#include <linux/splice.h>
#include <linux/sysfs.h>
#include <linux/miscdevice.h>
+#include <linux/falloc.h>
+
#include <asm/uaccess.h>
static DEFINE_IDR(loop_index_idr);
return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
}
-/**
- * do_lo_send_aops - helper for writing data to a loop device
- *
- * This is the fast version for backing filesystems which implement the address
- * space operations write_begin and write_end.
- */
-static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
- loff_t pos, struct page *unused)
-{
- struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
- struct address_space *mapping = file->f_mapping;
- pgoff_t index;
- unsigned offset, bv_offs;
- int len, ret;
-
- mutex_lock(&mapping->host->i_mutex);
- index = pos >> PAGE_CACHE_SHIFT;
- offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1);
- bv_offs = bvec->bv_offset;
- len = bvec->bv_len;
- while (len > 0) {
- sector_t IV;
- unsigned size, copied;
- int transfer_result;
- struct page *page;
- void *fsdata;
-
- IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
- size = PAGE_CACHE_SIZE - offset;
- if (size > len)
- size = len;
-
- ret = pagecache_write_begin(file, mapping, pos, size, 0,
- &page, &fsdata);
- if (ret)
- goto fail;
-
- file_update_time(file);
-
- transfer_result = lo_do_transfer(lo, WRITE, page, offset,
- bvec->bv_page, bv_offs, size, IV);
- copied = size;
- if (unlikely(transfer_result))
- copied = 0;
-
- ret = pagecache_write_end(file, mapping, pos, size, copied,
- page, fsdata);
- if (ret < 0 || ret != copied)
- goto fail;
-
- if (unlikely(transfer_result))
- goto fail;
-
- bv_offs += copied;
- len -= copied;
- offset = 0;
- index++;
- pos += copied;
- }
- ret = 0;
-out:
- mutex_unlock(&mapping->host->i_mutex);
- return ret;
-fail:
- ret = -1;
- goto out;
-}
-
/**
* __do_lo_send_write - helper for writing data to a loop device
*
/**
* do_lo_send_direct_write - helper for writing data to a loop device
*
- * This is the fast, non-transforming version for backing filesystems which do
- * not implement the address space operations write_begin and write_end.
- * It uses the write file operation which should be present on all writeable
- * filesystems.
+ * This is the fast, non-transforming version that does not need double
+ * buffering.
*/
static int do_lo_send_direct_write(struct loop_device *lo,
struct bio_vec *bvec, loff_t pos, struct page *page)
/**
* do_lo_send_write - helper for writing data to a loop device
*
- * This is the slow, transforming version for filesystems which do not
- * implement the address space operations write_begin and write_end. It
- * uses the write file operation which should be present on all writeable
- * filesystems.
- *
- * Using fops->write is slower than using aops->{prepare,commit}_write in the
- * transforming case because we need to double buffer the data as we cannot do
- * the transformations in place as we do not have direct access to the
- * destination pages of the backing file.
+ * This is the slow, transforming version that needs to double buffer the
+ * data as it cannot do the transformations in place without having direct
+ * access to the destination pages of the backing file.
*/
static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
loff_t pos, struct page *page)
struct page *page = NULL;
int i, ret = 0;
- do_lo_send = do_lo_send_aops;
- if (!(lo->lo_flags & LO_FLAGS_USE_AOPS)) {
+ if (lo->transfer != transfer_none) {
+ page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
+ if (unlikely(!page))
+ goto fail;
+ kmap(page);
+ do_lo_send = do_lo_send_write;
+ } else {
do_lo_send = do_lo_send_direct_write;
- if (lo->transfer != transfer_none) {
- page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
- if (unlikely(!page))
- goto fail;
- kmap(page);
- do_lo_send = do_lo_send_write;
- }
}
+
bio_for_each_segment(bvec, bio, i) {
ret = do_lo_send(lo, bvec, pos, page);
if (ret < 0)
}
}
+ /*
+ * We use punch hole to reclaim the free space used by the
+ * image a.k.a. discard. However we do support discard if
+ * encryption is enabled, because it may give an attacker
+ * useful information.
