#include <linux/uio.h>
#include <linux/namei.h>
#include <linux/log2.h>
+#include <linux/kmemleak.h>
#include <asm/uaccess.h>
#include "internal.h"
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
- return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode),
- iov, offset, nr_segs, blkdev_get_blocks, NULL);
+ return blockdev_direct_IO_no_locking_newtrunc(rw, iocb, inode,
+ I_BDEV(inode), iov, offset, nr_segs,
+ blkdev_get_blocks, NULL);
+}
+
+int __sync_blockdev(struct block_device *bdev, int wait)
+{
+ if (!bdev)
+ return 0;
+ if (!wait)
+ return filemap_flush(bdev->bd_inode->i_mapping);
+ return filemap_write_and_wait(bdev->bd_inode->i_mapping);
}
/*
*/
int sync_blockdev(struct block_device *bdev)
{
- int ret = 0;
-
- if (bdev)
- ret = filemap_write_and_wait(bdev->bd_inode->i_mapping);
- return ret;
+ return __sync_blockdev(bdev, 1);
}
EXPORT_SYMBOL(sync_blockdev);
{
struct super_block *sb = get_super(bdev);
if (sb) {
- int res = fsync_super(sb);
+ int res = sync_filesystem(sb);
drop_super(sb);
return res;
}
* freeze_bdev -- lock a filesystem and force it into a consistent state
* @bdev: blockdevice to lock
*
- * This takes the block device bd_mount_sem to make sure no new mounts
- * happen on bdev until thaw_bdev() is called.
* If a superblock is found on this device, we take the s_umount semaphore
* on it to make sure nobody unmounts until the snapshot creation is done.
* The reference counter (bd_fsfreeze_count) guarantees that only the last
int error = 0;
mutex_lock(&bdev->bd_fsfreeze_mutex);
- if (bdev->bd_fsfreeze_count > 0) {
- bdev->bd_fsfreeze_count++;
+ if (++bdev->bd_fsfreeze_count > 1) {
+ /*
+ * We don't even need to grab a reference - the first call
+ * to freeze_bdev grab an active reference and only the last
+ * thaw_bdev drops it.
+ */
sb = get_super(bdev);
+ drop_super(sb);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return sb;
}
- bdev->bd_fsfreeze_count++;
-
- down(&bdev->bd_mount_sem);
- sb = get_super(bdev);
- if (sb && !(sb->s_flags & MS_RDONLY)) {
- sb->s_frozen = SB_FREEZE_WRITE;
- smp_wmb();
-
- __fsync_super(sb);
-
- sb->s_frozen = SB_FREEZE_TRANS;
- smp_wmb();
-
- sync_blockdev(sb->s_bdev);
-
- if (sb->s_op->freeze_fs) {
- error = sb->s_op->freeze_fs(sb);
- if (error) {
- printk(KERN_ERR
- "VFS:Filesystem freeze failed\n");
- sb->s_frozen = SB_UNFROZEN;
- drop_super(sb);
- up(&bdev->bd_mount_sem);
- bdev->bd_fsfreeze_count--;
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- return ERR_PTR(error);
- }
- }
- }
+ sb = get_active_super(bdev);
+ if (!sb)
+ goto out;
+ error = freeze_super(sb);
+ if (error) {
+ deactivate_super(sb);
+ bdev->bd_fsfreeze_count--;
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return ERR_PTR(error);
+ }
+ deactivate_super(sb);
+ out:
sync_blockdev(bdev);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
-
- return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */
+ return sb; /* thaw_bdev releases s->s_umount */
}
EXPORT_SYMBOL(freeze_bdev);
*/
int thaw_bdev(struct block_device *bdev, struct super_block *sb)
{
- int error = 0;
+ int error = -EINVAL;
mutex_lock(&bdev->bd_fsfreeze_mutex);
- if (!bdev->bd_fsfreeze_count) {
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- return -EINVAL;
- }
+ if (!bdev->bd_fsfreeze_count)
+ goto out;
- bdev->bd_fsfreeze_count--;
- if (bdev->bd_fsfreeze_count > 0) {
- if (sb)
- drop_super(sb);
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- return 0;
- }
+ error = 0;
+ if (--bdev->bd_fsfreeze_count > 0)
+ goto out;
- if (sb) {
- BUG_ON(sb->s_bdev != bdev);
