File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
new file mode 100644
index 0000000..8ebfdd0
--- /dev/null
+++ b/fs/nfs/pagelist.c
@@ -0,0 +1,1308 @@
+/*
+ * 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 (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags)
+ || pos < hdr->io_start + hdr->good_bytes) {
+ 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, TASK_KILLABLE);
+ } 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_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
+ */
+static 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);
+}
+
+/*
+ * 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)
+{
+ nfs_pgio_data_destroy(hdr);
+ hdr->rw_ops->rw_free_header(hdr);
+}
+EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
+
+/**
+ * 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: initiated pgio call "
+ "(req %s/%llu, %u bytes @ offset %llu)\n",
+ 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);
+ 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;
+ 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
+ * @pg_ops: pointer to pageio operations
+ * @compl_ops: pointer to pageio completion operations
+ * @rw_ops: pointer to nfs read/write operations
+ * @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;
+
+ 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) {
+ list_splice_tail(&head, &mirror->pg_list);
+ mirror->pg_recoalesce = 1;
+ 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
+ * @mirror_idx: pointer to mirror index
+ */
+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,
+};