+ */
+ if (bio->bi_rw & REQ_DISCARD) {
+ struct file *file = lo->lo_backing_file;
+ int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
+
+ if ((!file->f_op->fallocate) ||
+ lo->lo_encrypt_key_size) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+ ret = file->f_op->fallocate(file, mode, pos,
+ bio->bi_size);
+ if (unlikely(ret && ret != -EINVAL &&
+ ret != -EOPNOTSUPP))
+ ret = -EIO;
+ goto out;
+ }
+
ret = lo_send(lo, bio, pos);
if ((bio->bi_rw & REQ_FUA) && !ret) {
return bio_list_pop(&lo->lo_bio_list);
}
-static int loop_make_request(struct request_queue *q, struct bio *old_bio)
+static void loop_make_request(struct request_queue *q, struct bio *old_bio)
{
struct loop_device *lo = q->queuedata;
int rw = bio_rw(old_bio);
loop_add_bio(lo, old_bio);
wake_up(&lo->lo_event);
spin_unlock_irq(&lo->lo_lock);
- return 0;
+ return;
out:
spin_unlock_irq(&lo->lo_lock);
bio_io_error(old_bio);
- return 0;
}
struct switch_request {
goto out_putf;
fput(old_file);
- if (max_part > 0)
+ if (lo->lo_flags & LO_FLAGS_PARTSCAN)
ioctl_by_bdev(bdev, BLKRRPART, 0);
return 0;
return sprintf(buf, "%s\n", autoclear ? "1" : "0");
}
+static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf)
+{
+ int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN);
+
+ return sprintf(buf, "%s\n", partscan ? "1" : "0");
+}
+
LOOP_ATTR_RO(backing_file);
LOOP_ATTR_RO(offset);
LOOP_ATTR_RO(sizelimit);
LOOP_ATTR_RO(autoclear);
+LOOP_ATTR_RO(partscan);
static struct attribute *loop_attrs[] = {
&loop_attr_backing_file.attr,
&loop_attr_offset.attr,
&loop_attr_sizelimit.attr,
&loop_attr_autoclear.attr,
+ &loop_attr_partscan.attr,
NULL,
};
&loop_attribute_group);
}
+static void loop_config_discard(struct loop_device *lo)
+{
+ struct file *file = lo->lo_backing_file;
+ struct inode *inode = file->f_mapping->host;
+ struct request_queue *q = lo->lo_queue;
+
+ /*
+ * We use punch hole to reclaim the free space used by the
+ * image a.k.a. discard. However we do support discard if
+ * encryption is enabled, because it may give an attacker
+ * useful information.
+ */
+ if ((!file->f_op->fallocate) ||
+ lo->lo_encrypt_key_size) {
+ q->limits.discard_granularity = 0;
+ q->limits.discard_alignment = 0;
+ q->limits.max_discard_sectors = 0;
+ q->limits.discard_zeroes_data = 0;
+ queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
+ return;
+ }
+
+ q->limits.discard_granularity = inode->i_sb->s_blocksize;
+ q->limits.discard_alignment = inode->i_sb->s_blocksize;
+ q->limits.max_discard_sectors = UINT_MAX >> 9;
+ q->limits.discard_zeroes_data = 1;
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
+}
+
static int loop_set_fd(struct loop_device *lo, fmode_t mode,
struct block_device *bdev, unsigned int arg)
{
mapping = file->f_mapping;
inode = mapping->host;
- if (!(file->f_mode & FMODE_WRITE))
- lo_flags |= LO_FLAGS_READ_ONLY;
-
error = -EINVAL;
- if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) {
- const struct address_space_operations *aops = mapping->a_ops;
-
- if (aops->write_begin)
- lo_flags |= LO_FLAGS_USE_AOPS;
- if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write)
- lo_flags |= LO_FLAGS_READ_ONLY;
+ if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
+ goto out_putf;
- lo_blocksize = S_ISBLK(inode->i_mode) ?
- inode->i_bdev->bd_block_size : PAGE_SIZE;
+ if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) ||
+ !file->f_op->write)
+ lo_flags |= LO_FLAGS_READ_ONLY;
- error = 0;
- } else {
- goto out_putf;
- }
+ lo_blocksize = S_ISBLK(inode->i_mode) ?
