Arne Jansen
2011-May-13 13:47 UTC
[PATCH v4 0/3] btrfs: quasi-round-robin for chunk allocation
In a multi device setup, the chunk allocator currently always allocates chunks on the devices in the same order. This leads to a very uneven distribution, especially with RAID1 or RAID10 and an uneven number of devices. This patch always sorts the devices before allocating, and allocates the stripes on the devices with the most available space, as long as there is enough space available. In a low space situation, it first tries to maximize striping. The patch also simplifies the allocator and reduces the checks for corner cases. The simplification is done by several means. First, it defines the properties of each RAID type upfront. These properties are used afterwards instead of differentiating cases in several places. Second, the old allocator defined a minimum stripe size for each block group type, tried to find a large enough chunk, and if this fails just allocates a smaller one. This is now done in one step. The largest possible chunk (up to max_chunk_size) is searched and allocated. Because we now have only one pass, the allocation of the map (struct map_lookup) is moved down to the point where the number of stripes is already known. This way we avoid reallocation of the map. We still avoid allocating stripes that are not a multiple of STRIPE_SIZE. Changes from v2: - bugfix for ''single'' raid type; the initial parameter initialization lacked a case for the ''single'' type, thus leaving devs_max at the wrong value Changes from v3: thanks to review of David Sterba: - move declarations from function-level to local scopes where possible - remove an unnecessary BUG_ON - change BUG -> WARN if a device is not writable and ignore the device - rename *num_bytes to num_bytes_out for consistency - transform a while loop that mimics a for loop into a for loop Arne Jansen (3): btrfs: move btrfs_cmp_device_free_bytes to super.c btrfs: heed alloc_start btrfs: quasi-round-robin for chunk allocation fs/btrfs/super.c | 26 +++ fs/btrfs/volumes.c | 521 +++++++++++++++++++--------------------------------- fs/btrfs/volumes.h | 16 +-- 3 files changed, 215 insertions(+), 348 deletions(-) -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Arne Jansen
2011-May-13 13:47 UTC
[PATCH v4 1/3] btrfs: move btrfs_cmp_device_free_bytes to super.c
this function won''t be used here anymore, so move it super.c where it
is
used for df-calculation
Signed-off-by: Arne Jansen <sensille@gmx.net>
---
fs/btrfs/super.c | 26 ++++++++++++++++++++++++++
fs/btrfs/volumes.c | 13 -------------
fs/btrfs/volumes.h | 15 ---------------
3 files changed, 26 insertions(+), 28 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 0ac712e..32fe8b3 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -913,6 +913,32 @@ static int btrfs_remount(struct super_block *sb, int
*flags, char *data)
return 0;
}
+/* Used to sort the devices by max_avail(descending sort) */
+static int btrfs_cmp_device_free_bytes(const void *dev_info1,
+ const void *dev_info2)
+{
+ if (((struct btrfs_device_info *)dev_info1)->max_avail >
+ ((struct btrfs_device_info *)dev_info2)->max_avail)
+ return -1;
+ else if (((struct btrfs_device_info *)dev_info1)->max_avail <
+ ((struct btrfs_device_info *)dev_info2)->max_avail)
+ return 1;
+ else
+ return 0;
+}
+
+/*
+ * sort the devices by max_avail, in which max free extent size of each device
+ * is stored.(Descending Sort)
+ */
+static inline void btrfs_descending_sort_devices(
+ struct btrfs_device_info *devices,
+ size_t nr_devices)
+{
+ sort(devices, nr_devices, sizeof(struct btrfs_device_info),
+ btrfs_cmp_device_free_bytes, NULL);
+}
+
/*
* The helper to calc the free space on the devices that can be used to store
* file data.
