Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull misc vfs updates from Al Viro:

 - bmap series from cmaiolino

 - getting rid of convolutions in copy_mount_options() (use a couple of
   copy_from_user() instead of the __get_user() crap)

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  saner copy_mount_options()
  fibmap: Reject negative block numbers
  fibmap: Use bmap instead of ->bmap method in ioctl_fibmap
  ecryptfs: drop direct calls to ->bmap
  cachefiles: drop direct usage of ->bmap method.
  fs: Enable bmap() function to properly return errors

10 files changed, 119 insertions, 111 deletions

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index e230052c2107..b952bd45bd6a 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -364,7 +364,7 @@ static int read_page(struct file *file, unsigned long index,
 	int ret = 0;
 	struct inode *inode = file_inode(file);
 	struct buffer_head *bh;
-	sector_t block;
+	sector_t block, blk_cur;
 
 	pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 		 (unsigned long long)index << PAGE_SHIFT);
@@ -375,17 +375,21 @@ static int read_page(struct file *file, unsigned long index,
 		goto out;
 	}
 	attach_page_buffers(page, bh);
-	block = index << (PAGE_SHIFT - inode->i_blkbits);
+	blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
 	while (bh) {
+		block = blk_cur;
+
 		if (count == 0)
 			bh->b_blocknr = 0;
 		else {
-			bh->b_blocknr = bmap(inode, block);
-			if (bh->b_blocknr == 0) {
-				/* Cannot use this file! */
+			ret = bmap(inode, &block);
+			if (ret || !block) {
 				ret = -EINVAL;
+				bh->b_blocknr = 0;
 				goto out;
 			}
+
+			bh->b_blocknr = block;
 			bh->b_bdev = inode->i_sb->s_bdev;
 			if (count < (1<<inode->i_blkbits))
 				count = 0;
@@ -399,7 +403,7 @@ static int read_page(struct file *file, unsigned long index,
 			set_buffer_mapped(bh);
 			submit_bh(REQ_OP_READ, 0, bh);
 		}
-		block++;
+		blk_cur++;
 		bh = bh->b_this_page;
 	}
 	page->index = index;
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 44a3ce1e4ce4..1dc97f2d6201 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -396,7 +396,7 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
 	struct cachefiles_object *object;
 	struct cachefiles_cache *cache;
 	struct inode *inode;
-	sector_t block0, block;
+	sector_t block;
 	unsigned shift;
 	int ret;
 
@@ -412,7 +412,6 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
 
 	inode = d_backing_inode(object->backer);
 	ASSERT(S_ISREG(inode->i_mode));
-	ASSERT(inode->i_mapping->a_ops->bmap);
 	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
@@ -428,12 +427,14 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
 	 *   enough for this as it doesn't indicate errors, but it's all we've
 	 *   got for the moment
 	 */
-	block0 = page->index;
-	block0 <<= shift;
+	block = page->index;
+	block <<= shift;
+
+	ret = bmap(inode, &block);
+	ASSERT(ret < 0);
 
-	block = inode->i_mapping->a_ops->bmap(inode->i_mapping, block0);
 	_debug("%llx -> %llx",
-	       (unsigned long long) block0,
+	       (unsigned long long) (page->index << shift),
 	       (unsigned long long) block);
 
 	if (block) {
@@ -711,7 +712,6 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
 
 	inode = d_backing_inode(object->backer);
 	ASSERT(S_ISREG(inode->i_mode));
-	ASSERT(inode->i_mapping->a_ops->bmap);
 	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
@@ -728,7 +728,7 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
 
 	ret = space ? -ENODATA : -ENOBUFS;
 	list_for_each_entry_safe(page, _n, pages, lru) {
-		sector_t block0, block;
+		sector_t block;
 
 		/* we assume the absence or presence of the first block is a
 		 * good enough indication for the page as a whole
@@ -736,13 +736,14 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
 		 *   good enough for this as it doesn't indicate errors, but
 		 *   it's all we've got for the moment
 		 */
-		block0 = page->index;
-		block0 <<= shift;
+		block = page->index;
+		block <<= shift;
+
+		ret = bmap(inode, &block);
+		ASSERT(!ret);
 
-		block = inode->i_mapping->a_ops->bmap(inode->i_mapping,
-						      block0);
 		_debug("%llx -> %llx",
-		       (unsigned long long) block0,
+		       (unsigned long long) (page->index << shift),
 		       (unsigned long long) block);
 
 		if (block) {
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index cffa0c1ec829..019572c6b39a 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -524,16 +524,12 @@ out:
 
