/* * linux/fs/nfs/write.c * * Write file data over NFS. * * Copyright (C) 1996, 1997, Olaf Kirch */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "delegation.h" #include "internal.h" #include "iostat.h" #include "nfs4_fs.h" #include "fscache.h" #include "pnfs.h" #include "nfstrace.h" #define NFSDBG_FACILITY NFSDBG_PAGECACHE #define MIN_POOL_WRITE (32) #define MIN_POOL_COMMIT (4) /* * Local function declarations */ static void nfs_redirty_request(struct nfs_page *req); static const struct rpc_call_ops nfs_commit_ops; static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops; static const struct nfs_commit_completion_ops nfs_commit_completion_ops; static const struct nfs_rw_ops nfs_rw_write_ops; static void nfs_clear_request_commit(struct nfs_page *req); static struct kmem_cache *nfs_wdata_cachep; static mempool_t *nfs_wdata_mempool; static struct kmem_cache *nfs_cdata_cachep; static mempool_t *nfs_commit_mempool; struct nfs_commit_data *nfs_commitdata_alloc(void) { struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO); if (p) { memset(p, 0, sizeof(*p)); INIT_LIST_HEAD(&p->pages); } return p; } EXPORT_SYMBOL_GPL(nfs_commitdata_alloc); void nfs_commit_free(struct nfs_commit_data *p) { mempool_free(p, nfs_commit_mempool); } EXPORT_SYMBOL_GPL(nfs_commit_free); static struct nfs_pgio_header *nfs_writehdr_alloc(void) { struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO); if (p) memset(p, 0, sizeof(*p)); return p; } static void nfs_writehdr_free(struct nfs_pgio_header *hdr) { mempool_free(hdr, nfs_wdata_mempool); } static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error) { ctx->error = error; smp_wmb(); set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags); } /* * nfs_page_find_head_request_locked - find head request associated with @page * * must be called while holding the inode lock. * * returns matching head request with reference held, or NULL if not found. */ static struct nfs_page * nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page) { struct nfs_page *req = NULL; if (PagePrivate(page)) req = (struct nfs_page *)page_private(page); else if (unlikely(PageSwapCache(page))) { struct nfs_page *freq, *t; /* Linearly search the commit list for the correct req */ list_for_each_entry_safe(freq, t, &nfsi->commit_info.list, wb_list) { if (freq->wb_page == page) { req = freq->wb_head; break; } } } if (req) { WARN_ON_ONCE(req->wb_head != req); kref_get(&req->wb_kref); } return req; } /* * nfs_page_find_head_request - find head request associated with @page * * returns matching head request with reference held, or NULL if not found. */ static struct nfs_page *nfs_page_find_head_request(struct page *page) { struct inode *inode = page_file_mapping(page)->host; struct nfs_page *req = NULL; spin_lock(&inode->i_lock); req = nfs_page_find_head_request_locked(NFS_I(inode), page); spin_unlock(&inode->i_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_file_mapping(page)->host; loff_t end, i_size; pgoff_t end_index; spin_lock(&inode->i_lock); i_size = i_size_read(inode); end_index = (i_size - 1) >> PAGE_CACHE_SHIFT; if (i_size > 0 && page_file_index(page) < end_index) goto out; end = page_file_offset(page) + ((loff_t)offset+count); if (i_size >= end) goto out; i_size_write(inode, end); nfs_inc_stats(inode, NFSIOS_EXTENDWRITE); out: spin_unlock(&inode->i_lock); } /* A writeback failed: mark the page as bad, and invalidate the page cache */ static void nfs_set_pageerror(struct page *page) { nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page)); } /* * nfs_page_group_search_locked * @head - head request of page group * @page_offset - offset into page * * Search page group with head @head to find a request that contains the * page offset @page_offset. * * Returns a pointer to the first matching nfs request, or NULL if no * match is found. * * Must be called with the page group lock held */ static struct nfs_page * nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset) { struct nfs_page *req; WARN_ON_ONCE(head != head->wb_head); WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_head->wb_flags)); req = head; do { if (page_offset >= req->wb_pgbase && page_offset < (req->wb_pgbase + req->wb_bytes)) return req; req = req->wb_this_page; } while (req != head); return NULL; } /* * nfs_page_group_covers_page * @head - head request of page group * * Return true if the page group with head @head covers the whole page, * returns false otherwise */ static bool nfs_page_group_covers_page(struct nfs_page *req) { struct nfs_page *tmp; unsigned int pos = 0; unsigned int len = nfs_page_length(req->wb_page); nfs_page_group_lock(req); do { tmp = nfs_page_group_search_locked(req->wb_head, pos); if (tmp) { /* no way this should happen */ WARN_ON_ONCE(tmp->wb_pgbase != pos); pos += tmp->wb_bytes - (pos - tmp->wb_pgbase); } } while (tmp && pos < len); nfs_page_group_unlock(req); WARN_ON_ONCE(pos > len); return pos == len; } /* We can set the PG_uptodate flag if we see that a write request * covers the full page. */ static void nfs_mark_uptodate(struct nfs_page *req) { if (PageUptodate(req->wb_page)) return; if (!nfs_page_group_covers_page(req)) return; SetPageUptodate(req->wb_page); } static int wb_priority(struct writeback_control *wbc) { if (wbc->for_reclaim) return FLUSH_HIGHPRI | FLUSH_STABLE; if (wbc->for_kupdate || wbc->for_background) return FLUSH_LOWPRI | FLUSH_COND_STABLE; return FLUSH_COND_STABLE; } /* * NFS congestion control */ int nfs_congestion_kb; #define NFS_CONGESTION_ON_THRESH (nfs_congestion_kb >> (PAGE_SHIFT-10)) #define NFS_CONGESTION_OFF_THRESH \ (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2)) static void nfs_set_page_writeback(struct