diff mbox

[V2,02/11] Btrfs: Compute and look up csums based on sectorsized blocks

Message ID 1438931158-20888-3-git-send-email-chandan@linux.vnet.ibm.com (mailing list archive)
State Superseded
Headers show

Commit Message

Chandan Rajendra Aug. 7, 2015, 7:05 a.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.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
 fs/btrfs/file-item.c | 90 +++++++++++++++++++++++++++++++++-------------------
 1 file changed, 57 insertions(+), 33 deletions(-)

Comments

Josef Bacik Aug. 7, 2015, 6:30 p.m. UTC | #1
On 08/07/2015 03:05 AM, 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>
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> ---
>   fs/btrfs/file-item.c | 90 +++++++++++++++++++++++++++++++++-------------------
>   1 file changed, 57 insertions(+), 33 deletions(-)
>
> diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> index 58ece65..d752051 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 +470,54 @@ 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);
>

I don't think we can have something kmap_atomic()'ed and then do 
allocations under it right?  That's why we only kmap_atomic(), do the 
copy, and then unmap, unless I'm forgetting something?  Thanks,

Josef
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Chandan Rajendra Aug. 9, 2015, 11:47 a.m. UTC | #2
On Friday 07 Aug 2015 14:30:21 Josef Bacik wrote:
> On 08/07/2015 03:05 AM, 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>
> > Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> > ---
> > 
> >   fs/btrfs/file-item.c | 90
> >   +++++++++++++++++++++++++++++++++------------------- 1 file changed, 57
> >   insertions(+), 33 deletions(-)
> > 
> > diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> > index 58ece65..d752051 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 +470,54 @@ 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);
> 
> I don't think we can have something kmap_atomic()'ed and then do
> allocations under it right?  That's why we only kmap_atomic(), do the
> copy, and then unmap, unless I'm forgetting something?  Thanks,
>
Josef, you are correct. I will fix it and send out version V3 of the patchset
soon. Thanks for the review.
diff mbox

Patch

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 58ece65..d752051 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 +470,54 @@  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)
+			>> inode->i_blkbits;
+
+
+		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;