From b4b7ff4b08e691656c9d77c758fc355833128ac0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 20 Jan 2016 14:01:31 -0300
Subject: Linux-libre 4.4-gnu

---
 fs/cachefiles/internal.h |  2 +-
 fs/cachefiles/namei.c    |  2 ++
 fs/cachefiles/rdwr.c     | 75 ++++++++++++++++++++++++------------------------
 3 files changed, 41 insertions(+), 38 deletions(-)

(limited to 'fs/cachefiles')

diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index aecd0859e..9c4b737a5 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -30,7 +30,7 @@ extern unsigned cachefiles_debug;
 #define CACHEFILES_DEBUG_KLEAVE	2
 #define CACHEFILES_DEBUG_KDEBUG	4
 
-#define cachefiles_gfp (__GFP_WAIT | __GFP_NORETRY | __GFP_NOMEMALLOC)
+#define cachefiles_gfp (__GFP_RECLAIM | __GFP_NORETRY | __GFP_NOMEMALLOC)
 
 /*
  * node records
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index fc1056f5c..c4b893453 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -655,6 +655,8 @@ lookup_again:
 			aops = d_backing_inode(object->dentry)->i_mapping->a_ops;
 			if (!aops->bmap)
 				goto check_error;
+			if (object->dentry->d_sb->s_blocksize > PAGE_SIZE)
+				goto check_error;
 
 			object->backer = object->dentry;
 		} else {
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 3cbb0e834..c0f3da392 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -414,9 +414,6 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
 	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
-	if (inode->i_sb->s_blocksize > PAGE_SIZE)
-		goto enobufs;
-
 	shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
 
 	op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
@@ -711,9 +708,6 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
 	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
-	if (inode->i_sb->s_blocksize > PAGE_SIZE)
-		goto all_enobufs;
-
 	shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
 
 	pagevec_init(&pagevec, 0);
@@ -885,7 +879,7 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
 	loff_t pos, eof;
 	size_t len;
 	void *data;
-	int ret;
+	int ret = -ENOBUFS;
 
 	ASSERT(op != NULL);
 	ASSERT(page != NULL);
@@ -905,6 +899,15 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
 	cache = container_of(object->fscache.cache,
 			     struct cachefiles_cache, cache);
 
+	pos = (loff_t)page->index << PAGE_SHIFT;
+
+	/* We mustn't write more data than we have, so we have to beware of a
+	 * partial page at EOF.
+	 */
+	eof = object->fscache.store_limit_l;
+	if (pos >= eof)
+		goto error;
+
 	/* write the page to the backing filesystem and let it store it in its
 	 * own time */
 	path.mnt = cache->mnt;
@@ -912,40 +915,38 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
 	file = dentry_open(&path, O_RDWR | O_LARGEFILE, cache->cache_cred);
 	if (IS_ERR(file)) {
 		ret = PTR_ERR(file);
-	} else {
-		pos = (loff_t) page->index << PAGE_SHIFT;
-
-		/* we mustn't write more data than we have, so we have
-		 * to beware of a partial page at EOF */
-		eof = object->fscache.store_limit_l;
-		len = PAGE_SIZE;
-		if (eof & ~PAGE_MASK) {
-			ASSERTCMP(pos, <, eof);
-			if (eof - pos < PAGE_SIZE) {
-				_debug("cut short %llx to %llx",
-				       pos, eof);
-				len = eof - pos;
-				ASSERTCMP(pos + len, ==, eof);
-			}
-		}
-
-		data = kmap(page);
-		ret = __kernel_write(file, data, len, &pos);
-		kunmap(page);
-		if (ret != len)
-			ret = -EIO;
-		fput(file);
+		goto error_2;
 	}
 
-	if (ret < 0) {
-		if (ret == -EIO)
-			cachefiles_io_error_obj(
-				object, "Write page to backing file failed");
-		ret = -ENOBUFS;
+	len = PAGE_SIZE;
+	if (eof & ~PAGE_MASK) {
+		if (eof - pos < PAGE_SIZE) {
+			_debug("cut short %llx to %llx",
+			       pos, eof);
+			len = eof - pos;
+			ASSERTCMP(pos + len, ==, eof);
+		}
 	}
 
-	_leave(" = %d", ret);
-	return ret;
+	data = kmap(page);
+	ret = __kernel_write(file, data, len, &pos);
+	kunmap(page);
+	fput(file);
+	if (ret != len)
+		goto error_eio;
+
+	_leave(" = 0");
+	return 0;
+
+error_eio:
+	ret = -EIO;
+error_2:
+	if (ret == -EIO)
+		cachefiles_io_error_obj(object,
+					"Write page to backing file failed");
+error:
+	_leave(" = -ENOBUFS [%d]", ret);
+	return -ENOBUFS;
 }
 
 /*
-- 
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