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![Josef Bacik](/assets/img/avatar_default.png)
Now that we've plumbed all of the callers to have the owner root and the level, plumb it down into alloc_extent_buffer(). Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
1085 lines
27 KiB
C
1085 lines
27 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/sched.h>
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#include <linux/pagemap.h>
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#include <linux/writeback.h>
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#include <linux/blkdev.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include "ctree.h"
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#include "volumes.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "dev-replace.h"
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#include "block-group.h"
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#undef DEBUG
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/*
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* This is the implementation for the generic read ahead framework.
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*
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* To trigger a readahead, btrfs_reada_add must be called. It will start
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* a read ahead for the given range [start, end) on tree root. The returned
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* handle can either be used to wait on the readahead to finish
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* (btrfs_reada_wait), or to send it to the background (btrfs_reada_detach).
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*
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* The read ahead works as follows:
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* On btrfs_reada_add, the root of the tree is inserted into a radix_tree.
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* reada_start_machine will then search for extents to prefetch and trigger
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* some reads. When a read finishes for a node, all contained node/leaf
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* pointers that lie in the given range will also be enqueued. The reads will
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* be triggered in sequential order, thus giving a big win over a naive
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* enumeration. It will also make use of multi-device layouts. Each disk
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* will have its on read pointer and all disks will by utilized in parallel.
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* Also will no two disks read both sides of a mirror simultaneously, as this
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* would waste seeking capacity. Instead both disks will read different parts
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* of the filesystem.
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* Any number of readaheads can be started in parallel. The read order will be
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* determined globally, i.e. 2 parallel readaheads will normally finish faster
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* than the 2 started one after another.
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*/
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#define MAX_IN_FLIGHT 6
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struct reada_extctl {
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struct list_head list;
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struct reada_control *rc;
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u64 generation;
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};
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struct reada_extent {
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u64 logical;
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u64 owner_root;
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struct btrfs_key top;
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struct list_head extctl;
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int refcnt;
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spinlock_t lock;
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struct reada_zone *zones[BTRFS_MAX_MIRRORS];
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int nzones;
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int scheduled;
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int level;
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};
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struct reada_zone {
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u64 start;
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u64 end;
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u64 elems;
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struct list_head list;
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spinlock_t lock;
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int locked;
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struct btrfs_device *device;
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struct btrfs_device *devs[BTRFS_MAX_MIRRORS]; /* full list, incl
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* self */
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int ndevs;
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struct kref refcnt;
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};
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struct reada_machine_work {
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struct btrfs_work work;
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struct btrfs_fs_info *fs_info;
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};
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static void reada_extent_put(struct btrfs_fs_info *, struct reada_extent *);
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static void reada_control_release(struct kref *kref);
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static void reada_zone_release(struct kref *kref);
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static void reada_start_machine(struct btrfs_fs_info *fs_info);
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static void __reada_start_machine(struct btrfs_fs_info *fs_info);
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static int reada_add_block(struct reada_control *rc, u64 logical,
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struct btrfs_key *top, u64 owner_root,
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u64 generation, int level);
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/* recurses */
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/* in case of err, eb might be NULL */
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static void __readahead_hook(struct btrfs_fs_info *fs_info,
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struct reada_extent *re, struct extent_buffer *eb,
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int err)
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{
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int nritems;
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int i;
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u64 bytenr;
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u64 generation;
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struct list_head list;
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spin_lock(&re->lock);
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/*
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* just take the full list from the extent. afterwards we
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* don't need the lock anymore
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*/
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list_replace_init(&re->extctl, &list);
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re->scheduled = 0;
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spin_unlock(&re->lock);
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/*
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* this is the error case, the extent buffer has not been
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* read correctly. We won't access anything from it and
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* just cleanup our data structures. Effectively this will
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* cut the branch below this node from read ahead.
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*/
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if (err)
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goto cleanup;
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/*
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* FIXME: currently we just set nritems to 0 if this is a leaf,
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* effectively ignoring the content. In a next step we could
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* trigger more readahead depending from the content, e.g.
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* fetch the checksums for the extents in the leaf.
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*/
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if (!btrfs_header_level(eb))
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goto cleanup;
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nritems = btrfs_header_nritems(eb);
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generation = btrfs_header_generation(eb);
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for (i = 0; i < nritems; i++) {
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struct reada_extctl *rec;
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u64 n_gen;
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struct btrfs_key key;
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struct btrfs_key next_key;
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btrfs_node_key_to_cpu(eb, &key, i);
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if (i + 1 < nritems)
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btrfs_node_key_to_cpu(eb, &next_key, i + 1);
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else
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next_key = re->top;
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bytenr = btrfs_node_blockptr(eb, i);
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n_gen = btrfs_node_ptr_generation(eb, i);
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list_for_each_entry(rec, &list, list) {
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struct reada_control *rc = rec->rc;
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/*
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* if the generation doesn't match, just ignore this
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* extctl. This will probably cut off a branch from
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* prefetch. Alternatively one could start a new (sub-)
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* prefetch for this branch, starting again from root.
