diff options
Diffstat (limited to 'kernel/fs/nfs/pagelist.c')
| -rw-r--r-- | kernel/fs/nfs/pagelist.c | 1309 |
1 files changed, 1309 insertions, 0 deletions
diff --git a/kernel/fs/nfs/pagelist.c b/kernel/fs/nfs/pagelist.c new file mode 100644 index 000000000..282b39369 --- /dev/null +++ b/kernel/fs/nfs/pagelist.c @@ -0,0 +1,1309 @@ +/* + * linux/fs/nfs/pagelist.c + * + * A set of helper functions for managing NFS read and write requests. + * The main purpose of these routines is to provide support for the + * coalescing of several requests into a single RPC call. + * + * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no> + * + */ + +#include <linux/slab.h> +#include <linux/file.h> +#include <linux/sched.h> +#include <linux/sunrpc/clnt.h> +#include <linux/nfs.h> +#include <linux/nfs3.h> +#include <linux/nfs4.h> +#include <linux/nfs_page.h> +#include <linux/nfs_fs.h> +#include <linux/nfs_mount.h> +#include <linux/export.h> + +#include "internal.h" +#include "pnfs.h" + +#define NFSDBG_FACILITY NFSDBG_PAGECACHE + +static struct kmem_cache *nfs_page_cachep; +static const struct rpc_call_ops nfs_pgio_common_ops; + +static bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount) +{ + p->npages = pagecount; + if (pagecount <= ARRAY_SIZE(p->page_array)) + p->pagevec = p->page_array; + else { + p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL); + if (!p->pagevec) + p->npages = 0; + } + return p->pagevec != NULL; +} + +struct nfs_pgio_mirror * +nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc) +{ + return nfs_pgio_has_mirroring(desc) ? + &desc->pg_mirrors[desc->pg_mirror_idx] : + &desc->pg_mirrors[0]; +} +EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror); + +void nfs_pgheader_init(struct nfs_pageio_descriptor *desc, + struct nfs_pgio_header *hdr, + void (*release)(struct nfs_pgio_header *hdr)) +{ + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + + + hdr->req = nfs_list_entry(mirror->pg_list.next); + hdr->inode = desc->pg_inode; + hdr->cred = hdr->req->wb_context->cred; + hdr->io_start = req_offset(hdr->req); + hdr->good_bytes = mirror->pg_count; + hdr->dreq = desc->pg_dreq; + hdr->layout_private = desc->pg_layout_private; + hdr->release = release; + hdr->completion_ops = desc->pg_completion_ops; + if (hdr->completion_ops->init_hdr) + hdr->completion_ops->init_hdr(hdr); + + hdr->pgio_mirror_idx = desc->pg_mirror_idx; +} +EXPORT_SYMBOL_GPL(nfs_pgheader_init); + +void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos) +{ + spin_lock(&hdr->lock); + if (pos < hdr->io_start + hdr->good_bytes) { + set_bit(NFS_IOHDR_ERROR, &hdr->flags); + clear_bit(NFS_IOHDR_EOF, &hdr->flags); + hdr->good_bytes = pos - hdr->io_start; + hdr->error = error; + } + spin_unlock(&hdr->lock); +} + +static inline struct nfs_page * +nfs_page_alloc(void) +{ + struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_NOIO); + if (p) + INIT_LIST_HEAD(&p->wb_list); + return p; +} + +static inline void +nfs_page_free(struct nfs_page *p) +{ + kmem_cache_free(nfs_page_cachep, p); +} + +static void +nfs_iocounter_inc(struct nfs_io_counter *c) +{ + atomic_inc(&c->io_count); +} + +static void +nfs_iocounter_dec(struct nfs_io_counter *c) +{ + if (atomic_dec_and_test(&c->io_count)) { + clear_bit(NFS_IO_INPROGRESS, &c->flags); + smp_mb__after_atomic(); + wake_up_bit(&c->flags, NFS_IO_INPROGRESS); + } +} + +static int +__nfs_iocounter_wait(struct nfs_io_counter *c) +{ + wait_queue_head_t *wq = bit_waitqueue(&c->flags, NFS_IO_INPROGRESS); + DEFINE_WAIT_BIT(q, &c->flags, NFS_IO_INPROGRESS); + int ret = 0; + + do { + prepare_to_wait(wq, &q.wait, TASK_KILLABLE); + set_bit(NFS_IO_INPROGRESS, &c->flags); + if (atomic_read(&c->io_count) == 0) + break; + ret = nfs_wait_bit_killable(&q.key); + } while (atomic_read(&c->io_count) != 0 && !ret); + finish_wait(wq, &q.wait); + return ret; +} + +/** + * nfs_iocounter_wait - wait for i/o to complete + * @c: nfs_io_counter to use + * + * returns -ERESTARTSYS if interrupted by a fatal signal. + * Otherwise returns 0 once the io_count hits 0. + */ +int +nfs_iocounter_wait(struct nfs_io_counter *c) +{ + if (atomic_read(&c->io_count) == 0) + return 0; + return __nfs_iocounter_wait(c); +} + +/* + * nfs_page_group_lock - lock the head of the page group + * @req - request in group that is to be locked + * @nonblock - if true don't block waiting for lock + * + * this lock must