Re: [PATCH] staging: lustre: llite: remove lloop device
From: Dilger, Andreas
Date: Thu Jun 09 2016 - 04:59:25 EST
On 2016/06/08, 16:50, "James Simmons" <jsimmons@xxxxxxxxxxxxx> wrote:
>The lloop device was original developed to work around
>the lack of direct I/O for the default loop back device.
>Also the lloop device greatly out performed the default
>loop back device. The lloop hasn't been worked on for
>some time and now it no longer out performs the loop
>device and loop now supports direct I/O. Since this is
>the case we can delete this device.
>
>Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
Reviewed-by: Andreas Dilger <andreas.dilger@xxxxxxxxx>
Cheers, Andreas
>---
> drivers/staging/lustre/lustre/Kconfig | 6 -
> drivers/staging/lustre/lustre/llite/Makefile | 3 -
> drivers/staging/lustre/lustre/llite/lloop.c | 883 --------------------------
> 3 files changed, 0 insertions(+), 892 deletions(-)
> delete mode 100644 drivers/staging/lustre/lustre/llite/lloop.c
>
>diff --git a/drivers/staging/lustre/lustre/Kconfig b/drivers/staging/lustre/lustre/Kconfig
>index 8ac7cd4..9f5d75f 100644
>--- a/drivers/staging/lustre/lustre/Kconfig
>+++ b/drivers/staging/lustre/lustre/Kconfig
>@@ -54,9 +54,3 @@ config LUSTRE_TRANSLATE_ERRNOS
> bool
> depends on LUSTRE_FS && !X86
> default y
>-
>-config LUSTRE_LLITE_LLOOP
>- tristate "Lustre virtual block device"
>- depends on LUSTRE_FS && BLOCK
>- depends on !PPC_64K_PAGES && !ARM64_64K_PAGES && !MICROBLAZE_64K_PAGES && !PAGE_SIZE_64KB && !IA64_PAGE_SIZE_64KB && !PARISC_PAGE_SIZE_64KB
>- default m
>diff --git a/drivers/staging/lustre/lustre/llite/Makefile b/drivers/staging/lustre/lustre/llite/Makefile
>index 2ce10ff..19701e7 100644
>--- a/drivers/staging/lustre/lustre/llite/Makefile
>+++ b/drivers/staging/lustre/lustre/llite/Makefile
>@@ -1,5 +1,4 @@
> obj-$(CONFIG_LUSTRE_FS) += lustre.o
>-obj-$(CONFIG_LUSTRE_LLITE_LLOOP) += llite_lloop.o
> lustre-y := dcache.o dir.o file.o llite_close.o llite_lib.o llite_nfs.o \
> rw.o namei.o symlink.o llite_mmap.o \
> xattr.o xattr_cache.o remote_perm.o llite_rmtacl.o \
>@@ -7,5 +6,3 @@ lustre-y := dcache.o dir.o file.o llite_close.o llite_lib.o llite_nfs.o \
> glimpse.o lcommon_cl.o lcommon_misc.o \
> vvp_dev.o vvp_page.o vvp_lock.o vvp_io.o vvp_object.o vvp_req.o \
> lproc_llite.o
>-
>-llite_lloop-y := lloop.o
>diff --git a/drivers/staging/lustre/lustre/llite/lloop.c b/drivers/staging/lustre/lustre/llite/lloop.c
>deleted file mode 100644
>index 813a9a3..0000000
>--- a/drivers/staging/lustre/lustre/llite/lloop.c
>+++ /dev/null
>@@ -1,883 +0,0 @@
>-/*
>- * GPL HEADER START
>- *
>- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
>- *
>- * This program is free software; you can redistribute it and/or modify
>- * it under the terms of the GNU General Public License version 2 only,
>- * as published by the Free Software Foundation.
>- *
>- * This program is distributed in the hope that it will be useful, but
>- * WITHOUT ANY WARRANTY; without even the implied warranty of
>- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>- * General Public License version 2 for more details (a copy is included
>- * in the LICENSE file that accompanied this code).
>- *
>- * You should have received a copy of the GNU General Public License
>- * version 2 along with this program; If not, see
>- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
>- *
>- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
>- * CA 95054 USA or visit www.sun.com if you need additional information or
>- * have any questions.