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* FIXME: move the generation check out of this loop
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*/
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#ifdef DEBUG
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if (rec->generation != generation) {
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btrfs_debug(fs_info,
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"generation mismatch for (%llu,%d,%llu) %llu != %llu",
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key.objectid, key.type, key.offset,
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rec->generation, generation);
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}
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#endif
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if (rec->generation == generation &&
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btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 &&
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btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0)
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reada_add_block(rc, bytenr, &next_key,
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btrfs_header_owner(eb), n_gen,
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btrfs_header_level(eb) - 1);
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}
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}
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cleanup:
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/*
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* free extctl records
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*/
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while (!list_empty(&list)) {
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struct reada_control *rc;
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struct reada_extctl *rec;
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rec = list_first_entry(&list, struct reada_extctl, list);
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list_del(&rec->list);
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rc = rec->rc;
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kfree(rec);
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kref_get(&rc->refcnt);
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if (atomic_dec_and_test(&rc->elems)) {
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kref_put(&rc->refcnt, reada_control_release);
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wake_up(&rc->wait);
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}
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kref_put(&rc->refcnt, reada_control_release);
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reada_extent_put(fs_info, re); /* one ref for each entry */
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}
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return;
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}
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int btree_readahead_hook(struct extent_buffer *eb, int err)
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{
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struct btrfs_fs_info *fs_info = eb->fs_info;
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int ret = 0;
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struct reada_extent *re;
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/* find extent */
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spin_lock(&fs_info->reada_lock);
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re = radix_tree_lookup(&fs_info->reada_tree,
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eb->start >> PAGE_SHIFT);
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if (re)
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re->refcnt++;
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spin_unlock(&fs_info->reada_lock);
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if (!re) {
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ret = -1;
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goto start_machine;
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}
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__readahead_hook(fs_info, re, eb, err);
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reada_extent_put(fs_info, re); /* our ref */
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start_machine:
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reada_start_machine(fs_info);
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return ret;
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}
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static struct reada_zone *reada_find_zone(struct btrfs_device *dev, u64 logical,
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struct btrfs_bio *bbio)
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{
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struct btrfs_fs_info *fs_info = dev->fs_info;
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int ret;
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struct reada_zone *zone;
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struct btrfs_block_group *cache = NULL;
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u64 start;
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u64 end;
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int i;
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zone = NULL;
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spin_lock(&fs_info->reada_lock);
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ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone,
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logical >> PAGE_SHIFT, 1);
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if (ret == 1 && logical >= zone->start && logical <= zone->end) {
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kref_get(&zone->refcnt);
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spin_unlock(&fs_info->reada_lock);
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return zone;
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}
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spin_unlock(&fs_info->reada_lock);
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cache = btrfs_lookup_block_group(fs_info, logical);
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if (!cache)
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return NULL;
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start = cache->start;
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end = start + cache->length - 1;
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btrfs_put_block_group(cache);
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zone = kzalloc(sizeof(*zone), GFP_KERNEL);
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if (!zone)
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return NULL;
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ret = radix_tree_preload(GFP_KERNEL);
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if (ret) {
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kfree(zone);
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return NULL;
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}
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zone->start = start;
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zone->end = end;
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INIT_LIST_HEAD(&zone->list);
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spin_lock_init(&zone->lock);
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zone->locked = 0;
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kref_init(&zone->refcnt);
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zone->elems = 0;
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zone->device = dev; /* our device always sits at index 0 */
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for (i = 0; i < bbio->num_stripes; ++i) {
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/* bounds have already been checked */
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zone->devs[i] = bbio->stripes[i].dev;
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}
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zone->ndevs = bbio->num_stripes;
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spin_lock(&fs_info->reada_lock);
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ret = radix_tree_insert(&dev->reada_zones,
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(unsigned long)(zone->end >> PAGE_SHIFT),
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zone);
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if (ret == -EEXIST) {
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kfree(zone);
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ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone,
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logical >> PAGE_SHIFT, 1);
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if (ret == 1 && logical >= zone->start && logical <= zone->end)
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kref_get(&zone->refcnt);
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else
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zone = NULL;
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}
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spin_unlock(&fs_info->reada_lock);
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radix_tree_preload_end();
