/* * linux/fs/nfs/write.c * * Writing file data over NFS. * * We do it like this: When a (user) process wishes to write data to an * NFS file, a write request is allocated that contains the RPC task data * plus some info on the page to be written, and added to the inode's * write chain. If the process writes past the end of the page, an async * RPC call to write the page is scheduled immediately; otherwise, the call * is delayed for a few seconds. * * Just like readahead, no async I/O is performed if wsize < PAGE_SIZE. * * Write requests are kept on the inode's writeback list. Each entry in * that list references the page (portion) to be written. When the * cache timeout has expired, the RPC task is woken up, and tries to * lock the page. As soon as it manages to do so, the request is moved * from the writeback list to the writelock list. * * Note: we must make sure never to confuse the inode passed in the * write_page request with the one in page->inode. As far as I understand * it, these are different when doing a swap-out. * * To understand everything that goes on here and in the NFS read code, * one should be aware that a page is locked in exactly one of the following * cases: * * - A write request is in progress. * - A user process is in generic_file_write/nfs_update_page * - A user process is in generic_file_read * * Also note that because of the way pages are invalidated in * nfs_revalidate_inode, the following assertions hold: * * - If a page is dirty, there will be no read requests (a page will * not be re-read unless invalidated by nfs_revalidate_inode). * - If the page is not uptodate, there will be no pending write * requests, and no process will be in nfs_update_page. * * FIXME: Interaction with the vmscan routines is not optimal yet. * Either vmscan must be made nfs-savvy, or we need a different page * reclaim concept that supports something like FS-independent * buffer_heads with a b_ops-> field. * * Copyright (C) 1996, 1997, Olaf Kirch */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "delegation.h" #include "internal.h" #include "iostat.h" #define NFSDBG_FACILITY NFSDBG_PAGECACHE #define MIN_POOL_WRITE (32) #define MIN_POOL_COMMIT (4) /* * Local function declarations */ static struct nfs_page * nfs_update_request(struct nfs_open_context*, struct page *, unsigned int, unsigned int); static void nfs_mark_request_dirty(struct nfs_page *req); static int nfs_wait_on_write_congestion(struct address_space *, int); static int nfs_wait_on_requests(struct inode *, unsigned long, unsigned int); static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how); static const struct rpc_call_ops nfs_write_partial_ops; static const struct rpc_call_ops nfs_write_full_ops; static const struct rpc_call_ops nfs_commit_ops; static kmem_cache_t *nfs_wdata_cachep; static mempool_t *nfs_wdata_mempool; static mempool_t *nfs_commit_mempool; static DECLARE_WAIT_QUEUE_HEAD(nfs_write_congestion); struct nfs_write_data *nfs_commit_alloc(void) { struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, SLAB_NOFS); if (p) { memset(p, 0, sizeof(*p)); INIT_LIST_HEAD(&p->pages); } return p; } void nfs_commit_rcu_free(struct rcu_head *head) { struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu); if (p && (p->pagevec != &p->page_array[0])) kfree(p->pagevec); mempool_free(p, nfs_commit_mempool); } void nfs_commit_free(struct nfs_write_data *wdata) { call_rcu_bh(&wdata->task.u.tk_rcu, nfs_commit_rcu_free); } struct nfs_write_data *nfs_writedata_alloc(size_t len) { unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, SLAB_NOFS); if (p) { memset(p, 0, sizeof(*p)); INIT_LIST_HEAD(&p->pages); p->npages = pagecount; if (pagecount <= ARRAY_SIZE(p->page_array)) p->pagevec = p->page_array; else { p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS); if (!p->pagevec) { mempool_free(p, nfs_wdata_mempool); p = NULL; } } } return p; } static void nfs_writedata_rcu_free(struct rcu_head *head) { struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu); if (p && (p->pagevec != &p->page_array[0])) kfree(p->pagevec); mempool_free(p, nfs_wdata_mempool); } static void nfs_writedata_free(struct nfs_write_data *wdata) { call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free); } void nfs_writedata_release(void *wdata) { nfs_writedata_free(wdata); } static struct nfs_page *nfs_page_find_request_locked(struct page *page) { struct nfs_page *req = NULL; if (PagePrivate(page)) { req = (struct nfs_page *)page_private(page); if (req != NULL) atomic_inc(&req->wb_count); } return req; } static struct nfs_page *nfs_page_find_request(struct page *page) { struct nfs_page *req = NULL; spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock; spin_lock(req_lock); req = nfs_page_find_request_locked(page); spin_unlock(req_lock); return req; } /* Adjust the file length if we're writing beyond the end */ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count) { struct inode *inode = page->mapping->host; loff_t end, i_size = i_size_read(inode); unsigned long end_index = (i_size - 1) >> PAGE_CACHE_SHIFT; if (i_size > 0 && page->index < end_index) return; end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count); if (i_size >= end) return; nfs_inc_stats(inode, NFSIOS_EXTENDWRITE); i_size_write(inode, end); } /* We can set the PG_uptodate flag if we see that a write request * covers the full page. */ static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count) { if (PageUptodate(page)) return; if (base != 0) return; if (count != nfs_page_length(page)) return; if (count != PAGE_CACHE_SIZE) memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count); SetPageUptodate(page); } static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page, unsigned int offset, unsigned int count) { struct nfs_page *req; int ret; for (;;) { req = nfs_update_request(ctx, page, offset, count); if (!IS_ERR(req)) break; ret = PTR_ERR(req); if (ret != -EBUSY) return ret; ret = nfs_wb_page(page->mapping->host, page); if (ret != 0) return ret; } /* Update file length */ nfs_grow_file(page, offset, count); /* Set the PG_uptodate flag? */ nfs_mark_uptodate(page, offset, count); nfs_unlock_request(req); return 0; } static int wb_priority(struct writeback_control *wbc) { if (wbc->for_reclaim) return FLUSH_HIGHPRI; if (wbc->for_kupdate) return FLUSH_LOWPRI; return 0; } /* * Find an associated nfs write request, and prepare to flush it out * Returns 1 if there was no write request, or if the request was * already tagged by nfs_set_page_dirty.Returns 0 if the request * was not tagged. * May also return an error if the user signalled nfs_wait_on_request(). */ static int nfs_page_mark_flush(struct page *page) { struct nfs_page *req; spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock; int ret; spin_lock(req_lock); for(;;) { req = nfs_page_find_request_locked(page); if (req == NULL) { spin_unlock(req_lock); return 1; } if (nfs_lock_request_dontget(req)) break; /* Note: If we hold the page lock, as is the case in nfs_writepage, * then the call to nfs_lock_request_dontget() will always * succeed provided that someone hasn't already marked the * request as dirty (in which case we don't care). */ spin_unlock(req_lock); ret = nfs_wait_on_request(req); nfs_release_request(req); if (ret != 0) return ret; spin_lock(req_lock); } spin_unlock(req_lock); if (test_and_set_bit(PG_FLUSHING, &req->wb_flags) == 0) { nfs_mark_request_dirty(req); set_page_writeback(page); } ret = test_bit(PG_NEED_FLUSH, &req->wb_flags); nfs_unlock_request(req); return ret; } /* * Write an mmapped page to the server. */ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc) { struct nfs_open_context *ctx; struct inode *inode = page->mapping->host; unsigned offset; int err; nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE); nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1); err = nfs_page_mark_flush(page); if (err <= 0) goto out; err = 0; offset = nfs_page_length(page); if (!offset) goto out; ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE); if (ctx == NULL) { err = -EBADF; goto out; } err = nfs_writepage_setup(ctx, page, 0, offset); put_nfs_open_context(ctx); if (err != 0) goto out; err = nfs_page_mark_flush(page); if (err > 0) err = 0; out: if (!wbc->for_writepages) nfs_flush_mapping(page->mapping, wbc, wb_priority(wbc)); return err; } int nfs_writepage(struct page *page, struct writeback_control *wbc) { int err; err = nfs_writepage_locked(page, wbc); unlock_page(page); return err; } /* * Note: causes nfs_update_request() to block on the assumption * that the writeback is generated due to memory pressure. */ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc) { struct backing_dev_info *bdi = mapping->backing_dev_info; struct inode *inode = mapping->host; int err; nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES); err = generic_writepages(mapping, wbc); if (err) return err; while (test_and_set_bit(BDI_write_congested, &bdi->state) != 0) { if (wbc->nonblocking) return 0; nfs_wait_on_write_congestion(mapping, 0); } err = nfs_flush_mapping(mapping, wbc, wb_priority(wbc)); if (err < 0) goto out; nfs_add_stats(inode, NFSIOS_WRITEPAGES, err); if (!wbc->nonblocking && wbc->sync_mode == WB_SYNC_ALL) { err = nfs_wait_on_requests(inode, 0, 0); if (err < 0) goto out; } err = nfs_commit_inode(inode, wb_priority(wbc)); if (err > 0) err = 0; out: clear_bit(BDI_write_congested, &bdi->state); wake_up_all(&nfs_write_congestion); congestion_end(WRITE); return err; } /* * Insert a write request into an inode */ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req) { struct nfs_inode *nfsi = NFS_I(inode); int error; error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req); BUG_ON(error == -EEXIST); if (error) return error; if (!nfsi->npages) { igrab(inode); nfs_begin_data_update(inode); if (nfs_have_delegation(inode, FMODE_WRITE)) nfsi->change_attr++; } SetPagePrivate(req->wb_page); set_page_private(req->wb_page, (unsigned long)req); nfsi->npages++; atomic_inc(&req->wb_count); return 0; } /* * Insert a write request into an inode */ static void nfs_inode_remove_request(struct nfs_page *req) { struct inode *inode = req->wb_context->dentry->d_inode; struct nfs_inode *nfsi = NFS_I(inode); BUG_ON (!NFS_WBACK_BUSY(req)); spin_lock(&nfsi->req_lock); set_page_private(req->wb_page, 0); ClearPagePrivate(req->wb_page); radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index); nfsi->npages--; if (!nfsi->npages) { spin_unlock(&nfsi->req_lock); nfs_end_data_update(inode); iput(inode); } else spin_unlock(&nfsi->req_lock); nfs_clear_request(req); nfs_release_request(req); } /* * Add a request to the inode's dirty list. */ static void nfs_mark_request_dirty(struct nfs_page *req) { struct inode *inode = req->wb_context->dentry->d_inode; struct nfs_inode *nfsi = NFS_I(inode); spin_lock(&nfsi->req_lock); radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_DIRTY); nfs_list_add_request(req, &nfsi->dirty); nfsi->ndirty++; spin_unlock(&nfsi->req_lock); mark_inode_dirty(inode); } static void nfs_redirty_request(struct nfs_page *req) { clear_bit(PG_FLUSHING, &req->wb_flags); __set_page_dirty_nobuffers(req->wb_page); } /* * Check if a request is dirty */ static inline int nfs_dirty_request(struct nfs_page *req) { return test_bit(PG_FLUSHING, &req->wb_flags) == 0; } #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) /* * Add a request to the inode's commit list. */ static void nfs_mark_request_commit(struct nfs_page *req) { struct inode *inode = req->wb_context->dentry->d_inode; struct nfs_inode *nfsi = NFS_I(inode); spin_lock(&nfsi->req_lock); nfs_list_add_request(req, &nfsi->commit); nfsi->ncommit++; spin_unlock(&nfsi->req_lock); inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); mark_inode_dirty(inode); } #endif /* * Wait for a request to complete. * * Interruptible by signals only if mounted with intr flag. */ static int nfs_wait_on_requests_locked(struct inode *inode, unsigned long idx_start, unsigned int npages) { struct nfs_inode *nfsi = NFS_I(inode); struct nfs_page *req; unsigned long idx_end, next; unsigned int res = 0; int error; if (npages == 0) idx_end = ~0; else idx_end = idx_start + npages - 1; next = idx_start; while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_WRITEBACK)) { if (req->wb_index > idx_end) break; next = req->wb_index + 1; BUG_ON(!NFS_WBACK_BUSY(req)); atomic_inc(&req->wb_count); spin_unlock(&nfsi->req_lock); error = nfs_wait_on_request(req); nfs_release_request(req); spin_lock(&nfsi->req_lock); if (error < 0) return error; res++; } return res; } static int nfs_wait_on_requests(struct inode *inode, unsigned long idx_start, unsigned int npages) { struct nfs_inode *nfsi = NFS_I(inode); int ret; spin_lock(&nfsi->req_lock); ret = nfs_wait_on_requests_locked(inode, idx_start, npages); spin_unlock(&nfsi->req_lock); return ret; } static void nfs_cancel_dirty_list(struct list_head *head) { struct nfs_page *req; while(!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_inode_remove_request(req); nfs_clear_page_writeback(req); } } static void nfs_cancel_commit_list(struct list_head *head) { struct nfs_page *req; while(!list_empty(head)) { req = nfs_list_entry(head->next); dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); nfs_list_remove_request(req); nfs_inode_remove_request(req); nfs_unlock_request(req); } } #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) /* * nfs_scan_commit - Scan an inode for commit requests * @inode: NFS inode to scan * @dst: destination list * @idx_start: lower bound of page->index to scan. * @npages: idx_start + npages sets the upper bound to scan. * * Moves requests from the inode's 'commit' request list. * The requests are *not* checked to ensure that they form a contiguous set. */ static int nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages) { struct nfs_inode *nfsi = NFS_I(inode); int res = 0; if (nfsi->ncommit != 0) { res = nfs_scan_list(nfsi, &nfsi->commit, dst, idx_start, npages); nfsi->ncommit -= res; if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit)) printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n"); } return res; } #else static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages) { return 0; } #endif static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr) { struct