Commit cb6db4e5 authored Aug 15, 2011 by Jeff Mahoney Committed by Chris Mason Aug 18, 2011

btrfs: btrfs_permission's RO check shouldn't apply to device nodes

This patch tightens the read-only access checks in btrfs_permission to
match the constraints in inode_permission. Currently, even though the
device node itself will be unmodified, read-write access to device nodes
is denied to when the device node resides on a read-only subvolume or a
is a file that has been marked read-only by the btrfs conversion utility.

With this patch applied, the check only affects regular files,
directories, and symlinks. It also restructures the code a bit so that
we don't duplicate the MAY_WRITE check for both tests.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

parent 93ee7a93

fs/btrfs/inode.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -7354,11 +7354,15 @@ static int btrfs_set_page_dirty(struct page *page)
		static int btrfs_permission(struct inode *inode, int mask)
		{
		struct btrfs_root *root = BTRFS_I(inode)->root;
		umode_t mode = inode->i_mode;

		if (btrfs_root_readonly(root) && (mask & MAY_WRITE))
		if (mask & MAY_WRITE &&
		(S_ISREG(mode) \|\| S_ISDIR(mode) \|\| S_ISLNK(mode))) {
		if (btrfs_root_readonly(root))
		return -EROFS;
		if ((BTRFS_I(inode)->flags & BTRFS_INODE_READONLY) && (mask & MAY_WRITE))
		if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
		return -EACCES;
		}
		return generic_permission(inode, mask);
		}

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