#define NFS_PARANOIA 1
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
-static void nfs_wback_lock(struct rpc_task *task);
+static void nfs_wback_begin(struct rpc_task *task);
static void nfs_wback_result(struct rpc_task *task);
static void nfs_cancel_request(struct nfs_wreq *req);
* Limit number of delayed writes
*/
static int nr_write_requests = 0;
-static int nr_failed_requests = 0;
static struct rpc_wait_queue write_queue = RPC_INIT_WAITQ("write_chain");
-struct nfs_wreq * nfs_failed_requests = NULL;
/* Hack for future NFS swap support */
#ifndef IS_SWAPFILE
# define IS_SWAPFILE(inode) (0)
#endif
-/*
- * Unlock a page after writing it
- */
-static inline void
-nfs_unlock_page(struct page *page)
-{
- dprintk("NFS: unlock %ld\n", page->offset);
- clear_bit(PG_locked, &page->flags);
- wake_up(&page->wait);
-
-#ifdef CONFIG_NFS_SWAP
- /* async swap-out support */
- if (test_and_clear_bit(PG_decr_after, &page->flags))
- atomic_dec(&page->count);
- if (test_and_clear_bit(PG_swap_unlock_after, &page->flags)) {
- /*
- * We're doing a swap, so check that this page is
- * swap-cached and do the necessary cleanup.
- */
- swap_after_unlock_page(page->offset);
- }
-#endif
-}
-
-/*
- * Transfer a page lock to a write request waiting for it.
- */
-static inline void
-transfer_page_lock(struct nfs_wreq *req)
-{
- dprintk("NFS: transfer_page_lock\n");
-
- req->wb_flags &= ~NFS_WRITE_WANTLOCK;
- req->wb_flags |= NFS_WRITE_LOCKED;
- rpc_wake_up_task(&req->wb_task);
-
- dprintk("NFS: wake up task %d (flags %x)\n",
- req->wb_task.tk_pid, req->wb_flags);
-}
-
/*
* Write a page synchronously.
* Offset is the data offset within the page.
inode->i_ino, fattr.fileid);
}
- nfs_unlock_page(page);
return written? written : result;
}
}
/*
- * Find a write request for a given page
+ * Find a non-busy write request for a given page to
+ * try to combine with.
*/
static inline struct nfs_wreq *
find_write_request(struct inode *inode, struct page *page)
{
+ pid_t pid = current->pid;
struct nfs_wreq *head, *req;
dprintk("NFS: find_write_request(%x/%ld, %p)\n",
if (!(req = head = NFS_WRITEBACK(inode)))
return NULL;
do {
- if (req->wb_page == page)
+ /*
+ * We can't combine with canceled requests or
+ * requests that have already been started..
+ */
+ if (req->wb_flags & (NFS_WRITE_CANCELLED | NFS_WRITE_INPROGRESS))
+ continue;
+
+ if (req->wb_page == page && req->wb_pid == pid)
return req;
+
+ /*
+ * Ehh, don't keep too many tasks queued..
+ */
+ rpc_wake_up_task(&req->wb_task);
+
} while ((req = WB_NEXT(req)) != head);
return NULL;
}
return found;
}
-/*
- * Find a failed write request by pid
- */
-static struct nfs_wreq *
-find_failed_request(struct inode *inode, pid_t pid)
-{
- struct nfs_wreq *head, *req;
-
- req = head = nfs_failed_requests;
- while (req != NULL) {
- if (req->wb_inode == inode && (pid == 0 || req->wb_pid == pid))
- return req;
- if ((req = WB_NEXT(req)) == head)
- break;
- }
- return NULL;
-}
-
-/*
- * Add a request to the failed list.
- */
-static void
-append_failed_request(struct nfs_wreq * req)
-{
- static int old_max = 16;
-
- append_write_request(&nfs_failed_requests, req);
- nr_failed_requests++;
- if (nr_failed_requests >= old_max) {
- printk("NFS: %d failed requests\n", nr_failed_requests);
- old_max = old_max << 1;
- }
-}
-
-/*
- * Remove a request from the failed list and free it.
- */
-static void
-remove_failed_request(struct nfs_wreq * req)
-{
- remove_write_request(&nfs_failed_requests, req);
- kfree(req);
- nr_failed_requests--;
-}
-
/*
* Find and release all failed requests for this inode.