>- *
>- * GPL HEADER END
>- */
>-/*
>- * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
>- * Use is subject to license terms.
>- *
>- * Copyright (c) 2011, 2012, Intel Corporation.
>- */
>-/*
>- * This file is part of Lustre, http://www.lustre.org/
>- * Lustre is a trademark of Sun Microsystems, Inc.
>- */
>-
>-/*
>- * linux/drivers/block/loop.c
>- *
>- * Written by Theodore Ts'o, 3/29/93
>- *
>- * Copyright 1993 by Theodore Ts'o. Redistribution of this file is
>- * permitted under the GNU General Public License.
>- *
>- * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
>- * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
>- *
>- * Fixed do_loop_request() re-entrancy - Vincent.Renardias@xxxxxxx Mar 20, 1997
>- *
>- * Added devfs support - Richard Gooch <rgooch@xxxxxxxxxxxxx> 16-Jan-1998
>- *
>- * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
>- *
>- * Loadable modules and other fixes by AK, 1998
>- *
>- * Maximum number of loop devices now dynamic via max_loop module parameter.
>- * Russell Kroll <rkroll@xxxxxxxxxxxx> 19990701
>- *
>- * Maximum number of loop devices when compiled-in now selectable by passing
>- * max_loop=<1-255> to the kernel on boot.
>- * Erik I. Bols?, <eriki@xxxxxxxxxx>, Oct 31, 1999
>- *
>- * Completely rewrite request handling to be make_request_fn style and
>- * non blocking, pushing work to a helper thread. Lots of fixes from
>- * Al Viro too.
>- * Jens Axboe <axboe@xxxxxxx>, Nov 2000
>- *
>- * Support up to 256 loop devices
>- * Heinz Mauelshagen <mge@xxxxxxxxxxx>, Feb 2002
>- *
>- * Support for falling back on the write file operation when the address space
>- * operations prepare_write and/or commit_write are not available on the
>- * backing filesystem.
>- * Anton Altaparmakov, 16 Feb 2005
>- *
>- * Still To Fix:
>- * - Advisory locking is ignored here.
>- * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
>- *
>- */
>-
>-#include <linux/module.h>
>-
>-#include <linux/sched.h>
>-#include <linux/fs.h>
>-#include <linux/file.h>
>-#include <linux/stat.h>
>-#include <linux/errno.h>
>-#include <linux/major.h>
>-#include <linux/wait.h>
>-#include <linux/blkdev.h>
>-#include <linux/blkpg.h>
>-#include <linux/init.h>
>-#include <linux/swap.h>
>-#include <linux/slab.h>
>-#include <linux/suspend.h>
>-#include <linux/writeback.h>
>-#include <linux/buffer_head.h> /* for invalidate_bdev() */
>-#include <linux/completion.h>
>-#include <linux/highmem.h>
>-#include <linux/gfp.h>
>-#include <linux/pagevec.h>
>-#include <linux/uaccess.h>
>-
>-#include "../include/lustre_lib.h"
>-#include "../include/lustre_lite.h"
>-#include "llite_internal.h"
>-
>-#define LLOOP_MAX_SEGMENTS LNET_MAX_IOV
>-
>-/* Possible states of device */
>-enum {
>- LLOOP_UNBOUND,
>- LLOOP_BOUND,
>- LLOOP_RUNDOWN,
>-};
>-
>-struct lloop_device {
>- int lo_number;
>- int lo_refcnt;
>- loff_t lo_offset;
>- loff_t lo_sizelimit;
>- int lo_flags;
>- struct file *lo_backing_file;
>- struct block_device *lo_device;
>- unsigned lo_blocksize;
>-
>- gfp_t old_gfp_mask;
>-
>- spinlock_t lo_lock;
>- struct bio *lo_bio;
>- struct bio *lo_biotail;
>- int lo_state;
>- struct semaphore lo_sem;
>- struct mutex lo_ctl_mutex;
>- atomic_t lo_pending;
>- wait_queue_head_t lo_bh_wait;
>-
>- struct request_queue *lo_queue;
>-
>- const struct lu_env *lo_env;
>- struct cl_io lo_io;
>- struct ll_dio_pages lo_pvec;
>-
>- /* data to handle bio for lustre. */
>- struct lo_request_data {
>- struct page *lrd_pages[LLOOP_MAX_SEGMENTS];
>- loff_t lrd_offsets[LLOOP_MAX_SEGMENTS];
>- } lo_requests[1];
>-};
>-
>-/*
>- * Loop flags
>- */
>-enum {
>- LO_FLAGS_READ_ONLY = 1,
>-};
>-
>-static int lloop_major;
>-#define MAX_LOOP_DEFAULT 16
>-static int max_loop = MAX_LOOP_DEFAULT;
>-static struct lloop_device *loop_dev;
>-static struct gendisk **disks;
>-static struct mutex lloop_mutex;
>-static void *ll_iocontrol_magic;
>-
>-static loff_t get_loop_size(struct lloop_device *lo, struct file *file)
>-{
>- loff_t size, offset, loopsize;
>-
>- /* Compute loopsize in bytes */
>- size = i_size_read(file->f_mapping->host);
>- offset = lo->lo_offset;
>- loopsize = size - offset;
>- if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
>- loopsize = lo->lo_sizelimit;
>-
>- /*
>- * Unfortunately, if we want to do I/O on the device,
>- * the number of 512-byte sectors has to fit into a sector_t.
