
|
|
if (btrfs_block_can_be_shared(root, eb))
|
|
upper->checked = 0;
|
|
else
|
|
upper->checked = 1;
|
|
|
|
/*
|
|
* Add the block to pending list if we need to check its
|
|
* backrefs, we only do this once while walking up a
|
|
* tree as we will catch anything else later on.
|
|
*/
|
|
if (!upper->checked && need_check) {
|
|
need_check = false;
|
|
list_add_tail(&edge->list[UPPER],
|
|
&cache->pending_edge);
|
|
} else {
|
|
if (upper->checked)
|
|
need_check = true;
|
|
INIT_LIST_HEAD(&edge->list[UPPER]);
|
|
}
|
|
} else {
|
|
upper = rb_entry(rb_node, struct btrfs_backref_node,
|
|
rb_node);
|
|
ASSERT(upper->checked);
|
|
INIT_LIST_HEAD(&edge->list[UPPER]);
|
|
if (!upper->owner)
|
|
upper->owner = btrfs_header_owner(eb);
|
|
}
|
|
btrfs_backref_link_edge(edge, lower, upper, LINK_LOWER);
|
|
|
|
if (rb_node) {
|
|
btrfs_put_root(root);
|
|
break;
|
|
}
|
|
lower = upper;
|
|
upper = NULL;
|
|
}
|
|
out:
|
|
btrfs_release_path(path);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Add backref node @cur into @cache.
|
|
*
|
|
* NOTE: Even if the function returned 0, @cur is not yet cached as its upper
|
|
* links aren't yet bi-directional. Needs to finish such links.
|
|
* Use btrfs_backref_finish_upper_links() to finish such linkage.
|
|
*
|
|
* @path: Released path for indirect tree backref lookup
|
|
* @iter: Released backref iter for extent tree search
|
|
* @node_key: The first key of the tree block
|
|
*/
|
|
int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
|
|
struct btrfs_path *path,
|
|
struct btrfs_backref_iter *iter,
|
|
struct btrfs_key *node_key,
|
|
struct btrfs_backref_node *cur)
|
|
{
|
|
struct btrfs_fs_info *fs_info = cache->fs_info;
|
|
struct btrfs_backref_edge *edge;
|
|
struct btrfs_backref_node *exist;
|
|
int ret;
|
|
|
|
ret = btrfs_backref_iter_start(iter, cur->bytenr);
|
|
if (ret < 0)
|
|
return ret;
|
|
/*
|
|
* We skip the first btrfs_tree_block_info, as we don't use the key
|
|
* stored in it, but fetch it from the tree block
|
|
*/
|
|
if (btrfs_backref_has_tree_block_info(iter)) {
|
|
ret = btrfs_backref_iter_next(iter);
|
|
if (ret < 0)
|
|
goto out;
|
|
/* No extra backref? This means the tree block is corrupted */
|
|
if (ret > 0) {
|
|
ret = -EUCLEAN;
|
|
goto out;
|
|
}
|
|
}
|
|
WARN_ON(cur->checked);
|
|
if (!list_empty(&cur->upper)) {
|
|
/*
|
|
* The backref was added previously when processing backref of
|
|
* type BTRFS_TREE_BLOCK_REF_KEY
|
|
*/
|
|
ASSERT(list_is_singular(&cur->upper));
|
|
edge = list_entry(cur->upper.next, struct btrfs_backref_edge,
|
|
list[LOWER]);
|
|
ASSERT(list_empty(&edge->list[UPPER]));
|
|
exist = edge->node[UPPER];
|
|
/*
|
|
* Add the upper level block to pending list if we need check
|
|
* its backrefs
|
|
*/
|
|
if (!exist->checked)
|
|
list_add_tail(&edge->list[UPPER], &cache->pending_edge);
|
|
} else {
|
|
exist = NULL;
|
|
}
|
|
|
|
for (; ret == 0; ret = btrfs_backref_iter_next(iter)) {
|
|
struct extent_buffer *eb;
|
|
struct btrfs_key key;
|
|
int type;
|
|
|
|
cond_resched();
|
|
eb = btrfs_backref_get_eb(iter);
|
|
|
|
key.objectid = iter->bytenr;
|
|
if (btrfs_backref_iter_is_inline_ref(iter)) {
|
|
struct btrfs_extent_inline_ref *iref;
|
|
|
|
/* Update key for inline backref */
|
|
iref = (struct btrfs_extent_inline_ref *)