page *page) { struct nfs_server *nfss = NFS_SERVER(page_file_mapping(page)->host); int ret = test_set_page_writeback(page); WARN_ON_ONCE(ret != 0); if (atomic_long_inc_return(&nfss->writeback) > NFS_CONGESTION_ON_THRESH) { set_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC); } } static void nfs_end_page_writeback(struct nfs_page *req) { struct inode *inode = page_file_mapping(req->wb_page)->host; struct nfs_server *nfss = NFS_SERVER(inode); if (!nfs_page_group_sync_on_bit(req, PG_WB_END)) return; end_page_writeback(req->wb_page); if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC); } /* nfs_page_group_clear_bits * @req - an nfs request * clears all page group related bits from @req */ static void nfs_page_group_clear_bits(struct nfs_page *req) { clear_bit(PG_TEARDOWN, &req->wb_flags); clear_bit(PG_UNLOCKPAGE, &req->wb_flags); clear_bit(PG_UPTODATE, &req->wb_flags); clear_bit(PG_WB_END, &req->wb_flags); clear_bit(PG_REMOVE, &req->wb_flags); } /* * nfs_unroll_locks_and_wait - unlock all newly locked reqs and wait on @req * * this is a helper function for nfs_lock_and_join_requests * * @inode - inode associated with request page group, must be holding inode lock * @head - head request of page group, must be holding head lock * @req - request that couldn't lock and needs to wait on the req bit lock * @nonblock - if true, don't actually wait * * NOTE: this must be called holding page_group bit lock and inode spin lock * and BOTH will be released before returning. * * returns 0 on success, < 0 on error. */ static int nfs_unroll_locks_and_wait(struct inode *inode, struct nfs_page *head, struct nfs_page *req, bool nonblock) __releases(&inode->i_lock) { struct nfs_page *tmp; int ret; /* relinquish all the locks successfully grabbed this run */ for (tmp = head ; tmp != req; tmp = tmp->wb_this_page) nfs_unlock_request(tmp); WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags)); /* grab a ref on the request that will be waited on */ kref_get(&req->wb_kref); nfs_page_group_unlock(head); spin_unlock(&inode->i_lock); /* release ref from nfs_page_find_head_request_locked */ nfs_release_request(head); if (!nonblock) ret = nfs_wait_on_request(req); else ret = -EAGAIN; nfs_release_request(req); return ret; } /* * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests * * @destroy_list - request list (using wb_this_page) terminated by @old_head * @old_head - the old head of the list * * All subrequests must be locked and removed from all lists, so at this point * they are only "active" in this function, and possibly in nfs_wait_on_request * with a reference held by some other context. */ static void nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list, struct nfs_page *old_head) { while (destroy_list) { struct nfs_page *subreq = destroy_list; destroy_list = (subreq->wb_this_page == old_head) ? NULL : subreq->wb_this_page; WARN_ON_ONCE(old_head != subreq->wb_head); /* make sure old group is not used */ subreq->wb_head = subreq; subreq->wb_this_page = subreq; nfs_clear_request_commit(subreq); /* subreq is now totally disconnected from page group or any * write / commit lists. last chance to wake any waiters */ nfs_unlock_request(subreq); if (!test_bit(PG_TEARDOWN, &subreq->wb_flags)) { /* release ref on old head request */ nfs_release_request(old_head); nfs_page_group_clear_bits(subreq); /* release the PG_INODE_REF reference */ if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) nfs_release_request(subreq); else WARN_ON_ONCE(1); } else { WARN_ON_ONCE(test_bit(PG_CLEAN, &subreq->wb_flags)); /* zombie requests have already released the last * reference and were waiting on the rest of the * group to complete. Since it's no longer part of a * group, simply free the request */ nfs_page_group_clear_bits(subreq); nfs_free_request(subreq); } } } /* * nfs_lock_and_join_requests - join all subreqs to the head req and return * a locked reference, cancelling any pending * operations for this page. * * @page - the page used to lookup the "page group" of nfs_page structures * @nonblock - if true, don't block waiting for request locks * * This function joins all sub requests to the head request by first * locking all requests in the group, cancelling any pending operations * and finally updating the head request to cover the whole range covered by * the (former) group. All subrequests are removed from any write or commit * lists, unlinked from the group and destroyed. * * Returns a locked, referenced pointer to the head request - which after * this call is guaranteed to be the only request associated with the page. * Returns NULL if no requests are found for @page, or a ERR_PTR if an * error was encountered. */ static struct nfs_page * nfs_lock_and_join_requests(struct page *page, bool nonblock) { struct inode *inode = page_file_mapping(page)->host; struct nfs_page *head, *subreq; struct nfs_page *destroy_list = NULL; unsigned int total_bytes; int ret; try_again: total_bytes = 0; WARN_ON_ONCE(destroy_list); spin_lock(&inode->i_lock); /* * A reference is taken only on the head request which acts as a * reference to the whole page group - the group will not be destroyed * until the head reference is released. */ head = nfs_page_find_head_request_locked(NFS_I(inode), page); if (!head) { spin_unlock(&inode->i_lock); return NULL; } /* lock each request in the page group */ nfs_page_group_lock(head); subreq = head; do { /* * Subrequests are always contiguous, non overlapping * and in order. If not, it's a programming error. */ WARN_ON_ONCE(subreq->wb_offset != (head->wb_offset + total_bytes)); /* keep track of how many bytes this group covers */ total_bytes += subreq->wb_bytes; if (!nfs_lock_request(subreq)) { /* releases page group bit lock and * inode spin lock and all references */ ret = nfs_unroll_locks_and_wait(inode, head, subreq, nonblock); if (ret == 0) goto try_again; return ERR_PTR(ret); } subreq = subreq->wb_this_page; } while (subreq != head); /* Now that all requests are locked, make sure they aren't on any list. * Commit list removal accounting is done after locks are dropped */ subreq = head; do { nfs_list_remove_request(subreq); subreq = subreq->wb_this_page; } while (subreq != head); /* unlink subrequests from head, destroy them later */ if (head->wb_this_page != head) { /* destroy list will be terminated by head */ destroy_list = head->wb_this_page; head->wb_this_page = head; /* change head request to cover whole range that * the former page group covered */ head->wb_bytes = total_bytes; } /* * prepare head request to be added to new pgio descriptor */ nfs_page_group_clear_bits(head); /* * some part of the group was still on the inode list - otherwise * the group wouldn't be involved in async write. * grab a reference for the head request, iff it needs one. */ if (!test_and_set_bit(PG_INODE_REF, &head->wb_flags)) kref_get(&head->wb_kref); nfs_page_group_unlock(head); /* drop lock to clear_request_commit the head req and clean up * requests on destroy list */ spin_unlock(&inode->i_lock); nfs_destroy_unlinked_subrequests(destroy_list, head); /* clean up commit list state */ nfs_clear_request_commit(head); /* still holds ref on head from nfs_page_find_head_request_locked * and still has lock on head from lock loop */ return head; } /* * Find an associated nfs write request, and prepare to flush it out * May return an error if the user signalled nfs_wait_on_request(). */ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio, struct page *page, bool nonblock) { struct nfs_page *req; int ret = 0; req = nfs_lock_and_join_requests(page, nonblock); if (!req) goto out; ret = PTR_ERR(req); if (IS_ERR(req)) goto out; nfs_set_page_writeback(page); WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags)); ret = 0; if (!nfs_pageio_add_request(pgio, req)) { nfs_redirty_request(req); ret = pgio->pg_error; } out: return ret; } static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio) { struct inode *inode = page_file_mapping(page)->host; int ret; nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE); nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1); nfs_pageio_cond_complete(pgio, page_file_index(page)); ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE); if (ret == -EAGAIN) { redirty_page_for_writepage(wbc, page); ret = 0; } return ret; } /* * Write an mmapped page to the server. */ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc) { struct nfs_pageio_descriptor pgio; int err; nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc), false, &nfs_async_write_completion_ops); err = nfs_do_writepage(page, wbc, &pgio); nfs_pageio_complete(&pgio); if (err < 0) return err; if (pgio.pg_error < 0) return pgio.pg_error; return 0; } int nfs_writepage(struct page *page, struct writeback_control *wbc) { int ret; ret = nfs_writepage_locked(page, wbc); unlock_page(page); return ret; } static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data) { int ret; ret = nfs_do_writepage(page, wbc, data); unlock_page(page); return ret; } int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc) { struct inode *inode = mapping->host; unsigned long *bitlock = &NFS_I(inode)->flags; struct nfs_pageio_descriptor pgio; int err; /* Stop dirtying of new pages while we sync */ err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING, nfs_wait_bit_killable, TASK_KILLABLE); if (err) goto out_err; nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES); nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false, &nfs_async_write_completion_ops); err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio); nfs_pageio_complete(&pgio); clear_bit_unlock(NFS_INO_FLUSHING, bitlock); smp_mb__after_atomic(); wake_up_bit(bitlock, NFS_INO_FLUSHING); if (err < 0) goto out_err; err = pgio.pg_error; if (err < 0) goto out_err; return 0; out_err: return err; } /* * Insert a write request into an inode */ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req) { struct nfs_inode *nfsi = NFS_I(inode); WARN_ON_ONCE(req->wb_this_page != req); /* Lock the request! */ nfs_lock_request(req); spin_lock(&inode->i_lock); if (!nfsi->npages && NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) inode->i_version++; /* * Swap-space should not get truncated. Hence no need to plug the race * with invalidate/truncate. */ if (likely(!PageSwapCache(req->wb_page))) { set_bit(PG_MAPPED, &req->wb_flags); SetPagePrivate(req->wb_page); set_page_private(req->wb_page, (unsigned long)req); } nfsi->npages++; /* this a head request for a page group - mark it as having an * extra reference so sub groups can follow suit */ WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags)); kref_get(&req->wb_kref); spin_unlock(&inode->i_lock); } /* * Remove a write request from 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); struct nfs_page *head; if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) { head = req->wb_head; spin_lock(&inode->i_lock); if (likely(!PageSwapCache(head->wb_page))) { set_page_private(head->wb_page, 0); ClearPagePrivate(head->wb_page); clear_bit(PG_MAPPED, &head->wb_flags); } nfsi->npages--; spin_unlock(&inode->i_lock); } if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) nfs_release_request(req); } static void nfs_mark_request_dirty(struct nfs_page *req) { __set_page_dirty_nobuffers(req->wb_page); } #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4) /** * nfs_request_add_commit_list - add request to a commit list * @req: pointer to a struct nfs_page * @dst: commit list head * @cinfo: holds list lock and accounting info * * This sets the PG_CLEAN bit, updates the cinfo count of * number of outstanding requests requiring a commit as well as * the MM page stats. * * The caller must _not_ hold the cinfo->lock, but must be * holding the nfs_page lock. */ void nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst, struct nfs_commit_info *cinfo) { set_bit(PG_CLEAN, &(req)->wb_flags); spin_lock(cinfo->lock); nfs_list_add_request(req, dst); cinfo->mds->ncommit++; spin_unlock(cinfo->lock); if (!cinfo->dreq) { inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info, BDI_RECLAIMABLE); __mark_inode_dirty(req->wb_context->dentry->d_inode, I_DIRTY_DATASYNC); } } EXPORT_SYMBOL_GPL(nfs_request_add_commit_list); /** * nfs_request_remove_commit_list - Remove request from a commit list * @req: pointer to a nfs_page * @cinfo: holds list lock and accounting info * * This clears the PG_CLEAN bit, and updates the cinfo's count of * number of outstanding requests requiring a commit * It does not update the MM page stats. * * The caller _must_ hold the cinfo->lock and the nfs_page lock. */ void nfs_request_remove_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo) { if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) return; nfs_list_remove_request(req); cinfo->mds->ncommit--; } EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list); static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo, struct inode *inode) { cinfo->lock = &inode->i_lock; cinfo->mds = &NFS_I(inode)->commit_info; cinfo->ds = pnfs_get_ds_info(inode); cinfo->dreq = NULL; cinfo->completion_ops = &nfs_commit_completion_ops; } void nfs_init_cinfo(struct nfs_commit_info *cinfo, struct inode *inode, struct nfs_direct_req *dreq) { if (dreq) nfs_init_cinfo_from_dreq(cinfo, dreq); else nfs_init_cinfo_from_inode(cinfo, inode); } EXPORT_SYMBOL_GPL(nfs_init_cinfo); /* * Add a request to the inode's commit list. */ void nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg, struct nfs_commit_info *cinfo) { if (pnfs_mark_request_commit(req, lseg, cinfo)) return; nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo); } static void nfs_clear_page_commit(struct page *page) { dec_zone_page_state(page, NR_UNSTABLE_NFS); dec_bdi_stat(page_file_mapping(page)->backing_dev_info, BDI_RECLAIMABLE); } static void nfs_clear_request_commit(struct nfs_page *req) { if (test_bit(PG_CLEAN, &req->wb_flags)) { struct inode *inode = req->wb_context->dentry->d_inode; struct nfs_commit_info cinfo; nfs_init_cinfo_from_inode(&cinfo, inode); if (!pnfs_clear_request_commit(req, &cinfo)) { spin_lock(cinfo.lock); nfs_request_remove_commit_list(req, &cinfo); spin_unlock(cinfo.lock); } nfs_clear_page_commit(req->wb_page); } } int nfs_write_need_commit(struct nfs_pgio_header *hdr) { if (hdr->verf.committed == NFS_DATA_SYNC) return hdr->lseg == NULL; return hdr->verf.committed != NFS_FILE_SYNC; } #else static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo, struct inode *inode) { } void nfs_init_cinfo(struct nfs_commit_info *cinfo, struct inode *inode, struct nfs_direct_req *dreq) { } void nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg, struct nfs_commit_info *cinfo) { } static void nfs_clear_request_commit(struct nfs_page *req) { } int nfs_write_need_commit(struct nfs_pgio_header *hdr) { return 0; } #endif static void nfs_write_completion(struct nfs_pgio_header *hdr) { struct nfs_commit_info cinfo; unsigned long bytes = 0; if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) goto out; nfs_init_cinfo_from_inode(&cinfo, hdr->inode); while (!list_empty(&hdr->pages)) { struct nfs_page *req = nfs_list_entry(hdr->pages.next); bytes += req->wb_bytes; nfs_list_remove_request(req); if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes < bytes)) { nfs_set_pageerror(req->wb_page); nfs_context_set_write_error(req->wb_context, hdr->error); goto remove_req; } if (nfs_write_need_commit(hdr)) { memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf)); nfs_mark_request_commit(req, hdr->lseg, &cinfo); goto next; } remove_req: nfs_inode_remove_request(req); next: nfs_unlock_request(req); nfs_end_page_writeback(req); nfs_release_request(req); } out: hdr->release(hdr); } #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4) unsigned long nfs_reqs_to_commit(struct nfs_commit_info *cinfo) { return cinfo->mds->ncommit; } /* cinfo->lock held by caller */ int nfs_scan_commit_list(struct list_head *src, struct list_head *dst, struct nfs_commit_info *cinfo, int max) { struct nfs_page *req, *tmp; int ret = 0; list_for_each_entry_safe(req, tmp, src, wb_list) { if (!nfs_lock_request(req)) continue; kref_get(&req->wb_kref); if (cond_resched_lock(cinfo->lock)) list_safe_reset_next(req, tmp, wb_list); nfs_request_remove_commit_list(req, cinfo); nfs_list_add_request(req, dst); ret++; if ((ret == max) && !cinfo->dreq) break; } return ret; } /* * nfs_scan_commit - Scan an inode for commit requests * @inode: NFS inode to scan * @dst: mds destination list * @cinfo: mds and ds lists of reqs ready to commit * * Moves requests from the inode's 'commit' request list. * The requests are *not* checked to ensure that they form a contiguous set. */ int nfs_scan_commit(struct inode *inode, struct list_head *dst, struct nfs_commit_info *cinfo) { int ret = 0; spin_lock(cinfo->lock); if (cinfo->mds->ncommit > 0) { const int max = INT_MAX; ret = nfs_scan_commit_list(&cinfo->mds->list, dst, cinfo, max); ret += pnfs_scan_commit_lists(inode, cinfo, max - ret); } spin_unlock(cinfo->lock); return ret; } #else unsigned long