[Ocfs2-devel] [PATCH 0/3] ocfs2: Add batched discard support

[Ocfs2-devel] [PATCH 0/3] ocfs2: Add batched discard support

[Tao Ma]

Hi all,
	This patch set adds batched discard support to ocfs2. Please check. Thanks.

Regards,
Tao

[Ocfs2-devel] [PATCH 0/3] ocfs2: Add batched discard support.

[Tao Ma]

Hi all,
	These are the patches for adding batched discard support in ocfs2. I
have tested it with xfstests 251 and it passed.

btw, I have also run some tests against it(bonnie++, postmark, ffsb and
fs_mark) and there are no big difference before and after the discard.

Regards,
Tao

[Ocfs2-devel] [PATCH 1/3] ocfs2: Add ocfs2_trim_fs for SSD trim support.

[Tao Ma]

From: Tao Ma <boyu.mt@taobao.com>

Add ocfs2_trim_fs to support trimming freed clusters in the
volume. A range will be given and all the freed clusters greater
than minlen will be discarded to the block layer.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
---
 fs/ocfs2/alloc.c |  156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ocfs2/alloc.h |    1 +
 2 files changed, 157 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 48aa9c7..93a3f92 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -29,6 +29,7 @@
 #include <linux/highmem.h>
 #include <linux/swap.h>
 #include <linux/quotaops.h>
+#include <linux/blkdev.h>
 
