From: Amir Goldstein Date: Tue, 31 Jan 2017 08:34:55 +0000 (+0200) Subject: vfs: deny fallocate() on directory X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=9e79b1326302589a035fe20e8cce7c1a7d8333ed;p=openwrt%2Fstaging%2Fblogic.git vfs: deny fallocate() on directory There was an obscure use case of fallocate of directory inode in the vfs helper with the comment: "Let individual file system decide if it supports preallocation for directories or not." But there is no in-tree file system that implements fallocate for directory operations. Deny an attempt to fallocate a directory with EISDIR error. This change is needed prior to converting sb_start_write() to file_start_write(), so freeze protection is correctly handled for cases of fallocate file and blockdev. Cc: linux-api@vger.kernel.org Cc: Al Viro Signed-off-by: Amir Goldstein Reviewed-by: Christoph Hellwig Signed-off-by: Miklos Szeredi --- diff --git a/fs/open.c b/fs/open.c index 9921f70bc5ca..f9118f4113e7 100644 --- a/fs/open.c +++ b/fs/open.c @@ -301,12 +301,10 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (S_ISFIFO(inode->i_mode)) return -ESPIPE; - /* - * Let individual file system decide if it supports preallocation - * for directories or not. - */ - if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode) && - !S_ISBLK(inode->i_mode)) + if (S_ISDIR(inode->i_mode)) + return -EISDIR; + + if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) return -ENODEV; /* Check for wrap through zero too */