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return zone;
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}
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static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info,
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u64 logical,
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struct btrfs_key *top,
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u64 owner_root, int level)
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{
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int ret;
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struct reada_extent *re = NULL;
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struct reada_extent *re_exist = NULL;
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struct btrfs_bio *bbio = NULL;
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struct btrfs_device *dev;
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struct btrfs_device *prev_dev;
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u64 length;
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int real_stripes;
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int nzones = 0;
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unsigned long index = logical >> PAGE_SHIFT;
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int dev_replace_is_ongoing;
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int have_zone = 0;
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spin_lock(&fs_info->reada_lock);
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re = radix_tree_lookup(&fs_info->reada_tree, index);
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if (re)
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re->refcnt++;
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spin_unlock(&fs_info->reada_lock);
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if (re)
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return re;
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re = kzalloc(sizeof(*re), GFP_KERNEL);
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if (!re)
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return NULL;
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re->logical = logical;
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re->top = *top;
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INIT_LIST_HEAD(&re->extctl);
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spin_lock_init(&re->lock);
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re->refcnt = 1;
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re->owner_root = owner_root;
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re->level = level;
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/*
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* map block
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*/
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length = fs_info->nodesize;
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ret = btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical,
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&length, &bbio, 0);
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if (ret || !bbio || length < fs_info->nodesize)
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goto error;
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if (bbio->num_stripes > BTRFS_MAX_MIRRORS) {
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btrfs_err(fs_info,
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"readahead: more than %d copies not supported",
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BTRFS_MAX_MIRRORS);
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goto error;
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}
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real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
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for (nzones = 0; nzones < real_stripes; ++nzones) {
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struct reada_zone *zone;
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dev = bbio->stripes[nzones].dev;
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/* cannot read ahead on missing device. */
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if (!dev->bdev)
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continue;
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zone = reada_find_zone(dev, logical, bbio);
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if (!zone)
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continue;
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re->zones[re->nzones++] = zone;
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spin_lock(&zone->lock);
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if (!zone->elems)
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kref_get(&zone->refcnt);
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++zone->elems;
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spin_unlock(&zone->lock);
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spin_lock(&fs_info->reada_lock);
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kref_put(&zone->refcnt, reada_zone_release);
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spin_unlock(&fs_info->reada_lock);
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}
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if (re->nzones == 0) {
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/* not a single zone found, error and out */
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goto error;
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}
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/* Insert extent in reada tree + all per-device trees, all or nothing */
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down_read(&fs_info->dev_replace.rwsem);
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ret = radix_tree_preload(GFP_KERNEL);
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if (ret) {
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up_read(&fs_info->dev_replace.rwsem);
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goto error;
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}
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spin_lock(&fs_info->reada_lock);
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ret = radix_tree_insert(&fs_info->reada_tree, index, re);
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if (ret == -EEXIST) {
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re_exist = radix_tree_lookup(&fs_info->reada_tree, index);
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re_exist->refcnt++;
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spin_unlock(&fs_info->reada_lock);
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radix_tree_preload_end();
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up_read(&fs_info->dev_replace.rwsem);
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goto error;
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}
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if (ret) {
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spin_unlock(&fs_info->reada_lock);
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radix_tree_preload_end();
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up_read(&fs_info->dev_replace.rwsem);
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goto error;
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}
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radix_tree_preload_end();
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prev_dev = NULL;
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dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(
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&fs_info->dev_replace);
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for (nzones = 0; nzones < re->nzones; ++nzones) {
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dev = re->zones[nzones]->device;
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if (dev == prev_dev) {
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/*
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* in case of DUP, just add the first zone. As both
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* are on the same device, there's nothing to gain
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* from adding both.
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* Also, it wouldn't work, as the tree is per device
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* and adding would fail with EEXIST
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*/
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continue;
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}
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if (!dev->bdev)
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continue;
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if (test_bit(BTRFS_DEV_STATE_NO_READA, &dev->dev_state))
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continue;
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|
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if (dev_replace_is_ongoing &&
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dev == fs_info->dev_replace.tgtdev) {
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/*
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* as this device is selected for reading only as
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* a last resort, skip it for read ahead.