>- */
>- return loopsize >> 9;
>-}
>-
>-static int do_bio_lustrebacked(struct lloop_device *lo, struct bio *head)
>-{
>- const struct lu_env *env = lo->lo_env;
>- struct cl_io *io = &lo->lo_io;
>- struct inode *inode = file_inode(lo->lo_backing_file);
>- struct cl_object *obj = ll_i2info(inode)->lli_clob;
>- pgoff_t offset;
>- int ret;
>- int rw;
>- u32 page_count = 0;
>- struct bio_vec bvec;
>- struct bvec_iter iter;
>- struct bio *bio;
>- ssize_t bytes;
>-
>- struct ll_dio_pages *pvec = &lo->lo_pvec;
>- struct page **pages = pvec->ldp_pages;
>- loff_t *offsets = pvec->ldp_offsets;
>-
>- truncate_inode_pages(inode->i_mapping, 0);
>-
>- /* initialize the IO */
>- memset(io, 0, sizeof(*io));
>- io->ci_obj = obj;
>- ret = cl_io_init(env, io, CIT_MISC, obj);
>- if (ret)
>- return io->ci_result;
>- io->ci_lockreq = CILR_NEVER;
>-
>- rw = head->bi_rw;
>- for (bio = head; bio ; bio = bio->bi_next) {
>- LASSERT(rw == bio->bi_rw);
>-
>- offset = (pgoff_t)(bio->bi_iter.bi_sector << 9) + lo->lo_offset;
>- bio_for_each_segment(bvec, bio, iter) {
>- BUG_ON(bvec.bv_offset != 0);
>- BUG_ON(bvec.bv_len != PAGE_SIZE);
>-
>- pages[page_count] = bvec.bv_page;
>- offsets[page_count] = offset;
>- page_count++;
>- offset += bvec.bv_len;
>- }
>- LASSERT(page_count <= LLOOP_MAX_SEGMENTS);
>- }
>-
>- ll_stats_ops_tally(ll_i2sbi(inode),
>- (rw == WRITE) ? LPROC_LL_BRW_WRITE : LPROC_LL_BRW_READ,
>- page_count);
>-
>- pvec->ldp_size = page_count << PAGE_SHIFT;
>- pvec->ldp_nr = page_count;
>-
>- /* FIXME: in ll_direct_rw_pages, it has to allocate many cl_page{}s to
>- * write those pages into OST. Even worse case is that more pages
>- * would be asked to write out to swap space, and then finally get here
>- * again.
>- * Unfortunately this is NOT easy to fix.
>- * Thoughts on solution:
>- * 0. Define a reserved pool for cl_pages, which could be a list of
>- * pre-allocated cl_pages;
>- * 1. Define a new operation in cl_object_operations{}, says clo_depth,
>- * which measures how many layers for this lustre object. Generally
>- * speaking, the depth would be 2, one for llite, and one for lovsub.
>- * However, for SNS, there will be more since we need additional page
>- * to store parity;
>- * 2. Reserve the # of (page_count * depth) cl_pages from the reserved
>- * pool. Afterwards, the clio would allocate the pages from reserved
>- * pool, this guarantees we needn't allocate the cl_pages from
>- * generic cl_page slab cache.
