diff options
Diffstat (limited to 'fs/nfs/write.c')
| -rw-r--r-- | fs/nfs/write.c | 1431 |
1 files changed, 1431 insertions, 0 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c new file mode 100644 index 000000000000..6f7a4af3bc46 --- /dev/null +++ b/fs/nfs/write.c @@ -0,0 +1,1431 @@ +/* + * linux/fs/nfs/write.c + * + * Writing file data over NFS. + * + * We do it like this: When a (user) process wishes to write data to an + * NFS file, a write request is allocated that contains the RPC task data + * plus some info on the page to be written, and added to the inode's + * write chain. If the process writes past the end of the page, an async + * RPC call to write the page is scheduled immediately; otherwise, the call + * is delayed for a few seconds. + * + * Just like readahead, no async I/O is performed if wsize < PAGE_SIZE. + * + * Write requests are kept on the inode's writeback list. Each entry in + * that list references the page (portion) to be written. When the + * cache timeout has expired, the RPC task is woken up, and tries to + * lock the page. As soon as it manages to do so, the request is moved + * from the writeback list to the writelock list. + * + * Note: we must make sure never to confuse the inode passed in the + * write_page request with the one in page->inode. As far as I understand + * it, these are different when doing a swap-out. + * + * To understand everything that goes on here and in the NFS read code, + * one should be aware that a page is locked in exactly one of the following + * cases: + * + * - A write request is in progress. + * - A user process is in generic_file_write/nfs_update_page + * - A user process is in generic_file_read + * + * Also note that because of the way pages are invalidated in + * nfs_revalidate_inode, the following assertions hold: + * + * - If a page is dirty, there will be no read requests (a page will + * not be re-read unless invalidated by nfs_revalidate_inode). + * - If the page is not uptodate, there will be no pending write + * requests, and no process will be in nfs_update_page. + * + * FIXME: Interaction with the vmscan routines is not optimal yet. + * Either vmscan must be made nfs-savvy, or we need a different page + * reclaim concept that supports something like FS-independent + * buffer_heads with a b_ops-> field. + * + * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de> + */ + +#include <linux/config.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/file.h> +#include <linux/mpage.h> +#include <linux/writeback.h> + +#include <linux/sunrpc/clnt.h> +#include <linux/nfs_fs.h> +#include <linux/nfs_mount.h> +#include <linux/nfs_page.h> +#include <asm/uaccess.h> +#include <linux/smp_lock.h> + +#include "delegation.h" + +#define NFSDBG_FACILITY NFSDBG_PAGECACHE + +#define MIN_POOL_WRITE (32) +#define MIN_POOL_COMMIT (4) + +/* + * Local function declarations + */ +static struct nfs_page * nfs_update_request(struct nfs_open_context*, + struct inode *, + struct page *, + unsigned int, unsigned int); +static void nfs_writeback_done_partial(struct nfs_write_data *, int); +static void nfs_writeback_done_full(struct nfs_write_data *, int); +static int nfs_wait_on_write_congestion(struct address_space *, int); +static int nfs_wait_on_requests(struct inode *, unsigned long, unsigned int); +static int nfs_flush_inode(struct inode *inode, unsigned long idx_start, + unsigned int npages, int how); + +static kmem_cache_t *nfs_wdata_cachep; +mempool_t *nfs_wdata_mempool; +static mempool_t *nfs_commit_mempool; + +static DECLARE_WAIT_QUEUE_HEAD(nfs_write_congestion); + +static inline struct nfs_write_data *nfs_commit_alloc(void) +{ + struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, SLAB_NOFS); + if (p) { + memset(p, 0, sizeof(*p)); + INIT_LIST_HEAD(&p->pages); + } + return p; +} + +static inline void nfs_commit_free(struct nfs_write_data *p) +{ + mempool_free(p, nfs_commit_mempool); +} + +static void nfs_writedata_release(struct rpc_task *task) +{ + struct nfs_write_data *wdata = (struct nfs_write_data *)task->tk_calldata; + nfs_writedata_free(wdata); +} + +/* Adjust the file length if we're writing beyond the end */ +static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count) +{ + struct inode *inode = page->mapping->host; + loff_t end, i_size = i_size_read(inode); + unsigned long end_index = (i_size - 1) >> PAGE_CACHE_SHIFT; + + if (i_size > 0 && page->index < end_index) + return; + end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count); + if (i_size >= end) + return; + i_size_write(inode, end); +} + +/* We can set the PG_uptodate flag if we see that a write request + * covers the full page. + */ +static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count) +{ + loff_t