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*/
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continue;
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}
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prev_dev = dev;
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ret = radix_tree_insert(&dev->reada_extents, index, re);
|
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if (ret) {
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while (--nzones >= 0) {
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dev = re->zones[nzones]->device;
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BUG_ON(dev == NULL);
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/* ignore whether the entry was inserted */
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radix_tree_delete(&dev->reada_extents, index);
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}
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radix_tree_delete(&fs_info->reada_tree, index);
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spin_unlock(&fs_info->reada_lock);
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up_read(&fs_info->dev_replace.rwsem);
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goto error;
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}
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have_zone = 1;
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}
|
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if (!have_zone)
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radix_tree_delete(&fs_info->reada_tree, index);
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spin_unlock(&fs_info->reada_lock);
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up_read(&fs_info->dev_replace.rwsem);
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|
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if (!have_zone)
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goto error;
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|
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btrfs_put_bbio(bbio);
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return re;
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|
|
error:
|
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for (nzones = 0; nzones < re->nzones; ++nzones) {
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struct reada_zone *zone;
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zone = re->zones[nzones];
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kref_get(&zone->refcnt);
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spin_lock(&zone->lock);
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--zone->elems;
|
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if (zone->elems == 0) {
|
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/*
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* no fs_info->reada_lock needed, as this can't be
|
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* the last ref
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*/
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kref_put(&zone->refcnt, reada_zone_release);
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}
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spin_unlock(&zone->lock);
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|
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spin_lock(&fs_info->reada_lock);
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kref_put(&zone->refcnt, reada_zone_release);
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spin_unlock(&fs_info->reada_lock);
|
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}
|
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btrfs_put_bbio(bbio);
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kfree(re);
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return re_exist;
|
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}
|
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|
|
static void reada_extent_put(struct btrfs_fs_info *fs_info,
|
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struct reada_extent *re)
|
|
{
|
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int i;
|
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unsigned long index = re->logical >> PAGE_SHIFT;
|
|
|
|
spin_lock(&fs_info->reada_lock);