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 8b9fb8c..a9f1fc2 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2282,19 +2282,6 @@ static noinline u64 chunk_bytes_by_type(u64 type, u64
calc_size,
return calc_size * num_stripes;
}
-/* Used to sort the devices by max_avail(descending sort) */
-int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2)
-{
- if (((struct btrfs_device_info *)dev_info1)->max_avail >
- ((struct btrfs_device_info *)dev_info2)->max_avail)
- return -1;
- else if (((struct btrfs_device_info *)dev_info1)->max_avail <
- ((struct btrfs_device_info *)dev_info2)->max_avail)
- return 1;
- else
- return 0;
-}
-
static int __btrfs_calc_nstripes(struct btrfs_fs_devices *fs_devices, u64 type,
int *num_stripes, int *min_stripes,
int *sub_stripes)
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index cc2eada..b502f01 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -157,21 +157,6 @@ struct map_lookup {
struct btrfs_bio_stripe stripes[];
};
-/* Used to sort the devices by max_avail(descending sort) */
-int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2);
-
-/*
- * sort the devices by max_avail, in which max free extent size of each device
- * is stored.(Descending Sort)
- */
-static inline void btrfs_descending_sort_devices(
- struct btrfs_device_info *devices,
- size_t nr_devices)
-{
- sort(devices, nr_devices, sizeof(struct btrfs_device_info),
- btrfs_cmp_device_free_bytes, NULL);
-}
-
int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
u64 end, u64 *length);
--
1.7.3.4
--
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currently alloc_start is disregarded if the requested chunk size is bigger than (device size - alloc_start), but smaller than the device size. The only situation where I see this could have made sense was when a chunk equal the size of the device has been requested. This was possible as the allocator failed to take alloc_start into account when calculating the request chunk size. As this gets fixed by this patch, the workaround is not necessary anymore. Signed-off-by: Arne Jansen <sensille@gmx.net> --- fs/btrfs/volumes.c | 5 +---- 1 files changed, 1 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index a9f1fc2..45c592a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -849,10 +849,7 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans, /* we don''t want to overwrite the superblock on the drive, * so we make sure to start at an offset of at least 1MB */ - search_start = 1024 * 1024; - - if (root->fs_info->alloc_start + num_bytes <= search_end) - search_start = max(root->fs_info->alloc_start, search_start); + search_start = max(root->fs_info->alloc_start, 1024ull * 1024); max_hole_start = search_start; max_hole_size = 0; -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Arne Jansen
2011-May-13 13:47 UTC
[PATCH v4 3/3] btrfs: quasi-round-robin for chunk allocation
In a multi device setup, the chunk allocator currently always allocates
chunks on the devices in the same order. This leads to a very uneven
distribution, especially with RAID1 or RAID10 and an uneven number of
devices.
This patch always sorts the devices before allocating, and allocates the
stripes on the devices with the most available space, as long as there
is enough space available. In a low space situation, it first tries to
maximize striping.
The patch also simplifies the allocator and reduces the checks for
corner cases.
The simplification is done by several means. First, it defines the
properties of each RAID type upfront. These properties are used afterwards
instead of differentiating cases in several places.
Second, the old allocator defined a minimum stripe size for each block
group type, tried to find a large enough chunk, and if this fails just
allocates a smaller one. This is now done in one step. The largest possible
chunk (up to max_chunk_size) is searched and allocated.
Because we now have only one pass, the allocation of the map (struct
map_lookup) is moved down to the point where the number of stripes is
already known. This way we avoid reallocation of the map.
We still avoid allocating stripes that are not a multiple of STRIPE_SIZE.
Signed-off-by: Arne Jansen <sensille@gmx.net>
---
fs/btrfs/volumes.c | 503 +++++++++++++++++++---------------------------------
fs/btrfs/volumes.h | 1 +
2 files changed, 188 insertions(+), 316 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 45c592a..ab55bfc 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2268,349 +2268,218 @@ static int btrfs_add_system_chunk(struct
