From 30460e1ea3e62f8457e087db9a309ed1031630da Mon Sep 17 00:00:00 2001 From: Carlos Maiolino Date: Thu, 9 Jan 2020 14:30:41 +0100 Subject: fs: Enable bmap() function to properly return errors By now, bmap() will either return the physical block number related to the requested file offset or 0 in case of error or the requested offset maps into a hole. This patch makes the needed changes to enable bmap() to proper return errors, using the return value as an error return, and now, a pointer must be passed to bmap() to be filled with the mapped physical block. It will change the behavior of bmap() on return: - negative value in case of error - zero on success or map fell into a hole In case of a hole, the *block will be zero too Since this is a prep patch, by now, the only error return is -EINVAL if ->bmap doesn't exist. Reviewed-by: Christoph Hellwig Signed-off-by: Carlos Maiolino Signed-off-by: Al Viro --- fs/inode.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) (limited to 'fs/inode.c') diff --git a/fs/inode.c b/fs/inode.c index 96d62d97694e..5dacfa1fb129 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1598,25 +1598,31 @@ 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 -- cgit v1.2.3