*/
int
nfs_check_failed_request(struct inode * inode)
{
- struct nfs_wreq * req;
- int found = 0;
-
- while ((req = find_failed_request(inode, 0)) != NULL) {
- remove_failed_request(req);
- found++;
- }
- return found;
+ /* FIXME! */
+ return 0;
}
/*
dprintk("nfs: trying to update write request %p\n", req);
+ /* not contiguous? */
+ if (rqlast < first || last < rqfirst)
+ return 0;
+
/* Check the credentials associated with this write request.
* If the buffer is owned by the same user, we can happily
* add our data without risking server permission problems.
rqfirst = first;
if (rqlast < last)
rqlast = last;
+
req->wb_offset = rqfirst;
req->wb_bytes = rqlast - rqfirst;
+ req->wb_count++;
return 1;
}
+static inline void
+free_write_request(struct nfs_wreq * req)
+{
+ if (!--req->wb_count) {
+ struct inode *inode = req->wb_inode;
+ remove_write_request(&NFS_WRITEBACK(inode), req);
+ kfree(req);
+ nr_write_requests--;
+ }
+}
+
/*
* Create and initialize a writeback request
*/
page->offset + offset, bytes);
/* FIXME: Enforce hard limit on number of concurrent writes? */
-
- wreq = (struct nfs_wreq *) kmalloc(sizeof(*wreq), GFP_USER);
+ wreq = (struct nfs_wreq *) kmalloc(sizeof(*wreq), GFP_KERNEL);
if (!wreq)
goto out_fail;
memset(wreq, 0, sizeof(*wreq));
task = &wreq->wb_task;
rpc_init_task(task, clnt, nfs_wback_result, RPC_TASK_NFSWRITE);
task->tk_calldata = wreq;
- task->tk_action = nfs_wback_lock;
+ task->tk_action = nfs_wback_begin;
rpcauth_lookupcred(task); /* Obtain user creds */
if (task->tk_status < 0)
wreq->wb_page = page;
wreq->wb_offset = offset;
wreq->wb_bytes = bytes;
+ wreq->wb_count = 2; /* One for the IO, one for us */
atomic_inc(&page->count);
* Schedule a writeback RPC call.
* If the server is congested, don't add to our backlog of queued
* requests but call it synchronously.
- * The function returns false if the page has been unlocked as the
- * consequence of a synchronous write call.
+ * The function returns whether we should wait for the thing or not.
*
* FIXME: Here we could walk the inode's lock list to see whether the
* page we're currently writing to has been write-locked by the caller.
dprintk("NFS: %4d schedule_write_request (sync)\n",
task->tk_pid);
/* Page is already locked */
- req->wb_flags |= NFS_WRITE_LOCKED;
rpc_clnt_sigmask(clnt, &oldmask);
rpc_execute(task);
rpc_clnt_sigunmask(clnt, &oldmask);
rpc_sleep_on(&write_queue, task, NULL, NULL);
}
- return sync == 0;
+ return sync;
}
/*
- * Wait for request to complete
- * This is almost a copy of __wait_on_page
+ * Wait for request to complete.
*/
-static inline int
+static int
wait_on_write_request(struct nfs_wreq *req)
{
+ struct rpc_clnt *clnt = NFS_CLIENT(req->wb_inode);
struct wait_queue wait = { current, NULL };
- struct page *page = req->wb_page;
- int retval;
sigset_t oldmask;
- struct rpc_clnt *clnt = NFS_CLIENT(req->wb_inode);
+ int retval;
+
+ /* Make sure it's started.. */
+ if (!WB_INPROGRESS(req))
+ rpc_wake_up_task(&req->wb_task);
rpc_clnt_sigmask(clnt, &oldmask);
- add_wait_queue(&page->wait, &wait);
- atomic_inc(&page->count);
+ add_wait_queue(&req->wb_wait, &wait);
for (;;) {
current->state = TASK_INTERRUPTIBLE;
retval = 0;
- if (!PageLocked(page))
+ if (req->wb_flags & NFS_WRITE_COMPLETE)
break;
retval = -ERESTARTSYS;
if (signalled())
break;
schedule();
}
- remove_wait_queue(&page->wait, &wait);
+ remove_wait_queue(&req->wb_wait, &wait);
current->state = TASK_RUNNING;
- /* N.B. page may have been unused, so we must use free_page() */
- free_page(page_address(page));
rpc_clnt_sigunmask(clnt, &oldmask);
return retval;
}
struct dentry *dentry = file->f_dentry;
struct inode *inode = dentry->d_inode;
struct nfs_wreq *req;
- int status = 0, page_locked = 1;
+ int synchronous = sync;
+ int retval;
dprintk("NFS: nfs_updatepage(%s/%s %d@%ld, sync=%d)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
* After returning, generic_file_write will wait on the
* page and retry the update.