|
|
((unsigned long)iter->cur_ptr);
|
|
type = btrfs_get_extent_inline_ref_type(eb, iref,
|
|
BTRFS_REF_TYPE_BLOCK);
|
|
if (type == BTRFS_REF_TYPE_INVALID) {
|
|
ret = -EUCLEAN;
|
|
goto out;
|
|
}
|
|
key.type = type;
|
|
key.offset = btrfs_extent_inline_ref_offset(eb, iref);
|
|
} else {
|
|
key.type = iter->cur_key.type;
|
|
key.offset = iter->cur_key.offset;
|
|
}
|
|
|
|
/*
|
|
* Parent node found and matches current inline ref, no need to
|
|
* rebuild this node for this inline ref
|
|
*/
|
|
if (exist &&
|
|
((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
|
|
exist->owner == key.offset) ||
|
|
(key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
|
|
exist->bytenr == key.offset))) {
|
|
exist = NULL;
|
|
continue;
|
|
}
|
|
|
|
/* SHARED_BLOCK_REF means key.offset is the parent bytenr */
|
|
if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
|
|
ret = handle_direct_tree_backref(cache, &key, cur);
|
|
if (ret < 0)
|
|
goto out;
|
|
continue;
|
|
} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
|
|
ret = -EINVAL;
|
|
btrfs_print_v0_err(fs_info);
|
|
btrfs_handle_fs_error(fs_info, ret, NULL);
|
|
goto out;
|
|
} else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
|
|
* means the root objectid. We need to search the tree to get
|
|
* its parent bytenr.
|
|
*/
|
|
ret = handle_indirect_tree_backref(cache, path, &key, node_key,
|
|
cur);
|
|
if (ret < 0)
|
|
goto out;
|
|
}
|
|
ret = 0;
|
|
cur->checked = 1;
|
|
WARN_ON(exist);
|
|
out:
|
|
btrfs_backref_iter_release(iter);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Finish the upwards linkage created by btrfs_backref_add_tree_node()
|
|
*/
|
|
int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
|
|
struct btrfs_backref_node *start)
|
|
{
|
|
struct list_head *useless_node = &cache->useless_node;
|
|
struct btrfs_backref_edge *edge;
|
|
struct rb_node *rb_node;
|
|
LIST_HEAD(pending_edge);
|
|
|
|
ASSERT(start->checked);
|
|
|
|
/* Insert this node to cache if it's not COW-only */
|
|
if (!start->cowonly) {
|
|
rb_node = rb_simple_insert(&cache->rb_root, start->bytenr,
|
|
&start->rb_node);
|
|
if (rb_node)
|
|
btrfs_backref_panic(cache->fs_info, start->bytenr,
|
|
-EEXIST);
|
|
list_add_tail(&start->lower, &cache->leaves);
|
|
}
|
|
|
|
/*
|
|
* Use breadth first search to iterate all related edges.
|
|
*
|
|
* The starting points are all the edges of this node
|
|
*/
|
|
list_for_each_entry(edge, &start->upper, list[LOWER])
|
|
list_add_tail(&edge->list[UPPER], &pending_edge);
|
|
|
|
while (!list_empty(&pending_edge)) {
|
|
struct btrfs_backref_node *upper;
|
|
struct btrfs_backref_node *lower;
|
|
|
|
edge = list_first_entry(&pending_edge,
|
|
struct btrfs_backref_edge, list[UPPER]);
|
|
list_del_init(&edge->list[UPPER]);
|
|
upper = edge->node[UPPER];
|
|
lower = edge->node[LOWER];
|
|
|
|
/* Parent is detached, no need to keep any edges */
|
|
if (upper->detached) {
|
|
list_del(&edge->list[LOWER]);
|
|
btrfs_backref_free_edge(cache, edge);
|
|
|
|
/* Lower node is orphan, queue for cleanup */
|
|
if (list_empty(&lower->upper))
|
|
list_add(&lower->list, useless_node);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* All new nodes added in current build_backref_tree() haven't
|
|
* been linked to the cache rb tree.