backing_dev_info *bdi = mapping->backing_dev_info; DEFINE_WAIT(wait); int ret = 0; might_sleep(); if (!bdi_write_congested(bdi)) return 0; nfs_inc_stats(mapping->host, NFSIOS_CONGESTIONWAIT); if (intr) { struct rpc_clnt *clnt = NFS_CLIENT(mapping->host); sigset_t oldset; rpc_clnt_sigmask(clnt, &oldset); prepare_to_wait(&nfs_write_congestion, &wait, TASK_INTERRUPTIBLE); if (bdi_write_congested(bdi)) { if (signalled()) ret = -ERESTARTSYS; else schedule(); } rpc_clnt_sigunmask(clnt, &oldset); } else { prepare_to_wait(&nfs_write_congestion, &wait, TASK_UNINTERRUPTIBLE); if (bdi_write_congested(bdi)) schedule(); } finish_wait(&nfs_write_congestion, &wait); return ret; } /* * Try to update any existing write request, or create one if there is none. * In order to match, the request's credentials must match those of * the calling process. * * Note: Should always be called with the Page Lock held! */ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx, struct page *page, unsigned int offset, unsigned int bytes) { struct inode *inode = page->mapping->host; struct nfs_inode *nfsi = NFS_I(inode); struct nfs_page *req, *new = NULL; unsigned long rqend, end; end = offset + bytes; if (nfs_wait_on_write_congestion(page->mapping, NFS_SERVER(inode)->flags & NFS_MOUNT_INTR)) return ERR_PTR(-ERESTARTSYS); for (;;) { /* Loop over all inode entries and see if we find * A request for the page we wish to update */ spin_lock(&nfsi->req_lock); req = nfs_page_find_request_locked(page); if (req) { if (!nfs_lock_request_dontget(req)) { int error; spin_unlock(&nfsi->req_lock); error = nfs_wait_on_request(req); nfs_release_request(req); if (error < 0) { if (new) nfs_release_request(new); return ERR_PTR(error); } continue; } spin_unlock(&nfsi->req_lock); if (new) nfs_release_request(new); break; } if (new) { int error; nfs_lock_request_dontget(new); error = nfs_inode_add_request(inode, new); if (error) { spin_unlock(&nfsi->req_lock); nfs_unlock_request(new); return ERR_PTR(error); } spin_unlock(&nfsi->req_lock); return new; } spin_unlock(&nfsi->req_lock); new = nfs_create_request(ctx, inode, page, offset, bytes); if (IS_ERR(new)) return new; } /* We have a request for our page. * If the creds don't match, or the * page addresses don't match, * tell the caller to wait on the conflicting * request. */ rqend = req->wb_offset + req->wb_bytes; if (req->wb_context != ctx || req->wb_page != page || !nfs_dirty_request(req) || offset > rqend || end < req->wb_offset) { nfs_unlock_request(req); return ERR_PTR(-EBUSY); } /* Okay, the request matches. Update the region */ if (offset < req->wb_offset) { req->wb_offset = offset; req->wb_pgbase = offset; req->wb_bytes = rqend - req->wb_offset; } if (end > rqend) req->wb_bytes = end - req->wb_offset; return req; } int nfs_flush_incompatible(struct file *file, struct page *page) { struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data; struct nfs_page *req; int do_flush, status; /* * Look for a request corresponding to this page. If there * is one, and it belongs to another file, we flush it out * before we try to copy anything into the page. Do this * due to the lack of an ACCESS-type call in NFSv2. * Also do the same if we find a request from an existing * dropped page. */ do { req = nfs_page_find_request(page); if (req == NULL) return 0; do_flush = req->wb_page != page || req->wb_context != ctx || !nfs_dirty_request(req); nfs_release_request(req); if (!do_flush) return 0; status = nfs_wb_page(page->mapping->host, page); } while (status == 0); return status; } /* * Update and possibly write a cached page of an NFS file. * * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad * things with a page scheduled for an RPC call (e.g. invalidate it). */ int nfs_updatepage(struct file *file, struct page *page, unsigned int offset, unsigned int count) { struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data; struct inode *inode = page->mapping->host; int status = 0; nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE); dprintk("NFS: nfs_updatepage(%s/%s %d@%Ld)\n", file->f_dentry->d_parent->d_name.name, file->f_dentry->d_name.name, count, (long long)(page_offset(page) +offset)); /* If we're not using byte range locks, and we know the page * is entirely in cache, it may be more efficient to avoid * fragmenting write requests. */ if (PageUptodate(page) && inode->i_flock == NULL && !