 #include <cluster/masklog.h>
 
@@ -7184,3 +7185,158 @@ out_commit:
 out:
 	return ret;
 }
+
+static int ocfs2_trim_extent(struct super_block *sb,
+			     struct ocfs2_group_desc *gd,
+			     int start, int count)
+{
+	u64 discard;
+
+	count = ocfs2_clusters_to_blocks(sb, count);
+	discard = le64_to_cpu(gd->bg_blkno) +
+			ocfs2_clusters_to_blocks(sb, start);
+
+	return sb_issue_discard(sb, discard, count, GFP_NOFS, 0);
+}
+
+static int ocfs2_trim_group(struct super_block *sb,
+			    struct ocfs2_group_desc *gd,
+			    int start, int max, int minbits)
+{
+	int ret = 0, count = 0, next;
+	void *bitmap = gd->bg_bitmap;
+
+	while (start < max) {
+		start = ocfs2_find_next_zero_bit(bitmap, max, start);
+		if (start >= max)
+			break;
+		next = ocfs2_find_next_bit(bitmap, max, start);
+
+		if ((next - start) >= minbits) {
+			ret = ocfs2_trim_extent(sb, gd,
+						start, next - start);
+			if (ret < 0) {
+				mlog_errno(ret);
+				break;
+			}
+			count += next - start;
+		}
+		start = next + 1;
+
+		if (fatal_signal_pending(current)) {
+			count = -ERESTARTSYS;
+			break;
+		}
+
+		if ((le16_to_cpu(gd->bg_free_bits_count) - count) < minbits)
+			break;
+	}
+
+	if (ret < 0)
+		count = ret;
+
+	return count;
+}
+
+int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
+{
+	struct ocfs2_super *osb = OCFS2_SB(sb);
+	u64 start, len, minlen, trimmed, first_group, last_group, group;
+	int ret, cnt, first_bit, last_bit;
+	struct buffer_head *main_bm_bh = NULL;
+	struct inode *main_bm_inode = NULL;
+	struct buffer_head *gd_bh = NULL;
+	struct ocfs2_dinode *main_bm;
+	struct ocfs2_group_desc *gd = NULL;
+
+	start = range->start >> osb->s_clustersize_bits;
+	len = range->len >> osb->s_clustersize_bits;
+	minlen = range->minlen >> osb->s_clustersize_bits;
+	trimmed = 0;
+
+	if (!len) {
+		range->len = 0;
+		return 0;
+	}
+
+	if (minlen >= osb->bitmap_cpg)
+		return -EINVAL;
+
+	main_bm_inode = ocfs2_get_system_file_inode(osb,
+						    GLOBAL_BITMAP_SYSTEM_INODE,
+						    OCFS2_INVALID_SLOT);
+	if (!main_bm_inode) {
+		ret = -EIO;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	mutex_lock(&main_bm_inode->i_mutex);
+
+	ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 0);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out_mutex;
+	}
+	main_bm = (struct ocfs2_dinode *)main_bm_bh->b_data;
+
+	if (start >= le32_to_cpu(main_bm->i_clusters)) {
+		ret = -EINVAL;
+		mlog_errno(ret);
+		goto out_unlock;
+	}
+
+	if (start + len > le32_to_cpu(main_bm->i_clusters))
+		len = le32_to_cpu(main_bm->i_clusters) - start;
+
+	/* Determine first and last group to examine based on start and len */
+	first_group = ocfs2_which_cluster_group(main_bm_inode, start);
+	if (first_group == osb->first_cluster_group_blkno)
+		first_bit = start;
+	else
+		first_bit = start - ocfs2_blocks_to_clusters(sb, first_group);
+	last_group = ocfs2_which_cluster_group(main_bm_inode, start + len - 1);
+	last_bit = osb->bitmap_cpg;
+
+	for (group = first_group; group <= last_group;) {
+		if (first_bit + len >= osb->bitmap_cpg)
+			last_bit = osb->bitmap_cpg;
+		else
+			last_bit = first_bit + len;
+
+		ret = ocfs2_read_group_descriptor(main_bm_inode,
+						  main_bm, group,
+						  &gd_bh);
+		if (ret < 0) {
+			mlog_errno(ret);
+			break;
+		}
+
+		gd = (struct ocfs2_group_desc *)gd_bh->b_data;
+		cnt = ocfs2_trim_group(sb, gd, first_bit, last_bit, minlen);
+		brelse(gd_bh);
+		gd_bh = NULL;
+		if (cnt < 0) {
+			ret = cnt;
+			mlog_errno(ret);
+			break;
+		}
+
+		trimmed += cnt;
+		len -= osb->bitmap_cpg - first_bit;
+		first_bit = 0;
+		if (group == osb->first_cluster_group_blkno)
+			group = ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
+		else
+			group += ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
+	}
+	range->len = trimmed * sb->s_blocksize;
+out_unlock:
+	ocfs2_inode_unlock(main_bm_inode, 0);
+	brelse(main_bm_bh);
+out_mutex:
+	mutex_unlock(&main_bm_inode->i_mutex);
+	iput(main_bm_inode);
+out:
+	return ret;
+}
diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
index 3bd08a0..ca381c5 100644
--- a/fs/ocfs2/alloc.h
+++ b/fs/ocfs2/alloc.h
@@ -239,6 +239,7 @@ int ocfs2_find_leaf(struct ocfs2_caching_info *ci,
 		    struct buffer_head **leaf_bh);
 int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster);
 
+int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range);
 /*
  * Helper function to look at the # of clusters in an extent record.
  */
-- 
1.6.3.GIT

[Ocfs2-devel] [PATCH 2/3] ocfs2: Add FITRIM ioctl.

[Tao Ma]

From: Tao Ma <boyu.mt@taobao.com>

Add the corresponding ioctl function for FITRIM.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
---
 fs/ocfs2/ioctl.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 8f13c59..312a28f 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -542,6 +542,29 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			return -EFAULT;
 
 		return ocfs2_info_handle(inode, &info, 0);
+	case FITRIM:
+	{
+		struct super_block *sb = inode->i_sb;
+		struct fstrim_range range;
+		int ret = 0;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		if (copy_from_user(&range, (struct fstrim_range *)arg,
+		    sizeof(range)))
+			return -EFAULT;
+
+		ret = ocfs2_trim_fs(sb, &range);
+		if (ret < 0)
+			return ret;
+
+		if (copy_to_user((struct fstrim_range *)arg, &range,
+		    sizeof(range)))
+			return -EFAULT;
+
+		return 0;
+	}
 	default:
 		return -ENOTTY;
 	}
@@ -569,6 +592,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 	case OCFS2_IOC_GROUP_EXTEND:
 	case OCFS2_IOC_GROUP_ADD:
 	case OCFS2_IOC_GROUP_ADD64:
+	case FITRIM:
 		break;
 	case OCFS2_IOC_REFLINK:
 		if (copy_from_user(&args, (struct reflink_arguments *)arg,
-- 
1.6.3.GIT

