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Merge branch 'jeffm-discard-4.3' into for-linus-4.3
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Chris Mason committed Aug 9, 2015
2 parents da2f0f7 + e33e17e commit 46cd285
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Showing 9 changed files with 342 additions and 58 deletions.
3 changes: 3 additions & 0 deletions fs/btrfs/ctree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3431,6 +3431,8 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 group_start,
struct extent_map *em);
void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info);
void btrfs_get_block_group_trimming(struct btrfs_block_group_cache *cache);
void btrfs_put_block_group_trimming(struct btrfs_block_group_cache *cache);
void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data);
Expand Down Expand Up @@ -4067,6 +4069,7 @@ __cold
void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
unsigned int line, int errno, const char *fmt, ...);

const char *btrfs_decode_error(int errno);

__cold
void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
Expand Down
9 changes: 9 additions & 0 deletions fs/btrfs/disk-io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3761,6 +3761,15 @@ void close_ctree(struct btrfs_root *root)
cancel_work_sync(&fs_info->async_reclaim_work);

if (!(fs_info->sb->s_flags & MS_RDONLY)) {
/*
* If the cleaner thread is stopped and there are
* block groups queued for removal, the deletion will be
* skipped when we quit the cleaner thread.
*/
mutex_lock(&root->fs_info->cleaner_mutex);
btrfs_delete_unused_bgs(root->fs_info);
mutex_unlock(&root->fs_info->cleaner_mutex);

ret = btrfs_commit_super(root);
if (ret)
btrfs_err(fs_info, "commit super ret %d", ret);
Expand Down
248 changes: 239 additions & 9 deletions fs/btrfs/extent-tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1882,10 +1882,77 @@ static int remove_extent_backref(struct btrfs_trans_handle *trans,
return ret;
}

static int btrfs_issue_discard(struct block_device *bdev,
u64 start, u64 len)
#define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
u64 *discarded_bytes)
{
return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
int j, ret = 0;
u64 bytes_left, end;
u64 aligned_start = ALIGN(start, 1 << 9);

if (WARN_ON(start != aligned_start)) {
len -= aligned_start - start;
len = round_down(len, 1 << 9);
start = aligned_start;
}

*discarded_bytes = 0;

if (!len)
return 0;

end = start + len;
bytes_left = len;

/* Skip any superblocks on this device. */
for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
u64 sb_start = btrfs_sb_offset(j);
u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
u64 size = sb_start - start;

if (!in_range(sb_start, start, bytes_left) &&
!in_range(sb_end, start, bytes_left) &&
!in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
continue;

/*
* Superblock spans beginning of range. Adjust start and
* try again.
*/
if (sb_start <= start) {
start += sb_end - start;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
continue;
}

if (size) {
ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
GFP_NOFS, 0);
if (!ret)
*discarded_bytes += size;
else if (ret != -EOPNOTSUPP)
return ret;
}

start = sb_end;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
}

if (bytes_left) {
ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
GFP_NOFS, 0);
if (!ret)
*discarded_bytes += bytes_left;
}
return ret;
}

int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
Expand All @@ -1906,14 +1973,16 @@ int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,


for (i = 0; i < bbio->num_stripes; i++, stripe++) {
u64 bytes;
if (!stripe->dev->can_discard)
continue;

ret = btrfs_issue_discard(stripe->dev->bdev,
stripe->physical,
stripe->length);
stripe->length,
&bytes);
if (!ret)
discarded_bytes += stripe->length;
discarded_bytes += bytes;
else if (ret != -EOPNOTSUPP)
break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */

Expand Down Expand Up @@ -6061,20 +6130,19 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_group_cache *block_group, *tmp;
struct list_head *deleted_bgs;
struct extent_io_tree *unpin;
u64 start;
u64 end;
int ret;

if (trans->aborted)
return 0;

if (fs_info->pinned_extents == &fs_info->freed_extents[0])
unpin = &fs_info->freed_extents[1];
else
unpin = &fs_info->freed_extents[0];

while (1) {
while (!trans->aborted) {
mutex_lock(&fs_info->unused_bg_unpin_mutex);
ret = find_first_extent_bit(unpin, 0, &start, &end,
EXTENT_DIRTY, NULL);
Expand All @@ -6093,6 +6161,34 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
cond_resched();
}