btrfs_trans_handle *trans,
return 0;
}
-static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
- int num_stripes, int sub_stripes)
-{
- if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
- return calc_size;
- else if (type & BTRFS_BLOCK_GROUP_RAID10)
- return calc_size * (num_stripes / sub_stripes);
- else
- return calc_size * num_stripes;
-}
-
-static int __btrfs_calc_nstripes(struct btrfs_fs_devices *fs_devices, u64 type,
- int *num_stripes, int *min_stripes,
- int *sub_stripes)
-{
- *num_stripes = 1;
- *min_stripes = 1;
- *sub_stripes = 0;
-
- if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
- *num_stripes = fs_devices->rw_devices;
- *min_stripes = 2;
- }
- if (type & (BTRFS_BLOCK_GROUP_DUP)) {
- *num_stripes = 2;
- *min_stripes = 2;
- }
- if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
- if (fs_devices->rw_devices < 2)
- return -ENOSPC;
- *num_stripes = 2;
- *min_stripes = 2;
- }
- if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
- *num_stripes = fs_devices->rw_devices;
- if (*num_stripes < 4)
- return -ENOSPC;
- *num_stripes &= ~(u32)1;
- *sub_stripes = 2;
- *min_stripes = 4;
- }
-
- return 0;
-}
-
-static u64 __btrfs_calc_stripe_size(struct btrfs_fs_devices *fs_devices,
- u64 proposed_size, u64 type,
- int num_stripes, int small_stripe)
-{
- int min_stripe_size = 1 * 1024 * 1024;
- u64 calc_size = proposed_size;
- u64 max_chunk_size = calc_size;
- int ncopies = 1;
-
- if (type & (BTRFS_BLOCK_GROUP_RAID1 |
- BTRFS_BLOCK_GROUP_DUP |
- BTRFS_BLOCK_GROUP_RAID10))
- ncopies = 2;
-
- if (type & BTRFS_BLOCK_GROUP_DATA) {
- max_chunk_size = 10 * calc_size;
- min_stripe_size = 64 * 1024 * 1024;
- } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
- max_chunk_size = 256 * 1024 * 1024;
- min_stripe_size = 32 * 1024 * 1024;
- } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
- calc_size = 8 * 1024 * 1024;
- max_chunk_size = calc_size * 2;
- min_stripe_size = 1 * 1024 * 1024;
- }
-
- /* we don''t want a chunk larger than 10% of writeable space */
- max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
- max_chunk_size);
-
- if (calc_size * num_stripes > max_chunk_size * ncopies) {
- calc_size = max_chunk_size * ncopies;
- do_div(calc_size, num_stripes);
- do_div(calc_size, BTRFS_STRIPE_LEN);
- calc_size *= BTRFS_STRIPE_LEN;
- }
-
- /* we don''t want tiny stripes */
- if (!small_stripe)
- calc_size = max_t(u64, min_stripe_size, calc_size);
-
- /*
- * we''re about to do_div by the BTRFS_STRIPE_LEN so lets make sure
- * we end up with something bigger than a stripe
- */
- calc_size = max_t(u64, calc_size, BTRFS_STRIPE_LEN);
-
- do_div(calc_size, BTRFS_STRIPE_LEN);
- calc_size *= BTRFS_STRIPE_LEN;
-
- return calc_size;
-}
-
-static struct map_lookup *__shrink_map_lookup_stripes(struct map_lookup *map,
- int num_stripes)
-{
- struct map_lookup *new;
- size_t len = map_lookup_size(num_stripes);
-
- BUG_ON(map->num_stripes < num_stripes);
-
- if (map->num_stripes == num_stripes)
- return map;
-
- new = kmalloc(len, GFP_NOFS);
- if (!new) {
- /* just change map->num_stripes */
- map->num_stripes = num_stripes;
- return map;
- }
-
- memcpy(new, map, len);
- new->num_stripes = num_stripes;
- kfree(map);
- return new;
-}
-
/*
- * helper to allocate device space from btrfs_device_info, in which we stored
- * max free space information of every device. It is used when we can not
- * allocate chunks by default size.
- *
- * By this helper, we can allocate a new chunk as larger as possible.
+ * sort the devices in descending order by max_avail, total_avail
*/
-static int __btrfs_alloc_tiny_space(struct btrfs_trans_handle *trans,
- struct btrfs_fs_devices *fs_devices,
- struct btrfs_device_info *devices,
- int nr_device, u64 type,
- struct map_lookup **map_lookup,
- int min_stripes, u64 *stripe_size)
+static int btrfs_cmp_device_info(const void *a, const void *b)
{
- int i, index, sort_again = 0;
- int min_devices = min_stripes;
- u64 max_avail, min_free;
- struct map_lookup *map = *map_lookup;
- int ret;
-
- if (nr_device < min_stripes)
- return -ENOSPC;
-
- btrfs_descending_sort_devices(devices, nr_device);
-
- max_avail = devices[0].max_avail;
- if (!max_avail)
- return -ENOSPC;
-
- for (i = 0; i < nr_device; i++) {
- /*
- * if dev_offset = 0, it means the free space of this device
- * is less than what we need, and we didn''t search max avail
- * extent on this device, so do it now.