|
|
if (--re->refcnt) {
|
|
spin_unlock(&fs_info->reada_lock);
|
|
return;
|
|
}
|
|
|
|
radix_tree_delete(&fs_info->reada_tree, index);
|
|
for (i = 0; i < re->nzones; ++i) {
|
|
struct reada_zone *zone = re->zones[i];
|
|
|
|
radix_tree_delete(&zone->device->reada_extents, index);
|
|
}
|
|
|
|
spin_unlock(&fs_info->reada_lock);
|
|
|
|
for (i = 0; i < re->nzones; ++i) {
|
|
struct reada_zone *zone = re->zones[i];
|
|
|
|
kref_get(&zone->refcnt);
|
|
spin_lock(&zone->lock);
|
|
--zone->elems;
|
|
if (zone->elems == 0) {
|
|
/* no fs_info->reada_lock needed, as this can't be
|
|
* the last ref */
|
|
kref_put(&zone->refcnt, reada_zone_release);
|
|
}
|
|
spin_unlock(&zone->lock);
|
|
|
|
spin_lock(&fs_info->reada_lock);
|
|
kref_put(&zone->refcnt, reada_zone_release);
|
|
spin_unlock(&fs_info->reada_lock);
|
|
}
|
|
|
|
kfree(re);
|
|
}
|
|
|
|
static void reada_zone_release(struct kref *kref)
|
|
{
|
|
struct reada_zone *zone = container_of(kref, struct reada_zone, refcnt);
|
|
|
|
lockdep_assert_held(&zone->device->fs_info->reada_lock);
|
|
|
|
radix_tree_delete(&zone->device->reada_zones,
|
|
zone->end >> PAGE_SHIFT);
|
|
|
|
kfree(zone);
|
|
}
|
|
|
|
static void reada_control_release(struct kref *kref)
|
|
{
|
|
struct reada_control *rc = container_of(kref, struct reada_control,
|
|
refcnt);
|
|
|
|
kfree(rc);
|
|
}
|
|
|
|
static int reada_add_block(struct reada_control *rc, u64 logical,
|
|
struct btrfs_key *top, u64 owner_root,
|
|
u64 generation, int level)
|
|
{
|
|
struct btrfs_fs_info *fs_info = rc->fs_info;
|
|
struct reada_extent *re;
|
|
struct reada_extctl *rec;
|
|
|
|
/* takes one ref */
|
|
re = reada_find_extent(fs_info, logical, top, owner_root, level);
|
|
if (!re)
|
|
return -1;
|
|
|
|
rec = kzalloc(sizeof(*rec), GFP_KERNEL);
|
|
if (!rec) {
|
|
reada_extent_put(fs_info, re);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
rec->rc = rc;
|
|
rec->generation = generation;
|
|
atomic_inc(&rc->elems);
|
|
|
|
spin_lock(&re->lock);
|
|
list_add_tail(&rec->list, &re->extctl);
|
|
spin_unlock(&re->lock);
|
|
|
|
/* leave the ref on the extent */
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* called with fs_info->reada_lock held
|
|
*/
|
|
static void reada_peer_zones_set_lock(struct reada_zone *zone, int lock)
|
|
{
|
|
int i;
|
|
unsigned long index = zone->end >> PAGE_SHIFT;
|
|
|
|
for (i = 0; i < zone->ndevs; ++i) {
|
|
struct reada_zone *peer;
|
|
peer = radix_tree_lookup(&zone->devs[i]->reada_zones, index);
|
|
if (peer && peer->device != zone->device)
|
|
peer->locked = lock;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* called with fs_info->reada_lock held
|
|
*/
|
|
static int reada_pick_zone(struct btrfs_device *dev)
|
|
{
|
|
struct reada_zone *top_zone = NULL;
|
|
struct reada_zone *top_locked_zone = NULL;
|
|
u64 top_elems = 0;
|
|
u64 top_locked_elems = 0;
|
|
unsigned long index = 0;
|
|
int ret;
|
|
|
|
if (dev->reada_curr_zone) {
|
|
reada_peer_zones_set_lock(dev->reada_curr_zone, 0);
|
|
kref_put(&dev->reada_curr_zone->refcnt, reada_zone_release);
|
|
dev->reada_curr_zone = NULL;
|
|
}
|
|
/* pick the zone with the most elements */
|
|
while (1) {
|
|
struct reada_zone *zone;
|
|
|
|
ret = radix_tree_gang_lookup(&dev->reada_zones,
|
|
(void **)&zone, index, 1);
|
|
if (ret == 0)
|
|
break;
|
|
index = (zone->end >> PAGE_SHIFT) + 1;
|
|
if (zone->locked) {
|
|
if (zone->elems > top_locked_elems) {
|
|
top_locked_elems = zone->elems;
|
|
top_locked_zone = zone;
|
|
}
|
|
} else {
|
|
if (zone->elems > top_elems) {
|
|
top_elems = zone->elems;
|
|
top_zone = zone;
|
|
}
|
|
}
|
|
}
|
|
if (top_zone)
|
|
dev->reada_curr_zone = top_zone;
|
|
else if (top_locked_zone)
|
|
dev->reada_curr_zone = top_locked_zone;
|
|
else
|
|
return 0;
|
|
|
|
dev->reada_next = dev->reada_curr_zone->start;
|
|
kref_get(&dev->reada_curr_zone->refcnt);
|
|
reada_peer_zones_set_lock(dev->reada_curr_zone, 1);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int reada_tree_block_flagged(struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 owner_root, int level, int mirror_num,
|
|
struct extent_buffer **eb)
|
|
{
|
|
struct extent_buffer *buf = NULL;
|
|
int ret;
|
|
|
|
buf = btrfs_find_create_tree_block(fs_info, bytenr, owner_root, level);
|
|
if (IS_ERR(buf))
|
|
return 0;
|
|
|
|
set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