*/
- if ((req = find_write_request(inode, page)) != NULL) {
- if (update_write_request(req, offset, count))
- goto updated;
+ req = find_write_request(inode, page);
+ if (req && update_write_request(req, offset, count))
+ goto updated;
- dprintk("NFS: wake up conflicting write request.\n");
- transfer_page_lock(req);
- return 0;
- }
-
- /* If wsize is smaller than page size, update and write
+ /*
+ * If wsize is smaller than page size, update and write
* page synchronously.
*/
if (NFS_SERVER(inode)->wsize < PAGE_SIZE)
return nfs_writepage_sync(dentry, inode, page, offset, count);
/* Create the write request. */
- status = -ENOBUFS;
req = create_write_request(dentry, inode, page, offset, count);
if (!req)
- goto done;
+ return -ENOBUFS;
+
+ /*
+ * Ok, there's another user of this page with the new request..
+ * Increment the usage count, and schedule the request (the
+ * end of the request will drop the usage count..)
+ */
+ atomic_inc(&page->count);
/* Schedule request */
- page_locked = schedule_write_request(req, sync);
+ synchronous = schedule_write_request(req, sync);
updated:
if (req->wb_bytes == PAGE_SIZE)
set_bit(PG_uptodate, &page->flags);
- /*
- * If we wrote up to the end of the chunk, transmit request now.
- * We should be a bit more intelligent about detecting whether a
- * process accesses the file sequentially or not.
- */
- if (page_locked && (offset + count >= PAGE_SIZE || sync))
- req->wb_flags |= NFS_WRITE_WANTLOCK;
-
- /* If the page was written synchronously, return any error that
- * may have happened; otherwise return the write count. */
- if (page_locked || (status = nfs_write_error(inode)) >= 0)
- status = count;
-
-done:
- /* Unlock page and wake up anyone sleeping on it */
- if (page_locked) {
- if (req && WB_WANTLOCK(req)) {
- transfer_page_lock(req);
- /* rpc_execute(&req->wb_task); */
- if (sync) {
- /* if signalled, ensure request is cancelled */
- if ((count = wait_on_write_request(req)) != 0) {
- nfs_cancel_request(req);
- status = count;
- }
- if ((count = nfs_write_error(inode)) < 0)
- status = count;
- }
+ retval = count;
+ if (synchronous) {
+ int status = wait_on_write_request(req);
+ if (status) {
+ nfs_cancel_request(req);
+ retval = status;
} else {
- if (status < 0) {
-printk("NFS: %s/%s write failed, clearing bit\n",
-dentry->d_parent->d_name.name, dentry->d_name.name);
- clear_bit(PG_uptodate, &page->flags);
- }
- nfs_unlock_page(page);
+ status = req->wb_status;
+ if (status < 0)
+ retval = status;
}
- }
-
- dprintk("NFS: nfs_updatepage returns %d (isize %ld)\n",
- status, inode->i_size);
- return status;
-}
-
-/*
- * Flush out a dirty page.
- */
-static void
-nfs_flush_request(struct nfs_wreq *req)
-{
- struct page *page = req->wb_page;
-
-#ifdef NFS_DEBUG_VERBOSE
-if (req->wb_inode != page->inode)
-printk("NFS: inode %ld no longer has page %p\n", req->wb_inode->i_ino, page);
-#endif
- dprintk("NFS: nfs_flush_request(%s/%s, @%ld)\n",
- req->wb_dentry->d_parent->d_name.name,
- req->wb_dentry->d_name.name, page->offset);
-
- req->wb_flags |= NFS_WRITE_WANTLOCK;
- if (!test_and_set_bit(PG_locked, &page->flags)) {
- transfer_page_lock(req);
- } else {
- printk(KERN_WARNING "NFS oops in %s: can't lock page!\n",
- __FUNCTION__);
- rpc_wake_up_task(&req->wb_task);
- }
-}
-
-/*
- * Flush writeback requests. See nfs_flush_dirty_pages for details.