(file->f_mode & O_SYNC)) { count = max(count + offset, nfs_page_length(page)); offset = 0; } status = nfs_writepage_setup(ctx, page, offset, count); __set_page_dirty_nobuffers(page); dprintk("NFS: nfs_updatepage returns %d (isize %Ld)\n", status, (long long)i_size_read(inode)); if (status < 0) ClearPageUptodate(page); return status; } static void nfs_writepage_release(struct nfs_page *req) { end_page_writeback(req->wb_page); #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) if (!PageError(req->wb_page)) { if (NFS_NEED_RESCHED(req)) { nfs_redirty_request(req); goto out; } else if (NFS_NEED_COMMIT(req)) { nfs_mark_request_commit(req); goto out; } } nfs_inode_remove_request(req); out: nfs_clear_commit(req); nfs_clear_reschedule(req); #else nfs_inode_remove_request(req); #endif nfs_clear_page_writeback(req); } static inline int flush_task_priority(int how) { switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) { case FLUSH_HIGHPRI: return RPC_PRIORITY_HIGH; case FLUSH_LOWPRI: return RPC_PRIORITY_LOW; } return RPC_PRIORITY_NORMAL; } /* * Set up the argument/result storage required for the RPC call. */ static void nfs_write_rpcsetup(struct nfs_page *req, struct nfs_write_data *data, const struct rpc_call_ops *call_ops, unsigned int count, unsigned int offset, int how) { struct inode *inode; int flags; /* Set up the RPC argument and reply structs * NB: take care not to mess about with data->commit et al. */ data->req = req; data->inode = inode = req->wb_context->dentry->d_inode; data->cred = req->wb_context->cred; data->args.fh = NFS_FH(inode); data->args.offset = req_offset(req) + offset; data->args.pgbase = req->wb_pgbase + offset; data->args.pages = data->pagevec; data->args.count = count; data->args.context = req->wb_context; data->res.fattr = &data->fattr; data->res.count = count; data->res.verf = &data->verf; nfs_fattr_init(&data->fattr); /* Set up the initial task struct. */ flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC; rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data); NFS_PROTO(inode)->write_setup(data, how); data->task.tk_priority = flush_task_priority(how); data->task.tk_cookie = (unsigned long)inode; dprintk("NFS: %4d initiated write call (req %s/%Ld, %u bytes @ offset %Lu)\n", data->task.tk_pid, inode->i_sb->s_id, (long long)NFS_FILEID(inode), count, (unsigned long long)data->args.offset); } static void nfs_execute_write(struct nfs_write_data *data) { struct rpc_clnt *clnt = NFS_CLIENT(data->inode); sigset_t oldset; rpc_clnt_sigmask(clnt, &oldset); rpc_execute(&data->task); rpc_clnt_sigunmask(clnt, &oldset); } /* * Generate multiple small requests to write out a single * contiguous dirty area on one page. */ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how) { struct nfs_page *req = nfs_list_entry(head->next); struct page *page = req->wb_page; struct nfs_write_data *data; size_t wsize = NFS_SERVER(inode)->wsize, nbytes; unsigned int offset; int requests = 0; LIST_HEAD(list); nfs_list_remove_request(req); nbytes = req->wb_bytes; do { size_t len = min(nbytes, wsize); data = nfs_writedata_alloc(len); if (!data) goto out_bad; list_add(&data->pages, &list); requests++; nbytes -= len; } while (nbytes != 0); atomic_set(&req->wb_complete, requests); ClearPageError(page); offset = 0; nbytes = req->wb_bytes; do { data = list_entry(list.next, struct nfs_write_data, pages); list_del_init(&data->pages); data->pagevec[0] = page; if (nbytes > wsize) { nfs_write_rpcsetup(req, data, &nfs_write_partial_ops, wsize, offset, how); offset += wsize; nbytes -= wsize; } else { nfs_write_rpcsetup(req, data, &nfs_write_partial_ops, nbytes, offset, how); nbytes = 0; } nfs_execute_write(data); } while (nbytes != 0); return 0; out_bad: while (!list_empty(&list)) { data = list_entry(list.next, struct nfs_write_data, pages); list_del(&data->pages); nfs_writedata_release(data); } nfs_redirty_request(req); nfs_clear_page_writeback(req); return -ENOMEM; } /* * Create an RPC task for the given 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. */ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how) { struct nfs_page *req; struct page **pages; struct nfs_write_data *data; unsigned int count; data = nfs_writedata_alloc(NFS_SERVER(inode)->wsize); if (!data) goto out_bad; pages = data->pagevec; count = 0; while (!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_list_add_request(req, &data->pages); ClearPageError(req->wb_page); *pages++ = req->wb_page; count += req->wb_bytes; } req = nfs_list_entry(data->pages.next); /* Set up the argument struct */ nfs_write_rpcsetup(req, data, &nfs_write_full_ops, count, 0, how); nfs_execute_write(data); return 0; out_bad: while (!list_empty(head)) { struct nfs_page *req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_redirty_request(req); nfs_clear_page_writeback(req); } return -ENOMEM; } static int nfs_flush_list(struct inode *inode, struct list_head *head, int npages, int how) { LIST_HEAD(one_request); int (*flush_one)(struct inode *, struct list_head *, int); struct nfs_page *req; int wpages = NFS_SERVER(inode)->wpages; int wsize = NFS_SERVER(inode)->wsize; int error; flush_one = nfs_flush_one; if (wsize < PAGE_CACHE_SIZE) flush_one = nfs_flush_multi; /* For single writes, FLUSH_STABLE is more efficient */ if (npages <= wpages && npages == NFS_I(inode)->npages && nfs_list_entry(head->next)->wb_bytes <= wsize) how |= FLUSH_STABLE; do { nfs_coalesce_requests(head, &one_request, wpages); req = nfs_list_entry(one_request.next); error = flush_one(inode, &one_request, how); if (error < 0) goto out_err; } while (!list_empty(head)); return 0; out_err: while (!