[Ocfs2-devel] [PATCH 3/3] ocfs2: Add trace event for trim.

[Tao Ma]

From: Tao Ma <boyu.mt@taobao.com>

Add the corresponding trace event for trim.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
---
 fs/ocfs2/alloc.c       |    7 +++++++
 fs/ocfs2/ocfs2_trace.h |   25 +++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 93a3f92..12f1c33 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -7196,6 +7196,8 @@ static int ocfs2_trim_extent(struct super_block *sb,
 	discard = le64_to_cpu(gd->bg_blkno) +
 			ocfs2_clusters_to_blocks(sb, start);
 
+	trace_ocfs2_trim_extent(sb, (unsigned long long)discard, count);
+
 	return sb_issue_discard(sb, discard, count, GFP_NOFS, 0);
 }
 
@@ -7206,6 +7208,9 @@ static int ocfs2_trim_group(struct super_block *sb,
 	int ret = 0, count = 0, next;
 	void *bitmap = gd->bg_bitmap;
 
+	trace_ocfs2_trim_group((unsigned long long)le64_to_cpu(gd->bg_blkno),
+			       start, max, minbits);
+
 	while (start < max) {
 		start = ocfs2_find_next_zero_bit(bitmap, max, start);
 		if (start >= max)
@@ -7289,6 +7294,8 @@ int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
 	if (start + len > le32_to_cpu(main_bm->i_clusters))
 		len = le32_to_cpu(main_bm->i_clusters) - start;
 
+	trace_ocfs2_trim_fs(start, len, minlen);
+
 	/* Determine first and last group to examine based on start and len */
 	first_group = ocfs2_which_cluster_group(main_bm_inode, start);
 	if (first_group == osb->first_cluster_group_blkno)
diff --git a/fs/ocfs2/ocfs2_trace.h b/fs/ocfs2/ocfs2_trace.h
index a1dae5b..9ab22a1 100644
--- a/fs/ocfs2/ocfs2_trace.h
+++ b/fs/ocfs2/ocfs2_trace.h
@@ -688,6 +688,31 @@ TRACE_EVENT(ocfs2_cache_block_dealloc,
 		  __entry->blkno, __entry->bit)
 );
 
+TRACE_EVENT(ocfs2_trim_extent,
+	TP_PROTO(struct super_block *sb, unsigned long long blk,
+		 unsigned long long count),
+	TP_ARGS(sb, blk, count),
+	TP_STRUCT__entry(
+		__field(int, dev_major)
+		__field(int, dev_minor)
+		__field(unsigned long long, blk)
+		__field(__u64,	count)
+	),
+	TP_fast_assign(
+		__entry->dev_major = MAJOR(sb->s_dev);
+		__entry->dev_minor = MINOR(sb->s_dev);
+		__entry->blk = blk;
+		__entry->count = count;
+	),
+	TP_printk("%d %d %llu %llu",
+		  __entry->dev_major, __entry->dev_minor,
+		  __entry->blk, __entry->count)
+);
+
+DEFINE_OCFS2_ULL_INT_INT_INT_EVENT(ocfs2_trim_group);
+
+DEFINE_OCFS2_ULL_ULL_ULL_EVENT(ocfs2_trim_fs);
+
 /* End of trace events for fs/ocfs2/alloc.c. */
 
 /* Trace events for fs/ocfs2/localalloc.c. */
-- 
1.6.3.GIT

[Ocfs2-devel] [PATCH 1/3] ocfs2: Add ocfs2_trim_fs for SSD trim support.

