Btrfs: Add mount -o ssd, which includes optimizations for seek free storage
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index fa65fe0..7a588ba 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -351,6 +351,7 @@
spinlock_t delalloc_lock;
spinlock_t new_trans_lock;
u64 delalloc_bytes;
+ u64 last_alloc;
};
/*
* in ram representation of the tree. extent_root is used for all allocations
@@ -444,6 +445,7 @@
#define BTRFS_MOUNT_NODATASUM (1 << 0)
#define BTRFS_MOUNT_NODATACOW (1 << 1)
#define BTRFS_MOUNT_NOBARRIER (1 << 2)
+#define BTRFS_MOUNT_SSD (1 << 3)
#define btrfs_clear_opt(o, opt) ((o) &= ~BTRFS_MOUNT_##opt)
#define btrfs_set_opt(o, opt) ((o) |= BTRFS_MOUNT_##opt)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 731a534..5d1f9bc 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -193,6 +193,7 @@
}
eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
read_extent_buffer_pages(tree, eb, start + PAGE_CACHE_SIZE, 1);
+ btrfs_clear_buffer_defrag(eb);
found_start = btrfs_header_bytenr(eb);
if (found_start != start) {
printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
@@ -676,6 +677,8 @@
fs_info->do_barriers = 1;
fs_info->closing = 0;
fs_info->total_pinned = 0;
+ fs_info->last_alloc = 0;
+
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
INIT_WORK(&fs_info->trans_work, btrfs_transaction_cleaner, fs_info);
#else
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2c569b4..b69a466 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1431,6 +1431,19 @@
data = BTRFS_BLOCK_GROUP_MIXED;
}
+ /* for SSD, cluster allocations together as much as possible */
+ if (btrfs_test_opt(root, SSD)) {
+ if (!data) {
+ if (root->fs_info->last_alloc)
+ hint_byte = root->fs_info->last_alloc;
+ else {
+ hint_byte = hint_byte &
+ ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
+ empty_size += 16 * 1024 * 1024;
+ }
+ }
+ }
+
search_end = min(search_end,
btrfs_super_total_bytes(&info->super_copy));
if (hint_byte) {
@@ -1456,6 +1469,19 @@
}
search_start = find_search_start(root, &block_group, search_start,
total_needed, data);
+
+ if (!data && btrfs_test_opt(root, SSD) && info->last_alloc &&
+ search_start != info->last_alloc) {
+ info->last_alloc = 0;
+ if (!empty_size) {
+ empty_size += 16 * 1024 * 1024;
+ total_needed += empty_size;
+ }
+ search_start = find_search_start(root, &block_group,
+ search_start, total_needed,
+ data);
+ }
+
search_start = stripe_align(root, search_start);
cached_start = search_start;
btrfs_init_path(path);
@@ -1610,6 +1636,8 @@
error:
btrfs_release_path(root, path);
btrfs_free_path(path);
+ if (btrfs_test_opt(root, SSD) && !ret && !data)
+ info->last_alloc = ins->objectid + ins->offset;
return ret;
}
/*
@@ -1778,7 +1806,8 @@
buf->start, buf->start + buf->len - 1,
EXTENT_CSUM, GFP_NOFS);
buf->flags |= EXTENT_CSUM;
- btrfs_set_buffer_defrag(buf);
+ if (!btrfs_test_opt(root, SSD))
+ btrfs_set_buffer_defrag(buf);
trans->blocks_used++;
return buf;
}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index e506de3..b6982f0 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -64,7 +64,7 @@
enum {
Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent,
- Opt_alloc_start, Opt_nobarrier, Opt_err,
+ Opt_alloc_start, Opt_nobarrier, Opt_ssd, Opt_err,
};
static match_table_t tokens = {
@@ -74,6 +74,7 @@
{Opt_nobarrier, "nobarrier"},
{Opt_max_extent, "max_extent=%s"},
{Opt_alloc_start, "alloc_start=%s"},
+ {Opt_ssd, "ssd"},
{Opt_err, NULL}
};
@@ -149,6 +150,12 @@
btrfs_set_opt(info->mount_opt, NODATASUM);
}
break;
+ case Opt_ssd:
+ if (info) {
+ printk("btrfs: use ssd allocation scheme\n");
+ btrfs_set_opt(info->mount_opt, SSD);
+ }
+ break;
case Opt_nobarrier:
if (info) {
printk("btrfs: turning off barriers\n");
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index b6bbfc1..163c01a 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -57,6 +57,7 @@
BUG_ON(!cur_trans);
root->fs_info->generation++;
root->fs_info->running_transaction = cur_trans;
+ root->fs_info->last_alloc = 0;
cur_trans->num_writers = 1;
cur_trans->num_joined = 0;
cur_trans->transid = root->fs_info->generation;
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index 5c58630..5935cbd 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -179,6 +179,9 @@
if (root->ref_cows == 0 && !is_extent)
goto out;
+ if (btrfs_test_opt(root, SSD))
+ goto out;
+
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;