Instead of tons of different local variables in find_free_extent(),
extract them into find_free_extent_ctl structure, and add better
explanation for them.
Some modification may looks redundant, but will later greatly simplify
function parameter list during find_free_extent() refactor.
Signed-off-by: Qu Wenruo <w...@suse.com>
---
fs/btrfs/extent-tree.c | 253 ++++++++++++++++++++++++++---------------
1 file changed, 161 insertions(+), 92 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index de6f75f5547b..dc10f6fd26af 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7212,6 +7212,55 @@ btrfs_release_block_group(struct btrfs_block_group_cache
*cache,
btrfs_put_block_group(cache);
}
+/*
+ * Internal used structure for find_free_extent() function.
+ * Wraps needed parameters.
+ */
+struct find_free_extent_ctl {
+ /* Basic allocation info */
+ u64 ram_bytes;
+ u64 num_bytes;
+ u64 empty_size;
+ u64 flags;
+ int delalloc;
+
+ /* Where to start the search inside the bg */
+ u64 search_start;
+
+ /* For clustered allocation */
+ u64 empty_cluster;
+
+ bool have_caching_bg;
+ bool orig_have_caching_bg;
+
+ /* RAID index, converted from flags */
+ int index;
+
+ /* Current loop number */
+ int loop;
+
+ /*
+ * Whether we're refilling a cluster, if true we need to re-search
+ * current block group but don't try to refill the cluster again.
+ */
+ bool retry_clustered;
+
+ /*
+ * Whether we're updating free space cache, if true we need to re-search
+ * current block group but don't try updating free space cache again.
+ */
+ bool retry_unclustered;
+
+ /* If current block group is cached */
+ int cached;
+
+ /* Max extent size found */
+ u64 max_extent_size;
+
+ /* Found result */
+ u64 found_offset;
+};
+
/*
* walks the btree of allocated extents and find a hole of a given size.
* The key ins is changed to record the hole:
@@ -7232,20 +7281,26 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_free_cluster *last_ptr = NULL;
struct btrfs_block_group_cache *block_group = NULL;
- u64 search_start = 0;
- u64 max_extent_size = 0;
- u64 empty_cluster = 0;
+ struct find_free_extent_ctl ffe_ctl = {0};
struct btrfs_space_info *space_info;
- int loop = 0;
- int index = btrfs_bg_flags_to_raid_index(flags);
- bool failed_cluster_refill = false;
- bool failed_alloc = false;
bool use_cluster = true;
- bool have_caching_bg = false;
- bool orig_have_caching_bg = false;
bool full_search = false;
WARN_ON(num_bytes < fs_info->sectorsize);
+
+ ffe_ctl.ram_bytes = ram_bytes;
+ ffe_ctl.num_bytes = num_bytes;
+ ffe_ctl.empty_size = empty_size;
+ ffe_ctl.flags = flags;
+ ffe_ctl.search_start = 0;
+ ffe_ctl.retry_clustered = false;
+ ffe_ctl.retry_unclustered = false;
+ ffe_ctl.delalloc = delalloc;
+ ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags);
+ ffe_ctl.have_caching_bg = false;
+ ffe_ctl.orig_have_caching_bg = false;
+ ffe_ctl.found_offset = 0;
+
ins->type = BTRFS_EXTENT_ITEM_KEY;
ins->objectid = 0;
ins->offset = 0;
@@ -7281,7 +7336,8 @@ static noinline int find_free_extent(struct btrfs_fs_info
*fs_info,
spin_unlock(&space_info->lock);
}
- last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
+ last_ptr = fetch_cluster_info(fs_info, space_info,
+ &ffe_ctl.empty_cluster);
if (last_ptr) {
spin_lock(&last_ptr->lock);
if (last_ptr->block_group)
@@ -7298,10 +7354,12 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
spin_unlock(&last_ptr->lock);
}
- search_start = max(search_start, first_logical_byte(fs_info, 0));
- search_start = max(search_start, hint_byte);
- if (search_start == hint_byte) {
- block_group = btrfs_lookup_block_group(fs_info, search_start);
+ ffe_ctl.search_start = max(ffe_ctl.search_start,
+ first_logical_byte(fs_info, 0));
+ ffe_ctl.search_start = max(ffe_ctl.search_start, hint_byte);
+ if (ffe_ctl.search_start == hint_byte) {
+ block_group = btrfs_lookup_block_group(fs_info,
+ ffe_ctl.search_start);
/*
* we don't want to use the block group if it doesn't match our
* allocation bits, or if its not cached.