[Sunil Mushran]

On 05/06/2011 02:27 AM, Tao Ma wrote:
> From: Tao Ma<boyu.mt@taobao.com>
>
> Add ocfs2_trim_fs to support trimming freed clusters in the
> volume. A range will be given and all the freed clusters greater
> than minlen will be discarded to the block layer.
>
> Signed-off-by: Tao Ma<boyu.mt@taobao.com>
> ---
>   fs/ocfs2/alloc.c |  156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   fs/ocfs2/alloc.h |    1 +
>   2 files changed, 157 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
> index 48aa9c7..93a3f92 100644
> --- a/fs/ocfs2/alloc.c
> +++ b/fs/ocfs2/alloc.c
> @@ -29,6 +29,7 @@
>   #include<linux/highmem.h>
>   #include<linux/swap.h>
>   #include<linux/quotaops.h>
> +#include<linux/blkdev.h>
>
>   #include<cluster/masklog.h>
>
> @@ -7184,3 +7185,158 @@ out_commit:
>   out:
>   	return ret;
>   }
> +
> +static int ocfs2_trim_extent(struct super_block *sb,
> +			     struct ocfs2_group_desc *gd,
> +			     int start, int count)

u32 will be better for start and count.

> +{
> +	u64 discard;
> +
> +	count = ocfs2_clusters_to_blocks(sb, count);

ocfs2_clusters_to_blocks() returns u64.

> +	discard = le64_to_cpu(gd->bg_blkno) +
> +			ocfs2_clusters_to_blocks(sb, start);
> +
> +	return sb_issue_discard(sb, discard, count, GFP_NOFS, 0);

> +}
> +
> +static int ocfs2_trim_group(struct super_block *sb,
> +			    struct ocfs2_group_desc *gd,
> +			    int start, int max, int minbits)
> +{
> +	int ret = 0, count = 0, next;
> +	void *bitmap = gd->bg_bitmap;
> +
> +	while (start<  max) {
> +		start = ocfs2_find_next_zero_bit(bitmap, max, start);
> +		if (start>= max)
> +			break;
> +		next = ocfs2_find_next_bit(bitmap, max, start);
> +
> +		if ((next - start)>= minbits) {
> +			ret = ocfs2_trim_extent(sb, gd,
> +						start, next - start);
> +			if (ret<  0) {
> +				mlog_errno(ret);
> +				break;
> +			}
> +			count += next - start;
> +		}
> +		start = next + 1;
> +
> +		if (fatal_signal_pending(current)) {
> +			count = -ERESTARTSYS;
> +			break;
> +		}
> +
> +		if ((le16_to_cpu(gd->bg_free_bits_count) - count)<  minbits)
> +			break;

This check could also be done earlier.

> +	}
> +
> +	if (ret<  0)
> +		count = ret;
> +
> +	return count;
> +}
> +
> +int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
> +{
> +	struct ocfs2_super *osb = OCFS2_SB(sb);
> +	u64 start, len, minlen, trimmed, first_group, last_group, group;
> +	int ret, cnt, first_bit, last_bit;
> +	struct buffer_head *main_bm_bh = NULL;
> +	struct inode *main_bm_inode = NULL;
> +	struct buffer_head *gd_bh = NULL;
> +	struct ocfs2_dinode *main_bm;
> +	struct ocfs2_group_desc *gd = NULL;
> +
> +	start = range->start>>  osb->s_clustersize_bits;
> +	len = range->len>>  osb->s_clustersize_bits;
> +	minlen = range->minlen>>  osb->s_clustersize_bits;
> +	trimmed = 0;
> +
> +	if (!len) {
> +		range->len = 0;
> +		return 0;
> +	}
> +
> +	if (minlen>= osb->bitmap_cpg)
> +		return -EINVAL;
> +
> +	main_bm_inode = ocfs2_get_system_file_inode(osb,
> +						    GLOBAL_BITMAP_SYSTEM_INODE,
> +						    OCFS2_INVALID_SLOT);
> +	if (!main_bm_inode) {
> +		ret = -EIO;
> +		mlog_errno(ret);
> +		goto out;
> +	}
> +
> +	mutex_lock(&main_bm_inode->i_mutex);
> +
> +	ret = ocfs2_inode_lock(main_bm_inode,&main_bm_bh, 0);
> +	if (ret<  0) {
> +		mlog_errno(ret);
> +		goto out_mutex;
> +	}
> +	main_bm = (struct ocfs2_dinode *)main_bm_bh->b_data;
> +
> +	if (start>= le32_to_cpu(main_bm->i_clusters)) {
> +		ret = -EINVAL;
> +		mlog_errno(ret);