- */
- if (!devices[i].dev_offset) {
- ret = find_free_dev_extent(trans, devices[i].dev,
- max_avail,
- &devices[i].dev_offset,
- &devices[i].max_avail);
- if (ret != 0 && ret != -ENOSPC)
- return ret;
- sort_again = 1;
- }
- }
-
- /* we update the max avail free extent of each devices, sort again */
- if (sort_again)
- btrfs_descending_sort_devices(devices, nr_device);
-
- if (type & BTRFS_BLOCK_GROUP_DUP)
- min_devices = 1;
-
- if (!devices[min_devices - 1].max_avail)
- return -ENOSPC;
-
- max_avail = devices[min_devices - 1].max_avail;
- if (type & BTRFS_BLOCK_GROUP_DUP)
- do_div(max_avail, 2);
-
- max_avail = __btrfs_calc_stripe_size(fs_devices, max_avail, type,
- min_stripes, 1);
- if (type & BTRFS_BLOCK_GROUP_DUP)
- min_free = max_avail * 2;
- else
- min_free = max_avail;
-
- if (min_free > devices[min_devices - 1].max_avail)
- return -ENOSPC;
-
- map = __shrink_map_lookup_stripes(map, min_stripes);
- *stripe_size = max_avail;
-
- index = 0;
- for (i = 0; i < min_stripes; i++) {
- map->stripes[i].dev = devices[index].dev;
- map->stripes[i].physical = devices[index].dev_offset;
- if (type & BTRFS_BLOCK_GROUP_DUP) {
- i++;
- map->stripes[i].dev = devices[index].dev;
- map->stripes[i].physical = devices[index].dev_offset +
- max_avail;
- }
- index++;
- }
- *map_lookup = map;
-
+ const struct btrfs_device_info *di_a = a;
+ const struct btrfs_device_info *di_b = b;
+
+ if (di_a->max_avail > di_b->max_avail)
+ return -1;
+ if (di_a->max_avail < di_b->max_avail)
+ return 1;
+ if (di_a->total_avail > di_b->total_avail)
+ return -1;
+ if (di_a->total_avail < di_b->total_avail)
+ return 1;
return 0;
}
static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
struct btrfs_root *extent_root,
struct map_lookup **map_ret,
- u64 *num_bytes, u64 *stripe_size,
+ u64 *num_bytes_out, u64 *stripe_size_out,
u64 start, u64 type)
{
struct btrfs_fs_info *info = extent_root->fs_info;
- struct btrfs_device *device = NULL;
struct btrfs_fs_devices *fs_devices = info->fs_devices;
struct list_head *cur;
- struct map_lookup *map;
+ struct map_lookup *map = NULL;
struct extent_map_tree *em_tree;
struct extent_map *em;
- struct btrfs_device_info *devices_info;
- struct list_head private_devs;
- u64 calc_size = 1024 * 1024 * 1024;
- u64 min_free;
- u64 avail;
- u64 dev_offset;
- int num_stripes;
- int min_stripes;
- int sub_stripes;
- int min_devices; /* the min number of devices we need */
- int i;
+ struct btrfs_device_info *devices_info = NULL;
+ u64 total_avail;
+ int num_stripes; /* total number of stripes to allocate */
+ int sub_stripes; /* sub_stripes info for map */
+ int dev_stripes; /* stripes per dev */
+ int devs_max; /* max devs to use */
+ int devs_min; /* min devs needed */
+ int devs_increment; /* ndevs has to be a multiple of this */
+ int ncopies; /* how many copies to data has */
int ret;
- int index;
+ u64 max_stripe_size;
+ u64 max_chunk_size;
+ u64 stripe_size;
+ u64 num_bytes;
+ int ndevs;
+ int i;
+ int j;
if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
(type & BTRFS_BLOCK_GROUP_DUP)) {
WARN_ON(1);
type &= ~BTRFS_BLOCK_GROUP_DUP;
}
+
if (list_empty(&fs_devices->alloc_list))
return -ENOSPC;
- ret = __btrfs_calc_nstripes(fs_devices, type, &num_stripes,
- &min_stripes, &sub_stripes);
- if (ret)
- return ret;
+ sub_stripes = 1;
+ dev_stripes = 1;
+ devs_increment = 1;
+ ncopies = 1;
+ devs_max = 0; /* 0 == as many as possible */
+ devs_min = 1;
+
+ /*
+ * define the properties of each RAID type.