be held if modifying the page group list + * + * return 0 on success, < 0 on error: -EDELAY if nonblocking or the + * result from wait_on_bit_lock + * + * NOTE: calling with nonblock=false should always have set the + * lock bit (see fs/buffer.c and other uses of wait_on_bit_lock + * with TASK_UNINTERRUPTIBLE), so there is no need to check the result. + */ +int +nfs_page_group_lock(struct nfs_page *req, bool nonblock) +{ + struct nfs_page *head = req->wb_head; + + WARN_ON_ONCE(head != head->wb_head); + + if (!test_and_set_bit(PG_HEADLOCK, &head->wb_flags)) + return 0; + + if (!nonblock) + return wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK, + TASK_UNINTERRUPTIBLE); + + return -EAGAIN; +} + +/* + * nfs_page_group_lock_wait - wait for the lock to clear, but don't grab it + * @req - a request in the group + * + * This is a blocking call to wait for the group lock to be cleared. + */ +void +nfs_page_group_lock_wait(struct nfs_page *req) +{ + struct nfs_page *head = req->wb_head; + + WARN_ON_ONCE(head != head->wb_head); + + wait_on_bit(&head->wb_flags, PG_HEADLOCK, + TASK_UNINTERRUPTIBLE); +} + +/* + * nfs_page_group_unlock - unlock the head of the page group + * @req - request in group that is to be unlocked + */ +void +nfs_page_group_unlock(struct nfs_page *req) +{ + struct nfs_page *head = req->wb_head; + + WARN_ON_ONCE(head != head->wb_head); + + smp_mb__before_atomic(); + clear_bit(PG_HEADLOCK, &head->wb_flags); + smp_mb__after_atomic(); + wake_up_bit(&head->wb_flags, PG_HEADLOCK); +} + +/* + * nfs_page_group_sync_on_bit_locked + * + * must be called with page group lock held + */ +static bool +nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit) +{ + struct nfs_page *head = req->wb_head; + struct nfs_page *tmp; + + WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags)); + WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags)); + + tmp = req->wb_this_page; + while (tmp != req) { + if (!test_bit(bit, &tmp->wb_flags)) + return false; + tmp = tmp->wb_this_page; + } + + /* true! reset all bits */ + tmp = req; + do { + clear_bit(bit, &tmp->wb_flags); + tmp = tmp->wb_this_page; + } while (tmp != req); + + return true; +} + +/* + * nfs_page_group_sync_on_bit - set bit on current request, but only + * return true if the bit is set for all requests in page group + * @req - request in page group + * @bit - PG_* bit that is used to sync page group + */ +bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit) +{ + bool ret; + + nfs_page_group_lock(req, false); + ret = nfs_page_group_sync_on_bit_locked(req, bit); + nfs_page_group_unlock(req); + + return ret; +} + +/* + * nfs_page_group_init - Initialize the page group linkage for @req + * @req - a new nfs request + * @prev - the previous request in page group, or NULL if @req is the first + * or only request in the group (the head). + */ +static inline void +nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev) +{ + struct inode *inode; + WARN_ON_ONCE(prev == req); + + if (!prev) { + /* a head request */ + req->wb_head = req; + req->wb_this_page = req; + } else { + /* a subrequest */ + WARN_ON_ONCE(prev->wb_this_page != prev->wb_head); + WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags)); + req->wb_head = prev->wb_head; + req->wb_this_page = prev->wb_this_page; + prev->wb_this_page = req; + + /* All subrequests take a ref on the head request until + * nfs_page_group_destroy is called */ + kref_get(&req->wb_head->wb_kref); + + /* grab extra ref and bump the request count if head request + * has extra ref from the write/commit path to handle handoff + * between write and commit lists. */ + if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) { + inode = page_file_mapping(req->wb_page)->host; + set_bit(PG_INODE_REF, &req->wb_flags); + kref_get(&req->wb_kref); + spin_lock(&inode->i_lock); + NFS_I(inode)->nrequests++; + spin_unlock(&inode->i_lock); + } + } +} + +/* + * nfs_page_group_destroy - sync the destruction of page groups + * @req - request that no longer needs the page group + * + * releases the page group reference from each member once all + * members have called this function. + */ +static void +nfs_page_group_destroy(struct kref *kref) +{ + struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref); + struct nfs_page *tmp, *next; + + /* subrequests must release the ref on the head request */ + if (req->wb_head != req) + nfs_release_request(req->wb_head); + + if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN)) + return; + + tmp = req; + do { + next = tmp->wb_this_page; + /* unlink and free */ + tmp->wb_this_page = tmp; + tmp->wb_head = tmp; + nfs_free_request(tmp); + tmp = next; + } while (tmp != req); +} + +/** + * nfs_create_request - Create an NFS read/write request. + * @ctx: open context to use + * @page: page to write + * @last: last nfs request created for this page group or NULL if head + * @offset: starting offset within the page for the write + * @count: number of bytes to read/write + * + * The page must be locked by the caller. This makes sure we never + * create two different requests for the same page. + * User should ensure it is safe to sleep in this function. + */ +struct nfs_page * +nfs_create_request(struct nfs_open_context *ctx, struct page *page, + struct nfs_page *last, unsigned int offset, + unsigned int count) +{ + struct nfs_page *req; + struct nfs_lock_context *l_ctx; + + if (test_bit(NFS_CONTEXT_BAD, &ctx->flags)) + return ERR_PTR(-EBADF); + /* try to allocate the request struct */ + req = nfs_page_alloc(); + if (req == NULL) + return ERR_PTR(-ENOMEM); + + /* get lock context early so we can deal with alloc failures */ + l_ctx = nfs_get_lock_context(ctx); + if (IS_ERR(l_ctx)) { + nfs_page_free(req); + return ERR_CAST(l_ctx); + } + req->wb_lock_context = l_ctx; + nfs_iocounter_inc(&l_ctx->io_count); + + /* Initialize the request struct. Initially, we assume a + * long write-back delay. This will be adjusted in + * update_nfs_request below if the region is not locked. */ + req->wb_page = page; + req->wb_index = page_file_index(page); + page_cache_get(page); + req->wb_offset = offset; + req->wb_pgbase = offset; + req->wb_bytes = count; + req->wb_context = get_nfs_open_context(ctx); + kref_init(&req->wb_kref); + nfs_page_group_init(req, last); + return req; +} + +/** + * nfs_unlock_request - Unlock request and wake up sleepers. + * @req: + */ +void nfs_unlock_request(struct nfs_page *req) +{ + if (!NFS_WBACK_BUSY(req)) { + printk(KERN_ERR "NFS: Invalid unlock attempted\n"); + BUG(); + } + smp_mb__before_atomic(); + clear_bit(PG_BUSY, &req->wb_flags); + smp_mb__after_atomic(); + wake_up_bit(&req->wb_flags, PG_BUSY); +} + +/** + * nfs_unlock_and_release_request - Unlock request and release the nfs_page + * @req: + */ +void nfs_unlock_and_release_request(struct nfs_page *req) +{ + nfs_unlock_request(req); + nfs_release_request(req); +} + +/* + * nfs_clear_request - Free up all resources allocated to the request + * @req: + * + * Release page and open context resources associated with a read/write + * request after it has completed. + */ +static void nfs_clear_request(struct nfs_page *req) +{ + struct page *page = req->wb_page; + struct nfs_open_context *ctx = req->wb_context; + struct nfs_lock_context *l_ctx = req->wb_lock_context; + + if (page != NULL) { + page_cache_release(page); + req->wb_page = NULL; + } + if (l_ctx != NULL) { + nfs_iocounter_dec(&l_ctx->io_count); + nfs_put_lock_context(l_ctx); + req->wb_lock_context = NULL; + } + if (ctx != NULL) { + put_nfs_open_context(ctx); + req->wb_context = NULL; + } +} + +/** + * nfs_release_request - Release the count on an NFS read/write request + * @req: request to release + * + * Note: Should never be called with the spinlock held! + */ +void nfs_free_request(struct nfs_page *req) +{ + WARN_ON_ONCE(req->wb_this_page != req); + + /* extra debug: make sure no sync bits are still set */ + WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags)); + WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags)); + WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags)); + WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags)); + WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags)); + + /* Release struct file and open context */ + nfs_clear_request(req); + nfs_page_free(req); +} + +void nfs_release_request(struct nfs_page *req) +{ + kref_put(&req->wb_kref, nfs_page_group_destroy); +} + +/** + * nfs_wait_on_request - Wait for a request to complete. + * @req: request to wait upon. + * + * Interruptible by fatal signals only. + * The user is responsible for holding a count on the request. + */ +int +nfs_wait_on_request(struct nfs_page *req) +{ + return