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authorChris Mason <chris.mason@oracle.com>2010-10-26 13:37:56 -0400
committerChris Mason <chris.mason@oracle.com>2010-10-29 11:25:35 -0400
commite5bc2458293b2af6c0b94435965c68cc70974b56 (patch)
treed4b79f61f2ff236b080583345b4dfd617b0fca07
parent3259f8bed2f0f57c2fdcdac1b510c3fa319ef97e (diff)
Btrfs: tune the chunk allocation to 5% of the FS as metadata
An earlier commit tried to keep us from allocating too many empty metadata chunks. It was somewhat too restrictive and could lead to ENOSPC errors on empty filesystems. This increases the limits to about 5% of the FS size, allowing more metadata chunks to be preallocated. Signed-off-by: Chris Mason <chris.mason@oracle.com>
-rw-r--r--fs/btrfs/extent-tree.c22
1 files changed, 18 insertions, 4 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 372fd224a11..980d6a3c342 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -580,6 +580,15 @@ static u64 div_factor(u64 num, int factor)
return num;
}
+static u64 div_factor_fine(u64 num, int factor)
+{
+ if (factor == 100)
+ return num;
+ num *= factor;
+ do_div(num, 100);
+ return num;
+}
+
u64 btrfs_find_block_group(struct btrfs_root *root,
u64 search_start, u64 search_hint, int owner)
{
@@ -3218,9 +3227,11 @@ static void force_metadata_allocation(struct btrfs_fs_info *info)
rcu_read_unlock();
}
-static int should_alloc_chunk(struct btrfs_space_info *sinfo, u64 alloc_bytes)
+static int should_alloc_chunk(struct btrfs_root *root,
+ struct btrfs_space_info *sinfo, u64 alloc_bytes)
{
u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
+ u64 thresh;
if (sinfo->bytes_used + sinfo->bytes_reserved +
alloc_bytes + 256 * 1024 * 1024 < num_bytes)
@@ -3230,8 +3241,10 @@ static int should_alloc_chunk(struct btrfs_space_info *sinfo, u64 alloc_bytes)
alloc_bytes < div_factor(num_bytes, 8))
return 0;
- if (num_bytes > 256 * 1024 * 1024 &&
- sinfo->bytes_used < div_factor(num_bytes, 3))
+ thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
+ 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;
@@ -3265,7 +3278,8 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
goto out;
}
- if (!force && !should_alloc_chunk(space_info, alloc_bytes)) {
+ if (!force && !should_alloc_chunk(extent_root, space_info,
+ alloc_bytes)) {
spin_unlock(&space_info->lock);
goto out;
}