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Merge branch 'foreign/zhaolei/reada' into for-chris-4.6

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This commit is contained in:
David Sterba
2016-02-26 15:38:30 +01:00
parent 23c1a966f2 7aff8cf4a6
commit ff7db6e05a
3 changed files with 141 additions and 137 deletions
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248
fs/btrfs/reada.c
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@@ -72,7 +72,7 @@ struct reada_extent {
spinlock_t lock;
struct reada_zone *zones[BTRFS_MAX_MIRRORS];
int nzones;
struct btrfs_device *scheduled_for;
int scheduled;
};
struct reada_zone {
@@ -101,67 +101,53 @@ static void reada_start_machine(struct btrfs_fs_info *fs_info);
static void __reada_start_machine(struct btrfs_fs_info *fs_info);
static int reada_add_block(struct reada_control *rc, u64 logical,
struct btrfs_key *top, int level, u64 generation);
struct btrfs_key *top, u64 generation);
/* recurses */
/* in case of err, eb might be NULL */
static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
u64 start, int err)
static void __readahead_hook(struct btrfs_fs_info *fs_info,
struct reada_extent *re, struct extent_buffer *eb,
u64 start, int err)
{
int level = 0;
int nritems;
int i;
u64 bytenr;
u64 generation;
struct reada_extent *re;
struct btrfs_fs_info *fs_info = root->fs_info;
struct list_head list;
unsigned long index = start >> PAGE_CACHE_SHIFT;
struct btrfs_device *for_dev;
if (eb)
level = btrfs_header_level(eb);
/* find extent */
spin_lock(&fs_info->reada_lock);
re = radix_tree_lookup(&fs_info->reada_tree, index);
if (re)
re->refcnt++;
spin_unlock(&fs_info->reada_lock);
if (!re)
return -1;
spin_lock(&re->lock);
/*
* just take the full list from the extent. afterwards we
* don't need the lock anymore
*/
list_replace_init(&re->extctl, &list);
for_dev = re->scheduled_for;
re->scheduled_for = NULL;
re->scheduled = 0;
spin_unlock(&re->lock);
if (err == 0) {
nritems = level ? btrfs_header_nritems(eb) : 0;
generation = btrfs_header_generation(eb);
/*
* FIXME: currently we just set nritems to 0 if this is a leaf,
* effectively ignoring the content. In a next step we could
* trigger more readahead depending from the content, e.g.
* fetch the checksums for the extents in the leaf.
*/
} else {
/*
* this is the error case, the extent buffer has not been
* read correctly. We won't access anything from it and
* just cleanup our data structures. Effectively this will
* cut the branch below this node from read ahead.
*/
nritems = 0;
generation = 0;
}
/*
* this is the error case, the extent buffer has not been
* read correctly. We won't access anything from it and
* just cleanup our data structures. Effectively this will
* cut the branch below this node from read ahead.
*/
if (err)
goto cleanup;
/*
* FIXME: currently we just set nritems to 0 if this is a leaf,
* effectively ignoring the content. In a next step we could
* trigger more readahead depending from the content, e.g.
* fetch the checksums for the extents in the leaf.
