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-rw-r--r--fs/btrfs/extent-tree.c95
1 files changed, 73 insertions, 22 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f619c3cb13b7..26479484180d 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -33,6 +33,25 @@
#include "locking.h"
#include "free-space-cache.h"
+/* control flags for do_chunk_alloc's force field
+ * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
+ * if we really need one.
+ *
+ * CHUNK_ALLOC_FORCE means it must try to allocate one
+ *
+ * CHUNK_ALLOC_LIMITED means to only try and allocate one
+ * if we have very few chunks already allocated. This is
+ * used as part of the clustering code to help make sure
+ * we have a good pool of storage to cluster in, without
+ * filling the FS with empty chunks
+ *
+ */
+enum {
+ CHUNK_ALLOC_NO_FORCE = 0,
+ CHUNK_ALLOC_FORCE = 1,
+ CHUNK_ALLOC_LIMITED = 2,
+};
+
static int update_block_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 bytenr, u64 num_bytes, int alloc);
@@ -3019,7 +3038,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
found->bytes_readonly = 0;
found->bytes_may_use = 0;
found->full = 0;
- found->force_alloc = 0;
+ found->force_alloc = CHUNK_ALLOC_NO_FORCE;
*space_info = found;
list_add_rcu(&found->list, &info->space_info);
atomic_set(&found->caching_threads, 0);
@@ -3150,7 +3169,7 @@ again:
if (!data_sinfo->full && alloc_chunk) {
u64 alloc_target;
- data_sinfo->force_alloc = 1;
+ data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
spin_unlock(&data_sinfo->lock);
alloc:
alloc_target = btrfs_get_alloc_profile(root, 1);
@@ -3160,7 +3179,8 @@ alloc:
ret = do_chunk_alloc(trans, root->fs_info->extent_root,
bytes + 2 * 1024 * 1024,
- alloc_target, 0);
+ alloc_target,
+ CHUNK_ALLOC_NO_FORCE);
btrfs_end_transaction(trans, root);
if (ret < 0) {
if (ret != -ENOSPC)
@@ -3239,31 +3259,56 @@ static void force_metadata_allocation(struct btrfs_fs_info *info)
rcu_read_lock();
list_for_each_entry_rcu(found, head, list) {
if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
- found->force_alloc = 1;
+ found->force_alloc = CHUNK_ALLOC_FORCE;
}
rcu_read_unlock();
}
static int should_alloc_chunk(struct btrfs_root *root,
- struct btrfs_space_info *sinfo, u64 alloc_bytes)
+ struct btrfs_space_info *sinfo, u64 alloc_bytes,
+ int force)
{
u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
+ u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
u64 thresh;
- if (sinfo->bytes_used + sinfo->bytes_reserved +
- alloc_bytes + 256 * 1024 * 1024 < num_bytes)
+ if (force == CHUNK_ALLOC_FORCE)
+ return 1;
+
+ /*
+ * in limited mode, we want to have some free space up to
+ * about 1% of the FS size.
+ */
+ if (force == CHUNK_ALLOC_LIMITED) {
+ thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
+ thresh = max_t(u64, 64 * 1024 * 1024,
+ div_factor_fine(thresh, 1));
+
+ if (num_bytes - num_allocated < thresh)
+ return 1;
+ }
+
+ /*
+ * we have two similar checks here, one based on percentage
+ * and once based on a hard number of 256MB. The idea
+ * is that if we have a good amount of free
+ * room, don't allocate a chunk. A good mount is
+ * less than 80% utilized of the chunks we have allocated,
+ * or more than 256MB free
+ */
+ if (num_allocated + alloc_bytes + 256 * 1024 * 1024 < num_bytes)
return 0;
- if (sinfo->bytes_used + sinfo->bytes_reserved +
- alloc_bytes < div_factor(num_bytes, 8))
+ if (num_allocated + alloc_bytes < div_factor(num_bytes, 8))
return 0;
thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
+
+ /* 256MB or 5% of the FS */
thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
return 0;
-
return 1;
}
@@ -3289,17 +3334,17 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
spin_lock(&space_info->lock);
if (space_info->force_alloc)
- force = 1;
+ force = space_info->force_alloc;
if (space_info->full) {
spin_unlock(&space_info->lock);
goto out;
}
- if (!force && !should_alloc_chunk(extent_root, space_info,
- alloc_bytes)) {
+ if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
spin_unlock(&space_info->lock);
goto out;
}
+
spin_unlock(&space_info->lock);
/*
@@ -3327,7 +3372,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
space_info->full = 1;
else
ret = 1;
- space_info->force_alloc = 0;
+ space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
spin_unlock(&space_info->lock);
out:
mutex_unlock(&extent_root->fs_info->chunk_mutex);
@@ -5303,11 +5348,13 @@ loop:
if (allowed_chunk_alloc) {
ret = do_chunk_alloc(trans, root, num_bytes +
- 2 * 1024 * 1024, data, 1);
+ 2 * 1024 * 1024, data,
+ CHUNK_ALLOC_LIMITED);
allowed_chunk_alloc = 0;
done_chunk_alloc = 1;
- } else if (!done_chunk_alloc) {
- space_info->force_alloc = 1;
+ } else if (!done_chunk_alloc &&
+ space_info->force_alloc == CHUNK_ALLOC_NO_FORCE) {
+ space_info->force_alloc = CHUNK_ALLOC_LIMITED;
}
if (loop < LOOP_NO_EMPTY_SIZE) {
@@ -5393,7 +5440,8 @@ again:
*/
if (empty_size || root->ref_cows)
ret = do_chunk_alloc(trans, root->fs_info->extent_root,
- num_bytes + 2 * 1024 * 1024, data, 0);
+ num_bytes + 2 * 1024 * 1024, data,
+ CHUNK_ALLOC_NO_FORCE);
WARN_ON(num_bytes < root->sectorsize);
ret = find_free_extent(trans, root, num_bytes, empty_size,
@@ -5405,7 +5453,7 @@ again:
num_bytes = num_bytes & ~(root->sectorsize - 1);
num_bytes = max(num_bytes, min_alloc_size);
do_chunk_alloc(trans, root->fs_info->extent_root,
- num_bytes, data, 1);
+ num_bytes, data, CHUNK_ALLOC_FORCE);
goto again;
}
if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
@@ -8109,13 +8157,15 @@ int btrfs_set_block_group_ro(struct btrfs_root *root,
alloc_flags = update_block_group_flags(root, cache->flags);
if (alloc_flags != cache->flags)
- do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1);
+ do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
+ CHUNK_ALLOC_FORCE);
ret = set_block_group_ro(cache);
if (!ret)
goto out;
alloc_flags = get_alloc_profile(root, cache->space_info->flags);
- ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1);
+ ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
+ CHUNK_ALLOC_FORCE);
if (ret < 0)
goto out;
ret = set_block_group_ro(cache);
@@ -8128,7 +8178,8 @@ int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 type)
{
u64 alloc_flags = get_alloc_profile(root, type);
- return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1);
+ return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
+ CHUNK_ALLOC_FORCE);
}
/*
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