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Commit 9e79b132 authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
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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 <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent af7bd4dc

fs/open.c

+4 −6
Original line number Diff line number Diff line
@@ -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 */