@@ -7323,7 +7381,7 @@ static noinline int find_free_extent(struct btrfs_fs_info
*fs_info,
btrfs_put_block_group(block_group);
up_read(&space_info->groups_sem);
} else {
- index = btrfs_bg_flags_to_raid_index(
+ ffe_ctl.index = btrfs_bg_flags_to_raid_index(
block_group->flags);
btrfs_lock_block_group(block_group, delalloc);
goto have_block_group;
@@ -7333,21 +7391,19 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
}
}
search:
- have_caching_bg = false;
- if (index == 0 || index == btrfs_bg_flags_to_raid_index(flags))
+ ffe_ctl.have_caching_bg = false;
+ if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) ||
+ ffe_ctl.index == 0)
full_search = true;
down_read(&space_info->groups_sem);
- list_for_each_entry(block_group, &space_info->block_groups[index],
- list) {
- u64 offset;
- int cached;
-
+ list_for_each_entry(block_group,
+ &space_info->block_groups[ffe_ctl.index], list) {
/* If the block group is read-only, we can skip it entirely. */
if (unlikely(block_group->ro))
continue;
btrfs_grab_block_group(block_group, delalloc);
- search_start = block_group->key.objectid;
+ ffe_ctl.search_start = block_group->key.objectid;
/*
* this can happen if we end up cycling through all the
@@ -7371,9 +7427,9 @@ static noinline int find_free_extent(struct btrfs_fs_info
*fs_info,
}
have_block_group:
- cached = block_group_cache_done(block_group);
- if (unlikely(!cached)) {
- have_caching_bg = true;
+ ffe_ctl.cached = block_group_cache_done(block_group);
+ if (unlikely(!ffe_ctl.cached)) {
+ ffe_ctl.have_caching_bg = true;
ret = cache_block_group(block_group, 0);
BUG_ON(ret < 0);
ret = 0;
@@ -7401,20 +7457,23 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
if (used_block_group != block_group &&
(used_block_group->ro ||
- !block_group_bits(used_block_group, flags)))
+ !block_group_bits(used_block_group,
+ ffe_ctl.flags)))
goto release_cluster;
- offset = btrfs_alloc_from_cluster(used_block_group,
+ ffe_ctl.found_offset = btrfs_alloc_from_cluster(
+ used_block_group,
last_ptr,
num_bytes,
used_block_group->key.objectid,
- &max_extent_size);
- if (offset) {
+ &ffe_ctl.max_extent_size);
+ if (ffe_ctl.found_offset) {
/* we have a block, we're done */
spin_unlock(&last_ptr->refill_lock);
trace_btrfs_reserve_extent_cluster(
used_block_group,
- search_start, num_bytes);
+ ffe_ctl.search_start,
+ num_bytes);
if (used_block_group != block_group) {
btrfs_release_block_group(block_group,
delalloc);
@@ -7440,7 +7499,7 @@ static noinline int find_free_extent(struct btrfs_fs_info
*fs_info,
* first, so that we stand a better chance of
* succeeding in the unclustered
* allocation. */
- if (loop >= LOOP_NO_EMPTY_SIZE &&
+ if (ffe_ctl.loop >= LOOP_NO_EMPTY_SIZE &&
used_block_group != block_group) {
spin_unlock(&last_ptr->refill_lock);
btrfs_release_block_group(used_block_group,
@@ -7458,18 +7517,19 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
btrfs_release_block_group(used_block_group,
delalloc);
refill_cluster:
- if (loop >= LOOP_NO_EMPTY_SIZE) {
+ if (ffe_ctl.loop >= LOOP_NO_EMPTY_SIZE) {
spin_unlock(&last_ptr->refill_lock);
goto unclustered_alloc;
}
aligned_cluster = max_t(unsigned long,
- empty_cluster + empty_size,
- block_group->full_stripe_len);
+ ffe_ctl.empty_cluster + empty_size,
+ block_group->full_stripe_len);
/* allocate a cluster in this block group */
ret = btrfs_find_space_cluster(fs_info, block_group,
- last_ptr, search_start,
+ last_ptr,
+ ffe_ctl.search_start,
num_bytes,
aligned_cluster);
if (ret == 0) {
@@ -7477,26 +7537,28 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