 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
 {
-	int rc = 0;
-	struct inode *inode;
-	struct inode *lower_inode;
-
-	inode = (struct inode *)mapping->host;
-	lower_inode = ecryptfs_inode_to_lower(inode);
-	if (lower_inode->i_mapping->a_ops->bmap)
-		rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
-							 block);
-	return rc;
+	struct inode *lower_inode = ecryptfs_inode_to_lower(mapping->host);
+	int ret = bmap(lower_inode, &block);
+
+	if (ret)
+		return 0;
+	return block;
 }
 
 const struct address_space_operations ecryptfs_aops = {
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 8bd9afa81c54..b27b72107911 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3666,12 +3666,16 @@ static int check_swap_activate(struct swap_info_struct *sis,
 			page_no < sis->max) {
 		unsigned block_in_page;
 		sector_t first_block;
+		sector_t block = 0;
+		int	 err = 0;
 
 		cond_resched();
 
-		first_block = bmap(inode, probe_block);
-		if (first_block == 0)
+		block = probe_block;
+		err = bmap(inode, &block);
+		if (err || !block)
 			goto bad_bmap;
+		first_block = block;
 
 		/*
 		 * It must be PAGE_SIZE aligned on-disk
@@ -3683,11 +3687,13 @@ static int check_swap_activate(struct swap_info_struct *sis,
 
 		for (block_in_page = 1; block_in_page < blocks_per_page;
 					block_in_page++) {
-			sector_t block;
 
-			block = bmap(inode, probe_block + block_in_page);
-			if (block == 0)
+			block = probe_block + block_in_page;
+			err = bmap(inode, &block);
+
+			if (err || !block)
 				goto bad_bmap;
+
 			if (block != first_block + block_in_page) {
 				/* Discontiguity */
 				probe_block++;
diff --git a/fs/inode.c b/fs/inode.c
index c7418b0b4168..7d57068b6b7a 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1599,25 +1599,31 @@ retry:
 }
 EXPORT_SYMBOL(iput);
 
+#ifdef CONFIG_BLOCK
 /**
  *	bmap	- find a block number in a file
- *	@inode: inode of file
- *	@block: block to find
- *
- *	Returns the block number on the device holding the inode that
- *	is the disk block number for the block of the file requested.
- *	That is, asked for block 4 of inode 1 the function will return the
- *	disk block relative to the disk start that holds that block of the
- *	file.
+ *	@inode:  inode owning the block number being requested
+ *	@block: pointer containing the block to find
+ *
+ *	Replaces the value in *block with the block number on the device holding
+ *	corresponding to the requested block number in the file.
+ *	That is, asked for block 4 of inode 1 the function will replace the
+ *	4 in *block, with disk block relative to the disk start that holds that
+ *	block of the file.
+ *
+ *	Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a
+ *	hole, returns 0 and *block is also set to 0.
  */
-sector_t bmap(struct inode *inode, sector_t block)
+int bmap(struct inode *inode, sector_t *block)
 {
-	sector_t res = 0;
-	if (inode->i_mapping->a_ops->bmap)
-		res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
-	return res;
+	if (!inode->i_mapping->a_ops->bmap)
+		return -EINVAL;
+
+	*block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block);
+	return 0;
 }
 EXPORT_SYMBOL(bmap);
+#endif
 
 /*
  * With relative atime, only update atime if the previous atime is
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 7c9a5df5a597..72d6848fb6ad 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -54,19 +54,32 @@ EXPORT_SYMBOL(vfs_ioctl);
 
 static int ioctl_fibmap(struct file *filp, int __user *p)
 {
-	struct address_space *mapping = filp->f_mapping;
-	int res, block;
+	struct inode *inode = file_inode(filp);
+	int error, ur_block;
+	sector_t block;
 
-	/* do we support this mess? */
-	if (!mapping->a_ops->bmap)
-		return -EINVAL;
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
-	res = get_user(block, p);
-	if (res)
-		return res;
-	res = mapping->a_ops->bmap(mapping, block);
-	return put_user(res, p);
+
+	error = get_user(ur_block, p);
+	if (error)
+		return error;
+
+	if (ur_block < 0)
+		return -EINVAL;
+
+	block = ur_block;
+	error = bmap(inode, &block);
+
+	if (error)
+		ur_block = 0;
+	else
+		ur_block = block;
+
+	if (put_user(ur_block, p))
+		error = -EFAULT;
+
+	return error;
 }
 