|
|
* So if we have upper->rb_node populated, this means a cache
|
|
* hit. We only need to link the edge, as @upper and all its
|
|
* parents have already been linked.
|
|
*/
|
|
if (!RB_EMPTY_NODE(&upper->rb_node)) {
|
|
if (upper->lowest) {
|
|
list_del_init(&upper->lower);
|
|
upper->lowest = 0;
|
|
}
|
|
|
|
list_add_tail(&edge->list[UPPER], &upper->lower);
|
|
continue;
|
|
}
|
|
|
|
/* Sanity check, we shouldn't have any unchecked nodes */
|
|
if (!upper->checked) {
|
|
ASSERT(0);
|
|
return -EUCLEAN;
|
|
}
|
|
|
|
/* Sanity check, COW-only node has non-COW-only parent */
|
|
if (start->cowonly != upper->cowonly) {
|
|
ASSERT(0);
|
|
return -EUCLEAN;
|
|
}
|
|
|
|
/* Only cache non-COW-only (subvolume trees) tree blocks */
|
|
if (!upper->cowonly) {
|
|
rb_node = rb_simple_insert(&cache->rb_root, upper->bytenr,
|
|
&upper->rb_node);
|
|
if (rb_node) {
|
|
btrfs_backref_panic(cache->fs_info,
|
|
upper->bytenr, -EEXIST);
|
|
return -EUCLEAN;
|
|
}
|
|
}
|
|
|
|
list_add_tail(&edge->list[UPPER], &upper->lower);
|
|
|
|
/*
|
|
* Also queue all the parent edges of this uncached node
|
|
* to finish the upper linkage
|
|
*/
|
|
list_for_each_entry(edge, &upper->upper, list[LOWER])
|
|
list_add_tail(&edge->list[UPPER], &pending_edge);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
|
|
struct btrfs_backref_node *node)
|
|
{
|
|
struct btrfs_backref_node *lower;
|
|
struct btrfs_backref_node *upper;
|
|
struct btrfs_backref_edge *edge;
|
|
|
|
while (!list_empty(&cache->useless_node)) {
|
|
lower = list_first_entry(&cache->useless_node,
|
|
struct btrfs_backref_node, list);
|
|
list_del_init(&lower->list);
|
|
}
|
|
while (!list_empty(&cache->pending_edge)) {
|
|
edge = list_first_entry(&cache->pending_edge,
|
|
struct btrfs_backref_edge, list[UPPER]);
|
|
list_del(&edge->list[UPPER]);
|
|
list_del(&edge->list[LOWER]);
|
|
lower = edge->node[LOWER];
|
|
upper = edge->node[UPPER];
|
|
btrfs_backref_free_edge(cache, edge);
|
|
|
|
/*
|
|
* Lower is no longer linked to any upper backref nodes and
|
|
* isn't in the cache, we can free it ourselves.
|
|
*/
|
|
if (list_empty(&lower->upper) &&
|
|
RB_EMPTY_NODE(&lower->rb_node))
|
|
list_add(&lower->list, &cache->useless_node);
|
|
|
|
if (!RB_EMPTY_NODE(&upper->rb_node))
|
|
continue;
|
|
|
|
/* Add this guy's upper edges to the list to process */
|
|
list_for_each_entry(edge, &upper->upper, list[LOWER])
|
|
list_add_tail(&edge->list[UPPER],
|
|
&cache->pending_edge);
|
|
if (list_empty(&upper->upper))
|
|
list_add(&upper->list, &cache->useless_node);
|
|
}
|
|
|
|
while (!list_empty(&cache->useless_node)) {
|
|
lower = list_first_entry(&cache->useless_node,
|
|
struct btrfs_backref_node, list);
|
|
list_del_init(&lower->list);
|
|
if (lower == node)
|
|
node = NULL;
|
|
btrfs_backref_drop_node(cache, lower);
|
|
}
|
|
|
|
btrfs_backref_cleanup_node(cache, node);
|
|
ASSERT(list_empty(&cache->useless_node) &&
|
|
list_empty(&cache->pending_edge));
|
|
}
|