[RFC,V11,08/21] Btrfs: subpagesize-blocksize: Compute and look up csums based on sectorsized blocks.
diff mbox

Message ID 1433172176-8742-9-git-send-email-chandan@linux.vnet.ibm.com
State New
Headers show

Commit Message

Chandan Rajendra June 1, 2015, 3:22 p.m. UTC
Checksums are applicable to sectorsize units. The current code uses
bio->bv_len units to compute and look up checksums. This works on machines
where sectorsize == PAGE_SIZE. This patch makes the checksum computation and
look up code to work with sectorsize units.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
 fs/btrfs/file-item.c | 87 ++++++++++++++++++++++++++++++++--------------------
 1 file changed, 54 insertions(+), 33 deletions(-)

Comments

Liu Bo July 1, 2015, 2:37 p.m. UTC | #1
On Mon, Jun 01, 2015 at 08:52:43PM +0530, Chandan Rajendra wrote:
> Checksums are applicable to sectorsize units. The current code uses
> bio->bv_len units to compute and look up checksums. This works on machines
> where sectorsize == PAGE_SIZE. This patch makes the checksum computation and
> look up code to work with sectorsize units.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>

Thanks,

-liubo

> 
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> ---
>  fs/btrfs/file-item.c | 87 ++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 54 insertions(+), 33 deletions(-)
> 
> diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> index 58ece65..65ab9c3 100644
> --- a/fs/btrfs/file-item.c
> +++ b/fs/btrfs/file-item.c
> @@ -172,6 +172,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
>  	u64 item_start_offset = 0;
>  	u64 item_last_offset = 0;
>  	u64 disk_bytenr;
> +	u64 page_bytes_left;
>  	u32 diff;
>  	int nblocks;
>  	int bio_index = 0;
> @@ -220,6 +221,8 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
>  	disk_bytenr = (u64)bio->bi_iter.bi_sector << 9;
>  	if (dio)
>  		offset = logical_offset;
> +
> +	page_bytes_left = bvec->bv_len;
>  	while (bio_index < bio->bi_vcnt) {
>  		if (!dio)
>  			offset = page_offset(bvec->bv_page) + bvec->bv_offset;
> @@ -243,7 +246,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
>  				if (BTRFS_I(inode)->root->root_key.objectid ==
>  				    BTRFS_DATA_RELOC_TREE_OBJECTID) {
>  					set_extent_bits(io_tree, offset,
> -						offset + bvec->bv_len - 1,
> +						offset + root->sectorsize - 1,
>  						EXTENT_NODATASUM, GFP_NOFS);
>  				} else {
>  					btrfs_info(BTRFS_I(inode)->root->fs_info,
> @@ -281,11 +284,17 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
>  found:
>  		csum += count * csum_size;
>  		nblocks -= count;
> -		bio_index += count;
> +
>  		while (count--) {
> -			disk_bytenr += bvec->bv_len;
> -			offset += bvec->bv_len;
> -			bvec++;
> +			disk_bytenr += root->sectorsize;
> +			offset += root->sectorsize;
> +			page_bytes_left -= root->sectorsize;
> +			if (!page_bytes_left) {
> +				bio_index++;
> +				bvec++;
> +				page_bytes_left = bvec->bv_len;
> +			}
> +
>  		}
>  	}
>  	btrfs_free_path(path);