- if (!(sb->s_flags & MS_RDONLY)) {
- if (sb->s_op->unfreeze_fs) {
- error = sb->s_op->unfreeze_fs(sb);
- if (error) {
- printk(KERN_ERR
- "VFS:Filesystem thaw failed\n");
- sb->s_frozen = SB_FREEZE_TRANS;
- bdev->bd_fsfreeze_count++;
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- return error;
- }
- }
- sb->s_frozen = SB_UNFROZEN;
- smp_wmb();
- wake_up(&sb->s_wait_unfrozen);
- }
- drop_super(sb);
- }
+ if (!sb)
+ goto out;
- up(&bdev->bd_mount_sem);
+ error = thaw_super(sb);
+ if (error) {
+ bdev->bd_fsfreeze_count++;
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return error;
+ }
+out:
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return 0;
}
return block_read_full_page(page, blkdev_get_block);
}
-static int blkdev_readpages(struct file *file, struct address_space *mapping,
- struct list_head *pages, unsigned nr_pages)
-{
- return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block);
-}
-
static int blkdev_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
*pagep = NULL;
- return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
- blkdev_get_block);
+ return block_write_begin_newtrunc(file, mapping, pos, len, flags,
+ pagep, fsdata, blkdev_get_block);
}
static int blkdev_write_end(struct file *file, struct address_space *mapping,
return retval;
}
-/*
- * Filp is never NULL; the only case when ->fsync() is called with
- * NULL first argument is nfsd_sync_dir() and that's not a directory.
- */
-
-static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
+int blkdev_fsync(struct file *filp, int datasync)
{
- return sync_blockdev(I_BDEV(filp->f_mapping->host));
+ struct inode *bd_inode = filp->f_mapping->host;
+ struct block_device *bdev = I_BDEV(bd_inode);
+ int error;
+
+ /*
+ * There is no need to serialise calls to blkdev_issue_flush with
+ * i_mutex and doing so causes performance issues with concurrent
+ * O_SYNC writers to a block device.
+ */
+ mutex_unlock(&bd_inode->i_mutex);
+
+ error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL, BLKDEV_IFL_WAIT);
+ if (error == -EOPNOTSUPP)
+ error = 0;
+
+ mutex_lock(&bd_inode->i_mutex);
+
+ return error;
}
+EXPORT_SYMBOL(blkdev_fsync);
/*
* pseudo-fs
{
struct bdev_inode *bdi = BDEV_I(inode);
- bdi->bdev.bd_inode_backing_dev_info = NULL;
kmem_cache_free(bdev_cachep, bdi);
}
memset(bdev, 0, sizeof(*bdev));
mutex_init(&bdev->bd_mutex);
- sema_init(&bdev->bd_mount_sem, 1);
INIT_LIST_HEAD(&bdev->bd_inodes);
INIT_LIST_HEAD(&bdev->bd_list);
#ifdef CONFIG_SYSFS
bd_mnt = kern_mount(&bd_type);
if (IS_ERR(bd_mnt))
panic("Cannot create bdev pseudo-fs");
+ /*
+ * This vfsmount structure is only used to obtain the
+ * blockdev_superblock, so tell kmemleak not to report it.
+ */
+ kmemleak_not_leak(bd_mnt);
blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
}
EXPORT_SYMBOL(bdget);
+/**
+ * bdgrab -- Grab a reference to an already referenced block device
+ * @bdev: Block device to grab a reference to.
+ */
+struct block_device *bdgrab(struct block_device *bdev)
+{
+ atomic_inc(&bdev->bd_inode->i_count);
+ return bdev;
+}
+
long nr_blockdev_pages(void)
{
struct block_device *bdev;
iput(bdev->bd_inode);
}
-int bd_claim(struct block_device *bdev, void *holder)
+/**
+ * bd_may_claim - test whether a block device can be claimed
+ * @bdev: block device of interest
+ * @whole: whole block device containing @bdev, may equal @bdev
+ * @holder: holder trying to claim @bdev
+ *
+ * Test whther @bdev can be claimed by @holder.
+ *
+ * CONTEXT:
+ * spin_lock(&bdev_lock).
+ *
+ * RETURNS:
+ * %true if @bdev can be claimed, %false otherwise.