+ * FIXME: move this to a global table and use it in all RAID
+ * calculation code
+ */
+ if (type & (BTRFS_BLOCK_GROUP_DUP)) {
+ dev_stripes = 2;
+ ncopies = 2;
+ devs_max = 1;
+ } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
+ devs_min = 2;
+ } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
+ devs_increment = 2;
+ ncopies = 2;
+ devs_max = 2;
+ devs_min = 2;
+ } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
+ sub_stripes = 2;
+ devs_increment = 2;
+ ncopies = 2;
+ devs_min = 4;
+ } else {
+ devs_max = 1;
+ }
+
+ if (type & BTRFS_BLOCK_GROUP_DATA) {
+ max_stripe_size = 1024 * 1024 * 1024;
+ max_chunk_size = 10 * max_stripe_size;
+ } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
+ max_stripe_size = 256 * 1024 * 1024;
+ max_chunk_size = max_stripe_size;
+ } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
+ max_stripe_size = 8 * 1024 * 1024;
+ max_chunk_size = 2 * max_stripe_size;
+ } else {
+ printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
+ type);
+ BUG_ON(1);
+ }
+
+ /* we don''t want a chunk larger than 10% of writeable space */
+ max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
+ max_chunk_size);
devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
GFP_NOFS);
if (!devices_info)
return -ENOMEM;
- map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
- if (!map) {
- ret = -ENOMEM;
- goto error;
- }
- map->num_stripes = num_stripes;
-
cur = fs_devices->alloc_list.next;
- index = 0;
- i = 0;
- calc_size = __btrfs_calc_stripe_size(fs_devices, calc_size, type,
- num_stripes, 0);
+ /*
+ * in the first pass through the devices list, we gather information
+ * about the available holes on each device.
+ */
+ ndevs = 0;
+ while (cur != &fs_devices->alloc_list) {
+ struct btrfs_device *device;
+ u64 max_avail;
+ u64 dev_offset;
- if (type & BTRFS_BLOCK_GROUP_DUP) {
- min_free = calc_size * 2;
- min_devices = 1;
- } else {
- min_free = calc_size;
- min_devices = min_stripes;
- }
-
- INIT_LIST_HEAD(&private_devs);
- while (index < num_stripes) {
device = list_entry(cur, struct btrfs_device, dev_alloc_list);
- BUG_ON(!device->writeable);
+
+ cur = cur->next;
+
+ if (!device->writeable) {
+ printk(KERN_ERR
+ "btrfs: read-only device in alloc_list\n");
+ WARN_ON(1);
+ continue;
+ }
+
+ if (!device->in_fs_metadata)
+ continue;
+
if (device->total_bytes > device->bytes_used)
- avail = device->total_bytes - device->bytes_used;
+ total_avail = device->total_bytes - device->bytes_used;
else
- avail = 0;
- cur = cur->next;
-
- if (device->in_fs_metadata && avail >= min_free) {
- ret = find_free_dev_extent(trans, device, min_free,
- &devices_info[i].dev_offset,
- &devices_info[i].max_avail);
- if (ret == 0) {
- list_move_tail(&device->dev_alloc_list,
- &private_devs);
- map->stripes[index].dev = device;
- map->stripes[index].physical - devices_info[i].dev_offset;
- index++;
- if (type & BTRFS_BLOCK_GROUP_DUP) {
- map->stripes[index].dev = device;
- map->stripes[index].physical - devices_info[i].dev_offset +
- calc_size;
- index++;
- }
- } else if (ret != -ENOSPC)
- goto error;
-
- devices_info[i].dev = device;
- i++;
- } else if (device->in_fs_metadata &&
- avail >= BTRFS_STRIPE_LEN) {
- devices_info[i].dev = device;
- devices_info[i].max_avail = avail;
- i++;
- }
-
- if (cur == &fs_devices->alloc_list)
- break;
- }
-
- list_splice(&private_devs, &fs_devices->alloc_list);
- if (index < num_stripes) {
- if (index >= min_stripes) {
- num_stripes = index;
- if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
- num_stripes /= sub_stripes;
- num_stripes *= sub_stripes;
- }
-
- map = __shrink_map_lookup_stripes(map, num_stripes);
- } else if (i >= min_devices) {
- ret = __btrfs_alloc_tiny_space(trans, fs_devices,
- devices_info, i, type,
- &map, min_stripes,
- &calc_size);
- if (ret)
- goto error;
- } else {
- ret = -ENOSPC;
+ total_avail = 0;
+ /* avail is off by max(alloc_start, 1MB), but that is the same
+ * for all devices, so it doesn''t hurt the sorting later on
+ */
+
+ ret = find_free_dev_extent(trans, device,
+ max_stripe_size * dev_stripes,
+ &dev_offset, &max_avail);
+ if (ret && ret != -ENOSPC)
goto error;
+
+ if (ret == 0)
+ max_avail = max_stripe_size * dev_stripes;
+
+ if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
+ continue;
+
+ devices_info[ndevs].dev_offset = dev_offset;
+ devices_info[ndevs].max_avail = max_avail;
+ devices_info[ndevs].total_avail = total_avail;
+ devices_info[ndevs].dev = device;
+ ++ndevs;
+ }
+
+ /*
+ * now sort the devices by hole size / available space
+ */
+ sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
+ btrfs_cmp_device_info, NULL);
+
+ /* round down to number of usable stripes */
+ ndevs -= ndevs % devs_increment;
+
+ if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
+ ret = -ENOSPC;
+ goto error;
+ }
+
+ if (devs_max && ndevs > devs_max)
+ ndevs = devs_max;
+ /*
+ * the primary goal is to maximize the number of stripes, so use as many
+ * devices as possible, even if the stripes are not maximum sized.