wait_on_bit_io(&req->wb_flags, PG_BUSY, + TASK_UNINTERRUPTIBLE); +} + +/* + * nfs_generic_pg_test - determine if requests can be coalesced + * @desc: pointer to descriptor + * @prev: previous request in desc, or NULL + * @req: this request + * + * Returns zero if @req can be coalesced into @desc, otherwise it returns + * the size of the request. + */ +size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, + struct nfs_page *prev, struct nfs_page *req) +{ + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + + + if (mirror->pg_count > mirror->pg_bsize) { + /* should never happen */ + WARN_ON_ONCE(1); + return 0; + } + + /* + * Limit the request size so that we can still allocate a page array + * for it without upsetting the slab allocator. + */ + if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) * + sizeof(struct page) > PAGE_SIZE) + return 0; + + return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes); +} +EXPORT_SYMBOL_GPL(nfs_generic_pg_test); + +struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops) +{ + struct nfs_pgio_header *hdr = ops->rw_alloc_header(); + + if (hdr) { + INIT_LIST_HEAD(&hdr->pages); + spin_lock_init(&hdr->lock); + hdr->rw_ops = ops; + } + return hdr; +} +EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc); + +/* + * nfs_pgio_header_free - Free a read or write header + * @hdr: The header to free + */ +void nfs_pgio_header_free(struct nfs_pgio_header *hdr) +{ + hdr->rw_ops->rw_free_header(hdr); +} +EXPORT_SYMBOL_GPL(nfs_pgio_header_free); + +/** + * nfs_pgio_data_destroy - make @hdr suitable for reuse + * + * Frees memory and releases refs from nfs_generic_pgio, so that it may + * be called again. + * + * @hdr: A header that has had nfs_generic_pgio called + */ +void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr) +{ + if (hdr->args.context) + put_nfs_open_context(hdr->args.context); + if (hdr->page_array.pagevec != hdr->page_array.page_array) + kfree(hdr->page_array.pagevec); +} +EXPORT_SYMBOL_GPL(nfs_pgio_data_destroy); + +/** + * nfs_pgio_rpcsetup - Set up arguments for a pageio call + * @hdr: The pageio hdr + * @count: Number of bytes to read + * @offset: Initial offset + * @how: How to commit data (writes only) + * @cinfo: Commit information for the call (writes only) + */ +static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr, + unsigned int count, unsigned int offset, + int how, struct nfs_commit_info *cinfo) +{ + struct nfs_page *req = hdr->req; + + /* Set up the RPC argument and reply structs + * NB: take care not to mess about with hdr->commit et al. */ + + hdr->args.fh = NFS_FH(hdr->inode); + hdr->args.offset = req_offset(req) + offset; + /* pnfs_set_layoutcommit needs this */ + hdr->mds_offset = hdr->args.offset; + hdr->args.pgbase = req->wb_pgbase + offset; + hdr->args.pages = hdr->page_array.pagevec; + hdr->args.count = count; + hdr->args.context = get_nfs_open_context(req->wb_context); + hdr->args.lock_context = req->wb_lock_context; + hdr->args.stable = NFS_UNSTABLE; + switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) { + case 0: + break; + case FLUSH_COND_STABLE: + if (nfs_reqs_to_commit(cinfo)) + break; + default: + hdr->args.stable = NFS_FILE_SYNC; + } + + hdr->res.fattr = &hdr->fattr; + hdr->res.count = count; + hdr->res.eof = 0; + hdr->res.verf = &hdr->verf; + nfs_fattr_init(&hdr->fattr); +} + +/** + * nfs_pgio_prepare - Prepare pageio hdr to go over the wire + * @task: The current task + * @calldata: pageio header to prepare + */ +static void nfs_pgio_prepare(struct rpc_task *task, void *calldata) +{ + struct nfs_pgio_header *hdr = calldata; + int err; + err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr); + if (err) + rpc_exit(task, err); +} + +int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr, + struct rpc_cred *cred, const struct nfs_rpc_ops *rpc_ops, + const struct rpc_call_ops *call_ops, int how, int flags) +{ + struct rpc_task *task; + struct rpc_message msg = { + .rpc_argp = &hdr->args, + .rpc_resp = &hdr->res, + .rpc_cred = cred, + }; + struct rpc_task_setup task_setup_data = { + .rpc_client = clnt, + .task = &hdr->task, + .rpc_message = &msg, + .callback_ops = call_ops, + .callback_data = hdr, + .workqueue = nfsiod_workqueue, + .flags = RPC_TASK_ASYNC | flags, + }; + int ret = 0; + + hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how); + + dprintk("NFS: %5u initiated pgio call " + "(req %s/%llu, %u