>- * Of course, if there is NOT enough pages in the pool, we might
>- * be asked to write less pages once, this purely depends on
>- * implementation. Anyway, we should be careful to avoid deadlocking.
>- */
>- inode_lock(inode);
>- bytes = ll_direct_rw_pages(env, io, rw, inode, pvec);
>- inode_unlock(inode);
>- cl_io_fini(env, io);
>- return (bytes == pvec->ldp_size) ? 0 : (int)bytes;
>-}
>-
>-/*
>- * Add bio to back of pending list
>- */
>-static void loop_add_bio(struct lloop_device *lo, struct bio *bio)
>-{
>- unsigned long flags;
>-
>- spin_lock_irqsave(&lo->lo_lock, flags);
>- if (lo->lo_biotail) {
>- lo->lo_biotail->bi_next = bio;
>- lo->lo_biotail = bio;
>- } else {
>- lo->lo_bio = lo->lo_biotail = bio;
>- }
>- spin_unlock_irqrestore(&lo->lo_lock, flags);
>-
>- atomic_inc(&lo->lo_pending);
>- if (waitqueue_active(&lo->lo_bh_wait))
>- wake_up(&lo->lo_bh_wait);
>-}
>-
>-/*
>- * Grab first pending buffer
>- */
>-static unsigned int loop_get_bio(struct lloop_device *lo, struct bio **req)
>-{
>- struct bio *first;
>- struct bio **bio;
>- unsigned int count = 0;
>- unsigned int page_count = 0;
>- int rw;
>-
>- spin_lock_irq(&lo->lo_lock);
>- first = lo->lo_bio;
>- if (unlikely(!first)) {
>- spin_unlock_irq(&lo->lo_lock);
>- return 0;
>- }
>-
>- /* TODO: need to split the bio, too bad. */
>- LASSERT(first->bi_vcnt <= LLOOP_MAX_SEGMENTS);
>-
>- rw = first->bi_rw;
>- bio = &lo->lo_bio;
>- while (*bio && (*bio)->bi_rw == rw) {
>- CDEBUG(D_INFO, "bio sector %llu size %u count %u vcnt%u\n",
>- (unsigned long long)(*bio)->bi_iter.bi_sector,
>- (*bio)->bi_iter.bi_size,
>- page_count, (*bio)->bi_vcnt);
>- if (page_count + (*bio)->bi_vcnt > LLOOP_MAX_SEGMENTS)
>- break;
>-
>- page_count += (*bio)->bi_vcnt;
>- count++;
>- bio = &(*bio)->bi_next;
>- }
>- if (*bio) {
>- /* Some of bios can't be mergeable. */
>- lo->lo_bio = *bio;
>- *bio = NULL;
>- } else {
>- /* Hit the end of queue */
>- lo->lo_biotail = NULL;
>- lo->lo_bio = NULL;
>- }
>- *req = first;
>- spin_unlock_irq(&lo->lo_lock);
>- return count;
>-}
>-
>-static blk_qc_t loop_make_request(struct request_queue *q, struct bio *old_bio)
>-{
>- struct lloop_device *lo = q->queuedata;
>- int rw = bio_rw(old_bio);
>- int inactive;
>-
>- blk_queue_split(q, &old_bio, q->bio_split);
>-
>- if (!lo)
>- goto err;
>-
>- CDEBUG(D_INFO, "submit bio sector %llu size %u\n",
>- (unsigned long long)old_bio->bi_iter.bi_sector,
>- old_bio->bi_iter.bi_size);
>-
>- spin_lock_irq(&lo->lo_lock);
>- inactive = lo->lo_state != LLOOP_BOUND;
>- spin_unlock_irq(&lo->lo_lock);
>- if (inactive)
>- goto err;
>-
>- if (rw == WRITE) {
>- if (lo->lo_flags & LO_FLAGS_READ_ONLY)
>- goto err;
>- } else if (rw == READA) {
>- rw = READ;
>- } else if (rw != READ) {
>- CERROR("lloop: unknown command (%x)\n", rw);
>- goto err;
>- }
>- loop_add_bio(lo, old_bio);
>- return BLK_QC_T_NONE;
>-err:
>- bio_io_error(old_bio);
>- return BLK_QC_T_NONE;
>-}
>-
>-static inline void loop_handle_bio(struct lloop_device *lo, struct bio *bio)
>-{
>- int ret;
>-
>- ret = do_bio_lustrebacked(lo, bio);
>- while (bio) {
>- struct bio *tmp = bio->bi_next;
>-
>- bio->bi_next = NULL;
>- bio->bi_error = ret;
>- bio_endio(bio);
>- bio = tmp;
>- }
>-}
>-
>-static inline int loop_active(struct lloop_device *lo)
>-{
>- return atomic_read(&lo->lo_pending) ||
>- (lo->lo_state == LLOOP_RUNDOWN);
>-}
>-
>-/*
>- * worker thread that handles reads/writes to file backed loop devices,
>- * to avoid blocking in our make_request_fn.