User error. No need to log it.

> +		goto out_unlock;
> +	}
> +
> +	if (start + len>  le32_to_cpu(main_bm->i_clusters))
> +		len = le32_to_cpu(main_bm->i_clusters) - start;
> +
> +	/* Determine first and last group to examine based on start and len */
> +	first_group = ocfs2_which_cluster_group(main_bm_inode, start);
> +	if (first_group == osb->first_cluster_group_blkno)
> +		first_bit = start;
> +	else
> +		first_bit = start - ocfs2_blocks_to_clusters(sb, first_group);
> +	last_group = ocfs2_which_cluster_group(main_bm_inode, start + len - 1);
> +	last_bit = osb->bitmap_cpg;
> +
> +	for (group = first_group; group<= last_group;) {
> +		if (first_bit + len>= osb->bitmap_cpg)
> +			last_bit = osb->bitmap_cpg;
> +		else
> +			last_bit = first_bit + len;
> +
> +		ret = ocfs2_read_group_descriptor(main_bm_inode,
> +						  main_bm, group,
> +						&gd_bh);
> +		if (ret<  0) {
> +			mlog_errno(ret);
> +			break;
> +		}
> +
> +		gd = (struct ocfs2_group_desc *)gd_bh->b_data;
> +		cnt = ocfs2_trim_group(sb, gd, first_bit, last_bit, minlen);
> +		brelse(gd_bh);
> +		gd_bh = NULL;
> +		if (cnt<  0) {
> +			ret = cnt;
> +			mlog_errno(ret);
> +			break;
> +		}
> +
> +		trimmed += cnt;
> +		len -= osb->bitmap_cpg - first_bit;
> +		first_bit = 0;
> +		if (group == osb->first_cluster_group_blkno)
> +			group = ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
> +		else
> +			group += ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
> +	}
> +	range->len = trimmed * sb->s_blocksize;
> +out_unlock:
> +	ocfs2_inode_unlock(main_bm_inode, 0);
> +	brelse(main_bm_bh);
> +out_mutex:
> +	mutex_unlock(&main_bm_inode->i_mutex);
> +	iput(main_bm_inode);
> +out:
> +	return ret;
> +}
> diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
> index 3bd08a0..ca381c5 100644
> --- a/fs/ocfs2/alloc.h
> +++ b/fs/ocfs2/alloc.h
> @@ -239,6 +239,7 @@ int ocfs2_find_leaf(struct ocfs2_caching_info *ci,
>   		    struct buffer_head **leaf_bh);
>   int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster);
>
> +int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range);
>   /*
>    * Helper function to look at the # of clusters in an extent record.
>    */

[Ocfs2-devel] [PATCH 1/3] ocfs2: Add ocfs2_trim_fs for SSD trim support.

