static ssize_t max_ratio_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct backing_dev_info *bdi = dev_get_drvdata(dev);
unsigned int ratio;
ssize_t ret;
ret = kstrtouint(buf, 10, &ratio);
if (ret < 0)
return ret;
ret = bdi_set_max_ratio(bdi, ratio);
if (!ret)
ret = count;
return ret;
}
static void fsg_lun_close(struct fsg_lun *curlun)
{
struct inode *inode = NULL;
struct backing_dev_info *bdi;
if (curlun->filp) {
inode = file_inode(curlun->filp);
if (inode->i_bdev) {
bdi = &inode->i_bdev->bd_queue->backing_dev_info;
if ((bdi->capabilities & BDI_CAP_STRICTLIMIT) &&
bdi_set_max_ratio(bdi, curlun->max_ratio))
pr_debug("%s, error in setting max_ratio\n",
__func__);
}
LDBG(curlun, "close backing file\n");
fput(curlun->filp);
curlun->filp = NULL;
}
}
static struct fuse_conn *new_conn(struct super_block *sb)
{
struct fuse_conn *fc;
int err;
fc = kzalloc(sizeof(*fc), GFP_KERNEL);
if (fc) {
spin_lock_init(&fc->lock);
mutex_init(&fc->inst_mutex);
atomic_set(&fc->count, 1);
init_waitqueue_head(&fc->waitq);
init_waitqueue_head(&fc->blocked_waitq);
init_waitqueue_head(&fc->reserved_req_waitq);
INIT_LIST_HEAD(&fc->pending);
INIT_LIST_HEAD(&fc->processing);
INIT_LIST_HEAD(&fc->io);
INIT_LIST_HEAD(&fc->interrupts);
INIT_LIST_HEAD(&fc->bg_queue);
atomic_set(&fc->num_waiting, 0);
fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
fc->bdi.unplug_io_fn = default_unplug_io_fn;
/* fuse does it's own writeback accounting */
fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
fc->dev = sb->s_dev;
err = bdi_init(&fc->bdi);
if (err)
goto error_kfree;
if (sb->s_bdev) {
err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
MAJOR(fc->dev), MINOR(fc->dev));
} else {
err = bdi_register_dev(&fc->bdi, fc->dev);
}
if (err)
goto error_bdi_destroy;
/*
* For a single fuse filesystem use max 1% of dirty +
* writeback threshold.
*
* This gives about 1M of write buffer for memory maps on a
* machine with 1G and 10% dirty_ratio, which should be more
* than enough.
*
* Privileged users can raise it by writing to
*
* /sys/class/bdi/<bdi>/max_ratio
*/
bdi_set_max_ratio(&fc->bdi, 1);
fc->reqctr = 0;
fc->blocked = 1;
fc->attr_version = 1;
get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
}
return fc;
error_bdi_destroy:
bdi_destroy(&fc->bdi);
error_kfree:
mutex_destroy(&fc->inst_mutex);
kfree(fc);
return NULL;
}
static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
{
int ro;
struct file *filp = NULL;
int rc = -EINVAL;
struct inode *inode = NULL;
struct backing_dev_info *bdi;
loff_t size;
loff_t num_sectors;
loff_t min_sectors;
unsigned int blkbits;
unsigned int blksize;
/* R/W if we can, R/O if we must */
ro = curlun->initially_ro;
if (!ro) {
filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
ro = 1;
}
if (ro)
filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
if (IS_ERR(filp)) {
LINFO(curlun, "unable to open backing file: %s\n", filename);
return PTR_ERR(filp);
}
if (!(filp->f_mode & FMODE_WRITE))
ro = 1;
inode = file_inode(filp);
if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
LINFO(curlun, "invalid file type: %s\n", filename);
goto out;
}
/*
* If we can't read the file, it's no good.
* If we can't write the file, use it read-only.
*/
if (!(filp->f_op->read || filp->f_op->aio_read)) {
LINFO(curlun, "file not readable: %s\n", filename);
goto out;
}
if (!(filp->f_op->write || filp->f_op->aio_write))
ro = 1;
size = i_size_read(inode->i_mapping->host);
if (size < 0) {
LINFO(curlun, "unable to find file size: %s\n", filename);
rc = (int) size;
goto out;
}
if (curlun->cdrom) {
blksize = 2048;
blkbits = 11;
} else if (inode->i_bdev) {
blksize = bdev_logical_block_size(inode->i_bdev);
blkbits = blksize_bits(blksize);
bdi = &inode->i_bdev->bd_queue->backing_dev_info;
if (bdi->capabilities & BDI_CAP_STRICTLIMIT) {
curlun->max_ratio = bdi->max_ratio;
curlun->nofua = 1;
if (bdi_set_max_ratio(bdi, uicc_ums_max_ratio))
pr_debug("%s, error in setting max_ratio\n",
__func__);
}
} else {
blksize = 512;
blkbits = 9;
}
num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
min_sectors = 1;
if (curlun->cdrom) {
min_sectors = 300; /* Smallest track is 300 frames */
if (num_sectors >= 256*60*75) {
num_sectors = 256*60*75 - 1;
LINFO(curlun, "file too big: %s\n", filename);
LINFO(curlun, "using only first %d blocks\n",
(int) num_sectors);
}
}
if (num_sectors < min_sectors) {
LINFO(curlun, "file too small: %s\n", filename);
rc = -ETOOSMALL;
goto out;
}
if (fsg_lun_is_open(curlun))
fsg_lun_close(curlun);
curlun->blksize = blksize;
curlun->blkbits = blkbits;
curlun->ro = ro;
curlun->filp = filp;
curlun->file_length = size;
curlun->num_sectors = num_sectors;
LDBG(curlun, "open backing file: %s\n", filename);
return 0;
out:
fput(filp);
return rc;
}