> @@ -432,6 +441,8 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
>  	struct bio_vec *bvec = bio->bi_io_vec;
>  	int bio_index = 0;
>  	int index;
> +	int nr_sectors;
> +	int i;
>  	unsigned long total_bytes = 0;
>  	unsigned long this_sum_bytes = 0;
>  	u64 offset;
> @@ -459,41 +470,51 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
>  		if (!contig)
>  			offset = page_offset(bvec->bv_page) + bvec->bv_offset;
>  
> -		if (offset >= ordered->file_offset + ordered->len ||
> -		    offset < ordered->file_offset) {
> -			unsigned long bytes_left;
> -			sums->len = this_sum_bytes;
> -			this_sum_bytes = 0;
> -			btrfs_add_ordered_sum(inode, ordered, sums);
> -			btrfs_put_ordered_extent(ordered);
> +		data = kmap_atomic(bvec->bv_page);
>  
> -			bytes_left = bio->bi_iter.bi_size - total_bytes;
>  
> -			sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
> -				       GFP_NOFS);
> -			BUG_ON(!sums); /* -ENOMEM */
> -			sums->len = bytes_left;
> -			ordered = btrfs_lookup_ordered_extent(inode, offset);
> -			BUG_ON(!ordered); /* Logic error */
> -			sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) +
> -				       total_bytes;
> -			index = 0;
> +		nr_sectors = (bvec->bv_len + root->sectorsize - 1)
> +			>> root->fs_info->sb->s_blocksize_bits;
> +
> +
> +		for (i = 0; i < nr_sectors; i++) {
> +			if (offset >= ordered->file_offset + ordered->len ||
> +				offset < ordered->file_offset) {
> +				unsigned long bytes_left;
> +				sums->len = this_sum_bytes;
> +				this_sum_bytes = 0;
> +				btrfs_add_ordered_sum(inode, ordered, sums);
> +				btrfs_put_ordered_extent(ordered);
> +
> +				bytes_left = bio->bi_iter.bi_size - total_bytes;
> +
> +				sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
> +					GFP_NOFS);
> +				BUG_ON(!sums); /* -ENOMEM */
> +				sums->len = bytes_left;
> +				ordered = btrfs_lookup_ordered_extent(inode, offset);
> +				BUG_ON(!ordered); /* Logic error */
> +				sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) +
> +					total_bytes;
> +				index = 0;
> +			}
> +
> +			sums->sums[index] = ~(u32)0;
> +			sums->sums[index]
> +				= btrfs_csum_data(data + bvec->bv_offset + (i * root->sectorsize),
> +						sums->sums[index],
> +						root->sectorsize);
> +			btrfs_csum_final(sums->sums[index],
> +					(char *)(sums->sums + index));
> +			index++;
> +			offset += root->sectorsize;
> +			this_sum_bytes += root->sectorsize;
> +			total_bytes += root->sectorsize;
>  		}
>  
> -		data = kmap_atomic(bvec->bv_page);
> -		sums->sums[index] = ~(u32)0;
> -		sums->sums[index] = btrfs_csum_data(data + bvec->bv_offset,
> -						    sums->sums[index],
> -						    bvec->bv_len);
>  		kunmap_atomic(data);
> -		btrfs_csum_final(sums->sums[index],
> -				 (char *)(sums->sums + index));
>  
>  		bio_index++;
> -		index++;
> -		total_bytes += bvec->bv_len;
> -		this_sum_bytes += bvec->bv_len;
> -		offset += bvec->bv_len;
>  		bvec++;
>  	}
>  	this_sum_bytes = 0;
> -- 
> 2.1.0
> 
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Patch
diff mbox