- */
-static struct nfs_wreq *
-nfs_flush_pages(struct inode *inode, pid_t pid, off_t offset, off_t len,
- int invalidate)
-{
- struct nfs_wreq *head, *req, *last = NULL;
- off_t rqoffset, rqend, end;
-
- end = len? offset + len : 0x7fffffffUL;
-
- req = head = NFS_WRITEBACK(inode);
- while (req != NULL) {
- dprintk("NFS: %4d nfs_flush inspect %s/%s @%ld fl %x\n",
- req->wb_task.tk_pid,
- req->wb_dentry->d_parent->d_name.name,
- req->wb_dentry->d_name.name,
- req->wb_page->offset, req->wb_flags);
- rqoffset = req->wb_page->offset + req->wb_offset;
- rqend = rqoffset + req->wb_bytes;
- if (rqoffset < end && offset < rqend &&
- (pid == 0 || req->wb_pid == pid)) {
- if (!WB_INPROGRESS(req) && !WB_HAVELOCK(req)) {
-#ifdef NFS_DEBUG_VERBOSE
-printk("nfs_flush: flushing inode=%ld, %d @ %lu\n",
-req->wb_inode->i_ino, req->wb_bytes, rqoffset);
-#endif
- nfs_flush_request(req);
- }
- last = req;
- }
- if (invalidate)
- req->wb_flags |= NFS_WRITE_INVALIDATE;
- if ((req = WB_NEXT(req)) == head)
- break;
+ if (retval < 0)
+ clear_bit(PG_uptodate, &page->flags);
}
- return last;
+ free_write_request(req);
+ return retval;
}
/*
}
/*
- * Flush out all dirty pages belonging to a certain user process and
- * maybe wait for the RPC calls to complete.
+ * Try to flush any dirty pages, returning a success marker..
*
- * Another purpose of this function is sync()ing a file range before a
- * write lock is released. This is what offset and length are for, even if
- * this isn't used by the nlm module yet.
+ * Unlike "nfs_flush_dirty_pages()" this does not invalidate
+ * the writes if it is interrupted. The caller will instead
+ * look at the error code and gracefully fail to do what it
+ * wanted to do.
*/
int
-nfs_flush_dirty_pages(struct inode *inode, pid_t pid, off_t offset, off_t len)
+nfs_flush_pages(struct inode *inode, pid_t pid, off_t offset, off_t len)
{
- struct nfs_wreq *last = NULL;
- int result = 0;
+ int retval;
- dprintk("NFS: flush_dirty_pages(%x/%ld for pid %d %ld/%ld)\n",
- inode->i_dev, inode->i_ino, current->pid, offset, len);
+ do {
+ struct nfs_wreq *req = NFS_WRITEBACK(inode);
+ struct nfs_wreq *head = req;
- for (;;) {
- /* Flush all pending writes for the pid and file region */
- last = nfs_flush_pages(inode, pid, offset, len, 0);
- if (last == NULL)
- break;
- result = wait_on_write_request(last);
- if (result) {
- nfs_cancel_dirty(inode,pid);
- break;
+ if (!req)
+ return 0;
+
+ /*
+ * Iterate over all outstanding write requests,
+ * looking for any that are ours..
+ */
+ for (;;) {
+ if (!(req->wb_flags & NFS_WRITE_COMPLETE)) {
+ if (!pid || req->wb_pid == pid)
+ break;
+ }
+ req = WB_NEXT(req);
+ if (req == head)
+ return 0;
}
- }
- return result;
-}
+ req->wb_count++;
+ retval = wait_on_write_request(req);
+ free_write_request(req);
+ } while (!retval);
+ return retval;
+}
/*
- * Flush out any pending write requests and flag that they be discarded
- * after the write is complete.
+ * Flush out all dirty pages belonging to a certain user process and
+ * maybe wait for the RPC calls to complete.
*
- * This function is called from nfs_refresh_inode just before it calls
- * invalidate_inode_pages. After nfs_flush_pages returns, we can be sure
- * that all dirty pages are locked, so that invalidate_inode_pages does
- * not throw away any dirty pages.
+ * Another purpose of this function is sync()ing a file range before a
+ * write lock is released. This is what offset and length are for, even if
+ * this isn't used by the nlm module yet.
