CIFS: Fix error paths in writeback code

[ Upstream commit 9a66396f1857cc1de06f4f4771797315e1a4ea56 ]

This patch aims to address writeback code problems related to error
paths. In particular it respects EINTR and related error codes and
stores and returns the first error occurred during writeback.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

4 files changed, 56 insertions, 9 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 6f227cc781e5..0ee0072c1f36 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1563,6 +1563,25 @@ static inline void free_dfs_info_array(struct dfs_info3_param *param,
 	kfree(param);
 }
 
+static inline bool is_interrupt_error(int error)
+{
+	switch (error) {
+	case -EINTR:
+	case -ERESTARTSYS:
+	case -ERESTARTNOHAND:
+	case -ERESTARTNOINTR:
+		return true;
+	}
+	return false;
+}
+
+static inline bool is_retryable_error(int error)
+{
+	if (is_interrupt_error(error) || error == -EAGAIN)
+		return true;
+	return false;
+}
+
 #define   MID_FREE 0
 #define   MID_REQUEST_ALLOCATED 1
 #define   MID_REQUEST_SUBMITTED 2
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 269471c8f42b..a5cb7b2d1ac5 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -2042,7 +2042,7 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 
 		for (j = 0; j < nr_pages; j++) {
 			unlock_page(wdata2->pages[j]);
-			if (rc != 0 && rc != -EAGAIN) {
+			if (rc != 0 && !is_retryable_error(rc)) {
 				SetPageError(wdata2->pages[j]);
 				end_page_writeback(wdata2->pages[j]);
 				put_page(wdata2->pages[j]);
@@ -2051,7 +2051,7 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 
 		if (rc) {
 			kref_put(&wdata2->refcount, cifs_writedata_release);
-			if (rc == -EAGAIN)
+			if (is_retryable_error(rc))
 				continue;
 			break;
 		}
@@ -2060,7 +2060,8 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 		i += nr_pages;
 	} while (i < wdata->nr_pages);
 
-	mapping_set_error(inode->i_mapping, rc);
+	if (rc != 0 && !is_retryable_error(rc))
+		mapping_set_error(inode->i_mapping, rc);
 	kref_put(&wdata->refcount, cifs_writedata_release);
 }
 
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 23cee91ed442..933013543eda 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -749,7 +749,8 @@ reopen_success:
 
 	if (can_flush) {
 		rc = filemap_write_and_wait(inode->i_mapping);
-		mapping_set_error(inode->i_mapping, rc);
+		if (!is_interrupt_error(rc))
+			mapping_set_error(inode->i_mapping, rc);
 
 		if (tcon->unix_ext)
 			rc = cifs_get_inode_info_unix(&inode, full_path,
@@ -2137,6 +2138,7 @@ static int cifs_writepages(struct address_space *mapping,
 	pgoff_t end, index;
 	struct cifs_writedata *wdata;
 	int rc = 0;
+	int saved_rc = 0;
 
 	/*
 	 * If wsize is smaller than the page cache size, default to writing
@@ -2163,8 +2165,10 @@ retry:
 
 		rc = server->ops->wait_mtu_credits(server, cifs_sb->wsize,
 						   &wsize, &credits);
-		if (rc)
+		if (rc != 0) {
+			done = true;
 			break;
+		}
 
 		tofind = min((wsize / PAGE_SIZE) - 1, end - index) + 1;
 
@@ -2172,6 +2176,7 @@ retry:
 						  &found_pages);
 		if (!wdata) {
 			rc = -ENOMEM;
+			done = true;
 			add_credits_and_wake_if(server, credits, 0);
 			break;
 		}
@@ -2200,7 +2205,7 @@ retry:
 		if (rc != 0) {
 			add_credits_and_wake_if(server, wdata->credits, 0);
 			for (i = 0; i < nr_pages; ++i) {
-				if (rc == -EAGAIN)
+				if (is_retryable_error(rc))
 					redirty_page_for_writepage(wbc,
 							   wdata->pages[i]);
 				else
@@ -2208,7 +2213,7 @@ retry:
 				end_page_writeback(wdata->pages[i]);
 				put_page(wdata->pages[i]);
 			}
-			if (rc != -EAGAIN)
+			if (!is_retryable_error(rc))
 				mapping_set_error(mapping, rc);
 		}
 		kref_put(&wdata->refcount, cifs_writedata_release);
@@ -2218,6 +2223,15 @@ retry:
 			continue;
 		}
 
+		/* Return immediately if we received a signal during writing */
+		if (is_interrupt_error(rc)) {
+			done = true;
+			break;
+		}
+
+		if (rc != 0 && saved_rc == 0)
+			saved_rc = rc;
+
 		wbc->nr_to_write -= nr_pages;
 		if (wbc->nr_to_write <= 0)
 			done = true;
@@ -2235,6 +2249,9 @@ retry:
 		goto retry;
 	}
 
+	if (saved_rc != 0)
+		rc = saved_rc;
+
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		mapping->writeback_index = index;
 
@@ -2266,8 +2283,8 @@ cifs_writepage_locked(struct page *page, struct writeback_control *wbc)
 	set_page_writeback(page);
 retry_write:
 	rc = cifs_partialpagewrite(page, 0, PAGE_SIZE);
-	if (rc == -EAGAIN) {
-		if (wbc->sync_mode == WB_SYNC_ALL)
+	if (is_retryable_error(rc)) {
+		if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN)
 			goto retry_write;
 		redirty_page_for_writepage(wbc, page);
 	} else if (rc != 0) {
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 1fadd314ae7f..53f3d08898af 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2261,6 +2261,11 @@ cifs_setattr_unix(struct dentry *direntry, struct iattr *attrs)
 	 * the flush returns error?
 	 */
 	rc = filemap_write_and_wait(inode->i_mapping);
+	if (is_interrupt_error(rc)) {
+		rc = -ERESTARTSYS;
+		goto out;
+	}
+
 	mapping_set_error(inode->i_mapping, rc);
 	rc = 0;
 
@@ -2404,6 +2409,11 @@ cifs_setattr_nounix(struct dentry *direntry, struct iattr *attrs)
 	 * the flush returns error?
 	 */
 	rc = filemap_write_and_wait(inode->i_mapping);
+	if (is_interrupt_error(rc)) {
+		rc = -ERESTARTSYS;
+		goto cifs_setattr_exit;
+	}
+
 	mapping_set_error(inode->i_mapping, rc);
 	rc = 0;