pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing

This patches moves parsing of the GETDEVICEINFO XDR to kernel space, as well
as the management of complex devices.  The reason for that is we might have
multiple outstanding complex devices after a NOTIFY_DEVICEID4_CHANGE, which
device mapper or md can't handle as they claim devices exclusively.

But as is turns out simple striping / concatenation is fairly trivial to
implement anyway, so we make our life simpler by reducing the reliance
on blkmapd.  For now we still use blkmapd by feeding it synthetic SIMPLE
device XDR to translate device signatures to device numbers, but in the
long runs I have plans to eliminate it entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 60 insertions, 32 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 65a6b19b17a..c41a718854e 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -114,13 +114,10 @@ bl_submit_bio(int rw, struct bio *bio)
 	return NULL;
 }
 
-static struct bio *bl_alloc_init_bio(int npg, sector_t isect,
-				     struct pnfs_block_extent *be,
-				     void (*end_io)(struct bio *, int err),
-				     struct parallel_io *par)
+static struct bio *
+bl_alloc_init_bio(int npg, struct block_device *bdev, sector_t disk_sector,
+		void (*end_io)(struct bio *, int err), struct parallel_io *par)
 {
-	struct pnfs_block_dev *dev =
-		container_of(be->be_device, struct pnfs_block_dev, d_node);
 	struct bio *bio;
 
 	npg = min(npg, BIO_MAX_PAGES);
@@ -131,32 +128,55 @@ static struct bio *bl_alloc_init_bio(int npg, sector_t isect,
 	}
 
 	if (bio) {
-		bio->bi_iter.bi_sector = isect - be->be_f_offset +
-			be->be_v_offset;
-		bio->bi_bdev = dev->d_bdev;
+		bio->bi_iter.bi_sector = disk_sector;
+		bio->bi_bdev = bdev;
 		bio->bi_end_io = end_io;
 		bio->bi_private = par;
 	}
 	return bio;
 }
 
-static struct bio *do_add_page_to_bio(struct bio *bio, int npg, int rw,
-				      sector_t isect, struct page *page,
-				      struct pnfs_block_extent *be,
-				      void (*end_io)(struct bio *, int err),
-				      struct parallel_io *par,
-				      unsigned int offset, int len)
+static struct bio *
+do_add_page_to_bio(struct bio *bio, int npg, int rw, sector_t isect,
+		struct page *page, struct pnfs_block_dev_map *map,
+		struct pnfs_block_extent *be,
+		void (*end_io)(struct bio *, int err),
+		struct parallel_io *par, unsigned int offset, int *len)
 {
-	isect = isect + (offset >> SECTOR_SHIFT);
+	struct pnfs_block_dev *dev =
+		container_of(be->be_device, struct pnfs_block_dev, node);
+	u64 disk_addr, end;
+
 	dprintk("%s: npg %d rw %d isect %llu offset %u len %d\n", __func__,
-		npg, rw, (unsigned long long)isect, offset, len);
+		npg, rw, (unsigned long long)isect, offset, *len);
+
+	/* translate to device offset */
+	isect += be->be_v_offset;
+	isect -= be->be_f_offset;
+
+	/* translate to physical disk offset */
+	disk_addr = (u64)isect << SECTOR_SHIFT;
+	if (disk_addr < map->start || disk_addr >= map->start + map->len) {
+		if (!dev->map(dev, disk_addr, map))
+			return ERR_PTR(-EIO);
+		bio = bl_submit_bio(rw, bio);
+	}
+	disk_addr += map->disk_offset;
+	disk_addr -= map->start;
+
+	/* limit length to what the device mapping allows */
+	end = disk_addr + *len;
+	if (end >= map->start + map->len)
+		*len = map->start + map->len - disk_addr;
+
 retry:
 	if (!bio) {
-		bio = bl_alloc_init_bio(npg, isect, be, end_io, par);
+		bio = bl_alloc_init_bio(npg, map->bdev,
+				disk_addr >> SECTOR_SHIFT, end_io, par);
 		if (!bio)
 			return ERR_PTR(-ENOMEM);
 	}
-	if (bio_add_page(bio, page, len, offset) < len) {
+	if (bio_add_page(bio, page, *len, offset) < *len) {
 		bio = bl_submit_bio(rw, bio);
 		goto retry;
 	}
@@ -203,6 +223,7 @@ static enum pnfs_try_status
 bl_read_pagelist(struct nfs_pgio_header *header)
 {
 	struct pnfs_block_layout *bl = BLK_LSEG2EXT(header->lseg);
+	struct pnfs_block_dev_map map = { .start = NFS4_MAX_UINT64 };
 	struct bio *bio = NULL;
 	struct pnfs_block_extent be;
 	sector_t isect, extent_length = 0;
@@ -248,28 +269,29 @@ bl_read_pagelist(struct nfs_pgio_header *header)
 				pg_len = PAGE_CACHE_SIZE - pg_offset;
 			else
 				pg_len = bytes_left;
-
-			f_offset += pg_len;
-			bytes_left -= pg_len;
-			isect += (pg_offset >> SECTOR_SHIFT);
-			extent_length -= (pg_offset >> SECTOR_SHIFT);
 		} else {
 			BUG_ON(pg_offset != 0);
 			pg_len = PAGE_CACHE_SIZE;
 		}
 
