All places outside of core VFS that checked ->read and ->write for being NULL or
called the methods directly are gone now, so NULL {read,write} with non-NULL
{read,write}_iter will do the right thing in all cases.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Now that we never use the backing_dev_info pointer in struct address_space
we can simply remove it and save 4 to 8 bytes in every inode.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since "BDI: Provide backing device capability information [try #3]" the
backing_dev_info structure also provides flags for the kind of mmap
operation available in a nommu environment, which is entirely unrelated
to it's original purpose.
Introduce a new nommu-only file operation to provide this information to
the nommu mmap code instead. Splitting this from the backing_dev_info
structure allows to remove lots of backing_dev_info instance that aren't
otherwise needed, and entirely gets rid of the concept of providing a
backing_dev_info for a character device. It also removes the need for
the mtd_inodefs filesystem.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
- Remove "Error" in format logging (already in pr_ level)
- Use modulename in pr_fmt instead of ROMFS: in each pr_ callsites.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Getting an inode by romfs_iget may lead to an err in fill_super, and the
err value should be return.
And it should return -ENOMEM instead while d_make_root fails, fix it too.
Signed-off-by: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Checks introduced in commit 4991e7251 ("romfs: do not use
mtd->get_unmapped_area directly") re-introduce problems fixed in the earlier
commit 2b4b2482e ("romfs: fix romfs_get_unmapped_area() argument check").
If a flat binary app is located at the end of a romfs, its page aligned
length may be outside of the romfs filesystem. The flat binary loader, via
nommu do_mmap_pgoff(), page aligns the length it is mmaping. So simple
offset+size checks will fail - returning EINVAL.
We can truncate the length to keep it inside the romfs filesystem, and that
also keeps the call to mtd_get_unmapped_area() happy.
Are there any side effects to truncating the size here though?
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
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 <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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 <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument. And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull MTD changes from David Woodhouse:
- Artem's cleanup of the MTD API continues apace.
- Fixes and improvements for ST FSMC and SuperH FLCTL NAND, amongst
others.
- More work on DiskOnChip G3, new driver for DiskOnChip G4.
- Clean up debug/warning printks in JFFS2 to use pr_<level>.
Fix up various trivial conflicts, largely due to changes in calling
conventions for things like dmaengine_prep_slave_sg() (new inline
wrapper to hide new parameter, clashing with rewrite of previously last
parameter that used to be an 'append' flag, and is now a bitmap of
'unsigned long flags').
(Also some header file fallout - like so many merges this merge window -
and silly conflicts with sparse fixes)
* tag 'for-linus-3.4' of git://git.infradead.org/mtd-2.6: (120 commits)
mtd: docg3 add protection against concurrency
mtd: docg3 refactor cascade floors structure
mtd: docg3 increase write/erase timeout
mtd: docg3 fix inbound calculations
mtd: nand: gpmi: fix function annotations
mtd: phram: fix section mismatch for phram_setup
mtd: unify initialization of erase_info->fail_addr
mtd: support ONFI multi lun NAND
mtd: sm_ftl: fix typo in major number.
mtd: add device-tree support to spear_smi
mtd: spear_smi: Remove default partition information from driver
mtd: Add device-tree support to fsmc_nand
mtd: fix section mismatch for doc_probe_device
mtd: nand/fsmc: Remove sparse warnings and errors
mtd: nand/fsmc: Add DMA support
mtd: nand/fsmc: Access the NAND device word by word whenever possible
mtd: nand/fsmc: Use dev_err to report error scenario
mtd: nand/fsmc: Use devm routines
mtd: nand/fsmc: Modify fsmc driver to accept nand timing parameters via platform
mtd: fsmc_nand: add pm callbacks to support hibernation
...
MTD pull for 3.3
* tag 'for-linus-3.3' of git://git.infradead.org/mtd-2.6: (113 commits)
mtd: Fix dependency for MTD_DOC200x
mtd: do not use mtd->block_markbad directly
logfs: do not use 'mtd->block_isbad' directly
mtd: introduce mtd_can_have_bb helper
mtd: do not use mtd->suspend and mtd->resume directly
mtd: do not use mtd->lock, unlock and is_locked directly
mtd: do not use mtd->sync directly
mtd: harmonize mtd_writev usage
mtd: do not use mtd->lock_user_prot_reg directly
mtd: mtd->write_user_prot_reg directly
mtd: do not use mtd->read_*_prot_reg directly
mtd: do not use mtd->get_*_prot_info directly
mtd: do not use mtd->read_oob directly
mtd: mtdoops: do not use mtd->panic_write directly
romfs: do not use mtd->get_unmapped_area directly
mtd: do not use mtd->get_unmapped_area directly
mtd: do use mtd->point directly
mtd: introduce mtd_has_oob helper
mtd: mtdcore: export symbols cleanup
mtd: clean-up the default_mtd_writev function
...
Fix up trivial edit/remove conflict in drivers/staging/spectra/lld_mtd.c
Remove direct usage of mtd->get_unmapped_area. Instead, just call
'mtd_get_unmapped_area()' which will return -EOPNOTSUPP if the function
is not implemented, and then test for this code.
We also translate -EOPNOTSUPP to -ENOSYS because this return code is
probably part of the kernel ABI which we do not want to break.
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
the cost of taking it into inode_init_always() will be negligible for pipes
and sockets and negative for everything else. Not to mention the removal of
boilerplate code from ->destroy_inode() instances...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Replace remaining direct i_nlink updates with a new set_nlink()
updater function.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
romfs_get_unmapped_area() checks argument `len' without considering
PAGE_ALIGN which will cause do_mmap_pgoff() return -EINVAL error after
commit f67d9b1576 ("nommu: add page_align to mmap").
Fix the check by changing it in same way ramfs_nommu_get_unmapped_area()
was changed in ramfs/file-nommu.c.
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.
The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.
In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.
The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
