diff options
Diffstat (limited to 'kernel/fs/nfs/write.c')
| -rw-r--r-- | kernel/fs/nfs/write.c | 2019 |
1 files changed, 2019 insertions, 0 deletions
diff --git a/kernel/fs/nfs/write.c b/kernel/fs/nfs/write.c new file mode 100644 index 000000000..dfc19f157 --- /dev/null +++ b/kernel/fs/nfs/write.c @@ -0,0 +1,2019 @@ +/* + * linux/fs/nfs/write.c + * + * Write file data over NFS. + * + * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de> + */ + +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/file.h> +#include <linux/writeback.h> +#include <linux/swap.h> +#include <linux/migrate.h> + +#include <linux/sunrpc/clnt.h> +#include <linux/nfs_fs.h> +#include <linux/nfs_mount.h> +#include <linux/nfs_page.h> +#include <linux/backing-dev.h> +#include <linux/export.h> + +#include <asm/uaccess.h> + +#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 void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo, + struct inode *inode); +static struct nfs_page * +nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi, + struct page *page); + +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))) + req = nfs_page_search_commits_for_head_request_locked(nfsi, + page); + + 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, false); + + 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) +{ + int ret = 0; + if (wbc->for_reclaim) + return FLUSH_HIGHPRI | FLUSH_STABLE; + if (wbc->sync_mode == WB_SYNC_ALL) + ret = FLUSH_COND_STABLE; + if (wbc->for_kupdate || wbc->for_background) + ret |= FLUSH_LOWPRI; + return ret; +} + +/* + * 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; + + /* 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; + } + + /* holding inode lock, so always make a non-blocking call to try the + * page group lock */ + ret = nfs_page_group_lock(head, true); + if (ret < 0) { + spin_unlock(&inode->i_lock); + + if (!nonblock && ret == -EAGAIN) { + nfs_page_group_lock_wait(head); + nfs_release_request(head); + goto try_again; + } + + nfs_release_request(head); + return ERR_PTR(ret); + } + + /* lock each request in the page group */ + subreq = head; + do { + /* + * Subrequests are always contiguous, non overlapping + * and in order - but may be repeated (mirrored writes). + */ + if (subreq->wb_offset == (head->wb_offset + total_bytes)) { + /* keep track of how many bytes this group covers */ + total_bytes += subreq->wb_bytes; + } else if (WARN_ON_ONCE(subreq->wb_offset < head->wb_offset || + ((subreq->wb_offset + subreq->wb_bytes) > + (head->wb_offset + total_bytes)))) { + nfs_page_group_unlock(head); + spin_unlock(&inode->i_lock); + return ERR_PTR(-EIO); + } + + 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_clear_request_commit(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 clean uprequests on destroy list */ + spin_unlock(&inode->i_lock); + + nfs_destroy_unlinked_subrequests(destroy_list, 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_action(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->nrequests && + 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->nrequests++; + /* this a head request for a page group - mark it as having an + * extra reference so sub groups can follow suit. + * This flag also informs pgio layer when to bump nrequests when + * adding subrequests. */ + 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 = d_inode(req->wb_context->dentry); + 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); + smp_mb__after_atomic(); + wake_up_page(head->wb_page, PG_private); + clear_bit(PG_MAPPED, &head->wb_flags); + } + nfsi->nrequests--; + spin_unlock(&inode->i_lock); + } else { + spin_lock(&inode->i_lock); + nfsi->nrequests--; + 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); +} + +/* + * nfs_page_search_commits_for_head_request_locked + * + * Search through commit lists on @inode for the head request for @page. + * Must be called while holding the inode (which is cinfo) lock. + * + * Returns the head request if found, or NULL if not found. + */ +static struct nfs_page * +nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi, + struct page *page) +{ + struct nfs_page *freq, *t; + struct nfs_commit_info cinfo; + struct inode *inode = &nfsi->vfs_inode; + + nfs_init_cinfo_from_inode(&cinfo, inode); + + /* search through pnfs commit lists */ + freq = pnfs_search_commit_reqs(inode, &cinfo, page); + if (freq) + return freq->wb_head; + + /* Linearly search the commit list for the correct request */ + list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) { + if (freq->wb_page == page) + return freq->wb_head; + } + + return NULL; +} + +/** + * 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) + nfs_mark_page_unstable(req->wb_page); +} +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, u32 ds_commit_idx) +{ + if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx)) + 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(inode_to_bdi(page_file_mapping(page)->host), BDI_RECLAIMABLE); +} + +/* Called holding inode (/cinfo) lock */ +static void +nfs_clear_request_commit(struct nfs_page *req) +{ + if (test_bit(PG_CLEAN, &req->wb_flags)) { + struct inode *inode = d_inode(req->wb_context->dentry); + struct nfs_commit_info cinfo; + + nfs_init_cinfo_from_inode(&cinfo, inode); + if (!pnfs_clear_request_commit(req, &cinfo)) { + nfs_request_remove_commit_list(req, &cinfo); + } + 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; +} + +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, + hdr->pgio_mirror_idx); + 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); +} + +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; +} + +/* + * 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: + if (req) + nfs_clear_request_commit(req); + spin_unlock(&inode->i_lock); + 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 file_lock_context *flctx = file_inode(file)->i_flctx; + 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 && flctx && + !