X-Git-Url: https://git.stricted.de/?a=blobdiff_plain;ds=sidebyside;f=fs%2Fcifs%2Ffile.c;h=8b0c656f2ab26d79c10648fa38129bb38fc52265;hb=b40a831c0f1d1cdd9342c5bf09f259d0834c442f;hp=48b29d24c9f4d58e225d060b70da4fc2e5ea5e5e;hpb=674825d05001e218afe5a04438683e1e597e14fb;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 48b29d24c9f4..8b0c656f2ab2 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -553,11 +553,10 @@ cifs_relock_file(struct cifsFileInfo *cfile)
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 	int rc = 0;
 
-	/* we are going to update can_cache_brlcks here - need a write access */
-	down_write(&cinode->lock_sem);
+	down_read(&cinode->lock_sem);
 	if (cinode->can_cache_brlcks) {
-		/* can cache locks - no need to push them */
-		up_write(&cinode->lock_sem);
+		/* can cache locks - no need to relock */
+		up_read(&cinode->lock_sem);
 		return rc;
 	}
 
@@ -568,7 +567,7 @@ cifs_relock_file(struct cifsFileInfo *cfile)
 	else
 		rc = tcon->ses->server->ops->push_mand_locks(cfile);
 
-	up_write(&cinode->lock_sem);
+	up_read(&cinode->lock_sem);
 	return rc;
 }
 
@@ -2354,7 +2353,7 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
 		 unsigned long nr_segs, loff_t *poffset)
 {
 	unsigned long nr_pages, i;
-	size_t copied, len, cur_len;
+	size_t bytes, copied, len, cur_len;
 	ssize_t total_written = 0;
 	loff_t offset;
 	struct iov_iter it;
@@ -2409,14 +2408,45 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
 
 		save_len = cur_len;
 		for (i = 0; i < nr_pages; i++) {
-			copied = min_t(const size_t, cur_len, PAGE_SIZE);
+			bytes = min_t(const size_t, cur_len, PAGE_SIZE);
 			copied = iov_iter_copy_from_user(wdata->pages[i], &it,
-							 0, copied);
+							 0, bytes);
 			cur_len -= copied;
 			iov_iter_advance(&it, copied);
+			/*
+			 * If we didn't copy as much as we expected, then that
+			 * may mean we trod into an unmapped area. Stop copying
+			 * at that point. On the next pass through the big
+			 * loop, we'll likely end up getting a zero-length
+			 * write and bailing out of it.
+			 */
+			if (copied < bytes)
+				break;
 		}
 		cur_len = save_len - cur_len;
 
+		/*
+		 * If we have no data to send, then that probably means that
+		 * the copy above failed altogether. That's most likely because
+		 * the address in the iovec was bogus. Set the rc to -EFAULT,
+		 * free anything we allocated and bail out.
+		 */
+		if (!cur_len) {
+			for (i = 0; i < nr_pages; i++)
+				put_page(wdata->pages[i]);
+			kfree(wdata);
+			rc = -EFAULT;
+			break;
+		}
+
+		/*
+		 * i + 1 now represents the number of pages we actually used in
+		 * the copy phase above. Bring nr_pages down to that, and free
+		 * any pages that we didn't use.
+		 */
+		for ( ; nr_pages > i + 1; nr_pages--)
+			put_page(wdata->pages[nr_pages - 1]);
+
 		wdata->sync_mode = WB_SYNC_ALL;
 		wdata->nr_pages = nr_pages;
 		wdata->offset = (__u64)offset;