nfs_reqs_to_commit(struct nfs_commit_info *cinfo) { return 0; } int nfs_scan_commit(struct inode *inode, struct list_head *dst, struct nfs_commit_info *cinfo) { return 0; } #endif /* * Search for an existing write request, and attempt to update * it to reflect a new dirty region on a given page. * * If the attempt fails, then the existing request is flushed out * to disk. */ static struct nfs_page *nfs_try_to_update_request(struct inode *inode, struct page *page, unsigned int offset, unsigned int bytes) { struct nfs_page *req; unsigned int rqend; unsigned int end; int error; if (!PagePrivate(page)) return NULL; end = offset + bytes; spin_lock(&inode->i_lock); for (;;) { req = nfs_page_find_head_request_locked(NFS_I(inode), page); if (req == NULL) goto out_unlock; /* should be handled by nfs_flush_incompatible */ WARN_ON_ONCE(req->wb_head != req); WARN_ON_ONCE(req->wb_this_page != req); rqend = req->wb_offset + req->wb_bytes; /* * Tell the caller to flush out the request if * the offsets are non-contiguous. * Note: nfs_flush_incompatible() will already * have flushed out requests having wrong owners. */ if (offset > rqend || end < req->wb_offset) goto out_flushme; if (nfs_lock_request(req)) break; /* The request is locked, so wait and then retry */ spin_unlock(&inode->i_lock); error = nfs_wait_on_request(req); nfs_release_request(req); if (error != 0) goto out_err; spin_lock(&inode->i_lock); } /* Okay, the request matches. Update the region */ if (offset < req->wb_offset) { req->wb_offset = offset; req->wb_pgbase = offset; } if (end > rqend) req->wb_bytes = end - req->wb_offset; else req->wb_bytes = rqend - req->wb_offset; out_unlock: spin_unlock(&inode->i_lock); if (req) nfs_clear_request_commit(req); return req; out_flushme: spin_unlock(&inode->i_lock); nfs_release_request(req); error = nfs_wb_page(inode, page); out_err: return ERR_PTR(error); } /* * Try to update an existing write request, or create one if there is none. * * Note: Should always be called with the Page Lock held to prevent races * if we have to add a new request. Also assumes that the caller has * already called nfs_flush_incompatible() if necessary. */ static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx, struct page *page, unsigned int offset, unsigned int bytes) { struct inode *inode = page_file_mapping(page)->host; struct nfs_page *req; req = nfs_try_to_update_request(inode, page, offset, bytes); if (req != NULL) goto out; req = nfs_create_request(ctx, page, NULL, offset, bytes); if (IS_ERR(req)) goto out; nfs_inode_add_request(inode, req); out: return req; } static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page, unsigned int offset, unsigned int count) { struct nfs_page *req; req = nfs_setup_write_request(ctx, page, offset, count); if (IS_ERR(req)) return PTR_ERR(req); /* Update file length */ nfs_grow_file(page, offset, count); nfs_mark_uptodate(req); nfs_mark_request_dirty(req); nfs_unlock_and_release_request(req); return 0; } int nfs_flush_incompatible(struct file *file, struct page *page) { struct nfs_open_context *ctx = nfs_file_open_context(file); struct nfs_lock_context *l_ctx; 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_head_request(page); if (req == NULL) return 0; l_ctx = req->wb_lock_context; do_flush = req->wb_page != page || req->wb_context != ctx; /* for now, flush if more than 1 request in page_group */ do_flush |= req->wb_this_page != req; if (l_ctx && ctx->dentry->d_inode->i_flock != NULL) { do_flush |= l_ctx->lockowner.l_owner != current->files || l_ctx->lockowner.l_pid != current->tgid; } nfs_release_request(req); if (!do_flush) return 0; status = nfs_wb_page(page_file_mapping(page)->host, page); } while (status == 0); return status; } /* * Avoid buffered writes when a open context credential's key would * expire soon. * * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL. * * Return 0 and set a credential flag which triggers the inode to flush * and performs NFS_FILE_SYNC writes if the key will expired within * RPC_KEY_EXPIRE_TIMEO. */ int nfs_key_timeout_notify(struct file *filp, struct inode *inode) { struct nfs_open_context *ctx = nfs_file_open_context(filp); struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth; return rpcauth_key_timeout_notify(auth, ctx->cred); } /* * Test if the open context credential key is marked to expire soon. */ bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx) { return rpcauth_cred_key_to_expire(ctx->cred); } /* * If the page cache is marked as unsafe or invalid, then we can't rely on * the PageUptodate() flag. In this case, we will need to turn off * write optimisations that depend on the page contents being correct. */ static bool nfs_write_pageuptodate(struct page *page, struct inode *inode) { struct nfs_inode *nfsi = NFS_I(inode); if (nfs_have_delegated_attributes(inode)) goto out; if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) return false; smp_rmb(); if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags)) return false; out: if (nfsi->cache_validity & NFS_INO_INVALID_DATA) return false; return PageUptodate(page) != 0; } /* If we know the page is up to date, and we're not using byte range locks (or * if we have the whole file locked for writing), it may be more efficient to * extend the write to cover the entire page in order to avoid fragmentation * inefficiencies. * * If the file is opened for synchronous writes then we can just skip the rest * of the checks. */ static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode) { if (file->f_flags & O_DSYNC) return 0; if (!nfs_write_pageuptodate(page, inode)) return 0; if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) return 1; if (inode->i_flock == NULL || (inode->i_flock->fl_start == 0 && inode->i_flock->fl_end == OFFSET_MAX && inode->i_flock->fl_type != F_RDLCK)) return 1; return 0; } /* * 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 = nfs_file_open_context(file); struct inode *inode = page_file_mapping(page)->host; int status = 0; nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE); dprintk("NFS: nfs_updatepage(%pD2 %d@%lld)\n", file, count, (long long)(page_file_offset(page) + offset)); if (nfs_can_extend_write(file, page, inode)) { count = max(count + offset, nfs_page_length(page)); offset = 0; } status = nfs_writepage_setup(ctx, page, offset, count); if (status < 0) nfs_set_pageerror(page); else __set_page_dirty_nobuffers(page); dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n", status, (long long)i_size_read(inode)); return status; } static 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; } static void nfs_initiate_write(struct nfs_pgio_header *hdr, struct rpc_message *msg, struct rpc_task_setup *task_setup_data, int how) { struct inode *inode = hdr->inode; int priority = flush_task_priority(how); task_setup_data->priority = priority; NFS_PROTO(inode)->write_setup(hdr, msg); nfs4_state_protect_write(NFS_SERVER(inode)->nfs_client, &task_setup_data->rpc_client, msg, hdr); } /* If a nfs_flush_* function fails, it should remove reqs from @head and * call this on each, which will prepare them to be retried on next * writeback using standard nfs. */ static void nfs_redirty_request(struct nfs_page *req) { nfs_mark_request_dirty(req); nfs_unlock_request(req); nfs_end_page_writeback(req); nfs_release_request(req); } static void nfs_async_write_error(struct list_head *head) { struct nfs_page *req; while (!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_redirty_request(req); } } static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = { .error_cleanup = nfs_async_write_error, .completion = nfs_write_completion, }; void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode, int ioflags, bool force_mds, const struct nfs_pgio_completion_ops *compl_ops) { struct nfs_server *server = NFS_SERVER(inode); const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops; #ifdef CONFIG_NFS_V4_1 if (server->pnfs_curr_ld && !force_mds) pg_ops = server->pnfs_curr_ld->pg_write_ops; #endif nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops, server->wsize, ioflags); } EXPORT_SYMBOL_GPL(nfs_pageio_init_write); void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio) { pgio->pg_ops = &nfs_pgio_rw_ops; pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize; } EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds); void nfs_commit_prepare(struct rpc_task *task, void *calldata) { struct nfs_commit_data *data = calldata; NFS_PROTO(data->inode)->commit_rpc_prepare(task, data); } static void nfs_writeback_release_common(struct nfs_pgio_header *hdr) { /* do nothing! */ } /* * Special version of should_remove_suid() that ignores capabilities. */ static int nfs_should_remove_suid(const struct inode *inode) { umode_t mode = inode->i_mode; int kill = 0; /* suid always must be killed */ if (unlikely(mode & S_ISUID)) kill = ATTR_KILL_SUID; /* * sgid without any exec bits is just a mandatory locking mark; leave * it alone. If some exec bits are set, it's a real sgid; kill it. */ if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) kill |= ATTR_KILL_SGID; if (unlikely(kill && S_ISREG(mode))) return kill; return 0; } /* * This function is called when the WRITE call is complete. */ static int nfs_writeback_done(struct rpc_task *task, struct nfs_pgio_header *hdr, struct inode *inode) { int 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(inode)->write_done(task, hdr); if (status != 0) return status; nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count); #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4) if (hdr->res.verf->committed < hdr->args.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; /* Note this will print the MDS for a DS write */ if (time_before(complain, jiffies)) { dprintk("NFS: faulty NFS server %s:" " (committed = %d) != (stable = %d)\n", NFS_SERVER(inode)->nfs_client->cl_hostname, hdr->res.verf->committed, hdr->args.stable); complain = jiffies + 300 * HZ; } } #endif /* Deal with the suid/sgid bit corner case */ if (nfs_should_remove_suid(inode)) nfs_mark_for_revalidate(inode); return 0; } /* * This function is called when the WRITE call is complete. */ static void nfs_writeback_result(struct rpc_task *task, struct nfs_pgio_header *hdr) { struct nfs_pgio_args *argp = &hdr->args; struct nfs_pgio_res *resp = &hdr->res; if (resp->count < argp->count) { static unsigned long complain; /* This a short write! */ nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE); /* Has the server at least made some progress? */ if (resp->count == 0) { if (time_before(complain, jiffies)) { printk(KERN_WARNING "NFS: Server wrote zero bytes, expected %u.