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 58ece65..65ab9c3 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -172,6 +172,7 @@  static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
 	u64 item_start_offset = 0;
 	u64 item_last_offset = 0;
 	u64 disk_bytenr;
+	u64 page_bytes_left;
 	u32 diff;
 	int nblocks;
 	int bio_index = 0;
@@ -220,6 +221,8 @@  static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
 	disk_bytenr = (u64)bio->bi_iter.bi_sector << 9;
 	if (dio)
 		offset = logical_offset;
+
+	page_bytes_left = bvec->bv_len;
 	while (bio_index < bio->bi_vcnt) {
 		if (!dio)
 			offset = page_offset(bvec->bv_page) + bvec->bv_offset;
@@ -243,7 +246,7 @@  static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
 				if (BTRFS_I(inode)->root->root_key.objectid ==
 				    BTRFS_DATA_RELOC_TREE_OBJECTID) {
 					set_extent_bits(io_tree, offset,
-						offset + bvec->bv_len - 1,
+						offset + root->sectorsize - 1,
 						EXTENT_NODATASUM, GFP_NOFS);
 				} else {
 					btrfs_info(BTRFS_I(inode)->root->fs_info,
@@ -281,11 +284,17 @@  static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
 found:
 		csum += count * csum_size;
 		nblocks -= count;
-		bio_index += count;
+
 		while (count--) {
-			disk_bytenr += bvec->bv_len;
-			offset += bvec->bv_len;
-			bvec++;
+			disk_bytenr += root->sectorsize;
+			offset += root->sectorsize;
+			page_bytes_left -= root->sectorsize;
+			if (!page_bytes_left) {
+				bio_index++;
+				bvec++;
+				page_bytes_left = bvec->bv_len;
+			}
+
 		}
 	}
 	btrfs_free_path(path);
@@ -432,6 +441,8 @@  int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 	struct bio_vec *bvec = bio->bi_io_vec;
 	int bio_index = 0;
 	int index;
+	int nr_sectors;
+	int i;
 	unsigned long total_bytes = 0;
 	unsigned long this_sum_bytes = 0;
 	u64 offset;
@@ -459,41 +470,51 @@  int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 		if (!contig)
 			offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 
-		if (offset >= ordered->file_offset + ordered->len ||
-		    offset < ordered->file_offset) {
-			unsigned long bytes_left;
-			sums->len = this_sum_bytes;
-			this_sum_bytes = 0;
-			btrfs_add_ordered_sum(inode, ordered, sums);
-			btrfs_put_ordered_extent(ordered);
+		data = kmap_atomic(bvec->bv_page);
 
-			bytes_left = bio->bi_iter.bi_size - total_bytes;
 
-			sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
-				       GFP_NOFS);
-			BUG_ON(!sums); /* -ENOMEM */
-			sums->len = bytes_left;
-			ordered = btrfs_lookup_ordered_extent(inode, offset);
-			BUG_ON(!ordered); /* Logic error */
-			sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) +
-				       total_bytes;
-			index = 0;
+		nr_sectors = (bvec->bv_len + root->sectorsize - 1)
+			>> root->fs_info->sb->s_blocksize_bits;
+
+
+		for (i = 0; i < nr_sectors; i++) {
+			if (offset >= ordered->file_offset + ordered->len ||
+				offset < ordered->file_offset) {
+				unsigned long bytes_left;
+				sums->len = this_sum_bytes;
+				this_sum_bytes = 0;
+				btrfs_add_ordered_sum(inode, ordered, sums);
+				btrfs_put_ordered_extent(ordered);
+
+				bytes_left = bio->bi_iter.bi_size - total_bytes;
+
+				sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
+					GFP_NOFS);
+				BUG_ON(!sums); /* -ENOMEM */
+				sums->len = bytes_left;
+				ordered = btrfs_lookup_ordered_extent(inode, offset);
+				BUG_ON(!ordered); /* Logic error */
+				sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) +
+					total_bytes;
+				index = 0;
+			}
+
+			sums->sums[index] = ~(u32)0;
+			sums->sums[index]
+				= btrfs_csum_data(data + bvec->bv_offset + (i * root->sectorsize),
+						sums->sums[index],
+						root->sectorsize);
+			btrfs_csum_final(sums->sums[index],
+					(char *)(sums->sums + index));
+			index++;
+			offset += root->sectorsize;
+			this_sum_bytes += root->sectorsize;
+			total_bytes += root->sectorsize;
 		}
 
-		data = kmap_atomic(bvec->bv_page);
-		sums->sums[index] = ~(u32)0;
-		sums->sums[index] = btrfs_csum_data(data + bvec->bv_offset,
-						    sums->sums[index],
-						    bvec->bv_len);
 		kunmap_atomic(data);
-		btrfs_csum_final(sums->sums[index],
-				 (char *)(sums->sums + index));
 
 		bio_index++;
-		index++;
-		total_bytes += bvec->bv_len;
-		this_sum_bytes += bvec->bv_len;
-		offset += bvec->bv_len;
 		bvec++;
 	}
 	this_sum_bytes = 0;