>- */
>-static int loop_thread(void *data)
>-{
>- struct lloop_device *lo = data;
>- struct bio *bio;
>- unsigned int count;
>- unsigned long times = 0;
>- unsigned long total_count = 0;
>-
>- struct lu_env *env;
>- int refcheck;
>- int ret = 0;
>-
>- set_user_nice(current, MIN_NICE);
>-
>- lo->lo_state = LLOOP_BOUND;
>-
>- env = cl_env_get(&refcheck);
>- if (IS_ERR(env)) {
>- ret = PTR_ERR(env);
>- goto out;
>- }
>-
>- lo->lo_env = env;
>- memset(&lo->lo_pvec, 0, sizeof(lo->lo_pvec));
>- lo->lo_pvec.ldp_pages = lo->lo_requests[0].lrd_pages;
>- lo->lo_pvec.ldp_offsets = lo->lo_requests[0].lrd_offsets;
>-
>- /*
>- * up sem, we are running
>- */
>- up(&lo->lo_sem);
>-
>- for (;;) {
>- wait_event(lo->lo_bh_wait, loop_active(lo));
>- if (!atomic_read(&lo->lo_pending)) {
>- int exiting = 0;
>-
>- spin_lock_irq(&lo->lo_lock);
>- exiting = (lo->lo_state == LLOOP_RUNDOWN);
>- spin_unlock_irq(&lo->lo_lock);
>- if (exiting)
>- break;
>- }
>-
>- bio = NULL;
>- count = loop_get_bio(lo, &bio);
>- if (!count) {
>- CWARN("lloop(minor: %d): missing bio\n", lo->lo_number);
>- continue;
>- }
>-
>- total_count += count;
>- if (total_count < count) { /* overflow */
>- total_count = count;
>- times = 1;
>- } else {
>- times++;
>- }
>- if ((times & 127) == 0) {
>- CDEBUG(D_INFO, "total: %lu, count: %lu, avg: %lu\n",
>- total_count, times, total_count / times);
>- }
>-
>- LASSERT(bio);
>- LASSERT(count <= atomic_read(&lo->lo_pending));
>- loop_handle_bio(lo, bio);
>- atomic_sub(count, &lo->lo_pending);
>- }
>- cl_env_put(env, &refcheck);
>-
>-out:
>- up(&lo->lo_sem);
>- return ret;
>-}
>-
>-static int loop_set_fd(struct lloop_device *lo, struct file *unused,
>- struct block_device *bdev, struct file *file)
>-{
>- struct inode *inode;
>- struct address_space *mapping;
>- int lo_flags = 0;
>- int error;
>- loff_t size;
>-
>- if (!try_module_get(THIS_MODULE))
>- return -ENODEV;
>-
>- error = -EBUSY;
>- if (lo->lo_state != LLOOP_UNBOUND)
>- goto out;
>-
>- mapping = file->f_mapping;
>- inode = mapping->host;
>-
>- error = -EINVAL;
>- if (!S_ISREG(inode->i_mode) || inode->i_sb->s_magic != LL_SUPER_MAGIC)
>- goto out;
>-
>- if (!(file->f_mode & FMODE_WRITE))
>- lo_flags |= LO_FLAGS_READ_ONLY;
>-
>- size = get_loop_size(lo, file);
>-
>- if ((loff_t)(sector_t)size != size) {
>- error = -EFBIG;
>- goto out;
>- }
>-
>- /* remove all pages in cache so as dirty pages not to be existent. */
>- truncate_inode_pages(mapping, 0);
>-
>- set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
>-
>- lo->lo_blocksize = PAGE_SIZE;
>- lo->lo_device = bdev;
>- lo->lo_flags = lo_flags;
>- lo->lo_backing_file = file;
>- lo->lo_sizelimit = 0;
>- lo->old_gfp_mask = mapping_gfp_mask(mapping);
>- mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
>-
>- lo->lo_bio = lo->lo_biotail = NULL;
>-
>- /*
>- * set queue make_request_fn, and add limits based on lower level
>- * device
>- */
>- blk_queue_make_request(lo->lo_queue, loop_make_request);
>- lo->lo_queue->queuedata = lo;
>-
>- /* queue parameters */
>- CLASSERT(PAGE_SIZE < (1 << (sizeof(unsigned short) * 8)));