|
|
|
|
ret = read_extent_buffer_pages(buf, WAIT_PAGE_LOCK, mirror_num);
|
|
if (ret) {
|
|
free_extent_buffer_stale(buf);
|
|
return ret;
|
|
}
|
|
|
|
if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
|
|
free_extent_buffer_stale(buf);
|
|
return -EIO;
|
|
} else if (extent_buffer_uptodate(buf)) {
|
|
*eb = buf;
|
|
} else {
|
|
free_extent_buffer(buf);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int reada_start_machine_dev(struct btrfs_device *dev)
|
|
{
|
|
struct btrfs_fs_info *fs_info = dev->fs_info;
|
|
struct reada_extent *re = NULL;
|
|
int mirror_num = 0;
|
|
struct extent_buffer *eb = NULL;
|
|
u64 logical;
|
|
int ret;
|
|
int i;
|
|
|
|
spin_lock(&fs_info->reada_lock);
|
|
if (dev->reada_curr_zone == NULL) {
|
|
ret = reada_pick_zone(dev);
|
|
if (!ret) {
|
|
spin_unlock(&fs_info->reada_lock);
|
|
return 0;
|
|
}
|
|
}
|
|
/*
|
|
* FIXME currently we issue the reads one extent at a time. If we have
|
|
* a contiguous block of extents, we could also coagulate them or use
|
|
* plugging to speed things up
|
|
*/
|
|
ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re,
|
|
dev->reada_next >> PAGE_SHIFT, 1);
|
|
if (ret == 0 || re->logical > dev->reada_curr_zone->end) {
|
|
ret = reada_pick_zone(dev);
|
|
if (!ret) {
|
|
spin_unlock(&fs_info->reada_lock);
|
|
return 0;
|
|
}
|
|
re = NULL;
|
|
ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re,
|
|
dev->reada_next >> PAGE_SHIFT, 1);
|
|
}
|
|
if (ret == 0) {
|
|
spin_unlock(&fs_info->reada_lock);
|
|
return 0;
|
|
}
|
|
dev->reada_next = re->logical + fs_info->nodesize;
|
|
re->refcnt++;
|
|
|
|
spin_unlock(&fs_info->reada_lock);
|
|
|
|
spin_lock(&re->lock);
|
|
if (re->scheduled || list_empty(&re->extctl)) {
|
|
spin_unlock(&re->lock);
|
|
reada_extent_put(fs_info, re);
|
|
return 0;
|
|
}
|
|
re->scheduled = 1;
|
|
spin_unlock(&re->lock);
|
|
|
|
/*
|
|
* find mirror num
|
|
*/
|
|
for (i = 0; i < re->nzones; ++i) {
|
|
if (re->zones[i]->device == dev) {
|
|
mirror_num = i + 1;
|
|
break;
|
|
}
|
|
}
|
|
logical = re->logical;
|
|
|
|
atomic_inc(&dev->reada_in_flight);
|
|
ret = reada_tree_block_flagged(fs_info, logical, re->owner_root,
|
|
re->level, mirror_num, &eb);
|
|
if (ret)
|
|
__readahead_hook(fs_info, re, NULL, ret);
|
|
else if (eb)
|
|
__readahead_hook(fs_info, re, eb, ret);
|
|
|
|
if (eb)
|
|
free_extent_buffer(eb);
|
|
|
|
atomic_dec(&dev->reada_in_flight);
|
|
reada_extent_put(fs_info, re);
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
static void reada_start_machine_worker(struct btrfs_work *work)
|
|
{
|
|
struct reada_machine_work *rmw;
|
|
int old_ioprio;
|
|
|
|
rmw = container_of(work, struct reada_machine_work, work);
|
|
|
|
old_ioprio = IOPRIO_PRIO_VALUE(task_nice_ioclass(current),
|
|
task_nice_ioprio(current));
|
|
set_task_ioprio(current, BTRFS_IOPRIO_READA);
|
|
__reada_start_machine(rmw->fs_info);
|
|
set_task_ioprio(current, old_ioprio);
|
|
|
|
atomic_dec(&rmw->fs_info->reada_works_cnt);
|
|
|
|
kfree(rmw);
|
|
}
|
|
|
|
/* Try to start up to 10k READA requests for a group of devices */
|
|
static int reada_start_for_fsdevs(struct btrfs_fs_devices *fs_devices)
|
|
{
|
|
u64 enqueued;
|
|
u64 total = 0;
|
|
struct btrfs_device *device;
|
|
|
|
do {
|
|
enqueued = 0;
|
|
list_for_each_entry(device, &fs_devices->devices, dev_list) {
|
|
if (atomic_read(&device->reada_in_flight) <
|
|
MAX_IN_FLIGHT)
|
|
enqueued += reada_start_machine_dev(device);
|
|
}
|
|
total += enqueued;
|
|
} while (enqueued && total < 10000);
|
|
|
|
return total;
|
|
}
|
|
|
|
static void __reada_start_machine(struct btrfs_fs_info *fs_info)
|
|
{
|
|
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices, *seed_devs;
|
|
int i;
|
|
u64 enqueued = 0;
|
|
|
|
mutex_lock(&fs_devices->device_list_mutex);
|
|
|
|
enqueued += reada_start_for_fsdevs(fs_devices);
|
|
list_for_each_entry(seed_devs, &fs_devices->seed_list, seed_list)
|
|
enqueued += reada_start_for_fsdevs(seed_devs);
|
|
|
|
mutex_unlock(&fs_devices->device_list_mutex);
|
|
if (enqueued == 0)
|
|
return;
|
|
|
|
/*
|
|
* If everything is already in the cache, this is effectively single
|
|
* threaded. To a) not hold the caller for too long and b) to utilize
|
|
* more cores, we broke the loop above after 10000 iterations and now
|
|
* enqueue to workers to finish it. This will distribute the load to
|
|
* the cores.