/*
* Transaction is finished. We don't need the lock anymore. We
* do need to clean up the block groups in case of a transaction
* abort.
*/
deleted_bgs = &trans->transaction->deleted_bgs;
list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
u64 trimmed = 0;

ret = -EROFS;
if (!trans->aborted)
ret = btrfs_discard_extent(root,
block_group->key.objectid,
block_group->key.offset,
&trimmed);

list_del_init(&block_group->bg_list);
btrfs_put_block_group_trimming(block_group);
btrfs_put_block_group(block_group);

if (ret) {
const char *errstr = btrfs_decode_error(ret);
btrfs_warn(fs_info,
"Discard failed while removing blockgroup: errno=%d %s\n",
ret, errstr);
}
}

return 0;
}

Expand Down Expand Up @@ -9830,6 +9926,11 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
* currently running transaction might finish and a new one start,
* allowing for new block groups to be created that can reuse the same
* physical device locations unless we take this special care.
*
* There may also be an implicit trim operation if the file system
* is mounted with -odiscard. The same protections must remain
* in place until the extents have been discarded completely when
* the transaction commit has completed.
*/
remove_em = (atomic_read(&block_group->trimming) == 0);
/*
Expand Down Expand Up @@ -9904,6 +10005,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
spin_lock(&fs_info->unused_bgs_lock);
while (!list_empty(&fs_info->unused_bgs)) {
u64 start, end;
int trimming;

block_group = list_first_entry(&fs_info->unused_bgs,
struct btrfs_block_group_cache,
Expand Down Expand Up @@ -10003,12 +10105,39 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);

/* DISCARD can flip during remount */
trimming = btrfs_test_opt(root, DISCARD);

/* Implicit trim during transaction commit. */
if (trimming)
btrfs_get_block_group_trimming(block_group);

/*
* Btrfs_remove_chunk will abort the transaction if things go
* horribly wrong.
*/
ret = btrfs_remove_chunk(trans, root,
block_group->key.objectid);

if (ret) {
if (trimming)
btrfs_put_block_group_trimming(block_group);
goto end_trans;
}

/*
* If we're not mounted with -odiscard, we can just forget
* about this block group. Otherwise we'll need to wait
* until transaction commit to do the actual discard.
*/
if (trimming) {
WARN_ON(!list_empty(&block_group->bg_list));
spin_lock(&trans->transaction->deleted_bgs_lock);
list_move(&block_group->bg_list,
&trans->transaction->deleted_bgs);
spin_unlock(&trans->transaction->deleted_bgs_lock);
btrfs_get_block_group(block_group);
}
end_trans:
btrfs_end_transaction(trans, root);
next:
Expand Down Expand Up @@ -10062,10 +10191,99 @@ int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
return unpin_extent_range(root, start, end, false);
}

/*
* It used to be that old block groups would be left around forever.
* Iterating over them would be enough to trim unused space. Since we
* now automatically remove them, we also need to iterate over unallocated
* space.
*
* We don't want a transaction for this since the discard may take a
* substantial amount of time. We don't require that a transaction be
* running, but we do need to take a running transaction into account
* to ensure that we're not discarding chunks that were released in
* the current transaction.
*
* Holding the chunks lock will prevent other threads from allocating
* or releasing chunks, but it won't prevent a running transaction
* from committing and releasing the memory that the pending chunks
* list head uses. For that, we need to take a reference to the
* transaction.
*/
static int btrfs_trim_free_extents(struct btrfs_device *device,
u64 minlen, u64 *trimmed)
{
u64 start = 0, len = 0;
int ret;

*trimmed = 0;

/* Not writeable = nothing to do. */
if (!device->writeable)
return 0;

/* No free space = nothing to do. */
if (device->total_bytes <= device->bytes_used)
return 0;

ret = 0;

while (1) {
struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
struct btrfs_transaction *trans;
u64 bytes;

ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
if (ret)
return ret;

down_read(&fs_info->commit_root_sem);

spin_lock(&fs_info->trans_lock);
trans = fs_info->running_transaction;
if (trans)
atomic_inc(&trans->use_count);
spin_unlock(&fs_info->trans_lock);

ret = find_free_dev_extent_start(trans, device, minlen, start,
&start, &len);
if (trans)
btrfs_put_transaction(trans);

if (ret) {
up_read(&fs_info->commit_root_sem);
mutex_unlock(&fs_info->chunk_mutex);
if (ret == -ENOSPC)
ret = 0;
break;
}

ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
up_read(&fs_info->commit_root_sem);
mutex_unlock(&fs_info->chunk_mutex);

if (ret)
break;

start += len;
*trimmed += bytes;

if (fatal_signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}

cond_resched();
}

return ret;
}

int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_group_cache *cache = NULL;
struct btrfs_device *device;
struct list_head *devices;
u64 group_trimmed;
u64 start;
u64 end;
Expand Down Expand Up @@ -10120,6 +10338,18 @@ int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
cache = next_block_group(fs_info->tree_root, cache);
}

mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
devices = &root->fs_info->fs_devices->alloc_list;
list_for_each_entry(device, devices, dev_alloc_list) {
ret = btrfs_trim_free_extents(device, range->minlen,
&group_trimmed);
if (ret)
break;

trimmed += group_trimmed;
}
mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);

range->len = trimmed;
return ret;
}
Expand Down
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