*/
if (!level)
goto cleanup;
nritems = btrfs_header_nritems(eb);
generation = btrfs_header_generation(eb);
for (i = 0; i < nritems; i++) {
struct reada_extctl *rec;
u64 n_gen;
@@ -188,19 +174,20 @@ static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
*/
#ifdef DEBUG
if (rec->generation != generation) {
btrfs_debug(root->fs_info,
"generation mismatch for (%llu,%d,%llu) %llu != %llu",
key.objectid, key.type, key.offset,
rec->generation, generation);
btrfs_debug(fs_info,
"generation mismatch for (%llu,%d,%llu) %llu != %llu",
key.objectid, key.type, key.offset,
rec->generation, generation);
}
#endif
if (rec->generation == generation &&
btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 &&
btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0)
reada_add_block(rc, bytenr, &next_key,
level - 1, n_gen);
reada_add_block(rc, bytenr, &next_key, n_gen);
}
}
cleanup:
/*
* free extctl records
*/
@@ -222,26 +209,37 @@ static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
reada_extent_put(fs_info, re); /* one ref for each entry */
}
reada_extent_put(fs_info, re); /* our ref */
if (for_dev)
atomic_dec(&for_dev->reada_in_flight);
return 0;
return;
}
/*
* start is passed separately in case eb in NULL, which may be the case with
* failed I/O
*/
int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
u64 start, int err)
int btree_readahead_hook(struct btrfs_fs_info *fs_info,
struct extent_buffer *eb, u64 start, int err)
{
int ret;
int ret = 0;
struct reada_extent *re;
ret = __readahead_hook(root, eb, start, err);
/* find extent */
spin_lock(&fs_info->reada_lock);
re = radix_tree_lookup(&fs_info->reada_tree,
start >> PAGE_CACHE_SHIFT);
if (re)
re->refcnt++;
spin_unlock(&fs_info->reada_lock);
if (!re) {
ret = -1;
goto start_machine;
}
reada_start_machine(root->fs_info);
__readahead_hook(fs_info, re, eb, start, err);
reada_extent_put(fs_info, re); /* our ref */
start_machine:
reada_start_machine(fs_info);
return ret;
}
@@ -260,18 +258,14 @@ static struct reada_zone *reada_find_zone(struct btrfs_fs_info *fs_info,
spin_lock(&fs_info->reada_lock);
ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone,
logical >> PAGE_CACHE_SHIFT, 1);
if (ret == 1)
if (ret == 1 && logical >= zone->start && logical <= zone->end) {
kref_get(&zone->refcnt);
spin_unlock(&fs_info->reada_lock);
if (ret == 1) {
if (logical >= zone->start && logical < zone->end)
return zone;
spin_lock(&fs_info->reada_lock);
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
return zone;
}
spin_unlock(&fs_info->reada_lock);
cache = btrfs_lookup_block_group(fs_info, logical);
if (!cache)
return NULL;
@@ -307,8 +301,10 @@ static struct reada_zone *reada_find_zone(struct btrfs_fs_info *fs_info,
kfree(zone);
ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone,
logical >> PAGE_CACHE_SHIFT, 1);
if (ret == 1)
if (ret == 1 && logical >= zone->start && logical <= zone->end)
kref_get(&zone->refcnt);
else
zone = NULL;
}
spin_unlock(&fs_info->reada_lock);
@@ -317,7 +313,7 @@ static struct reada_zone *reada_find_zone(struct btrfs_fs_info *fs_info,
static struct reada_extent *reada_find_extent(struct btrfs_root *root,
u64 logical,
struct btrfs_key *top, int level)
struct btrfs_key *top)
{
int ret;
struct reada_extent *re = NULL;
@@ -330,9 +326,9 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
u64 length;
int real_stripes;
int nzones = 0;
int i;
unsigned long index = logical >> PAGE_CACHE_SHIFT;
int dev_replace_is_ongoing;
int have_zone = 0;
spin_lock(&fs_info->reada_lock);
re = radix_tree_lookup(&fs_info->reada_tree, index);
@@ -375,11 +371,16 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
struct reada_zone *zone;
dev = bbio->stripes[nzones].dev;
/* cannot read ahead on missing device. */
if (!dev->bdev)
continue;
zone = reada_find_zone(fs_info, dev, logical, bbio);
if (!zone)
break;
continue;
re->zones[nzones] = zone;
re->zones[re->nzones++] = zone;
spin_lock(&zone->lock);
if (!zone->elems)
kref_get(&zone->refcnt);
@@ -389,8 +390,7 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
}
re->nzones = nzones;
if (nzones == 0) {
if (re->nzones == 0) {
/* not a single zone found, error and out */
goto error;
}
@@ -415,8 +415,9 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
prev_dev = NULL;
dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(
&fs_info->dev_replace);
for (i = 0; i < nzones; ++i) {
dev = bbio->stripes[i].dev;
for (nzones = 0; nzones < re->nzones; ++nzones) {
dev = re->zones[nzones]->device;
if (dev == prev_dev) {
/*
* in case of DUP, just add the first zone. As both
@@ -427,15 +428,9 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
*/
continue;
}
if (!dev->bdev) {
/*
* cannot read ahead on missing device, but for RAID5/6,
* REQ_GET_READ_MIRRORS return 1. So don't skip missing
* device for such case.