+		isect += (pg_offset >> SECTOR_SHIFT);
+		extent_length -= (pg_offset >> SECTOR_SHIFT);
+
 		if (is_hole(&be)) {
 			bio = bl_submit_bio(READ, bio);
 			/* Fill hole w/ zeroes w/o accessing device */
 			dprintk("%s Zeroing page for hole\n", __func__);
 			zero_user_segment(pages[i], pg_offset, pg_len);
+
+			/* invalidate map */
+			map.start = NFS4_MAX_UINT64;
 		} else {
 			bio = do_add_page_to_bio(bio,
 						 header->page_array.npages - i,
 						 READ,
-						 isect, pages[i], &be,
+						 isect, pages[i], &map, &be,
 						 bl_end_io_read, par,
-						 pg_offset, pg_len);
+						 pg_offset, &pg_len);
 			if (IS_ERR(bio)) {
 				header->pnfs_error = PTR_ERR(bio);
 				bio = NULL;
@@ -278,6 +300,8 @@ bl_read_pagelist(struct nfs_pgio_header *header)
 		}
 		isect += (pg_len >> SECTOR_SHIFT);
 		extent_length -= (pg_len >> SECTOR_SHIFT);
+		f_offset += pg_len;
+		bytes_left -= pg_len;
 	}
 	if ((isect << SECTOR_SHIFT) >= header->inode->i_size) {
 		header->res.eof = 1;
@@ -346,6 +370,7 @@ static enum pnfs_try_status
 bl_write_pagelist(struct nfs_pgio_header *header, int sync)
 {
 	struct pnfs_block_layout *bl = BLK_LSEG2EXT(header->lseg);
+	struct pnfs_block_dev_map map = { .start = NFS4_MAX_UINT64 };
 	struct bio *bio = NULL;
 	struct pnfs_block_extent be;
 	sector_t isect, extent_length = 0;
@@ -354,6 +379,7 @@ bl_write_pagelist(struct nfs_pgio_header *header, int sync)
 	size_t count = header->args.count;
 	struct page **pages = header->args.pages;
 	int pg_index = pg_index = header->args.pgbase >> PAGE_CACHE_SHIFT;
+	unsigned int pg_len;
 	struct blk_plug plug;
 	int i;
 
@@ -387,19 +413,21 @@ bl_write_pagelist(struct nfs_pgio_header *header, int sync)
 			extent_length = be.be_length - (isect - be.be_f_offset);
 		}
 
+		pg_len = PAGE_CACHE_SIZE;
 		bio = do_add_page_to_bio(bio, header->page_array.npages - i,
-					 WRITE, isect, pages[i], &be,
+					 WRITE, isect, pages[i], &map, &be,
 					 bl_end_io_write, par,
-					 0, PAGE_CACHE_SIZE);
+					 0, &pg_len);
 		if (IS_ERR(bio)) {
 			header->pnfs_error = PTR_ERR(bio);
 			bio = NULL;
 			goto out;
 		}
-		offset += PAGE_CACHE_SIZE;
-		count -= PAGE_CACHE_SIZE;
-		isect += PAGE_CACHE_SECTORS;
-		extent_length -= PAGE_CACHE_SECTORS;
+
+		offset += pg_len;
+		count -= pg_len;
+		isect += (pg_len >> SECTOR_SHIFT);
+		extent_length -= (pg_len >> SECTOR_SHIFT);
 	}
 
 	header->res.count = header->args.count;