From 6dfe5a049f2d48582050339d2a6b6fda36dfd14c Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 29 May 2015 07:40:08 +1000 Subject: xfs: xfs_attr_inactive leaves inconsistent attr fork state behind xfs_attr_inactive() is supposed to clean up the attribute fork when the inode is being freed. While it removes attribute fork extents, it completely ignores attributes in local format, which means that there can still be active attributes on the inode after xfs_attr_inactive() has run. This leads to problems with concurrent inode writeback - the in-core inode attribute fork is removed without locking on the assumption that nothing will be attempting to access the attribute fork after a call to xfs_attr_inactive() because it isn't supposed to exist on disk any more. To fix this, make xfs_attr_inactive() completely remove all traces of the attribute fork from the inode, regardless of it's state. Further, also remove the in-core attribute fork structure safely so that there is nothing further that needs to be done by callers to clean up the attribute fork. This means we can remove the in-core and on-disk attribute forks atomically. Also, on error simply remove the in-memory attribute fork. There's nothing that can be done with it once we have failed to remove the on-disk attribute fork, so we may as well just blow it away here anyway. cc: # 3.12 to 4.0 Reported-by: Waiman Long Signed-off-by: Dave Chinner Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- fs/xfs/xfs_inode.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'fs/xfs/xfs_inode.c') diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index d6ebc85192b7..1117dd3ba123 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1946,21 +1946,17 @@ xfs_inactive( /* * If there are attributes associated with the file then blow them away * now. The code calls a routine that recursively deconstructs the - * attribute fork. We need to just commit the current transaction - * because we can't use it for xfs_attr_inactive(). + * attribute fork. If also blows away the in-core attribute fork. */ - if (ip->i_d.di_anextents > 0) { - ASSERT(ip->i_d.di_forkoff != 0); - + if (XFS_IFORK_Q(ip)) { error = xfs_attr_inactive(ip); if (error) return; } - if (ip->i_afp) - xfs_idestroy_fork(ip, XFS_ATTR_FORK); - + ASSERT(!ip->i_afp); ASSERT(ip->i_d.di_anextents == 0); + ASSERT(ip->i_d.di_forkoff == 0); /* * Free the inode. -- cgit v1.2.3 From 22419ac9fe5e79483596cebdbd1d1209c18bac1a Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Fri, 29 May 2015 08:14:55 +1000 Subject: xfs: fix broken i_nlink accounting for whiteout tmpfile inode XFS uses the internal tmpfile() infrastructure for the whiteout inode used for RENAME_WHITEOUT operations. For tmpfile inodes, XFS allocates the inode, drops di_nlink, adds the inode to the agi unlinked list, calls d_tmpfile() which correspondingly drops i_nlink of the vfs inode, and then finishes the common inode setup (e.g., clear I_NEW and unlock). The d_tmpfile() call was originally made inxfs_create_tmpfile(), but was pulled up out of that function as part of the following commit to resolve a deadlock issue: 330033d6 xfs: fix tmpfile/selinux deadlock and initialize security As a result, callers of xfs_create_tmpfile() are responsible for either calling d_tmpfile() or fixing up i_nlink appropriately. The whiteout tmpfile allocation helper does neither. As a result, the vfs ->i_nlink becomes inconsistent with the on-disk ->di_nlink once xfs_rename() links it back into the source dentry and calls xfs_bumplink(). Update the assert in xfs_rename() to help detect this problem in the future and update xfs_rename_alloc_whiteout() to decrement the link count as part of the manual tmpfile inode setup. Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/xfs_inode.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'fs/xfs/xfs_inode.c') diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 1117dd3ba123..539a85fddbc2 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -2879,7 +2879,13 @@ xfs_rename_alloc_whiteout( if (error) return error; - /* Satisfy xfs_bumplink that this is a real tmpfile */ + /* + * Prepare the tmpfile inode as if it were created through the VFS. + * Otherwise, the link increment paths will complain about nlink 0->1. + * Drop the link count as done by d_tmpfile(), complete the inode setup + * and flag it as linkable. + */ + drop_nlink(VFS_I(tmpfile)); xfs_finish_inode_setup(tmpfile); VFS_I(tmpfile)->i_state |= I_LINKABLE; @@ -3147,7 +3153,7 @@ xfs_rename( * intermediate state on disk. */ if (wip) { - ASSERT(wip->i_d.di_nlink == 0); + ASSERT(VFS_I(wip)->i_nlink == 0 && wip->i_d.di_nlink == 0); error = xfs_bumplink(tp, wip); if (error) goto out_trans_abort; -- cgit v1.2.3