+ */
+ stripe_size = devices_info[ndevs-1].max_avail;
+ num_stripes = ndevs * dev_stripes;
+
+ if (stripe_size * num_stripes > max_chunk_size * ncopies) {
+ stripe_size = max_chunk_size * ncopies;
+ do_div(stripe_size, num_stripes);
+ }
+
+ do_div(stripe_size, dev_stripes);
+ do_div(stripe_size, BTRFS_STRIPE_LEN);
+ stripe_size *= BTRFS_STRIPE_LEN;
+
+ map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
+ if (!map) {
+ ret = -ENOMEM;
+ goto error;
+ }
+ map->num_stripes = num_stripes;
+
+ for (i = 0; i < ndevs; ++i) {
+ for (j = 0; j < dev_stripes; ++j) {
+ int s = i * dev_stripes + j;
+ map->stripes[s].dev = devices_info[i].dev;
+ map->stripes[s].physical = devices_info[i].dev_offset +
+ j * stripe_size;
}
}
map->sector_size = extent_root->sectorsize;
@@ -2621,11 +2490,12 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle
*trans,
map->sub_stripes = sub_stripes;
*map_ret = map;
- *stripe_size = calc_size;
- *num_bytes = chunk_bytes_by_type(type, calc_size,
- map->num_stripes, sub_stripes);
+ num_bytes = stripe_size * (num_stripes / ncopies);
- trace_btrfs_chunk_alloc(info->chunk_root, map, start, *num_bytes);
+ *stripe_size_out = stripe_size;
+ *num_bytes_out = num_bytes;
+
+ trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
em = alloc_extent_map(GFP_NOFS);
if (!em) {
@@ -2634,7 +2504,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle
*trans,
}
em->bdev = (struct block_device *)map;
em->start = start;
- em->len = *num_bytes;
+ em->len = num_bytes;
em->block_start = 0;
em->block_len = em->len;
@@ -2647,20 +2517,21 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle
*trans,
ret = btrfs_make_block_group(trans, extent_root, 0, type,
BTRFS_FIRST_CHUNK_TREE_OBJECTID,
- start, *num_bytes);
+ start, num_bytes);
BUG_ON(ret);
- index = 0;
- while (index < map->num_stripes) {
- device = map->stripes[index].dev;
- dev_offset = map->stripes[index].physical;
+ for (i = 0; i < map->num_stripes; ++i) {
+ struct btrfs_device *device;
+ u64 dev_offset;
+
+ device = map->stripes[i].dev;
+ dev_offset = map->stripes[i].physical;
ret = btrfs_alloc_dev_extent(trans, device,
info->chunk_root->root_key.objectid,
BTRFS_FIRST_CHUNK_TREE_OBJECTID,
- start, dev_offset, calc_size);
+ start, dev_offset, stripe_size);
BUG_ON(ret);
- index++;
}
kfree(devices_info);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index b502f01..37ae6e2 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -144,6 +144,7 @@ struct btrfs_device_info {
struct btrfs_device *dev;
u64 dev_offset;
u64 max_avail;
+ u64 total_avail;
};
struct map_lookup {
--
1.7.3.4
--
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