bytes @ offset %llu)\n", + hdr->task.tk_pid, + hdr->inode->i_sb->s_id, + (unsigned long long)NFS_FILEID(hdr->inode), + hdr->args.count, + (unsigned long long)hdr->args.offset); + + task = rpc_run_task(&task_setup_data); + if (IS_ERR(task)) { + ret = PTR_ERR(task); + goto out; + } + if (how & FLUSH_SYNC) { + ret = rpc_wait_for_completion_task(task); + if (ret == 0) + ret = task->tk_status; + } + rpc_put_task(task); +out: + return ret; +} +EXPORT_SYMBOL_GPL(nfs_initiate_pgio); + +/** + * nfs_pgio_error - Clean up from a pageio error + * @desc: IO descriptor + * @hdr: pageio header + */ +static int nfs_pgio_error(struct nfs_pageio_descriptor *desc, + struct nfs_pgio_header *hdr) +{ + struct nfs_pgio_mirror *mirror; + u32 midx; + + set_bit(NFS_IOHDR_REDO, &hdr->flags); + nfs_pgio_data_destroy(hdr); + hdr->completion_ops->completion(hdr); + /* TODO: Make sure it's right to clean up all mirrors here + * and not just hdr->pgio_mirror_idx */ + for (midx = 0; midx < desc->pg_mirror_count; midx++) { + mirror = &desc->pg_mirrors[midx]; + desc->pg_completion_ops->error_cleanup(&mirror->pg_list); + } + return -ENOMEM; +} + +/** + * nfs_pgio_release - Release pageio data + * @calldata: The pageio header to release + */ +static void nfs_pgio_release(void *calldata) +{ + struct nfs_pgio_header *hdr = calldata; + if (hdr->rw_ops->rw_release) + hdr->rw_ops->rw_release(hdr); + nfs_pgio_data_destroy(hdr); + hdr->completion_ops->completion(hdr); +} + +static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror, + unsigned int bsize) +{ + INIT_LIST_HEAD(&mirror->pg_list); + mirror->pg_bytes_written = 0; + mirror->pg_count = 0; + mirror->pg_bsize = bsize; + mirror->pg_base = 0; + mirror->pg_recoalesce = 0; +} + +/** + * nfs_pageio_init - initialise a page io descriptor + * @desc: pointer to descriptor + * @inode: pointer to inode + * @doio: pointer to io function + * @bsize: io block size + * @io_flags: extra parameters for the io function + */ +void nfs_pageio_init(struct nfs_pageio_descriptor *desc, + struct inode *inode, + const struct nfs_pageio_ops *pg_ops, + const struct nfs_pgio_completion_ops *compl_ops, + const struct nfs_rw_ops *rw_ops, + size_t bsize, + int io_flags) +{ + struct nfs_pgio_mirror *new; + int i; + + desc->pg_moreio = 0; + desc->pg_inode = inode; + desc->pg_ops = pg_ops; + desc->pg_completion_ops = compl_ops; + desc->pg_rw_ops = rw_ops; + desc->pg_ioflags = io_flags; + desc->pg_error = 0; + desc->pg_lseg = NULL; + desc->pg_dreq = NULL; + desc->pg_layout_private = NULL; + desc->pg_bsize = bsize; + + desc->pg_mirror_count = 1; + desc->pg_mirror_idx = 0; + + if (pg_ops->pg_get_mirror_count) { + /* until we have a request, we don't have an lseg and no + * idea how many mirrors there will be */ + new = kcalloc(NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX, + sizeof(struct nfs_pgio_mirror), GFP_KERNEL); + desc->pg_mirrors_dynamic = new; + desc->pg_mirrors = new; + + for (i = 0; i < NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX; i++) + nfs_pageio_mirror_init(&desc->pg_mirrors[i], bsize); + } else { + desc->pg_mirrors_dynamic = NULL; + desc->pg_mirrors = desc->pg_mirrors_static; + nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize); + } +} +EXPORT_SYMBOL_GPL(nfs_pageio_init); + +/** + * nfs_pgio_result - Basic pageio error handling + * @task: The task that ran + * @calldata: Pageio header to check + */ +static void nfs_pgio_result(struct rpc_task *task, void *calldata) +{ + struct nfs_pgio_header *hdr = calldata; + struct inode *inode = hdr->inode; + + dprintk("NFS: %s: %5u, (status %d)\n", __func__, + task->tk_pid, task->tk_status); + + if (hdr->rw_ops->rw_done(task, hdr, inode) != 0) + return; + if (task->tk_status < 0) + nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset); + else + hdr->rw_ops->rw_result(task, hdr); +} + +/* + * Create an RPC task for the given read or write request and kick it. + * The page must have been locked by the caller. + * + * It may happen that the page we're passed is not marked dirty. + * This is the case if nfs_updatepage detects a conflicting request + * that has been written but not committed. + */ +int nfs_generic_pgio(struct nfs_pageio_descriptor *desc, + struct nfs_pgio_header *hdr) +{ + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + + struct nfs_page *req; + struct page **pages, + *last_page; + struct list_head *head = &mirror->pg_list; + struct nfs_commit_info cinfo; + unsigned int pagecount, pageused; + + pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count); + if (!nfs_pgarray_set(&hdr->page_array, pagecount)) + return nfs_pgio_error(desc, hdr); + + nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq); + pages = hdr->page_array.pagevec; + last_page = NULL; + pageused = 0; + while (!list_empty(head)) { + req = nfs_list_entry(head->next); + nfs_list_remove_request(req); + nfs_list_add_request(req, &hdr->pages); + + if (!last_page || last_page != req->wb_page) { + pageused++; + if (pageused > pagecount) + break; + *pages++ = last_page = req->wb_page; + } + } + if (WARN_ON_ONCE(pageused != pagecount)) + return nfs_pgio_error(desc, hdr); + + if ((desc->pg_ioflags & FLUSH_COND_STABLE) && + (desc->pg_moreio || nfs_reqs_to_commit(&cinfo))) + desc->pg_ioflags &= ~FLUSH_COND_STABLE; + + /* Set up the argument struct */ + nfs_pgio_rpcsetup(hdr, mirror->pg_count, 0, desc->pg_ioflags, &cinfo); + desc->pg_rpc_callops = &nfs_pgio_common_ops; + return 0; +} +EXPORT_SYMBOL_GPL(nfs_generic_pgio); + +static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc) +{ + struct nfs_pgio_mirror *mirror; + struct nfs_pgio_header *hdr; + int ret; + + mirror = nfs_pgio_current_mirror(desc); + + hdr = nfs_pgio_header_alloc(desc->pg_rw_ops); + if (!hdr) { + /* TODO: make sure this is right with mirroring - or + * should it back out all mirrors? */ + desc->pg_completion_ops->error_cleanup(&mirror->pg_list); + return -ENOMEM; + } + nfs_pgheader_init(desc, hdr, nfs_pgio_header_free); + ret = nfs_generic_pgio(desc, hdr); + if (ret == 0) + ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode), + hdr, + hdr->cred, + NFS_PROTO(hdr->inode), + desc->pg_rpc_callops, + desc->pg_ioflags, 0); + return ret; +} + +/* + * nfs_pageio_setup_mirroring - determine if mirroring is to be used + * by calling the pg_get_mirror_count op + */ +static int nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio, + struct nfs_page *req) +{ + int mirror_count = 1; + + if (!pgio->pg_ops->pg_get_mirror_count) + return 0; + + mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req); + + if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) + return -EINVAL; + + if (WARN_ON_ONCE(!pgio->pg_mirrors_dynamic)) + return -EINVAL; + + pgio->pg_mirror_count = mirror_count; + + return 0; +} + +/* + * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1) + */ +void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio) +{ + pgio->pg_mirror_count = 1; + pgio->pg_mirror_idx = 0; +} + +static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio) +{ + pgio->pg_mirror_count = 1; + pgio->pg_mirror_idx = 0; + pgio->pg_mirrors = pgio->pg_mirrors_static; + kfree(pgio->pg_mirrors_dynamic); + pgio->pg_mirrors_dynamic = NULL; +} + +static bool nfs_match_open_context(const struct nfs_open_context *ctx1, + const struct nfs_open_context *ctx2) +{ + return ctx1->cred == ctx2->cred && ctx1->state == ctx2->state; +} + +static bool nfs_match_lock_context(const struct nfs_lock_context *l1, + const struct nfs_lock_context *l2) +{ + return l1->lockowner.l_owner == l2->lockowner.l_owner + && l1->lockowner.l_pid == l2->lockowner.l_pid; +} + +/** + * nfs_can_coalesce_requests - test two requests for compatibility + * @prev: pointer to nfs_page + * @req: pointer to nfs_page + * + * The nfs_page structures 'prev' and 'req' are compared to ensure that the + * page data area they describe is contiguous, and that their RPC + * credentials, NFSv4 open state, and lockowners are the same. + * + * Return 'true' if this is the case, else return 'false'. + */ +static bool nfs_can_coalesce_requests(struct nfs_page *prev, + struct nfs_page *req, + struct nfs_pageio_descriptor *pgio) +{ + size_t size; + struct file_lock_context *flctx; + + if (prev) { + if (!nfs_match_open_context(req->wb_context, prev->wb_context)) + return false; + flctx = d_inode(req->wb_context->dentry)->i_flctx; + if (flctx != NULL && + !