/* * linux/fs/nfs/blocklayout/blocklayout.c * * Module for the NFSv4.1 pNFS block layout driver. * * Copyright (c) 2006 The Regents of the University of Michigan. * All rights reserved. * * Andy Adamson * Fred Isaman * * permission is granted to use, copy, create derivative works and * redistribute this software and such derivative works for any purpose, * so long as the name of the university of michigan is not used in * any advertising or publicity pertaining to the use or distribution * of this software without specific, written prior authorization. if * the above copyright notice or any other identification of the * university of michigan is included in any copy of any portion of * this software, then the disclaimer below must also be included. * * this software is provided as is, without representation from the * university of michigan as to its fitness for any purpose, and without * warranty by the university of michigan of any kind, either express * or implied, including without limitation the implied warranties of * merchantability and fitness for a particular purpose. the regents * of the university of michigan shall not be liable for any damages, * including special, indirect, incidental, or consequential damages, * with respect to any claim arising out or in connection with the use * of the software, even if it has been or is hereafter advised of the * possibility of such damages. */ #include #include #include #include #include /* struct bio */ #include #include #include "../pnfs.h" #include "../nfs4session.h" #include "../internal.h" #include "blocklayout.h" #define NFSDBG_FACILITY NFSDBG_PNFS_LD MODULE_LICENSE("GPL"); MODULE_AUTHOR("Andy Adamson "); MODULE_DESCRIPTION("The NFSv4.1 pNFS Block layout driver"); static bool is_hole(struct pnfs_block_extent *be) { switch (be->be_state) { case PNFS_BLOCK_NONE_DATA: return true; case PNFS_BLOCK_INVALID_DATA: return be->be_tag ? false : true; default: return false; } } /* The data we are handed might be spread across several bios. We need * to track when the last one is finished. */ struct parallel_io { struct kref refcnt; void (*pnfs_callback) (void *data); void *data; }; static inline struct parallel_io *alloc_parallel(void *data) { struct parallel_io *rv; rv = kmalloc(sizeof(*rv), GFP_NOFS); if (rv) { rv->data = data; kref_init(&rv->refcnt); } return rv; } static inline void get_parallel(struct parallel_io *p) { kref_get(&p->refcnt); } static void destroy_parallel(struct kref *kref) { struct parallel_io *p = container_of(kref, struct parallel_io, refcnt); dprintk("%s enter\n", __func__); p->pnfs_callback(p->data); kfree(p); } static inline void put_parallel(struct parallel_io *p) { kref_put(&p->refcnt, destroy_parallel); } static struct bio * bl_submit_bio(int rw, struct bio *bio) { if (bio) { get_parallel(bio->bi_private); dprintk("%s submitting %s bio %u@%llu\n", __func__, rw == READ ? "read" : "write", bio->bi_iter.bi_size, (unsigned long long)bio->bi_iter.bi_sector); submit_bio(rw, 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) { 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); bio = bio_alloc(GFP_NOIO, npg); if (!bio && (current->flags & PF_MEMALLOC)) { while (!bio && (npg /= 2)) bio = bio_alloc(GFP_NOIO, npg); } if (bio) { bio->bi_iter.bi_sector = isect - be->be_f_offset + be->be_v_offset; bio->bi_bdev = dev->d_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) { isect = isect + (offset >> SECTOR_SHIFT); dprintk("%s: npg %d rw %d isect %llu offset %u len %d\n", __func__, npg, rw, (unsigned long long)isect, offset, len); retry: if (!bio) { bio = bl_alloc_init_bio(npg, isect, be, end_io, par); if (!bio) return ERR_PTR(-ENOMEM); } if (bio_add_page(bio, page, len, offset) < len) { bio = bl_submit_bio(rw, bio); goto retry; } return bio; } static void bl_end_io_read(struct bio *bio, int err) { struct parallel_io *par = bio->bi_private; if (err) { struct nfs_pgio_header *header = par->data; if (!header->pnfs_error) header->pnfs_error = -EIO; pnfs_set_lo_fail(header->lseg); } bio_put(bio); put_parallel(par); } static void bl_read_cleanup(struct work_struct *work) { struct rpc_task *task; struct nfs_pgio_header *hdr; dprintk("%s enter\n", __func__); task = container_of(work, struct rpc_task, u.tk_work); hdr = container_of(task, struct nfs_pgio_header, task); pnfs_ld_read_done(hdr); } static void bl_end_par_io_read(void *data) { struct nfs_pgio_header *hdr = data; hdr->task.tk_status = hdr->pnfs_error; INIT_WORK(&hdr->task.u.tk_work, bl_read_cleanup); schedule_work(&hdr->task.u.tk_work); } static enum pnfs_try_status bl_read_pagelist(struct nfs_pgio_header *header) { struct pnfs_block_layout *bl = BLK_LSEG2EXT(header->lseg); struct bio *bio = NULL; struct pnfs_block_extent be; sector_t isect, extent_length = 0; struct parallel_io *par; loff_t f_offset = header->args.offset; size_t bytes_left = header->args.count; unsigned int pg_offset, pg_len; struct page **pages = header->args.pages; int pg_index = header->args.pgbase >> PAGE_CACHE_SHIFT; const bool is_dio = (header->dreq != NULL); struct blk_plug plug; int i; dprintk("%s enter nr_pages %u offset %lld count %u\n", __func__, header->page_array.npages, f_offset, (unsigned int)header->args.count); par = alloc_parallel(header); if (!par) return PNFS_NOT_ATTEMPTED; par->pnfs_callback = bl_end_par_io_read; blk_start_plug(&plug); isect = (sector_t) (f_offset >> SECTOR_SHIFT); /* Code assumes extents are page-aligned */ for (i = pg_index; i < header->page_array.npages; i++) { if (extent_length <= 0) { /* We've used up the previous extent */ bio = bl_submit_bio(READ, bio); /* Get the next one */ if (!ext_tree_lookup(bl, isect, &be, false)) { header->pnfs_error = -EIO; goto out; } extent_length = be.be_length - (isect - be.be_f_offset); } pg_offset = f_offset & ~PAGE_CACHE_MASK; if (is_dio) { if (pg_offset + bytes_left > PAGE_CACHE_SIZE) 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; } 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); } else { bio = do_add_page_to_bio(bio, header->page_array.npages - i, READ, isect, pages[i], &be, bl_end_io_read, par, pg_offset, pg_len); if (IS_ERR(bio)) { header->pnfs_error = PTR_ERR(bio); bio = NULL; goto out; } } isect += (pg_len >> SECTOR_SHIFT); extent_length -= (pg_len >> SECTOR_SHIFT); } if ((isect << SECTOR_SHIFT) >= header->inode->i_size) { header->res.eof = 1; header->res.count = header->inode->i_size - header->args.offset; } else { header->res.count = (isect << SECTOR_SHIFT) - header->args.offset; } out: bl_submit_bio(READ, bio); blk_finish_plug(&plug); put_parallel(par); return PNFS_ATTEMPTED; } static void bl_end_io_write(struct bio *bio, int err) { struct parallel_io *par = bio->bi_private; const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct nfs_pgio_header *header = par->data; if (!uptodate) { if (!header->pnfs_error) header->pnfs_error = -EIO; pnfs_set_lo_fail(header->lseg); } bio_put(bio); put_parallel(par); } /* Function scheduled for call during bl_end_par_io_write, * it marks sectors as written and extends the commitlist. */ static void bl_write_cleanup(struct work_struct *work) { struct rpc_task *task = container_of(work, struct rpc_task, u.tk_work); struct nfs_pgio_header *hdr = container_of(task, struct nfs_pgio_header, task); dprintk("%s enter\n", __func__); if (likely(!hdr->pnfs_error)) { struct pnfs_block_layout *bl = BLK_LSEG2EXT(hdr->lseg); u64 start = hdr->args.offset & (loff_t)PAGE_CACHE_MASK; u64 end = (hdr->args.offset + hdr->args.count + PAGE_CACHE_SIZE - 1) & (loff_t)PAGE_CACHE_MASK; ext_tree_mark_written(bl, start >> SECTOR_SHIFT, (end - start) >> SECTOR_SHIFT); } pnfs_ld_write_done(hdr); } /* Called when last of bios associated with a bl_write_pagelist call finishes */ static void bl_end_par_io_write(void *data) { struct nfs_pgio_header *hdr = data; hdr->task.tk_status = hdr->pnfs_error; hdr->verf.committed = NFS_FILE_SYNC; INIT_WORK(&hdr->task.u.tk_work, bl_write_cleanup); schedule_work(&hdr->task.u.tk_work); } 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 bio *bio = NULL; struct pnfs_block_extent be; sector_t isect, extent_length = 0; struct parallel_io *par = NULL; loff_t offset = header->args.offset; size_t count = header->args.count; struct page **pages = header->args.pages; int pg_index = pg_index = header->args.pgbase >> PAGE_CACHE_SHIFT; struct blk_plug plug; int i; dprintk("%s enter, %Zu@%lld\n", __func__, count, offset); /* At this point, header->page_aray is a (sequential) list of nfs_pages. * We want to write each, and if there is an error set pnfs_error * to have it redone using nfs. */ par = alloc_parallel(header); if (!par) return PNFS_NOT_ATTEMPTED; par->pnfs_callback = bl_end_par_io_write; blk_start_plug(&plug); /* we always write out the whole page */ offset = offset & (loff_t)PAGE_CACHE_MASK; isect = offset >> SECTOR_SHIFT; for (i = pg_index; i < header->page_array.npages; i++) { if (extent_length <= 0) { /* We've used up the previous extent */ bio = bl_submit_bio(WRITE, bio); /* Get the next one */ if (!ext_tree_lookup(bl, isect, &be, true)) { header->pnfs_error = -EINVAL; goto out; } extent_length = be.be_length - (isect - be.be_f_offset); } bio = do_add_page_to_bio(bio, header->page_array.npages - i, WRITE, isect, pages[i], &be, bl_end_io_write, par, 0, PAGE_CACHE_SIZE); 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; } header->res.count = header->args.count; out: bl_submit_bio(WRITE, bio); blk_finish_plug(&plug); put_parallel(par); return PNFS_ATTEMPTED; } static void bl_free_layout_hdr(struct pnfs_layout_hdr *lo) { struct pnfs_block_layout *bl = BLK_LO2EXT(lo); int err; dprintk("%s enter\n", __func__); err = ext_tree_remove(bl, true, 0, LLONG_MAX); WARN_ON(err); kfree(bl); } static struct pnfs_layout_hdr *bl_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags) { struct pnfs_block_layout *bl; dprintk("%s enter\n", __func__); bl = kzalloc(sizeof(*bl), gfp_flags); if (!bl) return NULL; bl->bl_ext_rw = RB_ROOT; bl->bl_ext_ro = RB_ROOT; spin_lock_init(&bl->bl_ext_lock); return &bl->bl_layout; } static void bl_free_lseg(struct pnfs_layout_segment *lseg) { dprintk("%s enter\n", __func__); kfree(lseg); } /* Tracks info needed to ensure extents in layout obey constraints of spec */ struct layout_verification { u32 mode; /* R