|
|
*/
|
|
for (i = 0; i < 2; ++i) {
|
|
reada_start_machine(fs_info);
|
|
if (atomic_read(&fs_info->reada_works_cnt) >
|
|
BTRFS_MAX_MIRRORS * 2)
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void reada_start_machine(struct btrfs_fs_info *fs_info)
|
|
{
|
|
struct reada_machine_work *rmw;
|
|
|
|
rmw = kzalloc(sizeof(*rmw), GFP_KERNEL);
|
|
if (!rmw) {
|
|
/* FIXME we cannot handle this properly right now */
|
|
BUG();
|
|
}
|
|
btrfs_init_work(&rmw->work, reada_start_machine_worker, NULL, NULL);
|
|
rmw->fs_info = fs_info;
|
|
|
|
btrfs_queue_work(fs_info->readahead_workers, &rmw->work);
|
|
atomic_inc(&fs_info->reada_works_cnt);
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
static void dump_devs(struct btrfs_fs_info *fs_info, int all)
|
|
{
|
|
struct btrfs_device *device;
|
|
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
|
|
unsigned long index;
|
|
int ret;
|
|
int i;
|
|
int j;
|
|
int cnt;
|
|
|
|
spin_lock(&fs_info->reada_lock);
|
|
list_for_each_entry(device, &fs_devices->devices, dev_list) {
|
|
btrfs_debug(fs_info, "dev %lld has %d in flight", device->devid,
|
|
atomic_read(&device->reada_in_flight));
|
|
index = 0;
|
|
while (1) {
|
|
struct reada_zone *zone;
|
|
ret = radix_tree_gang_lookup(&device->reada_zones,
|
|
(void **)&zone, index, 1);
|
|
if (ret == 0)
|
|
break;
|
|
pr_debug(" zone %llu-%llu elems %llu locked %d devs",
|
|
zone->start, zone->end, zone->elems,
|
|
zone->locked);
|
|
for (j = 0; j < zone->ndevs; ++j) {
|
|
pr_cont(" %lld",
|
|
zone->devs[j]->devid);
|
|
}
|
|
if (device->reada_curr_zone == zone)
|
|
pr_cont(" curr off %llu",
|
|
device->reada_next - zone->start);
|
|
pr_cont("\n");
|
|
index = (zone->end >> PAGE_SHIFT) + 1;
|
|
}
|
|
cnt = 0;
|
|
index = 0;
|
|
while (all) {
|
|
struct reada_extent *re = NULL;
|
|
|
|
ret = radix_tree_gang_lookup(&device->reada_extents,
|
|
(void **)&re, index, 1);
|
|
if (ret == 0)
|
|
break;
|
|
pr_debug(" re: logical %llu size %u empty %d scheduled %d",
|
|
re->logical, fs_info->nodesize,
|
|
list_empty(&re->extctl), re->scheduled);
|
|
|
|
for (i = 0; i < re->nzones; ++i) {
|
|
pr_cont(" zone %llu-%llu devs",
|
|
re->zones[i]->start,
|
|
re->zones[i]->end);
|
|
for (j = 0; j < re->zones[i]->ndevs; ++j) {
|
|
pr_cont(" %lld",
|
|
re->zones[i]->devs[j]->devid);
|
|
}
|
|
}
|
|
pr_cont("\n");
|
|
index = (re->logical >> PAGE_SHIFT) + 1;
|
|
if (++cnt > 15)
|
|
break;
|
|
}
|
|
}
|
|
|
|
index = 0;
|
|
cnt = 0;
|
|
while (all) {
|
|
struct reada_extent *re = NULL;
|
|
|
|
ret = radix_tree_gang_lookup(&fs_info->reada_tree, (void **)&re,
|
|
index, 1);
|
|
if (ret == 0)
|
|
break;
|
|
if (!re->scheduled) {
|
|
index = (re->logical >> PAGE_SHIFT) + 1;
|
|
continue;
|
|
}
|
|
pr_debug("re: logical %llu size %u list empty %d scheduled %d",
|
|
re->logical, fs_info->nodesize,
|
|
list_empty(&re->extctl), re->scheduled);
|
|
for (i = 0; i < re->nzones; ++i) {
|
|
pr_cont(" zone %llu-%llu devs",
|
|
re->zones[i]->start,
|
|
re->zones[i]->end);
|
|
for (j = 0; j < re->zones[i]->ndevs; ++j) {
|
|
pr_cont(" %lld",
|
|
re->zones[i]->devs[j]->devid);
|
|
}
|
|
}
|
|
pr_cont("\n");
|
|
index = (re->logical >> PAGE_SHIFT) + 1;
|
|
}
|
|
spin_unlock(&fs_info->reada_lock);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* interface
|
|
*/
|
|
struct reada_control *btrfs_reada_add(struct btrfs_root *root,
|
|
struct btrfs_key *key_start, struct btrfs_key *key_end)
|
|
{
|
|
struct reada_control *rc;
|
|
u64 start;
|
|
u64 generation;
|
|
int ret;
|
|
int level;
|
|
struct extent_buffer *node;
|
|
static struct btrfs_key max_key = {
|
|
.objectid = (u64)-1,
|
|
.type = (u8)-1,
|
|
.offset = (u64)-1
|
|
};
|
|
|
|