[Tao Ma]

Hi Sunil,
	Thanks for the review.
On 05/10/2011 07:02 AM, Sunil Mushran wrote:
> On 05/06/2011 02:27 AM, Tao Ma wrote:
>> From: Tao Ma<boyu.mt@taobao.com>
>>
>> Add ocfs2_trim_fs to support trimming freed clusters in the
>> volume. A range will be given and all the freed clusters greater
>> than minlen will be discarded to the block layer.
>>
>> Signed-off-by: Tao Ma<boyu.mt@taobao.com>
>> ---
>>   fs/ocfs2/alloc.c |  156
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   fs/ocfs2/alloc.h |    1 +
>>   2 files changed, 157 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
>> index 48aa9c7..93a3f92 100644
>> --- a/fs/ocfs2/alloc.c
>> +++ b/fs/ocfs2/alloc.c
>> @@ -29,6 +29,7 @@
>>   #include<linux/highmem.h>
>>   #include<linux/swap.h>
>>   #include<linux/quotaops.h>
>> +#include<linux/blkdev.h>
>>
>>   #include<cluster/masklog.h>
>>
>> @@ -7184,3 +7185,158 @@ out_commit:
>>   out:
>>       return ret;
>>   }
>> +
>> +static int ocfs2_trim_extent(struct super_block *sb,
>> +                 struct ocfs2_group_desc *gd,
>> +                 int start, int count)
> 
> u32 will be better for start and count.
> 
>> +{
>> +    u64 discard;
>> +
>> +    count = ocfs2_clusters_to_blocks(sb, count);
> 
> ocfs2_clusters_to_blocks() returns u64.
fine. Actually my original thought was that both 'start' and 'count' are
within the range of a group. So it shouldn't be that much. But if you
prefer, I will change it.
> 
>> +    discard = le64_to_cpu(gd->bg_blkno) +
>> +            ocfs2_clusters_to_blocks(sb, start);
>> +
>> +    return sb_issue_discard(sb, discard, count, GFP_NOFS, 0);
> 
>> +}
>> +
>> +static int ocfs2_trim_group(struct super_block *sb,
>> +                struct ocfs2_group_desc *gd,
>> +                int start, int max, int minbits)
>> +{
>> +    int ret = 0, count = 0, next;
>> +    void *bitmap = gd->bg_bitmap;
>> +
>> +    while (start<  max) {
>> +        start = ocfs2_find_next_zero_bit(bitmap, max, start);
>> +        if (start>= max)
>> +            break;
>> +        next = ocfs2_find_next_bit(bitmap, max, start);
>> +
>> +        if ((next - start)>= minbits) {
>> +            ret = ocfs2_trim_extent(sb, gd,
>> +                        start, next - start);
>> +            if (ret<  0) {
>> +                mlog_errno(ret);
>> +                break;
>> +            }
>> +            count += next - start;
>> +        }
>> +        start = next + 1;
>> +
>> +        if (fatal_signal_pending(current)) {
>> +            count = -ERESTARTSYS;
>> +            break;
>> +        }
>> +
>> +        if ((le16_to_cpu(gd->bg_free_bits_count) - count)<  minbits)
>> +            break;
> 
> This check could also be done earlier.
oh, yes, I will add it. Thanks.
> 
>> +    }
>> +
>> +    if (ret<  0)
>> +        count = ret;
>> +
>> +    return count;
>> +}
>> +
>> +int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
>> +{
>> +    struct ocfs2_super *osb = OCFS2_SB(sb);
>> +    u64 start, len, minlen, trimmed, first_group, last_group, group;
>> +    int ret, cnt, first_bit, last_bit;
>> +    struct buffer_head *main_bm_bh = NULL;
>> +    struct inode *main_bm_inode = NULL;
>> +    struct buffer_head *gd_bh = NULL;
>> +    struct ocfs2_dinode *main_bm;
>> +    struct ocfs2_group_desc *gd = NULL;
>> +
>> +    start = range->start>>  osb->s_clustersize_bits;
>> +    len = range->len>>  osb->s_clustersize_bits;
>> +    minlen = range->minlen>>  osb->s_clustersize_bits;
>> +    trimmed = 0;
>> +
>> +    if (!len) {
>> +        range->len = 0;
>> +        return 0;
>> +    }
>> +
>> +    if (minlen>= osb->bitmap_cpg)
>> +        return -EINVAL;
>> +
>> +    main_bm_inode = ocfs2_get_system_file_inode(osb,
>> +                            GLOBAL_BITMAP_SYSTEM_INODE,
>> +                            OCFS2_INVALID_SLOT);
>> +    if (!main_bm_inode) {
>> +        ret = -EIO;
>> +        mlog_errno(ret);
>> +        goto out;
>> +    }
>> +
>> +    mutex_lock(&main_bm_inode->i_mutex);
>> +
>> +    ret = ocfs2_inode_lock(main_bm_inode,&main_bm_bh, 0);
>> +    if (ret<  0) {
>> +        mlog_errno(ret);
>> +        goto out_mutex;
>> +    }
>> +    main_bm = (struct ocfs2_dinode *)main_bm_bh->b_data;
>> +
>> +    if (start>= le32_to_cpu(main_bm->i_clusters)) {
>> +        ret = -EINVAL;
>> +        mlog_errno(ret);
> 
> User error. No need to log it.
yeah, thanks for the advice.