*/
+int
+nfs_flush_dirty_pages(struct inode *inode, pid_t pid, off_t offset, off_t len)
+{
+ int retval = nfs_flush_pages(inode, pid, offset, len);
+ if (retval)
+ nfs_cancel_dirty(inode,pid);
+ return retval;
+}
+
void
nfs_invalidate_pages(struct inode *inode)
{
- dprintk("NFS: nfs_invalidate_pages(%x/%ld)\n",
- inode->i_dev, inode->i_ino);
-
- nfs_flush_pages(inode, 0, 0, 0, 1);
+ nfs_cancel_dirty(inode,0);
}
/*
int
nfs_check_error(struct inode *inode)
{
- struct nfs_wreq *req;
- int status = 0;
-
- dprintk("nfs: checking for write error inode %04x/%ld\n",
- inode->i_dev, inode->i_ino);
-
- req = find_failed_request(inode, current->pid);
- if (req) {
- dprintk("nfs: write error %d inode %04x/%ld\n",
- req->wb_task.tk_status, inode->i_dev, inode->i_ino);
-
- status = req->wb_task.tk_status;
- remove_failed_request(req);
- }
- return status;
+ /* FIXME! */
+ return 0;
}
/*
* set up the RPC call info, and pass to the call FSM.
*/
static void
-nfs_wback_lock(struct rpc_task *task)
+nfs_wback_begin(struct rpc_task *task)
{
struct nfs_wreq *req = (struct nfs_wreq *) task->tk_calldata;
struct page *page = req->wb_page;
struct dentry *dentry = req->wb_dentry;
- dprintk("NFS: %4d nfs_wback_lock (%s/%s, status=%d flags=%x)\n",
+ dprintk("NFS: %4d nfs_wback_begin (%s/%s, status=%d flags=%x)\n",
task->tk_pid, dentry->d_parent->d_name.name,
dentry->d_name.name, task->tk_status, req->wb_flags);
- if (!WB_HAVELOCK(req))
- req->wb_flags |= NFS_WRITE_WANTLOCK;
-
- if (WB_WANTLOCK(req) && test_and_set_bit(PG_locked, &page->flags))
- goto out_locked;
- req->wb_flags &= ~NFS_WRITE_WANTLOCK;
- req->wb_flags |= NFS_WRITE_LOCKED;
task->tk_status = 0;
/* Setup the task struct for a writeback call */
req->wb_flags |= NFS_WRITE_INPROGRESS;
return;
-
-out_locked:
- printk("NFS: page already locked in writeback_lock!\n");
- task->tk_timeout = 2 * HZ;
- rpc_sleep_on(&write_queue, task, NULL, NULL);
- return;
}
/*
/* Set the WRITE_COMPLETE flag, but leave WRITE_INPROGRESS set */
req->wb_flags |= NFS_WRITE_COMPLETE;
+ req->wb_status = status;
+
if (status < 0) {
- /*
- * An error occurred. Report the error back to the
- * application by adding the request to the failed
- * requests list.
- */
- if (find_failed_request(inode, req->wb_pid))
- status = 0;
- clear_bit(PG_uptodate, &page->flags);
+ req->wb_flags |= NFS_WRITE_INVALIDATE;
} else if (!WB_CANCELLED(req)) {
struct nfs_fattr *fattr = &req->wb_fattr;
/* Update attributes as result of writeback.
}
}
- /*
- * This call might block, so we defer removing the request
- * from the inode's writeback list.
- */
rpc_release_task(task);
if (WB_INVALIDATE(req))
clear_bit(PG_uptodate, &page->flags);
- if (WB_HAVELOCK(req))
- nfs_unlock_page(page);
+ __free_page(page);
+
+ wake_up(&req->wb_wait);
+
/*
- * Now it's safe to remove the request from the inode's
- * writeback list and wake up any tasks sleeping on it.
- * If the request failed, add it to the failed list.
+ * FIXME!
+ *
+ * We should not free the request here if it has pending
+ * error status on it. We should just leave it around, to
+ * let the error be collected later. However, the error
+ * collecting routines are too stupid for that right now,
+ * so we just drop the error on the floor at this point
+ * for any async writes.
+ *
+ * This should not be a major headache to fix, but I want
+ * to validate basic operations first.
*/
- remove_write_request(&NFS_WRITEBACK(inode), req);
-
- if (status >= 0)
- kfree(req);
- else {
- dprintk("NFS: %4d saving write failure code\n", task->tk_pid);
- append_failed_request(req);
- }
-
- free_page(page_address(page));
- nr_write_requests--;
+ free_write_request(req);
}
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