*/
if (nzones > 1)
continue;
}
if (!dev->bdev)
continue;
if (dev_replace_is_ongoing &&
dev == fs_info->dev_replace.tgtdev) {
/*
@@ -447,8 +442,8 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
prev_dev = dev;
ret = radix_tree_insert(&dev->reada_extents, index, re);
if (ret) {
while (--i >= 0) {
dev = bbio->stripes[i].dev;
while (--nzones >= 0) {
dev = re->zones[nzones]->device;
BUG_ON(dev == NULL);
/* ignore whether the entry was inserted */
radix_tree_delete(&dev->reada_extents, index);
@@ -459,18 +454,21 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
btrfs_dev_replace_unlock(&fs_info->dev_replace);
goto error;
}
have_zone = 1;
}
spin_unlock(&fs_info->reada_lock);
btrfs_dev_replace_unlock(&fs_info->dev_replace);
if (!have_zone)
goto error;
btrfs_put_bbio(bbio);
return re;
error:
while (nzones) {
for (nzones = 0; nzones < re->nzones; ++nzones) {
struct reada_zone *zone;
--nzones;
zone = re->zones[nzones];
kref_get(&zone->refcnt);
spin_lock(&zone->lock);
@@ -531,8 +529,6 @@ static void reada_extent_put(struct btrfs_fs_info *fs_info,
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
}
if (re->scheduled_for)
atomic_dec(&re->scheduled_for->reada_in_flight);
kfree(re);
}
@@ -556,13 +552,13 @@ static void reada_control_release(struct kref *kref)
}
static int reada_add_block(struct reada_control *rc, u64 logical,
struct btrfs_key *top, int level, u64 generation)
struct btrfs_key *top, u64 generation)
{
struct btrfs_root *root = rc->root;
struct reada_extent *re;
struct reada_extctl *rec;
re = reada_find_extent(root, logical, top, level); /* takes one ref */
re = reada_find_extent(root, logical, top); /* takes one ref */
if (!re)
return -1;
@@ -662,7 +658,6 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
u64 logical;
int ret;
int i;
int need_kick = 0;
spin_lock(&fs_info->reada_lock);
if (dev->reada_curr_zone == NULL) {
@@ -679,7 +674,7 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
*/
ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re,
dev->reada_next >> PAGE_CACHE_SHIFT, 1);
if (ret == 0 || re->logical >= dev->reada_curr_zone->end) {
if (ret == 0 || re->logical > dev->reada_curr_zone->end) {
ret = reada_pick_zone(dev);
if (!ret) {
spin_unlock(&fs_info->reada_lock);
@@ -698,6 +693,15 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
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
*/
@@ -709,29 +713,20 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
}
logical = re->logical;
spin_lock(&re->lock);
if (re->scheduled_for == NULL) {
re->scheduled_for = dev;
need_kick = 1;
}
spin_unlock(&re->lock);
reada_extent_put(fs_info, re);
if (!need_kick)
return 0;
atomic_inc(&dev->reada_in_flight);
ret = reada_tree_block_flagged(fs_info->extent_root, logical,
mirror_num, &eb);
if (ret)
__readahead_hook(fs_info->extent_root, NULL, logical, ret);
__readahead_hook(fs_info, re, NULL, logical, ret);
else if (eb)
__readahead_hook(fs_info->extent_root, eb, eb->start, ret);
__readahead_hook(fs_info, re, eb, eb->start, ret);
if (eb)
free_extent_buffer(eb);
atomic_dec(&dev->reada_in_flight);
reada_extent_put(fs_info, re);
return 1;
}
@@ -752,6 +747,8 @@ static void reada_start_machine_worker(struct btrfs_work *work)
set_task_ioprio(current, BTRFS_IOPRIO_READA);
__reada_start_machine(fs_info);
set_task_ioprio(current, old_ioprio);
atomic_dec(&fs_info->reada_works_cnt);
}
static void __reada_start_machine(struct btrfs_fs_info *fs_info)
@@ -783,8 +780,12 @@ static void __reada_start_machine(struct btrfs_fs_info *fs_info)
* enqueue to workers to finish it. This will distribute the load to
* the cores.
