On Mon, Mar 31, 2014 at 03:15:44PM -0700, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > This is a note to let you know that I've just added the patch titled > > ext4: atomically set inode->i_flags in ext4_set_inode_flags() > > to the 3.10-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > ext4-atomically-set-inode-i_flags-in-ext4_set_inode_flags.patch > and it can be found in the queue-3.10 subdirectory. I was going to make a one or two minor changes based on akpm's changes, and this change hasn't been merged upstream yet. The plan was for this to go upstream in a few more days, after we finish off some last minute testing, and and fixing a bug in an existing patch in the ext4 tree that was discovered last week, so if you want to wait a week, this patch should be upstream by then (and hopefully sooner). OTOH, this is a security fix, and the bug has been reported and outstanding for a while, so if you want to push this sooner, that's fine. It should also be noted that a similar bug exists for btrfs and several other file systems (although btrfs is probably the most important mainstream fs that should get fixed sooner rather than later). Cheers, - Ted > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. > > > From 00a1a053ebe5febcfc2ec498bd894f035ad2aa06 Mon Sep 17 00:00:00 2001 > From: Theodore Ts'o <tytso@xxxxxxx> > Date: Sun, 30 Mar 2014 10:20:01 -0400 > Subject: ext4: atomically set inode->i_flags in ext4_set_inode_flags() > > From: Theodore Ts'o <tytso@xxxxxxx> > > commit 00a1a053ebe5febcfc2ec498bd894f035ad2aa06 upstream. > > Use cmpxchg() to atomically set i_flags instead of clearing out the > S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the > EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race > where an immutable file has the immutable flag cleared for a brief > window of time. > > Reported-by: John Sullivan <jsrhbz@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > --- > fs/ext4/inode.c | 15 +++++++++------ > include/linux/bitops.h | 15 +++++++++++++++ > 2 files changed, 24 insertions(+), 6 deletions(-) > > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -38,6 +38,7 @@ > #include <linux/slab.h> > #include <linux/ratelimit.h> > #include <linux/aio.h> > +#include <linux/bitops.h> > > #include "ext4_jbd2.h" > #include "xattr.h" > @@ -4044,18 +4045,20 @@ int ext4_get_inode_loc(struct inode *ino > void ext4_set_inode_flags(struct inode *inode) > { > unsigned int flags = EXT4_I(inode)->i_flags; > + unsigned int new_fl = 0; > > - inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); > if (flags & EXT4_SYNC_FL) > - inode->i_flags |= S_SYNC; > + new_fl |= S_SYNC; > if (flags & EXT4_APPEND_FL) > - inode->i_flags |= S_APPEND; > + new_fl |= S_APPEND; > if (flags & EXT4_IMMUTABLE_FL) > - inode->i_flags |= S_IMMUTABLE; > + new_fl |= S_IMMUTABLE; > if (flags & EXT4_NOATIME_FL) > - inode->i_flags |= S_NOATIME; > + new_fl |= S_NOATIME; > if (flags & EXT4_DIRSYNC_FL) > - inode->i_flags |= S_DIRSYNC; > + new_fl |= S_DIRSYNC; > + set_mask_bits(&inode->i_flags, > + S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC, new_fl); > } > > /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */ > --- a/include/linux/bitops.h > +++ b/include/linux/bitops.h > @@ -185,6 +185,21 @@ static inline unsigned long __ffs64(u64 > > #ifdef __KERNEL__ > > +#ifndef set_mask_bits > +#define set_mask_bits(ptr, _mask, _bits) \ > +({ \ > + const typeof(*ptr) mask = (_mask), bits = (_bits); \ > + typeof(*ptr) old, new; \ > + \ > + do { \ > + old = ACCESS_ONCE(*ptr); \ > + new = (old & ~mask) | bits; \ > + } while (cmpxchg(ptr, old, new) != old); \ > + \ > + new; \ > +}) > +#endif > + > #ifndef find_last_bit > /** > * find_last_bit - find the last set bit in a memory region > > > Patches currently in stable-queue which might be from tytso@xxxxxxx are > > queue-3.10/ext4-atomically-set-inode-i_flags-in-ext4_set_inode_flags.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html