+ */
+static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
+ void *holder)
{
- int res;
- spin_lock(&bdev_lock);
-
- /* first decide result */
if (bdev->bd_holder == holder)
- res = 0; /* already a holder */
+ return true; /* already a holder */
else if (bdev->bd_holder != NULL)
- res = -EBUSY; /* held by someone else */
+ return false; /* held by someone else */
else if (bdev->bd_contains == bdev)
- res = 0; /* is a whole device which isn't held */
+ return true; /* is a whole device which isn't held */
- else if (bdev->bd_contains->bd_holder == bd_claim)
- res = 0; /* is a partition of a device that is being partitioned */
- else if (bdev->bd_contains->bd_holder != NULL)
- res = -EBUSY; /* is a partition of a held device */
+ else if (whole->bd_holder == bd_claim)
+ return true; /* is a partition of a device that is being partitioned */
+ else if (whole->bd_holder != NULL)
+ return false; /* is a partition of a held device */
else
- res = 0; /* is a partition of an un-held device */
+ return true; /* is a partition of an un-held device */
+}
- /* now impose change */
- if (res==0) {
- /* note that for a whole device bd_holders
- * will be incremented twice, and bd_holder will
- * be set to bd_claim before being set to holder
- */
- bdev->bd_contains->bd_holders ++;
- bdev->bd_contains->bd_holder = bd_claim;
- bdev->bd_holders++;
- bdev->bd_holder = holder;
+/**
+ * bd_prepare_to_claim - prepare to claim a block device
+ * @bdev: block device of interest
+ * @whole: the whole device containing @bdev, may equal @bdev
+ * @holder: holder trying to claim @bdev
+ *
+ * Prepare to claim @bdev. This function fails if @bdev is already
+ * claimed by another holder and waits if another claiming is in
+ * progress. This function doesn't actually claim. On successful
+ * return, the caller has ownership of bd_claiming and bd_holder[s].
+ *
+ * CONTEXT:
+ * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
+ * it multiple times.
+ *
+ * RETURNS:
+ * 0 if @bdev can be claimed, -EBUSY otherwise.
+ */
+static int bd_prepare_to_claim(struct block_device *bdev,
+ struct block_device *whole, void *holder)
+{
+retry:
+ /* if someone else claimed, fail */
+ if (!bd_may_claim(bdev, whole, holder))
+ return -EBUSY;
+
+ /* if someone else is claiming, wait for it to finish */
+ if (whole->bd_claiming && whole->bd_claiming != holder) {
+ wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&bdev_lock);
+ schedule();
+ finish_wait(wq, &wait);
+ spin_lock(&bdev_lock);
+ goto retry;
+ }
+
+ /* yay, all mine */
+ return 0;
+}
+
+/**
+ * bd_start_claiming - start claiming a block device
+ * @bdev: block device of interest
+ * @holder: holder trying to claim @bdev
+ *
+ * @bdev is about to be opened exclusively. Check @bdev can be opened
+ * exclusively and mark that an exclusive open is in progress. Each
+ * successful call to this function must be matched with a call to
+ * either bd_finish_claiming() or bd_abort_claiming() (which do not
+ * fail).
+ *
+ * This function is used to gain exclusive access to the block device
+ * without actually causing other exclusive open attempts to fail. It
+ * should be used when the open sequence itself requires exclusive
+ * access but may subsequently fail.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * Pointer to the block device containing @bdev on success, ERR_PTR()
+ * value on failure.
+ */
+static struct block_device *bd_start_claiming(struct block_device *bdev,
+ void *holder)
+{
+ struct gendisk *disk;
+ struct block_device *whole;
+ int partno, err;
+
+ might_sleep();
+
+ /*
+ * @bdev might not have been initialized properly yet, look up
+ * and grab the outer block device the hard way.