(list_empty_careful(&flctx->flc_posix) && + list_empty_careful(&flctx->flc_flock))) { + 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; +} + +static bool +is_whole_file_wrlock(struct file_lock *fl) +{ + return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX && + fl->fl_type == F_WRLCK; +} + +/* 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) +{ + int ret; + struct file_lock_context *flctx = inode->i_flctx; + struct file_lock *fl; + + 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 (!flctx || (list_empty_careful(&flctx->flc_flock) && + list_empty_careful(&flctx->flc_posix))) + return 0; + + /* Check to see if there are whole file write locks */ + ret = 0; + spin_lock(&flctx->flc_lock); + if (!list_empty(&flctx->flc_posix)) { + fl = list_first_entry(&flctx->flc_posix, struct file_lock, + fl_list); + if (is_whole_file_wrlock(fl)) + ret = 1; + } else if (!list_empty(&flctx->flc_flock)) { + fl = list_first_entry(&flctx->flc_flock, struct file_lock, + fl_list); + if (fl->fl_type == F_WRLCK) + ret = 1; + } + spin_unlock(&flctx->flc_lock); + return ret; +} + +/* + * 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, + const struct nfs_rpc_ops *rpc_ops, + struct rpc_task_setup *task_setup_data, int how) +{ + int priority = flush_task_priority(how); + + task_setup_data->priority = priority; + rpc_ops->write_setup(hdr, msg); + + nfs4_state_protect_write(NFS_SERVER(hdr->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) +{ + struct nfs_pgio_mirror *mirror; + + pgio->pg_ops = &nfs_pgio_rw_ops; + + nfs_pageio_stop_mirroring(pgio); + + mirror = &pgio->pg_mirrors[0]; + mirror->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; +} + +static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr, + struct nfs_fattr *fattr) +{ + struct nfs_pgio_args *argp = &hdr->args; + struct nfs_pgio_res *resp = &hdr->res; + + if (!(fattr->valid & NFS_ATTR_FATTR_SIZE)) + return; + if (argp->offset + resp->count != fattr->size) + return; + if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) + return; + /* Set attribute barrier */ + nfs_fattr_set_barrier(fattr); +} + +void nfs_writeback_update_inode(struct nfs_pgio_header *hdr) +{ + struct nfs_fattr *fattr = hdr->res.fattr; + struct inode *inode = hdr->inode; + + if (fattr == NULL) + return; + spin_lock(&inode->i_lock); + nfs_writeback_check_extend(hdr, fattr); + nfs_post_op_update_inode_force_wcc_locked(inode, fattr); + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL_GPL(nfs_writeback_update_inode); + +/* + * 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 (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; + } + } + + /* 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); + } +} + + +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 nfs_rpc_ops *nfs_ops, + 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_ops->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); + +static loff_t nfs_get_lwb(struct list_head *head) +{ + loff_t lwb = 0; + struct nfs_page *req; + + list_for_each_entry(req, head, wb_list) + if (lwb < (req_offset(req) + req->wb_bytes)) + lwb = req_offset(req) + req->wb_bytes; + + return lwb; +} + +/* + * 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 = d_inode(first->wb_context->dentry); + + /* 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 */ + /* only set lwb for pnfs commit */ + if (lseg) + data->lwb = nfs_get_lwb(&data->pages); + 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, + u32 ds_commit_idx) +{ + 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, ds_commit_idx); + if (!cinfo->dreq) + nfs_clear_page_commit(req->wb_page); + 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, NFS_PROTO(inode), + data->mds_ops, how, 0); + out_bad: + nfs_retry_commit(head, NULL, cinfo, 0); + 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; + struct nfs_server *nfss; + + 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(d_inode(req->wb_context->dentry)), + 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); + } + nfss = NFS_SERVER(data->inode); + if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) + clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC); + + 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_action(&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->nrequests >> 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; +} + +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) +{ + int ret; + + trace_nfs_writeback_inode_enter(inode); + + ret = filemap_write_and_wait(inode->i_mapping); + if (ret) + goto out; + ret = nfs_commit_inode(inode, FLUSH_SYNC); + if (ret < 0) + goto out; + pnfs_sync_inode(inode, true); + ret = 0; + +out: + 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); + 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, +}; |