Regards,
Tao
> 
>> +        goto out_unlock;
>> +    }
>> +
>> +    if (start + len>  le32_to_cpu(main_bm->i_clusters))
>> +        len = le32_to_cpu(main_bm->i_clusters) - start;
>> +
>> +    /* Determine first and last group to examine based on start and
>> len */
>> +    first_group = ocfs2_which_cluster_group(main_bm_inode, start);
>> +    if (first_group == osb->first_cluster_group_blkno)
>> +        first_bit = start;
>> +    else
>> +        first_bit = start - ocfs2_blocks_to_clusters(sb, first_group);
>> +    last_group = ocfs2_which_cluster_group(main_bm_inode, start + len
>> - 1);
>> +    last_bit = osb->bitmap_cpg;
>> +
>> +    for (group = first_group; group<= last_group;) {
>> +        if (first_bit + len>= osb->bitmap_cpg)
>> +            last_bit = osb->bitmap_cpg;
>> +        else
>> +            last_bit = first_bit + len;
>> +
>> +        ret = ocfs2_read_group_descriptor(main_bm_inode,
>> +                          main_bm, group,
>> +                        &gd_bh);
>> +        if (ret<  0) {
>> +            mlog_errno(ret);
>> +            break;
>> +        }
>> +
>> +        gd = (struct ocfs2_group_desc *)gd_bh->b_data;
>> +        cnt = ocfs2_trim_group(sb, gd, first_bit, last_bit, minlen);
>> +        brelse(gd_bh);
>> +        gd_bh = NULL;
>> +        if (cnt<  0) {
>> +            ret = cnt;
>> +            mlog_errno(ret);
>> +            break;
>> +        }
>> +
>> +        trimmed += cnt;
>> +        len -= osb->bitmap_cpg - first_bit;
>> +        first_bit = 0;
>> +        if (group == osb->first_cluster_group_blkno)
>> +            group = ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
>> +        else
>> +            group += ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
>> +    }
>> +    range->len = trimmed * sb->s_blocksize;
>> +out_unlock:
>> +    ocfs2_inode_unlock(main_bm_inode, 0);
>> +    brelse(main_bm_bh);
>> +out_mutex:
>> +    mutex_unlock(&main_bm_inode->i_mutex);
>> +    iput(main_bm_inode);
>> +out:
>> +    return ret;
>> +}
>> diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
>> index 3bd08a0..ca381c5 100644
>> --- a/fs/ocfs2/alloc.h
>> +++ b/fs/ocfs2/alloc.h
>> @@ -239,6 +239,7 @@ int ocfs2_find_leaf(struct ocfs2_caching_info *ci,
>>               struct buffer_head **leaf_bh);
>>   int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32
>> v_cluster);
>>
>> +int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range);
>>   /*
>>    * Helper function to look at the # of clusters in an extent record.
>>    */
>