>- blk_queue_logical_block_size(lo->lo_queue,
>- (unsigned short)PAGE_SIZE);
>- blk_queue_max_hw_sectors(lo->lo_queue,
>- LLOOP_MAX_SEGMENTS << (PAGE_SHIFT - 9));
>- blk_queue_max_segments(lo->lo_queue, LLOOP_MAX_SEGMENTS);
>-
>- set_capacity(disks[lo->lo_number], size);
>- bd_set_size(bdev, size << 9);
>-
>- set_blocksize(bdev, lo->lo_blocksize);
>-
>- kthread_run(loop_thread, lo, "lloop%d", lo->lo_number);
>- down(&lo->lo_sem);
>- return 0;
>-
>-out:
>- /* This is safe: open() is still holding a reference. */
>- module_put(THIS_MODULE);
>- return error;
>-}
>-
>-static int loop_clr_fd(struct lloop_device *lo, struct block_device *bdev,
>- int count)
>-{
>- struct file *filp = lo->lo_backing_file;
>- gfp_t gfp = lo->old_gfp_mask;
>-
>- if (lo->lo_state != LLOOP_BOUND)
>- return -ENXIO;
>-
>- if (lo->lo_refcnt > count) /* we needed one fd for the ioctl */
>- return -EBUSY;
>-
>- if (!filp)
>- return -EINVAL;
>-
>- spin_lock_irq(&lo->lo_lock);
>- lo->lo_state = LLOOP_RUNDOWN;
>- spin_unlock_irq(&lo->lo_lock);
>- wake_up(&lo->lo_bh_wait);
>-
>- down(&lo->lo_sem);
>- lo->lo_backing_file = NULL;
>- lo->lo_device = NULL;
>- lo->lo_offset = 0;
>- lo->lo_sizelimit = 0;
>- lo->lo_flags = 0;
>- invalidate_bdev(bdev);
>- set_capacity(disks[lo->lo_number], 0);
>- bd_set_size(bdev, 0);
>- mapping_set_gfp_mask(filp->f_mapping, gfp);
>- lo->lo_state = LLOOP_UNBOUND;
>- fput(filp);
>- /* This is safe: open() is still holding a reference. */
>- module_put(THIS_MODULE);
>- return 0;
>-}
>-
>-static int lo_open(struct block_device *bdev, fmode_t mode)
>-{
>- struct lloop_device *lo = bdev->bd_disk->private_data;
>-
>- mutex_lock(&lo->lo_ctl_mutex);
>- lo->lo_refcnt++;
>- mutex_unlock(&lo->lo_ctl_mutex);
>-
>- return 0;
>-}
>-
>-static void lo_release(struct gendisk *disk, fmode_t mode)
>-{
>- struct lloop_device *lo = disk->private_data;
>-
>- mutex_lock(&lo->lo_ctl_mutex);
>- --lo->lo_refcnt;
>- mutex_unlock(&lo->lo_ctl_mutex);
>-}
>-
>-/* lloop device node's ioctl function. */
>-static int lo_ioctl(struct block_device *bdev, fmode_t mode,
>- unsigned int cmd, unsigned long arg)
>-{
>- struct lloop_device *lo = bdev->bd_disk->private_data;
>- struct inode *inode = NULL;
>- int err = 0;
>-
>- mutex_lock(&lloop_mutex);
>- switch (cmd) {
>- case LL_IOC_LLOOP_DETACH: {
>- err = loop_clr_fd(lo, bdev, 2);
>- if (err == 0)
>- blkdev_put(bdev, 0); /* grabbed in LLOOP_ATTACH */
>- break;
>- }
>-
>- case LL_IOC_LLOOP_INFO: {
>- struct lu_fid fid;
>-
>- if (!lo->lo_backing_file) {
>- err = -ENOENT;
>- break;
>- }
>- if (!inode)
>- inode = file_inode(lo->lo_backing_file);
>- if (lo->lo_state == LLOOP_BOUND)
>- fid = ll_i2info(inode)->lli_fid;
>- else
>- fid_zero(&fid);
>-
>- if (copy_to_user((void __user *)arg, &fid, sizeof(fid)))
>- err = -EFAULT;
>- break;
>- }
>-
>- default:
>- err = -EINVAL;
>- break;
>- }
>- mutex_unlock(&lloop_mutex);
>-
>- return err;
>-}
>-
>-static struct block_device_operations lo_fops = {
>- .owner = THIS_MODULE,
>- .open = lo_open,
>- .release = lo_release,
>- .ioctl = lo_ioctl,
>-};
>-
>-/* dynamic iocontrol callback.