\n", argp->count); complain = jiffies + 300 * HZ; } nfs_set_pgio_error(hdr, -EIO, argp->offset); task->tk_status = -EIO; return; } /* Was this an NFSv2 write or an NFSv3 stable write? */ if (resp->verf->committed != NFS_UNSTABLE) { /* Resend from where the server left off */ hdr->mds_offset += resp->count; 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_prepare(task); } } #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4) static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait) { int ret; if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags)) return 1; if (!may_wait) return 0; ret = out_of_line_wait_on_bit_lock(&nfsi->flags, NFS_INO_COMMIT, nfs_wait_bit_killable, TASK_KILLABLE); return (ret < 0) ? ret : 1; } static void nfs_commit_clear_lock(struct nfs_inode *nfsi) { clear_bit(NFS_INO_COMMIT, &nfsi->flags); smp_mb__after_atomic(); wake_up_bit(&nfsi->flags, NFS_INO_COMMIT); } void nfs_commitdata_release(struct nfs_commit_data *data) { put_nfs_open_context(data->context); nfs_commit_free(data); } EXPORT_SYMBOL_GPL(nfs_commitdata_release); int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data, const struct rpc_call_ops *call_ops, int how, int flags) { struct rpc_task *task; int priority = flush_task_priority(how); struct rpc_message msg = { .rpc_argp = &data->args, .rpc_resp = &data->res, .rpc_cred = data->cred, }; struct rpc_task_setup task_setup_data = { .task = &data->task, .rpc_client = clnt, .rpc_message = &msg, .callback_ops = call_ops, .callback_data = data, .workqueue = nfsiod_workqueue, .flags = RPC_TASK_ASYNC | flags, .priority = priority, }; /* Set up the initial task struct. */ NFS_PROTO(data->inode)->commit_setup(data, &msg); dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid); nfs4_state_protect(NFS_SERVER(data->inode)->nfs_client, NFS_SP4_MACH_CRED_COMMIT, &task_setup_data.rpc_client, &msg); task = rpc_run_task(&task_setup_data); if (IS_ERR(task)) return PTR_ERR(task); if (how & FLUSH_SYNC) rpc_wait_for_completion_task(task); rpc_put_task(task); return 0; } EXPORT_SYMBOL_GPL(nfs_initiate_commit); /* * Set up the argument/result storage required for the RPC call. */ void nfs_init_commit(struct nfs_commit_data *data, struct list_head *head, struct pnfs_layout_segment *lseg, struct nfs_commit_info *cinfo) { struct nfs_page *first = nfs_list_entry(head->next); struct inode *inode = first->wb_context->dentry->d_inode; /* 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); data->inode = inode; data->cred = first->wb_context->cred; data->lseg = lseg; /* reference transferred */ data->mds_ops = &nfs_commit_ops; data->completion_ops = cinfo->completion_ops; data->dreq = cinfo->dreq; 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->context = get_nfs_open_context(first->wb_context); data->res.fattr = &data->fattr; data->res.verf = &data->verf; nfs_fattr_init(&data->fattr); } EXPORT_SYMBOL_GPL(nfs_init_commit); void nfs_retry_commit(struct list_head *page_list, struct pnfs_layout_segment *lseg, struct nfs_commit_info *cinfo) { struct nfs_page *req; while (!list_empty(page_list)) { req = nfs_list_entry(page_list->next); nfs_list_remove_request(req); nfs_mark_request_commit(req, lseg, cinfo); if (!cinfo->dreq) { dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info, BDI_RECLAIMABLE); } nfs_unlock_and_release_request(req); } } EXPORT_SYMBOL_GPL(nfs_retry_commit); /* * Commit dirty pages */ static int nfs_commit_list(struct inode *inode, struct list_head *head, int how, struct nfs_commit_info *cinfo) { struct nfs_commit_data *data; data = nfs_commitdata_alloc(); if (!data) goto out_bad; /* Set up the argument struct */ nfs_init_commit(data, head, NULL, cinfo); atomic_inc(&cinfo->mds->rpcs_out); return nfs_initiate_commit(NFS_CLIENT(inode), data, data->mds_ops, how, 0); out_bad: nfs_retry_commit(head, NULL, cinfo); cinfo->completion_ops->error_cleanup(NFS_I(inode)); return -ENOMEM; } /* * COMMIT call returned */ static void nfs_commit_done(struct rpc_task *task, void *calldata) { struct nfs_commit_data *data = calldata; dprintk("NFS: %5u nfs_commit_done (status %d)\n", task->tk_pid, task->tk_status); /* Call the NFS version-specific code */ NFS_PROTO(data->inode)->commit_done(task, data); } static void nfs_commit_release_pages(struct nfs_commit_data *data) { struct nfs_page *req; int status = data->task.tk_status; struct nfs_commit_info cinfo; while (!list_empty(&data->pages)) { req = nfs_list_entry(data->pages.next); nfs_list_remove_request(req); nfs_clear_page_commit(req->wb_page); dprintk("NFS: commit (%s/%llu %d@%lld)", req->wb_context->dentry->d_sb->s_id, (unsigned long long)NFS_FILEID(req->wb_context->dentry->d_inode), req->wb_bytes, (long long)req_offset(req)); if (status < 0) { nfs_context_set_write_error(req->wb_context, status); nfs_inode_remove_request(req); dprintk(", error = %d\n", status); goto next; } /* Okay, COMMIT succeeded, apparently. Check the verifier * returned by the server against all stored verfs. */ if (!memcmp(&req->wb_verf, &data->verf.verifier, sizeof(req->wb_verf))) { /* 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_mark_request_dirty(req); set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags); next: nfs_unlock_and_release_request(req); } nfs_init_cinfo(&cinfo, data->inode, data->dreq); if (atomic_dec_and_test(&cinfo.mds->rpcs_out)) nfs_commit_clear_lock(NFS_I(data->inode)); } static void nfs_commit_release(void *calldata) { struct nfs_commit_data *data = calldata; data->completion_ops->completion(data); nfs_commitdata_release(calldata); } static const struct rpc_call_ops nfs_commit_ops = { .rpc_call_prepare = nfs_commit_prepare, .rpc_call_done = nfs_commit_done, .rpc_release = nfs_commit_release, }; static const struct nfs_commit_completion_ops nfs_commit_completion_ops = { .completion = nfs_commit_release_pages, .error_cleanup = nfs_commit_clear_lock, }; int nfs_generic_commit_list(struct inode *inode, struct list_head *head, int how, struct nfs_commit_info *cinfo) { int status; status = pnfs_commit_list(inode, head, how, cinfo); if (status == PNFS_NOT_ATTEMPTED) status = nfs_commit_list(inode, head, how, cinfo); return status; } int nfs_commit_inode(struct inode *inode, int how) { LIST_HEAD(head); struct nfs_commit_info cinfo; int may_wait = how & FLUSH_SYNC; int res; res = nfs_commit_set_lock(NFS_I(inode), may_wait); if (res <= 0) goto out_mark_dirty; nfs_init_cinfo_from_inode(&cinfo, inode); res = nfs_scan_commit(inode, &head, &cinfo); if (res) { int error; error = nfs_generic_commit_list(inode, &head, how, &cinfo); if (error < 0) return error; if (!may_wait) goto out_mark_dirty; error = wait_on_bit(&NFS_I(inode)->flags, NFS_INO_COMMIT, nfs_wait_bit_killable, TASK_KILLABLE); if (error < 0) return error; } else nfs_commit_clear_lock(NFS_I(inode)); return res; /* Note: If we exit without ensuring that the commit is complete, * we must mark the inode as dirty. Otherwise, future calls to * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure * that the data is on the disk. */ out_mark_dirty: __mark_inode_dirty(inode, I_DIRTY_DATASYNC); return res; } static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc) { struct nfs_inode *nfsi = NFS_I(inode); int flags = FLUSH_SYNC; int ret = 0; /* no commits means nothing needs to be done */ if (!nfsi->commit_info.ncommit) return ret; if (wbc->sync_mode == WB_SYNC_NONE) { /* Don't commit yet if this is a non-blocking flush and there * are a lot of outstanding writes for this mapping. */ if (nfsi->commit_info.ncommit <= (nfsi->npages >> 1)) goto out_mark_dirty; /* don't wait for the COMMIT response */ flags = 0; } ret = nfs_commit_inode(inode, flags); if (ret >= 0) { if (wbc->sync_mode == WB_SYNC_NONE) { if (ret < wbc->nr_to_write) wbc->nr_to_write -= ret; else wbc->nr_to_write = 0; } return 0; } out_mark_dirty: __mark_inode_dirty(inode, I_DIRTY_DATASYNC); return ret; } #else static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc) { return 0; } #endif int nfs_write_inode(struct inode *inode, struct writeback_control *wbc) { return nfs_commit_unstable_pages(inode, wbc); } EXPORT_SYMBOL_GPL(nfs_write_inode); /* * flush the inode to disk. */ int nfs_wb_all(struct inode *inode) { struct writeback_control wbc = { .sync_mode = WB_SYNC_ALL, .nr_to_write = LONG_MAX, .range_start = 0, .range_end = LLONG_MAX, }; int ret; trace_nfs_writeback_inode_enter(inode); ret = sync_inode(inode, &wbc); trace_nfs_writeback_inode_exit(inode, ret); return ret; } EXPORT_SYMBOL_GPL(nfs_wb_all); int nfs_wb_page_cancel(struct inode *inode, struct page *page) { struct nfs_page *req; int ret = 0; wait_on_page_writeback(page); /* blocking call to cancel all requests and join to a single (head) * request */ req = nfs_lock_and_join_requests(page, false); if (IS_ERR(req)) { ret = PTR_ERR(req); } else if (req) { /* all requests from this page have been cancelled by * nfs_lock_and_join_requests, so just remove the head * request from the inode / page_private pointer and * release it */ nfs_inode_remove_request(req); /* * In case nfs_inode_remove_request has marked the * page as being dirty */ cancel_dirty_page(page, PAGE_CACHE_SIZE); nfs_unlock_and_release_request(req); } 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) { loff_t range_start = page_file_offset(page); loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1); struct writeback_control wbc = { .sync_mode = WB_SYNC_ALL, .nr_to_write = 0, .range_start = range_start, .range_end = range_end, }; int ret; trace_nfs_writeback_page_enter(inode); for (;;) { wait_on_page_writeback(page); if (clear_page_dirty_for_io(page)) { ret = nfs_writepage_locked(page, &wbc); if (ret < 0) goto out_error; continue; } ret = 0; if (!PagePrivate(page)) break; ret = nfs_commit_inode(inode, FLUSH_SYNC); if (ret < 0) goto out_error; } out_error: trace_nfs_writeback_page_exit(inode, ret); return ret; } #ifdef CONFIG_MIGRATION int nfs_migrate_page(struct address_space *mapping, struct page *newpage, struct page *page, enum migrate_mode mode) { /* * If PagePrivate is set, then the page is currently associated with * an in-progress read or write request. Don't try to migrate it. * * FIXME: we could do this in principle, but we'll need a way to ensure * that we can safely release the inode reference while holding * the page lock. */ if (PagePrivate(page)) return -EBUSY; if (!nfs_fscache_release_page(page, GFP_KERNEL)) return -EBUSY; return migrate_page(mapping, newpage, page, mode); } #endif int __init nfs_init_writepagecache(void) { nfs_wdata_cachep = kmem_cache_create("nfs_write_data", sizeof(struct nfs_pgio_header), 0, SLAB_HWCACHE_ALIGN, 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) goto out_destroy_write_cache; nfs_cdata_cachep = kmem_cache_create("nfs_commit_data", sizeof(struct nfs_commit_data), 0, SLAB_HWCACHE_ALIGN, NULL); if (nfs_cdata_cachep == NULL) goto out_destroy_write_mempool; nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT, nfs_cdata_cachep); if (nfs_commit_mempool == NULL) goto out_destroy_commit_cache; /* * NFS congestion size, scale with available memory. * * 64MB: 8192k * 128MB: 11585k * 256MB: 16384k * 512MB: 23170k * 1GB: 32768k * 2GB: 46340k * 4GB: 65536k * 8GB: 92681k * 16GB: 131072k * * This allows larger machines to have larger/more transfers. * Limit the default to 256M */ nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10); if (nfs_congestion_kb > 256*1024) nfs_congestion_kb = 256*1024; return 0; out_destroy_commit_cache: kmem_cache_destroy(nfs_cdata_cachep); out_destroy_write_mempool: mempool_destroy(nfs_wdata_mempool); out_destroy_write_cache: kmem_cache_destroy(nfs_wdata_cachep); return -ENOMEM; } void nfs_destroy_writepagecache(void) { mempool_destroy(nfs_commit_mempool); kmem_cache_destroy(nfs_cdata_cachep); mempool_destroy(nfs_wdata_mempool); kmem_cache_destroy(nfs_wdata_cachep); } static const struct nfs_rw_ops nfs_rw_write_ops = { .rw_mode = FMODE_WRITE, .rw_alloc_header = nfs_writehdr_alloc, .rw_free_header = nfs_writehdr_free, .rw_release = nfs_writeback_release_common, .rw_done = nfs_writeback_done, .rw_result = nfs_writeback_result, .rw_initiate = nfs_initiate_write, };