kernel.git/fs/exofs/super.c, branch linux-3.11.y

fs: Limit sys_mount to only request filesystem modules.

2013-03-04T03:36:31Z

Modify the request_module to prefix the file system type with "fs-" and add aliases to all of the filesystems that can be built as modules to match. A common practice is to build all of the kernel code and leave code that is not commonly needed as modules, with the result that many users are exposed to any bug anywhere in the kernel. Looking for filesystems with a fs- prefix limits the pool of possible modules that can be loaded by mount to just filesystems trivially making things safer with no real cost. Using aliases means user space can control the policy of which filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf with blacklist and alias directives. Allowing simple, safe, well understood work-arounds to known problematic software. This also addresses a rare but unfortunate problem where the filesystem name is not the same as it's module name and module auto-loading would not work. While writing this patch I saw a handful of such cases. The most significant being autofs that lives in the module autofs4. This is relevant to user namespaces because we can reach the request module in get_fs_type() without having any special permissions, and people get uncomfortable when a user specified string (in this case the filesystem type) goes all of the way to request_module. After having looked at this issue I don't think there is any particular reason to perform any filtering or permission checks beyond making it clear in the module request that we want a filesystem module. The common pattern in the kernel is to call request_module() without regards to the users permissions. In general all a filesystem module does once loaded is call register_filesystem() and go to sleep. Which means there is not much attack surface exposed by loading a filesytem module unless the filesystem is mounted. In a user namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT, which most filesystems do not set today. Acked-by: Serge Hallyn Acked-by: Kees Cook Reported-by: Kees Cook Signed-off-by: "Eric W. Biederman"

exofs: drop lock/unlock super

2012-10-10T03:33:38Z

Removed lock/unlock super. Acked-by: Artem Bityutskiy Acked-by: Boaz Harrosh Signed-off-by: Marco Stornelli Signed-off-by: Al Viro

fs: push rcu_barrier() from deactivate_locked_super() to filesystems

2012-10-03T01:35:55Z

There's no reason to call rcu_barrier() on every deactivate_locked_super(). We only need to make sure that all delayed rcu free inodes are flushed before we destroy related cache. Removing rcu_barrier() from deactivate_locked_super() affects some fast paths. E.g. on my machine exit_group() of a last process in IPC namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time. Signed-off-by: Kirill A. Shutemov Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Al Viro

exofs: stop using s_dirt

2012-08-02T11:52:13Z

Exofs has the '->write_super()' handler and makes some use of the '->s_dirt' superblock flag, but it really needs neither of them because it never sets 's_dirt' to one which means the VFS never calls its '->write_super()' handler. Thus, remove both. Note, I am trying to remove both 's_dirt' and 'write_super()' from VFS altogether once all users are gone. Signed-off-by: Artem Bityutskiy Signed-off-by: Boaz Harrosh

exofs: Add SYSFS info for autologin/pNFS export

2012-05-21T09:24:01Z

Introduce sysfs infrastructure for exofs cluster filesystem. Each OSD target shows up as below in the sysfs hierarchy: /sys/fs/exofs/_/devX Where _ is the unique identification of a Superblock. Where devX: 0 <= X < device_table_size. They are ordered in device-table order as specified to the mkfs.exofs command Each OSD device devX has following attributes : osdname - ReadOnly systemid - ReadOnly uri - Read/Write It is up to user-mode to update devX/uri for support of autologin. These sysfs information are used both for autologin as well as support for exporting exofs via a pNFSD server in user-mode. (.eg NFS-Ganesha) Signed-off-by: Sachin Bhamare Signed-off-by: Boaz Harrosh

exofs: Fix CRASH on very early IO errors.

2012-05-20T16:42:41Z

If at exofs_fill_super() we had an early termination do to any error, like an IO error while reading the super-block. We would crash inside exofs_free_sbi(). This is because sbi->oc.numdevs was set to 1, before we actually have a device table at all. Fix it by moving the sbi->oc.numdevs = 1 to after the allocation of the device table. Reported-by: Johannes Schild Stable: This is a bug since v3.2.0 CC: Stable Tree Signed-off-by: Boaz Harrosh

Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd

2012-03-29T03:04:27Z

Pull trivial exofs changes from Boaz Harrosh: "Just nothingness really. The big exofs changes are reserved for the next merge window." * 'for-linus' of git://git.open-osd.org/linux-open-osd: exofs: Cap on the memcpy() size exofs: (trivial) Fix typo in super.c exofs: fix endian conversion in exofs_sync_fs()

switch open-coded instances of d_make_root() to new helper

2012-03-21T01:29:35Z

Signed-off-by: Al Viro

vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link}

2012-03-21T01:29:32Z

New field of struct super_block - ->s_max_links. Maximal allowed value of ->i_nlink or 0; in the latter case all checks still need to be done in ->link/->mkdir/->rename instances. Note that this limit applies both to directoris and to non-directories. Signed-off-by: Al Viro

exofs: Cap on the memcpy() size

2012-03-19T20:39:12Z

This data comes from the device, so probably it's fairly trustworthy but it makes the static checkers happy if we check it. [Boaz] the system_id_len is zero, if not present, or always OSD_SYSTEMID_LEN. So always copy OSD_SYSTEMID_LEN bytes. Signed-off-by: Dan Carpenter Signed-off-by: Boaz Harrosh