Had not been used for more than a decade and half; it used
to be a part of (in-kernel) ->select() API and it has been pining
for fjords since 2.1.23pre1. This is an ex-parrot...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There are some bits of linux/fs.h which are only used within the kernel and
shouldn't be in the UAPI. Move these from uapi/linux/fs.h into linux/fs.h.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It seems that was linux/blk_types.h incorrectly exported to fix up some missing
bits required by the exported parts of linux/fs.h (READ, WRITE, READA, etc.).
So unexport linux/blk_types.h and unexport the relevant bits of linux/fs.h.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jens Axboe <jaxboe@fusionio.com>
cc: Tejun Heo <tj@kernel.org>
cc: Al Viro <viro@ZenIV.linux.org.uk>
In the common case where a name is much smaller than PATH_MAX, an extra
allocation for struct filename is unnecessary. Before allocating a
separate one, try to embed the struct filename inside the buffer first. If
it turns out that that's not long enough, then fall back to allocating a
separate struct filename and redoing the copy.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Keep a pointer to the audit_names "slot" in struct filename.
Have all of the audit_inode callers pass a struct filename ponter to
audit_inode instead of a string pointer. If the aname field is already
populated, then we can skip walking the list altogether and just use it
directly.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
...and fix up the callers. For do_file_open_root, just declare a
struct filename on the stack and fill out the .name field. For
do_filp_open, make it also take a struct filename pointer, and fix up its
callers to call it appropriately.
For filp_open, add a variant that takes a struct filename pointer and turn
filp_open into a wrapper around it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.
For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.
This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.
Later, we'll add other information to the struct as it becomes
convenient.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
First, it's incorrect to call putname() after __getname_gfp() since the
bare __getname_gfp() call skips the auditing code, while putname()
doesn't.
mount_block_root allocates a PATH_MAX buffer via __getname_gfp, and then
calls get_fs_names to fill the buffer. That function can call
get_filesystem_list which assumes that that buffer is a full page in
size. On arches where PAGE_SIZE != 4k, then this could potentially
overrun.
In practice, it's hard to imagine the list of filesystem names even
approaching 4k, but it's best to be safe. Just allocate a page for this
purpose instead.
With this, we can also remove the __getname_gfp() definition since there
are no more callers.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull pile 2 of vfs updates from Al Viro:
"Stuff in this one - assorted fixes, lglock tidy-up, death to
lock_super().
There'll be a VFS pile tomorrow (with patches from Jeff Layton,
sanitizing getname() and related parts of audit and preparing for
ESTALE fixes), but I'd rather push the stuff in this one ASAP - some
of the bugs closed here are quite unpleasant."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: bogus warnings in fs/namei.c
consitify do_mount() arguments
lglock: add DEFINE_STATIC_LGLOCK()
lglock: make the per_cpu locks static
lglock: remove unused DEFINE_LGLOCK_LOCKDEP()
MAX_LFS_FILESIZE definition for 64bit needs LL...
tmpfs,ceph,gfs2,isofs,reiserfs,xfs: fix fh_len checking
vfs: drop lock/unlock super
ufs: drop lock/unlock super
sysv: drop lock/unlock super
hpfs: drop lock/unlock super
fat: drop lock/unlock super
ext3: drop lock/unlock super
exofs: drop lock/unlock super
dup3: Return an error when oldfd == newfd.
fs: handle failed audit_log_start properly
fs: prevent use after free in auditing when symlink following was denied
Pull block IO update from Jens Axboe:
"Core block IO bits for 3.7. Not a huge round this time, it contains:
- First series from Kent cleaning up and generalizing bio allocation
and freeing.
- WRITE_SAME support from Martin.
- Mikulas patches to prevent O_DIRECT crashes when someone changes
the block size of a device.
- Make bio_split() work on data-less bio's (like trim/discards).
- A few other minor fixups."
Fixed up silent semantic mis-merge as per Mikulas Patocka and Andrew
Morton. It is due to the VM no longer using a prio-tree (see commit
6b2dbba8b6: "mm: replace vma prio_tree with an interval tree").
So make set_blocksize() use mapping_mapped() instead of open-coding the
internal VM knowledge that has changed.
* 'for-3.7/core' of git://git.kernel.dk/linux-block: (26 commits)
block: makes bio_split support bio without data
scatterlist: refactor the sg_nents
scatterlist: add sg_nents
fs: fix include/percpu-rwsem.h export error
percpu-rw-semaphore: fix documentation typos
fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared
blockdev: turn a rw semaphore into a percpu rw semaphore
Fix a crash when block device is read and block size is changed at the same time
block: fix request_queue->flags initialization
block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()
block: ioctl to zero block ranges
block: Make blkdev_issue_zeroout use WRITE SAME
block: Implement support for WRITE SAME
block: Consolidate command flag and queue limit checks for merges
block: Clean up special command handling logic
block/blk-tag.c: Remove useless kfree
block: remove the duplicated setting for congestion_threshold
block: reject invalid queue attribute values
block: Add bio_clone_bioset(), bio_clone_kmalloc()
block: Consolidate bio_alloc_bioset(), bio_kmalloc()
...
Implement an interval tree as a replacement for the VMA prio_tree. The
algorithms are similar to lib/interval_tree.c; however that code can't be
directly reused as the interval endpoints are not explicitly stored in the
VMA. So instead, the common algorithm is moved into a template and the
details (node type, how to get interval endpoints from the node, etc) are
filled in using the C preprocessor.