or RW */ u64 start; /* Expected start of next non-COW extent */ u64 inval; /* Start of INVAL coverage */ u64 cowread; /* End of COW read coverage */ }; /* Verify the extent meets the layout requirements of the pnfs-block draft, * section 2.3.1. */ static int verify_extent(struct pnfs_block_extent *be, struct layout_verification *lv) { if (lv->mode == IOMODE_READ) { if (be->be_state == PNFS_BLOCK_READWRITE_DATA || be->be_state == PNFS_BLOCK_INVALID_DATA) return -EIO; if (be->be_f_offset != lv->start) return -EIO; lv->start += be->be_length; return 0; } /* lv->mode == IOMODE_RW */ if (be->be_state == PNFS_BLOCK_READWRITE_DATA) { if (be->be_f_offset != lv->start) return -EIO; if (lv->cowread > lv->start) return -EIO; lv->start += be->be_length; lv->inval = lv->start; return 0; } else if (be->be_state == PNFS_BLOCK_INVALID_DATA) { if (be->be_f_offset != lv->start) return -EIO; lv->start += be->be_length; return 0; } else if (be->be_state == PNFS_BLOCK_READ_DATA) { if (be->be_f_offset > lv->start) return -EIO; if (be->be_f_offset < lv->inval) return -EIO; if (be->be_f_offset < lv->cowread) return -EIO; /* It looks like you might want to min this with lv->start, * but you really don't. */ lv->inval = lv->inval + be->be_length; lv->cowread = be->be_f_offset + be->be_length; return 0; } else return -EIO; } static int decode_sector_number(__be32 **rp, sector_t *sp) { uint64_t s; *rp = xdr_decode_hyper(*rp, &s); if (s & 0x1ff) { printk(KERN_WARNING "NFS: %s: sector not aligned\n", __func__); return -1; } *sp = s >> SECTOR_SHIFT; return 0; } static int bl_alloc_extent(struct xdr_stream *xdr, struct pnfs_layout_hdr *lo, struct layout_verification *lv, struct list_head *extents, gfp_t gfp_mask) { struct pnfs_block_extent *be; struct nfs4_deviceid id; int error; __be32 *p; p = xdr_inline_decode(xdr, 28 + NFS4_DEVICEID4_SIZE); if (!p) return -EIO; be = kzalloc(sizeof(*be), GFP_NOFS); if (!be) return -ENOMEM; memcpy(&id, p, NFS4_DEVICEID4_SIZE); p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE); error = -EIO; be->be_device = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &id, lo->plh_lc_cred, gfp_mask); if (!be->be_device) goto out_free_be; /* * The next three values are read in as bytes, but stored in the * extent structure in 512-byte granularity. */ if (decode_sector_number(&p, &be->be_f_offset) < 0) goto out_put_deviceid; if (decode_sector_number(&p, &be->be_length) < 0) goto out_put_deviceid; if (decode_sector_number(&p, &be->be_v_offset) < 0) goto out_put_deviceid; be->be_state = be32_to_cpup(p++); error = verify_extent(be, lv); if (error) { dprintk("%s: extent verification failed\n", __func__); goto out_put_deviceid; } list_add_tail(&be->be_list, extents); return 0; out_put_deviceid: nfs4_put_deviceid_node(be->be_device); out_free_be: kfree(be); return error; } static struct pnfs_layout_segment * bl_alloc_lseg(struct pnfs_layout_hdr *lo, struct nfs4_layoutget_res *lgr, gfp_t gfp_mask) { struct layout_verification lv = { .mode = lgr->range.iomode, .start = lgr->range.offset >> SECTOR_SHIFT, .inval = lgr->range.offset >> SECTOR_SHIFT, .cowread = lgr->range.offset >> SECTOR_SHIFT, }; struct pnfs_block_layout *bl = BLK_LO2EXT(lo); struct pnfs_layout_segment *lseg; struct xdr_buf buf; struct xdr_stream xdr; struct page *scratch; int status, i; uint32_t count; __be32 *p; LIST_HEAD(extents); dprintk("---> %s\n", __func__); lseg = kzalloc(sizeof(*lseg), gfp_mask); if (!lseg) return ERR_PTR(-ENOMEM); status = -ENOMEM; scratch = alloc_page(gfp_mask); if (!scratch) goto out; xdr_init_decode_pages(&xdr, &buf, lgr->layoutp->pages, lgr->layoutp->len); xdr_set_scratch_buffer(&xdr, page_address(scratch), PAGE_SIZE); status = -EIO; p = xdr_inline_decode(&xdr, 4); if (unlikely(!p)) goto out_free_scratch; count = be32_to_cpup(p++); dprintk("%s: number of extents %d\n", __func__, count); /* * Decode individual extents, putting them in temporary staging area * until whole layout is decoded to make error recovery easier. */ for (i = 0; i < count; i++) { status = bl_alloc_extent(&xdr, lo, &lv, &extents, gfp_mask); if (status) goto process_extents; } if (lgr->range.offset + lgr->range.length != lv.start << SECTOR_SHIFT) { dprintk("%s Final length mismatch\n", __func__); status = -EIO; goto process_extents; } if (lv.start < lv.cowread) { dprintk("%s Final uncovered COW extent\n", __func__); status = -EIO; } process_extents: while (!list_empty(&extents)) { struct pnfs_block_extent *be = list_first_entry(&extents, struct pnfs_block_extent, be_list); list_del(&be->be_list); if (!status) status = ext_tree_insert(bl, be); if (status) { nfs4_put_deviceid_node(be->be_device); kfree(be); } } out_free_scratch: __free_page(scratch); out: dprintk("%s returns %d\n", __func__, status); if (status) { kfree(lseg); return ERR_PTR(status); } return lseg; } static void bl_return_range(struct pnfs_layout_hdr *lo, struct pnfs_layout_range *range) { struct pnfs_block_layout *bl = BLK_LO2EXT(lo); sector_t offset = range->offset >> SECTOR_SHIFT, end; int err; if (range->offset % 8) { dprintk("%s: offset %lld not block size aligned\n", __func__, range->offset); return; } if (range->length != NFS4_MAX_UINT64) { if (range->length % 8) { dprintk("%s: length %lld not block size aligned\n", __func__, range->length); return; } end = offset + (range->length >> SECTOR_SHIFT); } else { end = round_down(NFS4_MAX_UINT64, PAGE_SIZE); } err = ext_tree_remove(bl, range->iomode & IOMODE_RW, offset, end); } static int bl_prepare_layoutcommit(struct nfs4_layoutcommit_args *arg) { return ext_tree_prepare_commit(arg); } static void bl_cleanup_layoutcommit(struct nfs4_layoutcommit_data *lcdata) { ext_tree_mark_committed(&lcdata->args, lcdata->res.status); } static int bl_set_layoutdriver(struct nfs_server *server, const struct nfs_fh *fh) { dprintk("%s enter\n", __func__); if (server->pnfs_blksize == 0) { dprintk("%s Server did not return blksize\n", __func__); return -EINVAL; } if (server->pnfs_blksize > PAGE_SIZE) { printk(KERN_ERR "%s: pNFS blksize %d not supported.\n", __func__, server->pnfs_blksize); return -EINVAL; } return 0; } static bool is_aligned_req(struct nfs_pageio_descriptor *pgio, struct nfs_page *req, unsigned int alignment) { /* * Always accept buffered writes, higher layers take care of the * right alignment. */ if (pgio->pg_dreq == NULL) return true; if (!IS_ALIGNED(req->wb_offset, alignment)) return false; if (IS_ALIGNED(req->wb_bytes, alignment)) return true; if (req_offset(req) + req->wb_bytes == i_size_read(pgio->pg_inode)) { /* * If the write goes up to the inode size, just write * the full page. Data past the inode size is * guaranteed to be zeroed by the higher level client * code, and this behaviour is mandated by RFC 5663 * section 2.3.2. */ return true; } return false; } static void bl_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) { if (!is_aligned_req(pgio, req, SECTOR_SIZE)) { nfs_pageio_reset_read_mds(pgio); return; } pnfs_generic_pg_init_read(pgio, req); } /* * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number * of bytes (maximum @req->wb_bytes) that can be coalesced. */ static size_t bl_pg_test_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, struct nfs_page *req) { if (!is_aligned_req(pgio, req, SECTOR_SIZE)) return 0; return pnfs_generic_pg_test(pgio, prev, req); } /* * Return the number of contiguous bytes for a given inode * starting at page frame idx. */ static u64 pnfs_num_cont_bytes(struct inode *inode, pgoff_t idx) { struct address_space *mapping = inode->i_mapping; pgoff_t end; /* Optimize common case that writes from 0 to end of file */ end = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE); if (end != NFS_I(inode)->npages) { rcu_read_lock(); end = page_cache_next_hole(mapping, idx + 1, ULONG_MAX); rcu_read_unlock(); } if (!end) return i_size_read(inode) - (idx << PAGE_CACHE_SHIFT); else return (end - idx) << PAGE_CACHE_SHIFT; } static void bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) { u64 wb_size; if (!is_aligned_req(pgio, req, PAGE_SIZE)) { nfs_pageio_reset_write_mds(pgio); return; } if (pgio->pg_dreq == NULL) wb_size = pnfs_num_cont_bytes(pgio->pg_inode, req->wb_index); else wb_size = nfs_dreq_bytes_left(pgio->pg_dreq); pnfs_generic_pg_init_write(pgio, req, wb_size); } /* * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number * of bytes (maximum @req->wb_bytes) that can be coalesced. */ static size_t bl_pg_test_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, struct nfs_page *req) { if (!is_aligned_req(pgio, req, PAGE_SIZE)) return 0; return pnfs_generic_pg_test(pgio, prev, req); } static const struct nfs_pageio_ops bl_pg_read_ops = { .pg_init = bl_pg_init_read, .pg_test = bl_pg_test_read, .pg_doio = pnfs_generic_pg_readpages, }; static const struct nfs_pageio_ops bl_pg_write_ops = { .pg_init = bl_pg_init_write, .pg_test = bl_pg_test_write, .pg_doio = pnfs_generic_pg_writepages, }; static struct pnfs_layoutdriver_type blocklayout_type = { .id = LAYOUT_BLOCK_VOLUME, .name = "LAYOUT_BLOCK_VOLUME", .owner = THIS_MODULE, .flags = PNFS_LAYOUTRET_ON_SETATTR | PNFS_READ_WHOLE_PAGE, .read_pagelist = bl_read_pagelist, .write_pagelist = bl_write_pagelist, .alloc_layout_hdr = bl_alloc_layout_hdr, .free_layout_hdr = bl_free_layout_hdr, .alloc_lseg = bl_alloc_lseg, .free_lseg = bl_free_lseg, .return_range = bl_return_range, .prepare_layoutcommit = bl_prepare_layoutcommit, .cleanup_layoutcommit = bl_cleanup_layoutcommit, .set_layoutdriver = bl_set_layoutdriver, .alloc_deviceid_node = bl_alloc_deviceid_node, .free_deviceid_node = bl_free_deviceid_node, .pg_read_ops = &bl_pg_read_ops, .pg_write_ops = &bl_pg_write_ops, }; static int __init nfs4blocklayout_init(void) { int ret; dprintk("%s: NFSv4 Block Layout Driver Registering...\n", __func__); ret = pnfs_register_layoutdriver(&blocklayout_type); if (ret) goto out; ret = bl_init_pipefs(); if (ret) goto out_unregister; return 0; out_unregister: pnfs_unregister_layoutdriver(&blocklayout_type); out: return ret; } static void __exit nfs4blocklayout_exit(void) { dprintk("%s: NFSv4 Block Layout Driver Unregistering...\n", __func__); bl_cleanup_pipefs(); pnfs_unregister_layoutdriver(&blocklayout_type); } MODULE_ALIAS("nfs-layouttype4-3"); module_init(nfs4blocklayout_init); module_exit(nfs4blocklayout_exit);