From cb6db4e57632ba8589cc2f9fe1d0aa9116b87ab8 Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Mon, 15 Aug 2011 17:27:21 +0000 Subject: [PATCH] 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 Signed-off-by: Chris Mason --- fs/btrfs/inode.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 15fceef..0ccc743 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -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)) - return -EROFS; - if ((BTRFS_I(inode)->flags & BTRFS_INODE_READONLY) && (mask & MAY_WRITE)) - return -EACCES; + 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) + return -EACCES; + } return generic_permission(inode, mask); } -- 2.7.4