rc = kzalloc(sizeof(*rc), GFP_KERNEL);
|
|
if (!rc)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
rc->fs_info = root->fs_info;
|
|
rc->key_start = *key_start;
|
|
rc->key_end = *key_end;
|
|
atomic_set(&rc->elems, 0);
|
|
init_waitqueue_head(&rc->wait);
|
|
kref_init(&rc->refcnt);
|
|
kref_get(&rc->refcnt); /* one ref for having elements */
|
|
|
|
node = btrfs_root_node(root);
|
|
start = node->start;
|
|
generation = btrfs_header_generation(node);
|
|
level = btrfs_header_level(node);
|
|
free_extent_buffer(node);
|
|
|
|
ret = reada_add_block(rc, start, &max_key, root->root_key.objectid,
|
|
generation, level);
|
|
if (ret) {
|
|
kfree(rc);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
reada_start_machine(root->fs_info);
|
|
|
|
return rc;
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
int btrfs_reada_wait(void *handle)
|
|
{
|
|
struct reada_control *rc = handle;
|
|
struct btrfs_fs_info *fs_info = rc->fs_info;
|
|
|
|
while (atomic_read(&rc->elems)) {
|
|
if (!atomic_read(&fs_info->reada_works_cnt))
|
|
reada_start_machine(fs_info);
|
|
wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
|
|
5 * HZ);
|
|
dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0);
|
|
}
|
|
|
|
dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0);
|
|
|
|
kref_put(&rc->refcnt, reada_control_release);
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
int btrfs_reada_wait(void *handle)
|
|
{
|
|
struct reada_control *rc = handle;
|
|
struct btrfs_fs_info *fs_info = rc->fs_info;
|
|
|
|
while (atomic_read(&rc->elems)) {
|
|
if (!atomic_read(&fs_info->reada_works_cnt))
|
|
reada_start_machine(fs_info);
|
|
wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
|
|
(HZ + 9) / 10);
|
|
}
|
|
|
|
kref_put(&rc->refcnt, reada_control_release);
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
void btrfs_reada_detach(void *handle)
|
|
{
|
|
struct reada_control *rc = handle;
|
|
|
|
kref_put(&rc->refcnt, reada_control_release);
|
|
}
|
|
|
|
/*
|
|
* Before removing a device (device replace or device remove ioctls), call this
|
|
* function to wait for all existing readahead requests on the device and to
|
|
* make sure no one queues more readahead requests for the device.
|
|
*
|
|
* Must be called without holding neither the device list mutex nor the device
|
|
* replace semaphore, otherwise it will deadlock.
|
|
*/
|
|
void btrfs_reada_remove_dev(struct btrfs_device *dev)
|
|
{
|
|
struct btrfs_fs_info *fs_info = dev->fs_info;
|
|
|
|
/* Serialize with readahead extent creation at reada_find_extent(). */
|
|
spin_lock(&fs_info->reada_lock);
|
|
set_bit(BTRFS_DEV_STATE_NO_READA, &dev->dev_state);
|
|
spin_unlock(&fs_info->reada_lock);
|
|
|
|
/*
|
|
* There might be readahead requests added to the radix trees which
|
|
* were not yet added to the readahead work queue. We need to start
|
|
* them and wait for their completion, otherwise we can end up with
|
|
* use-after-free problems when dropping the last reference on the
|
|
* readahead extents and their zones, as they need to access the
|
|
* device structure.
|
|
*/
|
|
reada_start_machine(fs_info);
|
|
btrfs_flush_workqueue(fs_info->readahead_workers);
|
|
}
|
|
|
|
/*
|
|
* If when removing a device (device replace or device remove ioctls) an error
|
|
* happens after calling btrfs_reada_remove_dev(), call this to undo what that
|
|
* function did. This is safe to call even if btrfs_reada_remove_dev() was not
|
|
* called before.
|
|
*/
|
|
void btrfs_reada_undo_remove_dev(struct btrfs_device *dev)
|
|
{
|
|
spin_lock(&dev->fs_info->reada_lock);
|
|
clear_bit(BTRFS_DEV_STATE_NO_READA, &dev->dev_state);
|
|
spin_unlock(&dev->fs_info->reada_lock);
|
|
}
|