* now pull our allocation out of this
* cluster
*/
- offset = btrfs_alloc_from_cluster(block_group,
- last_ptr,
- num_bytes,
- search_start,
- &max_extent_size);
- if (offset) {
+ ffe_ctl.found_offset = btrfs_alloc_from_cluster(
+ block_group, last_ptr,
+ num_bytes, ffe_ctl.search_start,
+ &ffe_ctl.max_extent_size);
+ if (ffe_ctl.found_offset) {
/* we found one, proceed */
spin_unlock(&last_ptr->refill_lock);
trace_btrfs_reserve_extent_cluster(
- block_group, search_start,
+ block_group,
+ ffe_ctl.search_start,
num_bytes);
goto checks;
}
- } else if (!cached && loop > LOOP_CACHING_NOWAIT
- && !failed_cluster_refill) {
+ } else if (!ffe_ctl.cached && ffe_ctl.loop >
+ LOOP_CACHING_NOWAIT
+ && !ffe_ctl.retry_clustered) {
spin_unlock(&last_ptr->refill_lock);
- failed_cluster_refill = true;
+ ffe_ctl.retry_clustered = true;
wait_block_group_cache_progress(block_group,
- num_bytes + empty_cluster + empty_size);
+ num_bytes + ffe_ctl.empty_cluster +
+ empty_size);
goto have_block_group;
}
@@ -7522,89 +7584,96 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
last_ptr->fragmented = 1;
spin_unlock(&last_ptr->lock);
}
- if (cached) {
+ if (ffe_ctl.cached) {
struct btrfs_free_space_ctl *ctl =
block_group->free_space_ctl;
spin_lock(&ctl->tree_lock);
if (ctl->free_space <
- num_bytes + empty_cluster + empty_size) {
- if (ctl->free_space > max_extent_size)
- max_extent_size = ctl->free_space;
+ num_bytes + ffe_ctl.empty_cluster + empty_size) {
+ if (ctl->free_space > ffe_ctl.max_extent_size)
+ ffe_ctl.max_extent_size =
ctl->free_space;
spin_unlock(&ctl->tree_lock);
goto loop;
}
spin_unlock(&ctl->tree_lock);
}
- offset = btrfs_find_space_for_alloc(block_group, search_start,
- num_bytes, empty_size,
- &max_extent_size);
+ ffe_ctl.found_offset = btrfs_find_space_for_alloc(block_group,
+ ffe_ctl.search_start, num_bytes, empty_size,
+ &ffe_ctl.max_extent_size);
/*
* If we didn't find a chunk, and we haven't failed on this
* block group before, and this block group is in the middle of
* caching and we are ok with waiting, then go ahead and wait
- * for progress to be made, and set failed_alloc to true.
+ * for progress to be made, and set ffe_ctl.retry_unclustered to
+ * true.
*
- * If failed_alloc is true then we've already waited on this
- * block group once and should move on to the next block group.
+ * If ffe_ctl.retry_unclustered is true then we've already
+ * waited on this block group once and should move on to the
+ * next block group.
*/
- if (!offset && !failed_alloc && !cached &&
- loop > LOOP_CACHING_NOWAIT) {
+ if (!ffe_ctl.found_offset && !ffe_ctl.retry_unclustered &&
+ !ffe_ctl.cached && ffe_ctl.loop > LOOP_CACHING_NOWAIT) {
wait_block_group_cache_progress(block_group,
num_bytes + empty_size);
- failed_alloc = true;
+ ffe_ctl.retry_unclustered = true;
goto have_block_group;
- } else if (!offset) {
+ } else if (!ffe_ctl.found_offset) {
goto loop;
}
checks:
- search_start = round_up(offset, fs_info->stripesize);
+ ffe_ctl.search_start = round_up(ffe_ctl.found_offset,
+ fs_info->stripesize);
/* move on to the next group */
- if (search_start + num_bytes >
+ if (ffe_ctl.search_start + num_bytes >
block_group->key.objectid + block_group->key.offset) {
- btrfs_add_free_space(block_group, offset, num_bytes);
+ btrfs_add_free_space(block_group, ffe_ctl.found_offset,
+ num_bytes);
goto loop;
}
- if (offset < search_start)
- btrfs_add_free_space(block_group, offset,
- search_start - offset);
+ if (ffe_ctl.found_offset < ffe_ctl.search_start)
+ btrfs_add_free_space(block_group, ffe_ctl.found_offset,