+ inode->i_bdev->bd_block_size : PAGE_SIZE;
+ error = -EFBIG;
size = get_loop_size(lo, file);
-
- if ((loff_t)(sector_t)size != size) {
- error = -EFBIG;
+ if ((loff_t)(sector_t)size != size)
goto out_putf;
- }
- if (!(mode & FMODE_WRITE))
- lo_flags |= LO_FLAGS_READ_ONLY;
+ error = 0;
set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
}
lo->lo_state = Lo_bound;
wake_up_process(lo->lo_thread);
- if (max_part > 0)
+ if (part_shift)
+ lo->lo_flags |= LO_FLAGS_PARTSCAN;
+ if (lo->lo_flags & LO_FLAGS_PARTSCAN)
ioctl_by_bdev(bdev, BLKRRPART, 0);
return 0;
return err;
}
-static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
+static int loop_clr_fd(struct loop_device *lo)
{
struct file *filp = lo->lo_backing_file;
gfp_t gfp = lo->old_gfp_mask;
+ struct block_device *bdev = lo->lo_device;
if (lo->lo_state != Lo_bound)
return -ENXIO;
lo->lo_offset = 0;
lo->lo_sizelimit = 0;
lo->lo_encrypt_key_size = 0;
- lo->lo_flags = 0;
lo->lo_thread = NULL;
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
lo->lo_state = Lo_unbound;
/* This is safe: open() is still holding a reference. */
module_put(THIS_MODULE);
- if (max_part > 0 && bdev)
+ if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev)
ioctl_by_bdev(bdev, BLKRRPART, 0);
+ lo->lo_flags = 0;
+ if (!part_shift)
+ lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
mutex_unlock(&lo->lo_ctl_mutex);
/*
* Need not hold lo_ctl_mutex to fput backing file.
if (figure_loop_size(lo))
return -EFBIG;
}
+ loop_config_discard(lo);
memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
(info->lo_flags & LO_FLAGS_AUTOCLEAR))
lo->lo_flags ^= LO_FLAGS_AUTOCLEAR;
+ if ((info->lo_flags & LO_FLAGS_PARTSCAN) &&
+ !(lo->lo_flags & LO_FLAGS_PARTSCAN)) {
+ lo->lo_flags |= LO_FLAGS_PARTSCAN;
+ lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
+ ioctl_by_bdev(lo->lo_device, BLKRRPART, 0);
+ }
+
lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
lo->lo_init[0] = info->lo_init[0];
lo->lo_init[1] = info->lo_init[1];
break;
case LOOP_CLR_FD:
/* loop_clr_fd would have unlocked lo_ctl_mutex on success */
- err = loop_clr_fd(lo, bdev);
+ err = loop_clr_fd(lo);
if (!err)
goto out_unlocked;
break;
* In autoclear mode, stop the loop thread
* and remove configuration after last close.
*/
- err = loop_clr_fd(lo, NULL);
+ err = loop_clr_fd(lo);
if (!err)
goto out_unlocked;
} else {
if (!disk)
goto out_free_queue;
+ /*
+ * Disable partition scanning by default. The in-kernel partition
+ * scanning can be requested individually per-device during its
+ * setup. Userspace can always add and remove partitions from all
+ * devices. The needed partition minors are allocated from the
+ * extended minor space, the main loop device numbers will continue
+ * to match the loop minors, regardless of the number of partitions
+ * used.
+ *
+ * If max_part is given, partition scanning is globally enabled for
+ * all loop devices. The minors for the main loop devices will be
+ * multiples of max_part.
+ *
+ * Note: Global-for-all-devices, set-only-at-init, read-only module
+ * parameteters like 'max_loop' and 'max_part' make things needlessly
+ * complicated, are too static, inflexible and may surprise
+ * userspace tools. Parameters like this in general should be avoided.
+ */
+ if (!part_shift)
+ disk->flags |= GENHD_FL_NO_PART_SCAN;
+ disk->flags |= GENHD_FL_EXT_DEVT;
mutex_init(&lo->lo_ctl_mutex);
lo->lo_number = i;
lo->lo_thread = NULL;
git.openpandora.org / pandora-kernel.git / blobdiff