>- * This callback is registered in lloop_init and will be called by
>- * ll_iocontrol_call.
>- *
>- * This is a llite regular file ioctl function. It takes the responsibility
>- * of attaching or detaching a file by a lloop's device number.
>- */
>-static enum llioc_iter lloop_ioctl(struct inode *unused, struct file *file,
>- unsigned int cmd, unsigned long arg,
>- void *magic, int *rcp)
>-{
>- struct lloop_device *lo = NULL;
>- struct block_device *bdev = NULL;
>- int err = 0;
>- dev_t dev;
>-
>- if (magic != ll_iocontrol_magic)
>- return LLIOC_CONT;
>-
>- if (!disks) {
>- err = -ENODEV;
>- goto out1;
>- }
>-
>- CWARN("Enter llop_ioctl\n");
>-
>- mutex_lock(&lloop_mutex);
>- switch (cmd) {
>- case LL_IOC_LLOOP_ATTACH: {
>- struct lloop_device *lo_free = NULL;
>- int i;
>-
>- for (i = 0; i < max_loop; i++, lo = NULL) {
>- lo = &loop_dev[i];
>- if (lo->lo_state == LLOOP_UNBOUND) {
>- if (!lo_free)
>- lo_free = lo;
>- continue;
>- }
>- if (file_inode(lo->lo_backing_file) == file_inode(file))
>- break;
>- }
>- if (lo || !lo_free) {
>- err = -EBUSY;
>- goto out;
>- }
>-
>- lo = lo_free;
>- dev = MKDEV(lloop_major, lo->lo_number);
>-
>- /* quit if the used pointer is writable */
>- if (put_user((long)old_encode_dev(dev), (long __user *)arg)) {
>- err = -EFAULT;
>- goto out;
>- }
>-
>- bdev = blkdev_get_by_dev(dev, file->f_mode, NULL);
>- if (IS_ERR(bdev)) {
>- err = PTR_ERR(bdev);
>- goto out;
>- }
>-
>- get_file(file);
>- err = loop_set_fd(lo, NULL, bdev, file);
>- if (err) {
>- fput(file);
>- blkdev_put(bdev, 0);
>- }
>-
>- break;
>- }
>-
>- case LL_IOC_LLOOP_DETACH_BYDEV: {
>- int minor;
>-
>- dev = old_decode_dev(arg);
>- if (MAJOR(dev) != lloop_major) {
>- err = -EINVAL;
>- goto out;
>- }
>-
>- minor = MINOR(dev);
>- if (minor > max_loop - 1) {
>- err = -EINVAL;
>- goto out;
>- }
>-
>- lo = &loop_dev[minor];
>- if (lo->lo_state != LLOOP_BOUND) {
>- err = -EINVAL;
>- goto out;
>- }
>-
>- bdev = lo->lo_device;
>- err = loop_clr_fd(lo, bdev, 1);
>- if (err == 0)
>- blkdev_put(bdev, 0); /* grabbed in LLOOP_ATTACH */
>-
>- break;
>- }
>-
>- default:
>- err = -EINVAL;
>- break;
>- }
>-
>-out:
>- mutex_unlock(&lloop_mutex);
>-out1:
>- if (rcp)
>- *rcp = err;
>- return LLIOC_STOP;
>-}
>-
>-static int __init lloop_init(void)
>-{
>- int i;
>- unsigned int cmdlist[] = {
>- LL_IOC_LLOOP_ATTACH,
>- LL_IOC_LLOOP_DETACH_BYDEV,
>- };
>-
>- if (max_loop < 1 || max_loop > 256) {
>- max_loop = MAX_LOOP_DEFAULT;