+ ffe_ctl.search_start - ffe_ctl.found_offset);
ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
num_bytes, delalloc);
if (ret == -EAGAIN) {
- btrfs_add_free_space(block_group, offset, num_bytes);
+ btrfs_add_free_space(block_group, ffe_ctl.found_offset,
+ num_bytes);
goto loop;
}
btrfs_inc_block_group_reservations(block_group);
/* we are all good, lets return */
- ins->objectid = search_start;
+ ins->objectid = ffe_ctl.search_start;
ins->offset = num_bytes;
- trace_btrfs_reserve_extent(block_group, search_start,
num_bytes);
+ trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start,
+ num_bytes);
btrfs_release_block_group(block_group, delalloc);
break;
loop:
- failed_cluster_refill = false;
- failed_alloc = false;
+ ffe_ctl.retry_clustered = false;
+ ffe_ctl.retry_unclustered = false;
BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
- index);
+ ffe_ctl.index);
btrfs_release_block_group(block_group, delalloc);
cond_resched();
}
up_read(&space_info->groups_sem);
- if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
- && !orig_have_caching_bg)
- orig_have_caching_bg = true;
+ if ((ffe_ctl.loop == LOOP_CACHING_NOWAIT) && ffe_ctl.have_caching_bg
+ && !ffe_ctl.orig_have_caching_bg)
+ ffe_ctl.orig_have_caching_bg = true;
- if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
+ if (!ins->objectid && ffe_ctl.loop >= LOOP_CACHING_WAIT &&
+ ffe_ctl.have_caching_bg)
goto search;
- if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
+ if (!ins->objectid && ++ffe_ctl.index < BTRFS_NR_RAID_TYPES)
goto search;
/*
@@ -7615,23 +7684,23 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
* LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
* again
*/
- if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
- index = 0;
- if (loop == LOOP_CACHING_NOWAIT) {
+ if (!ins->objectid && ffe_ctl.loop < LOOP_NO_EMPTY_SIZE) {
+ ffe_ctl.index = 0;
+ if (ffe_ctl.loop == LOOP_CACHING_NOWAIT) {
/*
* We want to skip the LOOP_CACHING_WAIT step if we
* don't have any uncached bgs and we've already done a
* full search through.
*/
- if (orig_have_caching_bg || !full_search)
- loop = LOOP_CACHING_WAIT;
+ if (ffe_ctl.orig_have_caching_bg || !full_search)
+ ffe_ctl.loop = LOOP_CACHING_WAIT;
else
- loop = LOOP_ALLOC_CHUNK;
+ ffe_ctl.loop = LOOP_ALLOC_CHUNK;
} else {
- loop++;
+ ffe_ctl.loop++;
}
- if (loop == LOOP_ALLOC_CHUNK) {
+ if (ffe_ctl.loop == LOOP_ALLOC_CHUNK) {
struct btrfs_trans_handle *trans;
int exist = 0;
@@ -7654,7 +7723,7 @@ static noinline int find_free_extent(struct btrfs_fs_info
*fs_info,
* case.
*/
if (ret == -ENOSPC)
- loop = LOOP_NO_EMPTY_SIZE;
+ ffe_ctl.loop = LOOP_NO_EMPTY_SIZE;
/*
* Do not bail out on ENOSPC since we
@@ -7670,18 +7739,18 @@ static noinline int find_free_extent(struct
btrfs_fs_info *fs_info,
goto out;
}
- if (loop == LOOP_NO_EMPTY_SIZE) {
+ if (ffe_ctl.loop == LOOP_NO_EMPTY_SIZE) {
/*
* Don't loop again if we already have no empty_size and
* no empty_cluster.
*/
if (empty_size == 0 &&
- empty_cluster == 0) {
+ ffe_ctl.empty_cluster == 0) {
ret = -ENOSPC;
goto out;
}
empty_size = 0;
- empty_cluster = 0;
+ ffe_ctl.empty_cluster = 0;
}
goto search;
@@ -7698,9 +7767,9 @@ static noinline int find_free_extent(struct btrfs_fs_info
*fs_info,
out:
if (ret == -ENOSPC) {
spin_lock(&space_info->lock);
- space_info->max_extent_size = max_extent_size;
+ space_info->max_extent_size = ffe_ctl.max_extent_size;
spin_unlock(&space_info->lock);
- ins->offset = max_extent_size;
+ ins->offset = ffe_ctl.max_extent_size;
}
return ret;
}
--
2.19.1