Once the interval tree functions are available, using them as a
replacement to the VMA prio tree is a relatively simple, mechanical job.
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/nfs/internal.h: In function ‘nfs_super_set_maxbytes’:
fs/nfs/internal.h:547:21: warning: comparison between signed and
unsigned integer expressions [-Wsign-compare]
Seen with gcc (GCC) 4.6.3 20120306 (Red Hat 4.6.3-2).
Commit 42cb56ae made s_maxbytes a loff_t, thus the type of
MAX_LFS_FILESIZE should also be a loff_t.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We get the following export error on the include file:
usr/include/linux/fs.h:13: included file 'linux/percpu-rwsem.h' is not exported
Move the include inside the __KERNEL__ section.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This avoids cache line bouncing when many processes lock the semaphore
for read.
New percpu lock implementation
The lock consists of an array of percpu unsigned integers, a boolean
variable and a mutex.
When we take the lock for read, we enter rcu read section, check for a
"locked" variable. If it is false, we increase a percpu counter on the
current cpu and exit the rcu section. If "locked" is true, we exit the
rcu section, take the mutex and drop it (this waits until a writer
finished) and retry.
Unlocking for read just decreases percpu variable. Note that we can
unlock on a difference cpu than where we locked, in this case the
counter underflows. The sum of all percpu counters represents the number
of processes that hold the lock for read.
When we need to lock for write, we take the mutex, set "locked" variable
to true and synchronize rcu. Since RCU has been synchronized, no
processes can create new read locks. We wait until the sum of percpu
counters is zero - when it is, there are no readers in the critical
section.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The kernel may crash when block size is changed and I/O is issued
simultaneously.
Because some subsystems (udev or lvm) may read any block device anytime,
the bug actually puts any code that changes a block device size in
jeopardy.
The crash can be reproduced if you place "msleep(1000)" to
blkdev_get_blocks just before "bh->b_size = max_blocks <<
inode->i_blkbits;".
Then, run "dd if=/dev/ram0 of=/dev/null bs=4k count=1 iflag=direct"
While it is waiting in msleep, run "blockdev --setbsz 2048 /dev/ram0"
You get a BUG.
The direct and non-direct I/O is written with the assumption that block
size does not change. It doesn't seem practical to fix these crashes
one-by-one there may be many crash possibilities when block size changes
at a certain place and it is impossible to find them all and verify the
code.
This patch introduces a new rw-lock bd_block_size_semaphore. The lock is
taken for read during I/O. It is taken for write when changing block
size. Consequently, block size can't be changed while I/O is being
submitted.
For asynchronous I/O, the patch only prevents block size change while
the I/O is being submitted. The block size can change when the I/O is in
progress or when the I/O is being finished. This is acceptable because
there are no accesses to block size when asynchronous I/O is being
finished.
The patch prevents block size changing while the device is mapped with
mmap.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Introduce a BLKZEROOUT ioctl which can be used to clear block ranges by
way of blkdev_issue_zeroout().
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Finally we can kill the 'sync_supers' kernel thread along with the
'->write_super()' superblock operation because all the users are gone.
Now every file-system is supposed to self-manage own superblock and
its dirty state.
The nice thing about killing this thread is that it improves power management.
Indeed, 'sync_supers' is a source of monotonic system wake-ups - it woke up
every 5 seconds no matter what - even if there were no dirty superblocks and
even if there were no file-systems using this service (e.g., btrfs and
journalled ext4 do not need it). So it was wasting power most of the time. And
because the thread was in the core of the kernel, all systems had to have it.
So I am quite happy to make it go away.
Interestingly, this thread is a left-over from the pdflush kernel thread which
was a self-forking kernel thread responsible for all the write-back in old
Linux kernels. It was turned into per-block device BDI threads, and
'sync_supers' was a left-over. Thus, R.I.P, pdflush as well.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull second vfs pile from Al Viro:
"The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the
deadlock reproduced by xfstests 068), symlink and hardlink restriction
patches, plus assorted cleanups and fixes.
Note that another fsfreeze deadlock (emergency thaw one) is *not*
dealt with - the series by Fernando conflicts a lot with Jan's, breaks
userland ABI (FIFREEZE semantics gets changed) and trades the deadlock
for massive vfsmount leak; this is going to be handled next cycle.
There probably will be another pull request, but that stuff won't be
in it."
Fix up trivial conflicts due to unrelated changes next to each other in
drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c}
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
delousing target_core_file a bit
Documentation: Correct s_umount state for freeze_fs/unfreeze_fs
fs: Remove old freezing mechanism
ext2: Implement freezing
btrfs: Convert to new freezing mechanism
nilfs2: Convert to new freezing mechanism
ntfs: Convert to new freezing mechanism
fuse: Convert to new freezing mechanism
gfs2: Convert to new freezing mechanism
ocfs2: Convert to new freezing mechanism
xfs: Convert to new freezing code
ext4: Convert to new freezing mechanism
fs: Protect write paths by sb_start_write - sb_end_write
fs: Skip atime update on frozen filesystem
fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
fs: Improve filesystem freezing handling
switch the protection of percpu_counter list to spinlock
nfsd: Push mnt_want_write() outside of i_mutex
btrfs: Push mnt_want_write() outside of i_mutex
fat: Push mnt_want_write() outside of i_mutex
...
In commit 3b6e2723f3 ("locks: prevent side-effects of
locks_release_private before file_lock is initialized") we removed the
last user of lm_release_private without removing the field itself.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
