File descriptors (even those for writing) do not hold freeze protection.
Thus mark_files_ro() must call __mnt_drop_write() to only drop protection
against remount read-only. Calling mnt_drop_write_file() as we do now
results in:
[ BUG: bad unlock balance detected! ]
3.7.0-rc6-00028-g88e75b6 #101 Not tainted
-------------------------------------
kworker/1:2/79 is trying to release lock (sb_writers) at:
[<ffffffff811b33b4>] mnt_drop_write+0x24/0x30
but there are no more locks to release!
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The code that relied on that flag was ripped out of btrfs quite some
time ago, and never added back. Josef indicated that he was going to
take a different approach to the problem in btrfs, and that we
could just eliminate this flag.
Cc: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When path_init is called with a valid dfd, that code checks permissions
on the open directory fd and returns an error if the check fails. This
permission check is redundant, however.
Both callers of path_init immediately call link_path_walk afterward. The
first thing that link_path_walk does for pathnames that do not consist
only of slashes is to check for exec permissions at the starting point of
the path walk. And this check in path_init() is on the path taken only
when *name != '/' && *name != '\0'.
In most cases, these checks are very quick, but when the dfd is for a
file on a NFS mount with the actimeo=0, each permission check goes
out onto the wire. The result is 2 identical ACCESS calls.
Given that these codepaths are fairly "hot", I think it makes sense to
eliminate the permission check in path_init and simply assume that the
caller will eventually check the permissions before proceeding.
Reported-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The compiler may optimize the while loop and make the check just be done once,
so we should use ACCESS_ONCE() to guard access to ->mnt_flags
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull sparc fixes from David Miller:
"Please pull to get these sparc AES/DES/CAMELLIA crypto bug fixes as
well as an addition of a pte_accessible() define for sparc64 and a
hugetlb fix from Dave Kleikamp."
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
sparc64: Set CRYPTO_TFM_REQ_MAY_SLEEP consistently in CAMELLIA code.
sparc64: Set CRYPTO_TFM_REQ_MAY_SLEEP consistently in DES code.
sparc64: Fix ECB looping constructs in AES code.
sparc64: Set CRYPTO_TFM_REQ_MAY_SLEEP consistently in AES code.
sparc64: Fix AES ctr mode block size.
sparc64: Fix unrolled AES 256-bit key loops.
sparc64: Define pte_accessible()
sparc: huge_ptep_set_* functions need to call set_huge_pte_at()
Marco Stornelli
Jan Kara
Jeff Layton
Al Viro
Miao Xie
Linus Torvalds