 /**
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index eb8ca446d1ab..a49d0e670ddf 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -794,18 +794,22 @@ int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
 {
 	int err = 0;
 	unsigned long long ret;
+	sector_t block = 0;
 
 	if (journal->j_inode) {
-		ret = bmap(journal->j_inode, blocknr);
-		if (ret)
-			*retp = ret;
-		else {
+		block = blocknr;
+		ret = bmap(journal->j_inode, &block);
+
+		if (ret || !block) {
 			printk(KERN_ALERT "%s: journal block not found "
 					"at offset %lu on %s\n",
 			       __func__, blocknr, journal->j_devname);
 			err = -EIO;
 			jbd2_journal_abort(journal, err);
+		} else {
+			*retp = block;
 		}
+
 	} else {
 		*retp = blocknr; /* +journal->j_blk_offset */
 	}
@@ -1243,11 +1247,14 @@ journal_t *jbd2_journal_init_dev(struct block_device *bdev,
 journal_t *jbd2_journal_init_inode(struct inode *inode)
 {
 	journal_t *journal;
+	sector_t blocknr;
 	char *p;
-	unsigned long long blocknr;
+	int err = 0;
+
+	blocknr = 0;
+	err = bmap(inode, &blocknr);
 
-	blocknr = bmap(inode, 0);
-	if (!blocknr) {
+	if (err || !blocknr) {
 		pr_err("%s: Cannot locate journal superblock\n",
 			__func__);
 		return NULL;
diff --git a/fs/namespace.c b/fs/namespace.c
index 5e1bf611a9eb..85b5f7bea82e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2979,39 +2979,10 @@ static void shrink_submounts(struct mount *mnt)
 	}
 }
 
-/*
- * Some copy_from_user() implementations do not return the exact number of
- * bytes remaining to copy on a fault.  But copy_mount_options() requires that.
- * Note that this function differs from copy_from_user() in that it will oops
- * on bad values of `to', rather than returning a short copy.
- */
-static long exact_copy_from_user(void *to, const void __user * from,
-				 unsigned long n)
-{
-	char *t = to;
-	const char __user *f = from;
-	char c;
-
-	if (!access_ok(from, n))
-		return n;
-
-	while (n) {
-		if (__get_user(c, f)) {
-			memset(t, 0, n);
-			break;
-		}
-		*t++ = c;
-		f++;
-		n--;
-	}
-	return n;
-}
-
 void *copy_mount_options(const void __user * data)
 {
-	int i;
-	unsigned long size;
 	char *copy;
+	unsigned size;
 
 	if (!data)
 		return NULL;
@@ -3020,22 +2991,16 @@ void *copy_mount_options(const void __user * data)
 	if (!copy)
 		return ERR_PTR(-ENOMEM);
 
-	/* We only care that *some* data at the address the user
-	 * gave us is valid.  Just in case, we'll zero
-	 * the remainder of the page.
-	 */
-	/* copy_from_user cannot cross TASK_SIZE ! */
-	size = TASK_SIZE - (unsigned long)untagged_addr(data);
-	if (size > PAGE_SIZE)
-		size = PAGE_SIZE;
+	size = PAGE_SIZE - offset_in_page(data);
 
-	i = size - exact_copy_from_user(copy, data, size);
-	if (!i) {
+	if (copy_from_user(copy, data, size)) {
 		kfree(copy);
 		return ERR_PTR(-EFAULT);
 	}
-	if (i != PAGE_SIZE)
-		memset(copy + i, 0, PAGE_SIZE - i);
+	if (size != PAGE_SIZE) {
+		if (copy_from_user(copy + size, data + size, PAGE_SIZE - size))
+			memset(copy + size, 0, PAGE_SIZE - size);
+	}
 	return copy;
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6eae91c0668f..320d51b24325 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2876,9 +2876,16 @@ static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
 
 extern void emergency_sync(void);
 extern void emergency_remount(void);
+
 #ifdef CONFIG_BLOCK
-extern sector_t bmap(struct inode *, sector_t);
+extern int bmap(struct inode *inode, sector_t *block);
+#else
+static inline int bmap(struct inode *inode,  sector_t *block)
+{
+	return -EINVAL;
+}
 #endif
+
 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
 extern int inode_permission(struct inode *, int);
 extern int generic_permission(struct inode *, int);
diff --git a/mm/page_io.c b/mm/page_io.c
index 3a198deb8bb1..76965be1d40e 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -177,8 +177,9 @@ int generic_swapfile_activate(struct swap_info_struct *sis,
 
 		cond_resched();
 
-		first_block = bmap(inode, probe_block);
-		if (first_block == 0)
+		first_block = probe_block;
+		ret = bmap(inode, &first_block);
+		if (ret || !first_block)
 			goto bad_bmap;
 
 		/*
@@ -193,9 +194,11 @@ int generic_swapfile_activate(struct swap_info_struct *sis,
 					block_in_page++) {
 			sector_t block;
 
-			block = bmap(inode, probe_block + block_in_page);
-			if (block == 0)
+			block = probe_block + block_in_page;
+			ret = bmap(inode, &block);
+			if (ret || !block)
 				goto bad_bmap;
+
 			if (block != first_block + block_in_page) {
 				/* Discontiguity */
 				probe_block++;