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_redirty_request(req); nfs_clear_page_writeback(req); } return error; } /* * Handle a write reply that flushed part of a page. */ static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata) { struct nfs_write_data *data = calldata; struct nfs_page *req = data->req; struct page *page = req->wb_page; dprintk("NFS: write (%s/%Ld %d@%Ld)", req->wb_context->dentry->d_inode->i_sb->s_id, (long long)NFS_FILEID(req->wb_context->dentry->d_inode), req->wb_bytes, (long long)req_offset(req)); if (nfs_writeback_done(task, data) != 0) return; if (task->tk_status < 0) { ClearPageUptodate(page); SetPageError(page); req->wb_context->error = task->tk_status; dprintk(", error = %d\n", task->tk_status); } else { #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) if (data->verf.committed < NFS_FILE_SYNC) { if (!NFS_NEED_COMMIT(req)) { nfs_defer_commit(req); memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf)); dprintk(" defer commit\n"); } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) { nfs_defer_reschedule(req); dprintk(" server reboot detected\n"); } } else #endif dprintk(" OK\n"); } if (atomic_dec_and_test(&req->wb_complete)) nfs_writepage_release(req); } static const struct rpc_call_ops nfs_write_partial_ops = { .rpc_call_done = nfs_writeback_done_partial, .rpc_release = nfs_writedata_release, }; /* * Handle a write reply that flushes a whole page. * * FIXME: There is an inherent race with invalidate_inode_pages and * writebacks since the page->count is kept > 1 for as long * as the page has a write request pending. */ static void nfs_writeback_done_full(struct rpc_task *task, void *calldata) { struct nfs_write_data *data = calldata; struct nfs_page *req; struct page *page; if (nfs_writeback_done(task, data) != 0) return; /* Update attributes as result of writeback. */ while (!list_empty(&data->pages)) { req = nfs_list_entry(data->pages.next); nfs_list_remove_request(req); page = req->wb_page; dprintk("NFS: write (%s/%Ld %d@%Ld)", req->wb_context->dentry->d_inode->i_sb->s_id, (long long)NFS_FILEID(req->wb_context->dentry->d_inode), req->wb_bytes, (long long)req_offset(req)); if (task->tk_status < 0) { ClearPageUptodate(page); SetPageError(page); req->wb_context->error = task->tk_status; end_page_writeback(page); nfs_inode_remove_request(req); dprintk(", error = %d\n", task->tk_status); goto next; } end_page_writeback(page); #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) if (data->args.stable != NFS_UNSTABLE || data->verf.committed == NFS_FILE_SYNC) { nfs_inode_remove_request(req); dprintk(" OK\n"); goto next; } memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf)); nfs_mark_request_commit(req); dprintk(" marked for commit\n"); #else nfs_inode_remove_request(req); #endif next: nfs_clear_page_writeback(req); } } static const struct rpc_call_ops nfs_write_full_ops = { .rpc_call_done = nfs_writeback_done_full, .rpc_release = nfs_writedata_release, }; /* * This function is called when the WRITE call is complete. */ int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data) { struct nfs_writeargs *argp = &data->args; struct nfs_writeres *resp = &data->res; int status; dprintk("NFS: %4d nfs_writeback_done (status %d)\n", task->tk_pid, task->tk_status); /* * ->write_done will attempt to use post-op attributes to detect * conflicting writes by other clients. A strict interpretation * of close-to-open would allow us to continue caching even if * another writer had changed the file, but some applications * depend on tighter cache coherency when writing. */ status = NFS_PROTO(data->inode)->write_done(task, data); if (status != 0) return status; nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count); #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) if (resp->verf->committed < argp->stable && task->tk_status >= 0) { /* We tried a write call, but the server did not * commit data to stable storage even though we * requested it. * Note: There is a known bug in Tru64 < 5.0 in which * the server reports NFS_DATA_SYNC, but performs * NFS_FILE_SYNC. We therefore implement this checking * as a dprintk() in order to avoid filling syslog. */ static unsigned long complain; if (time_before(complain, jiffies)) { dprintk("NFS: faulty NFS server %s:" " (committed = %d) != (stable = %d)\n", NFS_SERVER(data->inode)->nfs_client->cl_hostname, resp->verf->committed, argp->stable); complain = jiffies + 300 * HZ; } } #endif /* Is this a short write? */ if (task->tk_status >= 0 && resp->count < argp->count) { static unsigned long complain; nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE); /* Has the server at least made some progress? */ if (resp->count != 0) { /* Was this an NFSv2 write or an NFSv3 stable write? */ if (resp->verf->committed != NFS_UNSTABLE) { /* Resend from where the server left off */ argp->offset += resp->count; argp->pgbase += resp->count; argp->count -= resp->count; } else { /* Resend as a stable write in order to avoid * headaches in the case of a server crash. */ argp->stable = NFS_FILE_SYNC; } rpc_restart_call(task); return -EAGAIN; } if (time_before(complain, jiffies)) { printk(KERN_WARNING "NFS: Server wrote zero bytes, expected %u.\n", argp->count); complain = jiffies + 300 * HZ; } /* Can't do anything about it except throw an error. */ task->tk_status = -EIO; } return 0; } #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) void nfs_commit_release(void *wdata) { nfs_commit_free(wdata); } /* * Set up the argument/result storage required for the RPC call. */ static void nfs_commit_rpcsetup(struct list_head *head, struct nfs_write_data *data, int how) { struct nfs_page *first; struct inode *inode; int flags; /* Set up the RPC argument and reply structs * NB: take care not to mess about with data->commit et al. */ list_splice_init(head, &data->pages); first = nfs_list_entry(data->pages.next); inode = first->wb_context->dentry->d_inode; data->inode = inode; data->cred = first->wb_context->cred; data->args.fh = NFS_FH(data->inode); /* Note: we always request a commit of the entire inode */ data->args.offset = 0; data->args.count = 0; data->res.count = 0; data->res.fattr = &data->fattr; data->res.verf = &data->verf; nfs_fattr_init(&data->fattr); /* Set up the initial task struct. */ flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC; rpc_init_task(&data->task, NFS_CLIENT(inode), flags, &nfs_commit_ops, data); NFS_PROTO(inode)->commit_setup(data, how); data->task.tk_priority = flush_task_priority(how); data->task.tk_cookie = (unsigned long)inode; dprintk("NFS: %4d initiated commit call\n", data->task.tk_pid); } /* * Commit dirty pages */ static int nfs_commit_list(struct inode *inode, struct list_head *head, int how) { struct nfs_write_data *data; struct nfs_page *req; data = nfs_commit_alloc(); if (!data) goto out_bad; /* Set up the argument struct */ nfs_commit_rpcsetup(head, data, how); nfs_execute_write(data); return 0; out_bad: while (!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_mark_request_commit(req); dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); nfs_clear_page_writeback(req); } return -ENOMEM; } /* * COMMIT call returned */ static void nfs_commit_done(struct rpc_task *task, void *calldata) { struct nfs_write_data *data = calldata; struct nfs_page *req; dprintk("NFS: %4d nfs_commit_done (status %d)\n", task->tk_pid, task->tk_status); /* Call the NFS version-specific code */ if (NFS_PROTO(data->inode)->commit_done(task, data) != 0) return; while (!list_empty(&data->pages)) { req = nfs_list_entry(data->pages.next); nfs_list_remove_request(req); dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); dprintk("NFS: commit (%s/%Ld %d@%Ld)", req->wb_context->dentry->d_inode->i_sb->s_id, (long long)NFS_FILEID(req->wb_context->dentry->d_inode), req->wb_bytes, (long long)req_offset(req)); if (task->tk_status < 0) { req->wb_context->error = task->tk_status; nfs_inode_remove_request(req); dprintk(", error = %d\n", task->tk_status); goto next; } /* Okay, COMMIT succeeded, apparently. Check the verifier * returned by the server against all stored verfs. */ if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) { /* We have a match */ nfs_inode_remove_request(req); dprintk(" OK\n"); goto next; } /* We have a mismatch. Write the page again */ dprintk(" mismatch\n"); nfs_redirty_request(req); next: nfs_clear_page_writeback(req); } } static const struct rpc_call_ops nfs_commit_ops = { .rpc_call_done = nfs_commit_done, .rpc_release = nfs_commit_release, }; #else static inline int nfs_commit_list(struct inode *inode, struct list_head *head, int how) { return 0; } #endif static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how) { struct nfs_inode *nfsi = NFS_I(mapping->host); LIST_HEAD(head); long res; spin_lock(&nfsi->req_lock); res = nfs_scan_dirty(mapping, wbc, &head); spin_unlock(&nfsi->req_lock); if (res) { int error = nfs_flush_list(mapping->host, &head, res, how); if (error < 0) return error; } return res; } #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) int