>- CWARN("lloop: invalid max_loop (must be between 1 and 256), using default (%u)\n",
>- max_loop);
>- }
>-
>- lloop_major = register_blkdev(0, "lloop");
>- if (lloop_major < 0)
>- return -EIO;
>-
>- CDEBUG(D_CONFIG, "registered lloop major %d with %u minors\n",
>- lloop_major, max_loop);
>-
>- ll_iocontrol_magic = ll_iocontrol_register(lloop_ioctl, 2, cmdlist);
>- if (!ll_iocontrol_magic)
>- goto out_mem1;
>-
>- loop_dev = kcalloc(max_loop, sizeof(*loop_dev), GFP_KERNEL);
>- if (!loop_dev)
>- goto out_mem1;
>-
>- disks = kcalloc(max_loop, sizeof(*disks), GFP_KERNEL);
>- if (!disks)
>- goto out_mem2;
>-
>- for (i = 0; i < max_loop; i++) {
>- disks[i] = alloc_disk(1);
>- if (!disks[i])
>- goto out_mem3;
>- }
>-
>- mutex_init(&lloop_mutex);
>-
>- for (i = 0; i < max_loop; i++) {
>- struct lloop_device *lo = &loop_dev[i];
>- struct gendisk *disk = disks[i];
>-
>- lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
>- if (!lo->lo_queue)
>- goto out_mem4;
>-
>- mutex_init(&lo->lo_ctl_mutex);
>- sema_init(&lo->lo_sem, 0);
>- init_waitqueue_head(&lo->lo_bh_wait);
>- lo->lo_number = i;
>- spin_lock_init(&lo->lo_lock);
>- disk->major = lloop_major;
>- disk->first_minor = i;
>- disk->fops = &lo_fops;
>- sprintf(disk->disk_name, "lloop%d", i);
>- disk->private_data = lo;
>- disk->queue = lo->lo_queue;
>- }
>-
>- /* We cannot fail after we call this, so another loop!*/
>- for (i = 0; i < max_loop; i++)
>- add_disk(disks[i]);
>- return 0;
>-
>-out_mem4:
>- while (i--)
>- blk_cleanup_queue(loop_dev[i].lo_queue);
>- i = max_loop;
>-out_mem3:
>- while (i--)
>- put_disk(disks[i]);
>- kfree(disks);
>-out_mem2:
>- kfree(loop_dev);
>-out_mem1:
>- unregister_blkdev(lloop_major, "lloop");
>- ll_iocontrol_unregister(ll_iocontrol_magic);
>- CERROR("lloop: ran out of memory\n");
>- return -ENOMEM;
>-}
>-
>-static void lloop_exit(void)
>-{
>- int i;
>-
>- ll_iocontrol_unregister(ll_iocontrol_magic);
>- for (i = 0; i < max_loop; i++) {
>- del_gendisk(disks[i]);
>- blk_cleanup_queue(loop_dev[i].lo_queue);
>- put_disk(disks[i]);
>- }
>-
>- unregister_blkdev(lloop_major, "lloop");
>-
>- kfree(disks);
>- kfree(loop_dev);
>-}
>-
>-module_param(max_loop, int, 0444);
>-MODULE_PARM_DESC(max_loop, "maximum of lloop_device");
>-MODULE_AUTHOR("OpenSFS, Inc. <http://www.lustre.org/>");
>-MODULE_DESCRIPTION("Lustre virtual block device");
>-MODULE_VERSION(LUSTRE_VERSION_STRING);
>-MODULE_LICENSE("GPL");
>-
>-module_init(lloop_init);
>-module_exit(lloop_exit);
>--
>1.7.1
>
>