end_offs; + + if (PageUptodate(page)) + return; + if (base != 0) + return; + if (count == PAGE_CACHE_SIZE) { + SetPageUptodate(page); + return; + } + + end_offs = i_size_read(page->mapping->host) - 1; + if (end_offs < 0) + return; + /* Is this the last page? */ + if (page->index != (unsigned long)(end_offs >> PAGE_CACHE_SHIFT)) + return; + /* This is the last page: set PG_uptodate if we cover the entire + * extent of the data, then zero the rest of the page. + */ + if (count == (unsigned int)(end_offs & (PAGE_CACHE_SIZE - 1)) + 1) { + memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count); + SetPageUptodate(page); + } +} + +/* + * Write a page synchronously. + * Offset is the data offset within the page. + */ +static int nfs_writepage_sync(struct nfs_open_context *ctx, struct inode *inode, + struct page *page, unsigned int offset, unsigned int count, + int how) +{ + unsigned int wsize = NFS_SERVER(inode)->wsize; + int result, written = 0; + struct nfs_write_data *wdata; + + wdata = nfs_writedata_alloc(); + if (!wdata) + return -ENOMEM; + + wdata->flags = how; + wdata->cred = ctx->cred; + wdata->inode = inode; + wdata->args.fh = NFS_FH(inode); + wdata->args.context = ctx; + wdata->args.pages = &page; + wdata->args.stable = NFS_FILE_SYNC; + wdata->args.pgbase = offset; + wdata->args.count = wsize; + wdata->res.fattr = &wdata->fattr; + wdata->res.verf = &wdata->verf; + + dprintk("NFS: nfs_writepage_sync(%s/%Ld %d@%Ld)\n", + inode->i_sb->s_id, + (long long)NFS_FILEID(inode), + count, (long long)(page_offset(page) + offset)); + + nfs_begin_data_update(inode); + do { + if (count < wsize) + wdata->args.count = count; + wdata->args.offset = page_offset(page) + wdata->args.pgbase; + + result = NFS_PROTO(inode)->write(wdata); + + if (result < 0) { + /* Must mark the page invalid after I/O error */ + ClearPageUptodate(page); + goto io_error; + } + if (result < wdata->args.count) + printk(KERN_WARNING "NFS: short write, count=%u, result=%d\n", + wdata->args.count, result); + + wdata->args.offset += result; + wdata->args.pgbase += result; + written += result; + count -= result; + } while (count); + /* Update file length */ + nfs_grow_file(page, offset, written); + /* Set the PG_uptodate flag? */ + nfs_mark_uptodate(page, offset, written); + + if (PageError(page)) + ClearPageError(page); + +io_error: + nfs_end_data_update_defer(inode); + nfs_writedata_free(wdata); + return written ? written : result; +} + +static int nfs_writepage_async(struct nfs_open_context *ctx, + struct inode *inode, struct page *page, + unsigned int offset, unsigned int count) +{ + struct nfs_page *req; + int status; + + req = nfs_update_request(ctx, inode, page, offset, count); + status = (IS_ERR(req)) ? PTR_ERR(req) : 0; + if (status < 0) + goto out; + /* Update file length */ + nfs_grow_file(page, offset, count); + /* Set the PG_uptodate flag? */ + nfs_mark_uptodate(page, offset, count); + nfs_unlock_request(req); + out: + return status; +} + +static int wb_priority(struct writeback_control *wbc) +{ + if (wbc->for_reclaim) + return FLUSH_HIGHPRI; + if (wbc->for_kupdate) + return FLUSH_LOWPRI; + return 0; +} + +/* + * Write an mmapped page to the server. + */ +int nfs_writepage(struct page *page, struct writeback_control *wbc) +{ + struct nfs_open_context *ctx; + struct inode *inode = page->mapping->host; + unsigned long end_index; + unsigned offset = PAGE_CACHE_SIZE; + loff_t i_size = i_size_read(inode); + int inode_referenced = 0; + int priority = wb_priority(wbc); + int err; + + /* + * Note: We need to ensure that we have a reference to the inode + * if we are to do asynchronous writes. If not, waiting + * in nfs_wait_on_request() may deadlock with clear_inode(). + * + * If igrab() fails here, then it is in any case safe to + * call nfs_wb_page(), since there will be no pending writes. + */ + if (igrab(inode) != 0) + inode_referenced = 1; + end_index = i_size >> PAGE_CACHE_SHIFT; + + /* Ensure we've flushed out any previous writes */ + nfs_wb_page_priority(inode, page, priority); + + /* easy case */ + if (page->index < end_index) + goto do_it; + /* things got complicated... */ + offset = i_size & (PAGE_CACHE_SIZE-1); + + /* OK, are we completely out? */ + err = 0; /* potential race with truncate - ignore */ + if (page->index >= end_index+1 || !offset) + goto out; +do_it: + ctx = nfs_find_open_context(inode, FMODE_WRITE); + if (ctx == NULL) { + err = -EBADF; + goto out; + } + lock_kernel(); + if (!IS_SYNC(inode) && inode_referenced) { + err = nfs_writepage_async(ctx, inode, page, 0, offset); + if (err >= 0) { + err = 0; + if (wbc->for_reclaim) + nfs_flush_inode(inode, 0, 0, FLUSH_STABLE); + } + } else { + err = nfs_writepage_sync(ctx, inode, page, 0, + offset, priority); + if (err >= 0) { + if (err != offset) + redirty_page_for_writepage(wbc, page); + err = 0; + } + } + unlock_kernel(); + put_nfs_open_context(ctx); +out: + unlock_page(page); + if (inode_referenced) + iput(inode); + return err; +} + +/* + * Note: causes nfs_update_request() to block on the assumption + * that the writeback is generated due to memory pressure. + */ +int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc) +{ + struct backing_dev_info *bdi = mapping->backing_dev_info; + struct inode *inode = mapping->host; + int err; + + err = generic_writepages(mapping, wbc); + if (err) + return err; + while (test_and_set_bit(BDI_write_congested, &bdi->state) != 0) { + if (wbc->nonblocking) + return 0; + nfs_wait_on_write_congestion(mapping, 0); + } + err = nfs_flush_inode(inode, 0, 0, wb_priority(wbc)); + if (err < 0) + goto out; + wbc->nr_to_write -= err; + if (!wbc->nonblocking && wbc->sync_mode == WB_SYNC_ALL) { + err = nfs_wait_on_requests(inode, 0, 0); + if (err < 0) + goto out; + } + err = nfs_commit_inode(inode, 0, 0, wb_priority(wbc)); + if (err > 0) { + wbc->nr_to_write -= err; + err = 0; + } +out: + clear_bit(BDI_write_congested, &bdi->state); + wake_up_all(&nfs_write_congestion); + return err; +} + +/* + * Insert a write request into an inode + */ +static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req) +{ + struct nfs_inode *nfsi = NFS_I(inode); + int error; + + error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req); + BUG_ON(error == -EEXIST); + if (error) + return error; + if (!nfsi->npages) { + igrab(inode); + nfs_begin_data_update(inode); + if (nfs_have_delegation(inode, FMODE_WRITE)) + nfsi->change_attr++; + } + nfsi->npages++; + atomic_inc(&req->wb_count); + return 0; +} + +/* + * Insert a write request into an inode + */ +static void nfs_inode_remove_request(struct nfs_page *req) +{ + struct inode *inode = req->wb_context->dentry->d_inode; + struct nfs_inode *nfsi = NFS_I(inode); + + BUG_ON (!NFS_WBACK_BUSY(req)); + + spin_lock(&nfsi->req_lock); + radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index); + nfsi->npages--; + if (!nfsi->npages) { + spin_unlock(&nfsi->req_lock); + nfs_end_data_update_defer(inode); + iput(inode); + } else + spin_unlock(&nfsi->req_lock); + nfs_clear_request(req); + nfs_release_request(req); +} + +/* + * Find a request + */ +static inline struct nfs_page * +_nfs_find_request(struct inode *inode, unsigned long index) +{ + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_page *req; + + req = (struct nfs_page*)radix_tree_lookup(&nfsi->nfs_page_tree, index); + if (req) + atomic_inc(&req->wb_count); + return req; +} + +static struct nfs_page * +nfs_find_request(struct inode *inode, unsigned long index) +{ + struct nfs_page *req; + struct nfs_inode *nfsi = NFS_I(inode); + + spin_lock(&nfsi->req_lock); + req = _nfs_find_request(inode, index); + spin_unlock(&nfsi->req_lock); + return req; +} + +/* + * Add a request to the inode's dirty list. + */ +static void +nfs_mark_request_dirty(struct nfs_page *req) +{ + struct inode *inode = req->wb_context->dentry->d_inode; + struct nfs_inode *nfsi = NFS_I(inode); + + spin_lock(&nfsi->req_lock); + nfs_list_add_request(req, &nfsi->dirty); + nfsi->ndirty++; + spin_unlock(&nfsi->req_lock); + inc_page_state(nr_dirty); + mark_inode_dirty(inode); +} + +/* + * Check if a request is dirty + */ +static inline int +nfs_dirty_request(struct nfs_page *req) +{ + struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode); + return !list_empty(&req->wb_list) && req->wb_list_head == &nfsi->dirty; +} + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) +/* + * Add a request to the inode's commit list. + */ +static void +nfs_mark_request_commit(struct nfs_page *req) +{ + struct inode *inode = req->wb_context->dentry->d_inode; + struct nfs_inode *nfsi = NFS_I(inode); + + spin_lock(&nfsi->req_lock); + nfs_list_add_request(req, &nfsi->commit); + nfsi->ncommit++; + spin_unlock(&nfsi->req_lock); + inc_page_state(nr_unstable); + mark_inode_dirty(inode); +} +#endif + +/* + * Wait for a request to complete. + * + * Interruptible by signals only if mounted with intr flag. + */ +static int +nfs_wait_on_requests(struct inode *inode, unsigned long idx_start, unsigned int npages) +{ + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_page *req; + unsigned long idx_end, next; + unsigned int res = 0; + int error; + + if (npages == 0) + idx_end = ~0; + else + idx_end = idx_start + npages - 1; + + spin_lock(&nfsi->req_lock); + next = idx_start; + while (radix_tree_gang_lookup(&nfsi->nfs_page_tree, (void **)&req, next, 1)) { + if (req->wb_index > idx_end) + break; + + next = req->wb_index + 1; + if (!NFS_WBACK_BUSY(req)) + continue; + + atomic_inc(&req->wb_count); + spin_unlock(&nfsi->req_lock); + error = nfs_wait_on_request(req); + nfs_release_request(req); + if (error < 0) + return error; + spin_lock(&nfsi->req_lock); + res++; + } + spin_unlock(&nfsi->req_lock); + return res; +} + +/* + * nfs_scan_dirty - Scan an inode for dirty requests + * @inode: NFS inode to scan + * @dst: destination list + * @idx_start: lower bound of page->index to scan. + * @npages: idx_start + npages sets the upper bound to scan. + * + * Moves requests from the inode's dirty page list. + * The requests are *not* checked to ensure that they form a contiguous set. + */ +static int +nfs_scan_dirty(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages) +{ + struct nfs_inode *nfsi = NFS_I(inode); + int res; + res = nfs_scan_list(&nfsi->dirty, dst, idx_start, npages); + nfsi->ndirty -= res; + sub_page_state(nr_dirty,res); + if ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty)) + printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n"); + return res; +} + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) +/* + * nfs_scan_commit - Scan an inode for commit requests + * @inode: NFS inode to scan + * @dst: destination list + * @idx_start: lower bound of page->index to scan. + * @npages: idx_start + npages sets the upper bound to scan. + * + * Moves requests from the inode's 'commit' request list. + * The requests are *not* checked to ensure that they form a contiguous set. + */ +static int +nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages) +{ + struct nfs_inode *nfsi = NFS_I(inode); + int res; + res = nfs_scan_list(&nfsi->commit, dst, idx_start, npages); + nfsi->ncommit -= res; + if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit)) + printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n"); + return res; +} +#endif + +static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr) +{ + struct backing_dev_info *bdi = mapping->backing_dev_info; + DEFINE_WAIT(wait); + int ret = 0; + + might_sleep(); + + if (!bdi_write_congested(bdi)) + return 0; + if (intr) { + struct rpc_clnt *clnt = NFS_CLIENT(mapping->host); + sigset_t oldset; + + rpc_clnt_sigmask(clnt, &oldset); + prepare_to_wait(&nfs_write_congestion, &wait, TASK_INTERRUPTIBLE); + if (bdi_write_congested(bdi)) { + if (signalled()) + ret = -ERESTARTSYS; + else + schedule(); + } + rpc_clnt_sigunmask(clnt, &oldset); + } else { + prepare_to_wait(&nfs_write_congestion, &wait, TASK_UNINTERRUPTIBLE); + if (bdi_write_congested(bdi)) + schedule(); + } + finish_wait(&nfs_write_congestion, &wait); + return ret; +} + + +/* + * Try to update any existing write request, or create one if there is none. + * In order to match, the request's credentials must match those of + * the calling process. + * + * Note: Should always be called with the Page Lock held! + */ +static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx, + struct inode *inode, struct page *page, + unsigned int offset, unsigned int bytes) +{ + struct nfs_server *server = NFS_SERVER(inode); + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_page *req, *new = NULL; + unsigned long rqend, end; + + end = offset + bytes; + + if (nfs_wait_on_write_congestion(page->mapping, server->flags & NFS_MOUNT_INTR)) + return ERR_PTR(-ERESTARTSYS); + for (;;) { + /* Loop over all inode entries and see if we find + * A request for the page we wish to update + */ + spin_lock(&nfsi->req_lock); + req = _nfs_find_request(inode, page->index); + if (req) { + if (!nfs_lock_request_dontget(req)) { + int error; + spin_unlock(&nfsi->req_lock); + error = nfs_wait_on_request(req); + nfs_release_request(req); + if (error < 0) + return ERR_PTR(error); + continue; + } + spin_unlock(&nfsi->req_lock); + if (new) + nfs_release_request(new); + break; + } + + if (new) { + int error; + nfs_lock_request_dontget(new); + error = nfs_inode_add_request(inode, new); + if (error) { + spin_unlock(&nfsi->req_lock); + nfs_unlock_request(new); + return ERR_PTR(error); + } + spin_unlock(&nfsi->req_lock); + nfs_mark_request_dirty(new); + return new; + } + spin_unlock(&nfsi->req_lock); + + new = nfs_create_request(ctx, inode, page, offset, bytes); + if (IS_ERR(new)) + return new; + } + + /* We have a request for our page. + * If the creds don't match, or the + * page addresses don't match, + * tell the caller to wait on the conflicting + * request. + */ + rqend = req->wb_offset + req->wb_bytes; + if (req->wb_context != ctx + || req->wb_page != page + || !nfs_dirty_request(req) + || offset > rqend || end < req->wb_offset) { + nfs_unlock_request(req); + return ERR_PTR(-EBUSY); + } + + /* Okay, the request matches. Update the region */ + if (offset < req->wb_offset) { + req->wb_offset = offset; + req->wb_pgbase = offset; + req->wb_bytes = rqend - req->wb_offset; + } + + if (end > rqend) + req->wb_bytes = end - req->wb_offset; + + return req; +} + +int nfs_flush_incompatible(struct file *file, struct page *page) +{ + struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data; + struct inode *inode = page->mapping->host; + struct nfs_page *req; + int status = 0; + /* + * 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. + */ + req = nfs_find_request(inode, page->index); + if (req) { + if (req->wb_page != page || ctx != req->wb_context) + status = nfs_wb_page(inode, page); + nfs_release_request(req); + } + return (status < 0) ? status : 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 = (struct nfs_open_context *)file->private_data; + struct dentry *dentry = file->f_dentry; + struct inode *inode = page->mapping->host; + struct nfs_page *req; + int status = 0; + + dprintk("NFS: nfs_updatepage(%s/%s %d@%Ld)\n", + dentry->d_parent->d_name.name, dentry->d_name.name, + count, (long long)(page_offset(page) +offset)); + + if (IS_SYNC(inode)) { + status = nfs_writepage_sync(ctx, inode, page, offset, count, 0); + if (status > 0) { + if (offset == 0 && status == PAGE_CACHE_SIZE) + SetPageUptodate(page); + return 0; + } + return status; + } + + /* If we're not using byte range locks, and we know the page + * is entirely in cache, it may be more efficient to avoid + * fragmenting write requests. + */ + if (PageUptodate(page) && inode->i_flock == NULL) { + loff_t end_offs = i_size_read(inode) - 1; + unsigned long end_index = end_offs >> PAGE_CACHE_SHIFT; + + count += offset; + offset = 0; + if (unlikely(end_offs < 0)) { + /* Do nothing */ + } else if (page->index == end_index) { + unsigned int pglen; + pglen = (unsigned int)(end_offs & (PAGE_CACHE_SIZE-1)) + 1; + if (count < pglen) + count = pglen; + } else if (page->index < end_index) + count = PAGE_CACHE_SIZE; + } + + /* + * Try to find an NFS request corresponding to this page + * and update it. + * If the existing request cannot be updated, we must flush + * it out now. + */ + do { + req = nfs_update_request(ctx, inode, page, offset, count); + status = (IS_ERR(req)) ? PTR_ERR(req) : 0; + if (status != -EBUSY) + break; + /* Request could not be updated. Flush it out and try again */ + status = nfs_wb_page(inode, page); + } while (status >= 0); + if (status < 0) + goto done; + + status = 0; + + /* Update file length */ + nfs_grow_file(page, offset, count); + /* Set the PG_uptodate flag? */ + nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes); + nfs_unlock_request(req); +done: + dprintk("NFS: nfs_updatepage returns %d (isize %Ld)\n", + status, (long long)i_size_read(inode)); + if (status < 0) + ClearPageUptodate(page); + return status; +} + +static void nfs_writepage_release(struct nfs_page *req) +{ + end_page_writeback(req->wb_page); + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) + if (!PageError(req->wb_page)) { + if (NFS_NEED_RESCHED(req)) { + nfs_mark_request_dirty(req); + goto out; + } else if (NFS_NEED_COMMIT(req)) { + nfs_mark_request_commit(req); + goto out; + } + } + nfs_inode_remove_request(req); + +out: + nfs_clear_commit(req); + nfs_clear_reschedule(req); +#else + nfs_inode_remove_request(req); +#endif + nfs_unlock_request(req); +} + +static inline int flush_task_priority(int how) +{ + switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) { + case FLUSH_HIGHPRI: + return RPC_PRIORITY_HIGH; + case FLUSH_LOWPRI: + return RPC_PRIORITY_LOW; + } + return RPC_PRIORITY_NORMAL; +} + +/* + * Set up the argument/result storage required for the RPC call. + */ +static void nfs_write_rpcsetup(struct nfs_page *req, + struct nfs_write_data *data, + unsigned int count, unsigned int offset, + int how) +{ + struct rpc_task *task = &data->task; + struct inode *inode; + + /* Set up the RPC argument and reply structs + * NB: take care not to mess about with data->commit et al. */ + + data->req = req; + data->inode = inode = req->wb_context->dentry->d_inode; + data->cred = req->wb_context->cred; + + data->args.fh = NFS_FH(inode); + data->args.offset = req_offset(req) + offset; + data->args.pgbase = req->wb_pgbase + offset; + data->args.pages = data->pagevec; + data->args.count = count; + data->args.context = req->wb_context; + + data->res.fattr = &data->fattr; + data->res.count = count; + data->res.verf = &data->verf; + + NFS_PROTO(inode)->write_setup(data, how); + + data->task.tk_priority = flush_task_priority(how); + data->task.tk_cookie = (unsigned long)inode; + data->task.tk_calldata = data; + /* Release requests */ + data->task.tk_release = nfs_writedata_release; + + dprintk("NFS: %4d initiated write call (req %s/%Ld, %u bytes @ offset %Lu)\n", + task->tk_pid, + inode->i_sb->s_id, + (long long)NFS_FILEID(inode), + count, + (unsigned long long)data->args.offset); +} + +static void