kernel.git/fs/aio.c, branch linux-2.6.37.y

aio: wake all waiters when destroying ctx

2011-03-27T19:00:09Z

commit e91f90bb0bb10be9cc8efd09a3cf4ecffcad0db1 upstream. The test program below will hang because io_getevents() uses add_wait_queue_exclusive(), which means the wake_up() in io_destroy() only wakes up one of the threads. Fix this by using wake_up_all() in the aio code paths where we want to make sure no one gets stuck. // t.c -- compile with gcc -lpthread -laio t.c #include #include #include #include static const int nthr = 2; void *getev(void *ctx) { struct io_event ev; io_getevents(ctx, 1, 1, &ev, NULL); printf("io_getevents returned\n"); return NULL; } int main(int argc, char *argv[]) { io_context_t ctx = 0; pthread_t thread[nthr]; int i; io_setup(1024, &ctx); for (i = 0; i < nthr; ++i) pthread_create(&thread[i], NULL, getev, ctx); sleep(1); io_destroy(ctx); for (i = 0; i < nthr; ++i) pthread_join(thread[i], NULL); return 0; } Signed-off-by: Roland Dreier Reviewed-by: Jeff Moyer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

new helper: ihold()

2010-10-26T01:26:11Z

Clones an existing reference to inode; caller must already hold one. Signed-off-by: Al Viro

aio: bump i_count instead of using igrab

2010-10-26T01:18:23Z

The aio batching code is using igrab to get an extra reference on the inode so it can safely batch. igrab will go ahead and take the global inode spinlock, which can be a bottleneck on large machines doing lots of AIO. In this case, igrab isn't required because we already have a reference on the file handle. It is safe to just bump the i_count directly on the inode. Benchmarking shows this patch brings IOP/s on tons of flash up by about 2.5X. Signed-off-by: Chris Mason

aio: do not return ERESTARTSYS as a result of AIO

2010-09-23T00:22:39Z

OCFS2 can return ERESTARTSYS from its write function when the process is signalled while waiting for a cluster lock (and the filesystem is mounted with intr mount option). Generally, it seems reasonable to allow filesystems to return this error code from its IO functions. As we must not leak ERESTARTSYS (and similar error codes) to userspace as a result of an AIO operation, we have to properly convert it to EINTR inside AIO code (restarting the syscall isn't really an option because other AIO could have been already submitted by the same io_submit syscall). Signed-off-by: Jan Kara Reviewed-by: Jeff Moyer Cc: Christoph Hellwig Cc: Zach Brown Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

aio: check for multiplication overflow in do_io_submit

2010-09-15T00:02:37Z

Tavis Ormandy pointed out that do_io_submit does not do proper bounds checking on the passed-in iocb array: if (unlikely(nr < 0)) return -EINVAL; if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(iocbpp))))) return -EFAULT; ^^^^^^^^^^^^^^^^^^ The attached patch checks for overflow, and if it is detected, the number of iocbs submitted is scaled down to a number that will fit in the long. This is an ok thing to do, as sys_io_submit is documented as returning the number of iocbs submitted, so callers should handle a return value of less than the 'nr' argument passed in. Reported-by: Tavis Ormandy Signed-off-by: Jeff Moyer Signed-off-by: Linus Torvalds

aio: fix wrong subsystem comments

2010-08-05T20:21:23Z

- sys_io_destroy(): acutually return -EINVAL if the context pointed to is invalidIndex: linux-2.6.33-rc4/fs/aio.c - sys_io_getevents(): An argument specifying timeout is not `when', but `timeout'. - sys_io_getevents(): Should describe what is returned if this syscall succeeds. Signed-off-by: Satoru Takeuchi Signed-off-by: Randy Dunlap Reviewed-by: Jeff Moyer Signed-off-by: Linus Torvalds

get rid of the magic around f_count in aio

2010-05-28T02:03:07Z

__aio_put_req() plays sick games with file refcount. What it wants is fput() from atomic context; it's almost always done with f_count > 1, so they only have to deal with delayed work in rare cases when their reference happens to be the last one. Current code decrements f_count and if it hasn't hit 0, everything is fine. Otherwise it keeps a pointer to struct file (with zero f_count!) around and has delayed work do __fput() on it. Better way to do it: use atomic_long_add_unless( , -1, 1) instead of !atomic_long_dec_and_test(). IOW, decrement it only if it's not the last reference, leave refcount alone if it was. And use normal fput() in delayed work. I've made that atomic_long_add_unless call a new helper - fput_atomic(). Drops a reference to file if it's safe to do in atomic (i.e. if that's not the last one), tells if it had been able to do that. aio.c converted to it, __fput() use is gone. req->ki_file *always* contributes to refcount now. And __fput() became static. Signed-off-by: Al Viro

aio: fix the compat vectored operations

2010-05-27T16:12:53Z

The aio compat code was not converting the struct iovecs from 32bit to 64bit pointers, causing either EINVAL to be returned from io_getevents, or EFAULT as the result of the I/O. This patch passes a compat flag to io_submit to signal that pointer conversion is necessary for a given iocb array. A variant of this was tested by Michael Tokarev. I have also updated the libaio test harness to exercise this code path with good success. Further, I grabbed a copy of ltp and ran the testcases/kernel/syscall/readv and writev tests there (compiled with -m32 on my 64bit system). All seems happy, but extra eyes on this would be welcome. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix CONFIG_COMPAT=n build] Signed-off-by: Jeff Moyer Reported-by: Michael Tokarev Cc: Zach Brown Cc: [2.6.35.1] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

aio: remove unused field

2009-12-16T15:20:13Z

Don't know the reason, but it appears ki_wait field of iocb never gets used. Signed-off-by: Shaohua Li Cc: Jeff Moyer Cc: Benjamin LaHaise Cc: Zach Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

block: move bdi/address_space unplug functions to backing-dev.h

2009-10-29T12:59:26Z

There's nothing block related about them, the backing device is used by things like NFS etc as well. This gets rid of the need to protect such calls by CONFIG_BLOCK. Signed-off-by: Jens Axboe