nfs_commit_inode(struct inode *inode, int how) { struct nfs_inode *nfsi = NFS_I(inode); LIST_HEAD(head); int res; spin_lock(&nfsi->req_lock); res = nfs_scan_commit(inode, &head, 0, 0); spin_unlock(&nfsi->req_lock); if (res) { int error = nfs_commit_list(inode, &head, how); if (error < 0) return error; } return res; } #endif long nfs_sync_mapping_wait(struct address_space *mapping, struct writeback_control *wbc, int how) { struct inode *inode = mapping->host; struct nfs_inode *nfsi = NFS_I(inode); unsigned long idx_start, idx_end; unsigned int npages = 0; LIST_HEAD(head); int nocommit = how & FLUSH_NOCOMMIT; long pages, ret; /* FIXME */ if (wbc->range_cyclic) idx_start = 0; else { idx_start = wbc->range_start >> PAGE_CACHE_SHIFT; idx_end = wbc->range_end >> PAGE_CACHE_SHIFT; if (idx_end > idx_start) { unsigned long l_npages = 1 + idx_end - idx_start; npages = l_npages; if (sizeof(npages) != sizeof(l_npages) && (unsigned long)npages != l_npages) npages = 0; } } how &= ~FLUSH_NOCOMMIT; spin_lock(&nfsi->req_lock); do { wbc->pages_skipped = 0; ret = nfs_wait_on_requests_locked(inode, idx_start, npages); if (ret != 0) continue; pages = nfs_scan_dirty(mapping, wbc, &head); if (pages != 0) { spin_unlock(&nfsi->req_lock); if (how & FLUSH_INVALIDATE) { nfs_cancel_dirty_list(&head); ret = pages; } else ret = nfs_flush_list(inode, &head, pages, how); spin_lock(&nfsi->req_lock); continue; } if (wbc->pages_skipped != 0) continue; if (nocommit) break; pages = nfs_scan_commit(inode, &head, idx_start, npages); if (pages == 0) { if (wbc->pages_skipped != 0) continue; break; } if (how & FLUSH_INVALIDATE) { spin_unlock(&nfsi->req_lock); nfs_cancel_commit_list(&head); ret = pages; spin_lock(&nfsi->req_lock); continue; } pages += nfs_scan_commit(inode, &head, 0, 0); spin_unlock(&nfsi->req_lock); ret = nfs_commit_list(inode, &head, how); spin_lock(&nfsi->req_lock); } while (ret >= 0); spin_unlock(&nfsi->req_lock); return ret; } /* * flush the inode to disk. */ int nfs_wb_all(struct inode *inode) { struct address_space *mapping = inode->i_mapping; struct writeback_control wbc = { .bdi = mapping->backing_dev_info, .sync_mode = WB_SYNC_ALL, .nr_to_write = LONG_MAX, .for_writepages = 1, .range_cyclic = 1, }; int ret; ret = generic_writepages(mapping, &wbc); if (ret < 0) goto out; ret = nfs_sync_mapping_wait(mapping, &wbc, 0); if (ret >= 0) return 0; out: __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); return ret; } int nfs_sync_mapping_range(struct address_space *mapping, loff_t range_start, loff_t range_end, int how) { struct writeback_control wbc = { .bdi = mapping->backing_dev_info, .sync_mode = WB_SYNC_ALL, .nr_to_write = LONG_MAX, .range_start = range_start, .range_end = range_end, .for_writepages = 1, }; int ret; if (!(how & FLUSH_NOWRITEPAGE)) { ret = generic_writepages(mapping, &wbc); if (ret < 0) goto out; } ret = nfs_sync_mapping_wait(mapping, &wbc, how); if (ret >= 0) return 0; out: __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); return ret; } int nfs_wb_page_priority(struct inode *inode, struct page *page, int how) { loff_t range_start = page_offset(page); loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1); struct writeback_control wbc = { .bdi = page->mapping->backing_dev_info, .sync_mode = WB_SYNC_ALL, .nr_to_write = LONG_MAX, .range_start = range_start, .range_end = range_end, }; int ret; BUG_ON(!PageLocked(page)); if (!(how & FLUSH_NOWRITEPAGE) && clear_page_dirty_for_io(page)) { ret = nfs_writepage_locked(page, &wbc); if (ret < 0) goto out; } ret = nfs_sync_mapping_wait(page->mapping, &wbc, how); if (ret >= 0) return 0; out: __mark_inode_dirty(inode, I_DIRTY_PAGES); return ret; } /* * Write back all requests on one page - we do this before reading it. */ int nfs_wb_page(struct inode *inode, struct page* page) { return nfs_wb_page_priority(inode, page, FLUSH_STABLE); } int nfs_set_page_dirty(struct page *page) { struct nfs_page *req; req = nfs_page_find_request(page); if (req != NULL) { /* Mark any existing write requests for flushing */ set_bit(PG_NEED_FLUSH, &req->wb_flags); nfs_release_request(req); } return __set_page_dirty_nobuffers(page); } int __init nfs_init_writepagecache(void) { nfs_wdata_cachep = kmem_cache_create("nfs_write_data", sizeof(struct nfs_write_data), 0, SLAB_HWCACHE_ALIGN, NULL, NULL); if (nfs_wdata_cachep == NULL) return -ENOMEM; nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE, nfs_wdata_cachep); if (nfs_wdata_mempool == NULL) return -ENOMEM; nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT, nfs_wdata_cachep); if (nfs_commit_mempool == NULL) return -ENOMEM; return 0; } void nfs_destroy_writepagecache(void) { mempool_destroy(nfs_commit_mempool); mempool_destroy(nfs_wdata_mempool); kmem_cache_destroy(nfs_wdata_cachep); }