nfs_execute_write(struct nfs_write_data *data) +{ + struct rpc_clnt *clnt = NFS_CLIENT(data->inode); + sigset_t oldset; + + rpc_clnt_sigmask(clnt, &oldset); + lock_kernel(); + rpc_execute(&data->task); + unlock_kernel(); + rpc_clnt_sigunmask(clnt, &oldset); +} + +/* + * Generate multiple small requests to write out a single + * contiguous dirty area on one page. + */ +static int nfs_flush_multi(struct list_head *head, struct inode *inode, int how) +{ + struct nfs_page *req = nfs_list_entry(head->next); + struct page *page = req->wb_page; + struct nfs_write_data *data; + unsigned int wsize = NFS_SERVER(inode)->wsize; + unsigned int nbytes, offset; + int requests = 0; + LIST_HEAD(list); + + nfs_list_remove_request(req); + + nbytes = req->wb_bytes; + for (;;) { + data = nfs_writedata_alloc(); + if (!data) + goto out_bad; + list_add(&data->pages, &list); + requests++; + if (nbytes <= wsize) + break; + nbytes -= wsize; + } + atomic_set(&req->wb_complete, requests); + + ClearPageError(page); + SetPageWriteback(page); + offset = 0; + nbytes = req->wb_bytes; + do { + data = list_entry(list.next, struct nfs_write_data, pages); + list_del_init(&data->pages); + + data->pagevec[0] = page; + data->complete = nfs_writeback_done_partial; + + if (nbytes > wsize) { + nfs_write_rpcsetup(req, data, wsize, offset, how); + offset += wsize; + nbytes -= wsize; + } else { + nfs_write_rpcsetup(req, data, nbytes, offset, how); + nbytes = 0; + } + nfs_execute_write(data); + } while (nbytes != 0); + + return 0; + +out_bad: + while (!list_empty(&list)) { + data = list_entry(list.next, struct nfs_write_data, pages); + list_del(&data->pages); + nfs_writedata_free(data); + } + nfs_mark_request_dirty(req); + nfs_unlock_request(req); + return -ENOMEM; +} + +/* + * Create an RPC task for the given write request and kick it. + * The page must have been locked by the caller. + * + * It may happen that the page we're passed is not marked dirty. + * This is the case if nfs_updatepage detects a conflicting request + * that has been written but not committed. + */ +static int nfs_flush_one(struct list_head *head, struct inode *inode, int how) +{ + struct nfs_page *req; + struct page **pages; + struct nfs_write_data *data; + unsigned int count; + + if (NFS_SERVER(inode)->wsize < PAGE_CACHE_SIZE) + return nfs_flush_multi(head, inode, how); + + data = nfs_writedata_alloc(); + if (!data) + goto out_bad; + + pages = data->pagevec; + count = 0; + while (!list_empty(head)) { + req = nfs_list_entry(head->next); + nfs_list_remove_request(req); + nfs_list_add_request(req, &data->pages); + ClearPageError(req->wb_page); + SetPageWriteback(req->wb_page); + *pages++ = req->wb_page; + count += req->wb_bytes; + } + req = nfs_list_entry(data->pages.next); + + data->complete = nfs_writeback_done_full; + /* Set up the argument struct */ + nfs_write_rpcsetup(req, data, count, 0, how); + + nfs_execute_write(data); + return 0; + out_bad: + while (!list_empty(head)) { + struct nfs_page *req = nfs_list_entry(head->next); + nfs_list_remove_request(req); + nfs_mark_request_dirty(req); + nfs_unlock_request(req); + } + return -ENOMEM; +} + +static int +nfs_flush_list(struct list_head *head, int wpages, int how) +{ + LIST_HEAD(one_request); + struct nfs_page *req; + int error = 0; + unsigned int pages = 0; + + while (!list_empty(head)) { + pages += nfs_coalesce_requests(head, &one_request, wpages); + req = nfs_list_entry(one_request.next); + error = nfs_flush_one(&one_request, req->wb_context->dentry->d_inode, how); + if (error < 0) + break; + } + if (error >= 0) + return pages; + + while (!list_empty(head)) { + req = nfs_list_entry(head->next); + nfs_list_remove_request(req); + nfs_mark_request_dirty(req); + nfs_unlock_request(req); + } + return error; +} + +/* + * Handle a write reply that flushed part of a page. + */ +static void nfs_writeback_done_partial(struct nfs_write_data *data, int status) +{ + struct nfs_page *req = data->req; + struct page *page = req->wb_page; + + dprintk("NFS: write (%s/%Ld %d@%Ld)", + req->wb_context->dentry->d_inode->i_sb->s_id, + (long long)NFS_FILEID(req->wb_context->dentry->d_inode), + req->wb_bytes, + (long long)req_offset(req)); + + if (status < 0) { + ClearPageUptodate(page); + SetPageError(page); + req->wb_context->error = status; + dprintk(", error = %d\n", status); + } else { +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) + if (data->verf.committed < NFS_FILE_SYNC) { + if (!NFS_NEED_COMMIT(req)) { + nfs_defer_commit(req); + memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf)); + dprintk(" defer commit\n"); + } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) { + nfs_defer_reschedule(req); + dprintk(" server reboot detected\n"); + } + } else +#endif + dprintk(" OK\n"); + } + + if (atomic_dec_and_test(&req->wb_complete)) + nfs_writepage_release(req); +} + +/* + * Handle a write reply that flushes a whole page. + * + * FIXME: There is an inherent race with invalidate_inode_pages and + * writebacks since the page->count is kept > 1 for as long + * as the page has a write request pending. + */ +static void nfs_writeback_done_full(struct nfs_write_data *data, int status) +{ + struct nfs_page *req; + struct page *page; + + /* Update attributes as result of writeback. */ + while (!list_empty(&data->pages)) { + req = nfs_list_entry(data->pages.next); + nfs_list_remove_request(req); + page = req->wb_page; + + dprintk("NFS: write (%s/%Ld %d@%Ld)", + req->wb_context->dentry->d_inode->i_sb->s_id, + (long long)NFS_FILEID(req->wb_context->dentry->d_inode), + req->wb_bytes, + (long long)req_offset(req)); + + if (status < 0) { + ClearPageUptodate(page); + SetPageError(page); + req->wb_context->error = status; + end_page_writeback(page); + nfs_inode_remove_request(req); + dprintk(", error = %d\n", status); + goto next; + } + end_page_writeback(page); + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) + if (data->args.stable != NFS_UNSTABLE || data->verf.committed == NFS_FILE_SYNC) { + nfs_inode_remove_request(req); + dprintk(" OK\n"); + goto next; + } + memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf)); + nfs_mark_request_commit(req); + dprintk(" marked for commit\n"); +#else + nfs_inode_remove_request(req); +#endif + next: + nfs_unlock_request(req); + } +} + +/* + * This function is called when the WRITE call is complete. + */ +void nfs_writeback_done(struct rpc_task *task) +{ + struct nfs_write_data *data = (struct nfs_write_data *) task->tk_calldata; + struct nfs_writeargs *argp = &data->args; + struct nfs_writeres *resp = &data->res; + + dprintk("NFS: %4d nfs_writeback_done (status %d)\n", + task->tk_pid, task->tk_status); + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) + if (resp->verf->committed < argp->stable && task->tk_status >= 0) { + /* We tried a write call, but the server did not + * commit data to stable storage even though we + * requested it. + * Note: There is a known bug in Tru64 < 5.0 in which + * the server reports NFS_DATA_SYNC, but performs + * NFS_FILE_SYNC. We therefore implement this checking + * as a dprintk() in order to avoid filling syslog. + */ + static unsigned long complain; + + if (time_before(complain, jiffies)) { + dprintk("NFS: faulty NFS server %s:" + " (committed = %d) != (stable = %d)\n", + NFS_SERVER(data->inode)->hostname, + resp->verf->committed, argp->stable); + complain = jiffies + 300 * HZ; + } + } +#endif + /* Is this a short write? */ + if (task->tk_status >= 0 && resp->count < argp->count) { + static unsigned long complain; + + /* Has the server at least made some progress? */ + if (resp->count != 0) { + /* Was this an NFSv2 write or an NFSv3 stable write? */ + if (resp->verf->committed != NFS_UNSTABLE) { + /* Resend from where the server left off */ + argp->offset += resp->count; + argp->pgbase += resp->count; + argp->count -= resp->count; + } else { + /* Resend as a stable write in order to avoid + * headaches in the case of a server crash. + */ + argp->stable = NFS_FILE_SYNC; + } + rpc_restart_call(task); + return; + } + if (time_before(complain, jiffies)) { + printk(KERN_WARNING + "NFS: Server wrote zero bytes, expected %u.\n", + argp->count); + complain = jiffies + 300 * HZ; + } + /* Can't do anything about it except throw an error. */ + task->tk_status = -EIO; + } + + /* + * Process the nfs_page list + */ + data->complete(data, task->tk_status); +} + + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) +static void nfs_commit_release(struct rpc_task *task) +{ + struct nfs_write_data *wdata = (struct nfs_write_data *)task->tk_calldata; + nfs_commit_free(wdata); +} + +/* + * Set up the argument/result storage required for the RPC call. + */ +static void nfs_commit_rpcsetup(struct list_head *head, + struct nfs_write_data *data, int how) +{ + struct rpc_task *task = &data->task; + struct nfs_page *first, *last; + struct inode *inode; + loff_t start, end, len; + + /* Set up the RPC argument and reply structs + * NB: take care not to mess about with data->commit et al. */ + + list_splice_init(head, &data->pages); + first = nfs_list_entry(data->pages.next); + last = nfs_list_entry(data->pages.prev); + inode = first->wb_context->dentry->d_inode; + + /* + * Determine the offset range of requests in the COMMIT call. + * We rely on the fact that data->pages is an ordered list... + */ + start = req_offset(first); + end = req_offset(last) + last->wb_bytes; + len = end - start; + /* If 'len' is not a 32-bit quantity, pass '0' in the COMMIT call */ + if (end >= i_size_read(inode) || len < 0 || len > (~((u32)0) >> 1)) + len = 0; + + data->inode = inode; + data->cred = first->wb_context->cred; + + data->args.fh = NFS_FH(data->inode); + data->args.offset = start; + data->args.count = len; + data->res.count = len; + data->res.fattr = &data->fattr; + data->res.verf = &data->verf; + + NFS_PROTO(inode)->commit_setup(data, how); + + data->task.tk_priority = flush_task_priority(how); + data->task.tk_cookie = (unsigned long)inode; + data->task.tk_calldata = data; + /* Release requests */ + data->task.tk_release = nfs_commit_release; + + dprintk("NFS: %4d initiated commit call\n", task->tk_pid); +} + +/* + * Commit dirty pages + */ +static int +nfs_commit_list(struct list_head *head, int how) +{ + struct nfs_write_data *data; + struct nfs_page *req; + + data = nfs_commit_alloc(); + + if (!data) + goto out_bad; + + /* Set up the argument struct */ + nfs_commit_rpcsetup(head, data, how); + + nfs_execute_write(data); + return 0; + out_bad: + while (!list_empty(head)) { + req = nfs_list_entry(head->next); + nfs_list_remove_request(req); + nfs_mark_request_commit(req); + nfs_unlock_request(req); + } + return -ENOMEM; +} + +/* + * COMMIT call returned + */ +void +nfs_commit_done(struct rpc_task *task) +{ + struct nfs_write_data *data = (struct nfs_write_data *)task->tk_calldata; + struct nfs_page *req; + int res = 0; + + dprintk("NFS: %4d nfs_commit_done (status %d)\n", + task->tk_pid, task->tk_status); + + while (!list_empty(&data->pages)) { + req = nfs_list_entry(data->pages.next); + nfs_list_remove_request(req); + + dprintk("NFS: commit (%s/%Ld %d@%Ld)", + req->wb_context->dentry->d_inode->i_sb->s_id, + (long long)NFS_FILEID(req->wb_context->dentry->d_inode), + req->wb_bytes, + (long long)req_offset(req)); + if (task->tk_status < 0) { + req->wb_context->error = task->tk_status; + nfs_inode_remove_request(req); + dprintk(", error = %d\n", task->tk_status); + goto next; + } + + /* Okay, COMMIT succeeded, apparently. Check the verifier + * returned by the server against all stored verfs. */ + if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) { + /* We have a match */ + nfs_inode_remove_request(req); + dprintk(" OK\n"); + goto next; + } + /* We have a mismatch. Write the page again */ + dprintk(" mismatch\n"); + nfs_mark_request_dirty(req); + next: + nfs_unlock_request(req); + res++; + } + sub_page_state(nr_unstable,res); +} +#endif + +static int nfs_flush_inode(struct inode *inode, unsigned long idx_start, + unsigned int npages, int how) +{ + struct nfs_inode *nfsi = NFS_I(inode); + LIST_HEAD(head); + int res, + error = 0; + + spin_lock(&nfsi->req_lock); + res = nfs_scan_dirty(inode, &head, idx_start, npages); + spin_unlock(&nfsi->req_lock); + if (res) + error = nfs_flush_list(&head, NFS_SERVER(inode)->wpages, how); + if (error < 0) + return error; + return res; +} + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) +int nfs_commit_inode(struct inode *inode, unsigned long idx_start, + unsigned int npages, int how) +{ + struct nfs_inode *nfsi = NFS_I(inode); + LIST_HEAD(head); + int res, + error = 0; + + spin_lock(&nfsi->req_lock); + res = nfs_scan_commit(inode, &head, idx_start, npages); + if (res) { + res += nfs_scan_commit(inode, &head, 0, 0); + spin_unlock(&nfsi->req_lock); + error = nfs_commit_list(&head, how); + } else + spin_unlock(&nfsi->req_lock); + if (error < 0) + return error; + return res; +} +#endif + +int nfs_sync_inode(struct inode *inode, unsigned long idx_start, + unsigned int npages, int how) +{ + int error, + wait; + + wait = how & FLUSH_WAIT; + how &= ~FLUSH_WAIT; + + do { + error = 0; + if (wait) + error = nfs_wait_on_requests(inode, idx_start, npages); + if (error == 0) + error = nfs_flush_inode(inode, idx_start, npages, how); +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) + if (error == 0) + error = nfs_commit_inode(inode, idx_start, npages, how); +#endif + } while (error > 0); + return error; +} + +int nfs_init_writepagecache(void) +{ + nfs_wdata_cachep = kmem_cache_create("nfs_write_data", + sizeof(struct nfs_write_data), + 0, SLAB_HWCACHE_ALIGN, + NULL, NULL); + if (nfs_wdata_cachep == NULL) + return -ENOMEM; + + nfs_wdata_mempool = mempool_create(MIN_POOL_WRITE, + mempool_alloc_slab, + mempool_free_slab, + nfs_wdata_cachep); + if (nfs_wdata_mempool == NULL) + return -ENOMEM; + + nfs_commit_mempool = mempool_create(MIN_POOL_COMMIT, + mempool_alloc_slab, + mempool_free_slab, + nfs_wdata_cachep); + if (nfs_commit_mempool == NULL) + return -ENOMEM; + + return 0; +} + +void nfs_destroy_writepagecache(void) +{ + mempool_destroy(nfs_commit_mempool); + mempool_destroy(nfs_wdata_mempool); + if (kmem_cache_destroy(nfs_wdata_cachep)) + printk(KERN_INFO "nfs_write_data: not all structures were freed\n"); +} + |