*/
for (i = 0; i < 2; ++i)
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)
@@ -801,6 +802,7 @@ static void reada_start_machine(struct btrfs_fs_info *fs_info)
rmw->fs_info = fs_info;
btrfs_queue_work(fs_info->readahead_workers, &rmw->work);
atomic_inc(&fs_info->reada_works_cnt);
}
#ifdef DEBUG
@@ -848,10 +850,9 @@ static void dump_devs(struct btrfs_fs_info *fs_info, int all)
if (ret == 0)
break;
printk(KERN_DEBUG
" re: logical %llu size %u empty %d for %lld",
" re: logical %llu size %u empty %d scheduled %d",
re->logical, fs_info->tree_root->nodesize,
list_empty(&re->extctl), re->scheduled_for ?
re->scheduled_for->devid : -1);
list_empty(&re->extctl), re->scheduled);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
@@ -878,27 +879,21 @@ static void dump_devs(struct btrfs_fs_info *fs_info, int all)
index, 1);
if (ret == 0)
break;
if (!re->scheduled_for) {
if (!re->scheduled) {
index = (re->logical >> PAGE_CACHE_SHIFT) + 1;
continue;
}
printk(KERN_DEBUG
"re: logical %llu size %u list empty %d for %lld",
"re: logical %llu size %u list empty %d scheduled %d",
re->logical, fs_info->tree_root->nodesize,
list_empty(&re->extctl),
re->scheduled_for ? re->scheduled_for->devid : -1);
list_empty(&re->extctl), re->scheduled);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
re->zones[i]->start,
re->zones[i]->end);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
re->zones[i]->start,
re->zones[i]->end);
for (j = 0; j < re->zones[i]->ndevs; ++j) {
printk(KERN_CONT " %lld",
re->zones[i]->devs[j]->devid);
}
for (j = 0; j < re->zones[i]->ndevs; ++j) {
printk(KERN_CONT " %lld",
re->zones[i]->devs[j]->devid);
}
}
printk(KERN_CONT "\n");
@@ -917,7 +912,6 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
struct reada_control *rc;
u64 start;
u64 generation;
int level;
int ret;
struct extent_buffer *node;
static struct btrfs_key max_key = {
@@ -940,11 +934,10 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
node = btrfs_root_node(root);
start = node->start;
level = btrfs_header_level(node);
generation = btrfs_header_generation(node);
free_extent_buffer(node);
ret = reada_add_block(rc, start, &max_key, level, generation);
ret = reada_add_block(rc, start, &max_key, generation);
if (ret) {
kfree(rc);
return ERR_PTR(ret);
@@ -959,8 +952,11 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
int btrfs_reada_wait(void *handle)
{
struct reada_control *rc = handle;
struct btrfs_fs_info *fs_info = rc->root->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(rc->root->fs_info,
@@ -977,9 +973,13 @@ int btrfs_reada_wait(void *handle)
int btrfs_reada_wait(void *handle)
{
struct reada_control *rc = handle;
struct btrfs_fs_info *fs_info = rc->root->fs_info;
while (atomic_read(&rc->elems)) {
wait_event(rc->wait, atomic_read(&rc->elems) == 0);
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);