(list_empty_careful(&flctx->flc_posix) && + list_empty_careful(&flctx->flc_flock)) && + !nfs_match_lock_context(req->wb_lock_context, + prev->wb_lock_context)) + return false; + if (req_offset(req) != req_offset(prev) + prev->wb_bytes) + return false; + if (req->wb_page == prev->wb_page) { + if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes) + return false; + } else { + if (req->wb_pgbase != 0 || + prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE) + return false; + } + } + size = pgio->pg_ops->pg_test(pgio, prev, req); + WARN_ON_ONCE(size > req->wb_bytes); + if (size && size < req->wb_bytes) + req->wb_bytes = size; + return size > 0; +} + +/** + * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list. + * @desc: destination io descriptor + * @req: request + * + * Returns true if the request 'req' was successfully coalesced into the + * existing list of pages 'desc'. + */ +static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, + struct nfs_page *req) +{ + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + + struct nfs_page *prev = NULL; + + if (mirror->pg_count != 0) { + prev = nfs_list_entry(mirror->pg_list.prev); + } else { + if (desc->pg_ops->pg_init) + desc->pg_ops->pg_init(desc, req); + mirror->pg_base = req->wb_pgbase; + } + if (!nfs_can_coalesce_requests(prev, req, desc)) + return 0; + nfs_list_remove_request(req); + nfs_list_add_request(req, &mirror->pg_list); + mirror->pg_count += req->wb_bytes; + return 1; +} + +/* + * Helper for nfs_pageio_add_request and nfs_pageio_complete + */ +static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) +{ + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + + + if (!list_empty(&mirror->pg_list)) { + int error = desc->pg_ops->pg_doio(desc); + if (error < 0) + desc->pg_error = error; + else + mirror->pg_bytes_written += mirror->pg_count; + } + if (list_empty(&mirror->pg_list)) { + mirror->pg_count = 0; + mirror->pg_base = 0; + } +} + +/** + * nfs_pageio_add_request - Attempt to coalesce a request into a page list. + * @desc: destination io descriptor + * @req: request + * + * This may split a request into subrequests which are all part of the + * same page group. + * + * Returns true if the request 'req' was successfully coalesced into the + * existing list of pages 'desc'. + */ +static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, + struct nfs_page *req) +{ + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + + struct nfs_page *subreq; + unsigned int bytes_left = 0; + unsigned int offset, pgbase; + + nfs_page_group_lock(req, false); + + subreq = req; + bytes_left = subreq->wb_bytes; + offset = subreq->wb_offset; + pgbase = subreq->wb_pgbase; + + do { + if (!nfs_pageio_do_add_request(desc, subreq)) { + /* make sure pg_test call(s) did nothing */ + WARN_ON_ONCE(subreq->wb_bytes != bytes_left); + WARN_ON_ONCE(subreq->wb_offset != offset); + WARN_ON_ONCE(subreq->wb_pgbase != pgbase); + + nfs_page_group_unlock(req); + desc->pg_moreio = 1; + nfs_pageio_doio(desc); + if (desc->pg_error < 0) + return 0; + if (mirror->pg_recoalesce) + return 0; + /* retry add_request for this subreq */ + nfs_page_group_lock(req, false); + continue; + } + + /* check for buggy pg_test call(s) */ + WARN_ON_ONCE(subreq->wb_bytes + subreq->wb_pgbase > PAGE_SIZE); + WARN_ON_ONCE(subreq->wb_bytes > bytes_left); + WARN_ON_ONCE(subreq->wb_bytes == 0); + + bytes_left -= subreq->wb_bytes; + offset += subreq->wb_bytes; + pgbase += subreq->wb_bytes; + + if (bytes_left) { + subreq = nfs_create_request(req->wb_context, + req->wb_page, + subreq, pgbase, bytes_left); + if (IS_ERR(subreq)) + goto err_ptr; + nfs_lock_request(subreq); + subreq->wb_offset = offset; + subreq->wb_index = req->wb_index; + } + } while (bytes_left > 0); + + nfs_page_group_unlock(req); + return 1; +err_ptr: + desc->pg_error = PTR_ERR(subreq); + nfs_page_group_unlock(req); + return 0; +} + +static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc) +{ + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + LIST_HEAD(head); + + do { + list_splice_init(&mirror->pg_list, &head); + mirror->pg_bytes_written -= mirror->pg_count; + mirror->pg_count = 0; + mirror->pg_base = 0; + mirror->pg_recoalesce = 0; + + desc->pg_moreio = 0; + + while (!list_empty(&head)) { + struct nfs_page *req; + + req = list_first_entry(&head, struct nfs_page, wb_list); + nfs_list_remove_request(req); + if (__nfs_pageio_add_request(desc, req)) + continue; + if (desc->pg_error < 0) + return 0; + break; + } + } while (mirror->pg_recoalesce); + return 1; +} + +static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc, + struct nfs_page *req) +{ + int ret; + + do { + ret = __nfs_pageio_add_request(desc, req); + if (ret) + break; + if (desc->pg_error < 0) + break; + ret = nfs_do_recoalesce(desc); + } while (ret); + + return ret; +} + +int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, + struct nfs_page *req) +{ + u32 midx; + unsigned int pgbase, offset, bytes; + struct nfs_page *dupreq, *lastreq; + + pgbase = req->wb_pgbase; + offset = req->wb_offset; + bytes = req->wb_bytes; + + nfs_pageio_setup_mirroring(desc, req); + + for (midx = 0; midx < desc->pg_mirror_count; midx++) { + if (midx) { + nfs_page_group_lock(req, false); + + /* find the last request */ + for (lastreq = req->wb_head; + lastreq->wb_this_page != req->wb_head; + lastreq = lastreq->wb_this_page) + ; + + dupreq = nfs_create_request(req->wb_context, + req->wb_page, lastreq, pgbase, bytes); + + if (IS_ERR(dupreq)) { + nfs_page_group_unlock(req); + return 0; + } + + nfs_lock_request(dupreq); + nfs_page_group_unlock(req); + dupreq->wb_offset = offset; + dupreq->wb_index = req->wb_index; + } else + dupreq = req; + + if (nfs_pgio_has_mirroring(desc)) + desc->pg_mirror_idx = midx; + if (!nfs_pageio_add_request_mirror(desc, dupreq)) + return 0; + } + + return 1; +} + +/* + * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an + * nfs_pageio_descriptor + * @desc: pointer to io descriptor + */ +static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc, + u32 mirror_idx) +{ + struct nfs_pgio_mirror *mirror = &desc->pg_mirrors[mirror_idx]; + u32 restore_idx = desc->pg_mirror_idx; + + if (nfs_pgio_has_mirroring(desc)) + desc->pg_mirror_idx = mirror_idx; + for (;;) { + nfs_pageio_doio(desc); + if (!mirror->pg_recoalesce) + break; + if (!nfs_do_recoalesce(desc)) + break; + } + desc->pg_mirror_idx = restore_idx; +} + +/* + * nfs_pageio_resend - Transfer requests to new descriptor and resend + * @hdr - the pgio header to move request from + * @desc - the pageio descriptor to add requests to + * + * Try to move each request (nfs_page) from @hdr to @desc then attempt + * to send them. + * + * Returns 0 on success and < 0 on error. + */ +int nfs_pageio_resend(struct nfs_pageio_descriptor *desc, + struct nfs_pgio_header *hdr) +{ + LIST_HEAD(failed); + + desc->pg_dreq = hdr->dreq; + while (!list_empty(&hdr->pages)) { + struct nfs_page *req = nfs_list_entry(hdr->pages.next); + + nfs_list_remove_request(req); + if (!nfs_pageio_add_request(desc, req)) + nfs_list_add_request(req, &failed); + } + nfs_pageio_complete(desc); + if (!list_empty(&failed)) { + list_move(&failed, &hdr->pages); + return -EIO; + } + return 0; +} +EXPORT_SYMBOL_GPL(nfs_pageio_resend); + +/** + * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor + * @desc: pointer to io descriptor + */ +void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) +{ + u32 midx; + + for (midx = 0; midx < desc->pg_mirror_count; midx++) + nfs_pageio_complete_mirror(desc, midx); + + if (desc->pg_ops->pg_cleanup) + desc->pg_ops->pg_cleanup(desc); + nfs_pageio_cleanup_mirroring(desc); +} + +/** + * nfs_pageio_cond_complete - Conditional I/O completion + * @desc: pointer to io descriptor + * @index: page index + * + * It is important to ensure that processes don't try to take locks + * on non-contiguous ranges of pages as that might deadlock. This + * function should be called before attempting to wait on a locked + * nfs_page. It will complete the I/O if the page index 'index' + * is not contiguous with the existing list of pages in 'desc'. + */ +void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index) +{ + struct nfs_pgio_mirror *mirror; + struct nfs_page *prev; + u32 midx; + + for (midx = 0; midx < desc->pg_mirror_count; midx++) { + mirror = &desc->pg_mirrors[midx]; + if (!list_empty(&mirror->pg_list)) { + prev = nfs_list_entry(mirror->pg_list.prev); + if (index != prev->wb_index + 1) + nfs_pageio_complete_mirror(desc, midx); + } + } +} + +int __init nfs_init_nfspagecache(void) +{ + nfs_page_cachep = kmem_cache_create("nfs_page", + sizeof(struct nfs_page), + 0, SLAB_HWCACHE_ALIGN, + NULL); + if (nfs_page_cachep == NULL) + return -ENOMEM; + + return 0; +} + +void nfs_destroy_nfspagecache(void) +{ + kmem_cache_destroy(nfs_page_cachep); +} + +static const struct rpc_call_ops nfs_pgio_common_ops = { + .rpc_call_prepare = nfs_pgio_prepare, + .rpc_call_done = nfs_pgio_result, + .rpc_release = nfs_pgio_release, +}; + +const struct nfs_pageio_ops nfs_pgio_rw_ops = { + .pg_test = nfs_generic_pg_test, + .pg_doio = nfs_generic_pg_pgios, +}; |