+ */
+ disk = get_gendisk(bdev->bd_dev, &partno);
+ if (!disk)
+ return ERR_PTR(-ENXIO);
+
+ whole = bdget_disk(disk, 0);
+ module_put(disk->fops->owner);
+ put_disk(disk);
+ if (!whole)
+ return ERR_PTR(-ENOMEM);
+
+ /* prepare to claim, if successful, mark claiming in progress */
+ spin_lock(&bdev_lock);
+
+ err = bd_prepare_to_claim(bdev, whole, holder);
+ if (err == 0) {
+ whole->bd_claiming = holder;
+ spin_unlock(&bdev_lock);
+ return whole;
+ } else {
+ spin_unlock(&bdev_lock);
+ bdput(whole);
+ return ERR_PTR(err);
}
+}
+
+/* releases bdev_lock */
+static void __bd_abort_claiming(struct block_device *whole, void *holder)
+{
+ BUG_ON(whole->bd_claiming != holder);
+ whole->bd_claiming = NULL;
+ wake_up_bit(&whole->bd_claiming, 0);
+
spin_unlock(&bdev_lock);
- return res;
+ bdput(whole);
}
+/**
+ * bd_abort_claiming - abort claiming a block device
+ * @whole: whole block device returned by bd_start_claiming()
+ * @holder: holder trying to claim @bdev
+ *
+ * Abort a claiming block started by bd_start_claiming(). Note that
+ * @whole is not the block device to be claimed but the whole device
+ * returned by bd_start_claiming().
+ *
+ * CONTEXT:
+ * Grabs and releases bdev_lock.
+ */
+static void bd_abort_claiming(struct block_device *whole, void *holder)
+{
+ spin_lock(&bdev_lock);
+ __bd_abort_claiming(whole, holder); /* releases bdev_lock */
+}
+
+/* increment holders when we have a legitimate claim. requires bdev_lock */
+static void __bd_claim(struct block_device *bdev, struct block_device *whole,
+ void *holder)
+{
+ /* note that for a whole device bd_holders
+ * will be incremented twice, and bd_holder will
+ * be set to bd_claim before being set to holder
+ */
+ whole->bd_holders++;
+ whole->bd_holder = bd_claim;
+ bdev->bd_holders++;
+ bdev->bd_holder = holder;
+}
+
+/**
+ * bd_finish_claiming - finish claiming a block device
+ * @bdev: block device of interest (passed to bd_start_claiming())
+ * @whole: whole block device returned by bd_start_claiming()
+ * @holder: holder trying to claim @bdev
+ *
+ * Finish a claiming block started by bd_start_claiming().
+ *
+ * CONTEXT:
+ * Grabs and releases bdev_lock.
+ */
+static void bd_finish_claiming(struct block_device *bdev,
+ struct block_device *whole, void *holder)
+{
+ spin_lock(&bdev_lock);
+ BUG_ON(!bd_may_claim(bdev, whole, holder));
+ __bd_claim(bdev, whole, holder);
+ __bd_abort_claiming(whole, holder); /* not actually an abort */
+}
+
+/**
+ * bd_claim - claim a block device
+ * @bdev: block device to claim
+ * @holder: holder trying to claim @bdev
+ *
+ * Try to claim @bdev which must have been opened successfully.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * 0 if successful, -EBUSY if @bdev is already claimed.
+ */
+int bd_claim(struct block_device *bdev, void *holder)
+{
+ struct block_device *whole = bdev->bd_contains;
+ int res;
+
+ might_sleep();
+
+ spin_lock(&bdev_lock);
+ res = bd_prepare_to_claim(bdev, whole, holder);
+ if (res == 0)
+ __bd_claim(bdev, whole, holder);
+ spin_unlock(&bdev_lock);
+
+ return res;
+}
EXPORT_SYMBOL(bd_claim);
void bd_release(struct block_device *bdev)
int check_disk_change(struct block_device *bdev)
{
struct gendisk *disk = bdev->bd_disk;
- struct block_device_operations * bdops = disk->fops;
+ const struct block_device_operations *bdops = disk->fops;
if (!bdops->media_changed)
return 0;
bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
}
} else {
- put_disk(disk);
module_put(disk->fops->owner);
+ put_disk(disk);
disk = NULL;
if (bdev->bd_contains == bdev) {
if (bdev->bd_disk->fops->open) {
static int blkdev_open(struct inode * inode, struct file * filp)
{
+ struct block_device *whole = NULL;
struct block_device *bdev;
int res;
if (bdev == NULL)
return -ENOMEM;
+ if (filp->f_mode & FMODE_EXCL) {
+ whole = bd_start_claiming(bdev, filp);
+ if (IS_ERR(whole)) {
+ bdput(bdev);
+ return PTR_ERR(whole);
+ }
+ }
+
filp->f_mapping = bdev->bd_inode->i_mapping;
res = blkdev_get(bdev, filp->f_mode);
- if (res)
- return res;
- if (filp->f_mode & FMODE_EXCL) {
- res = bd_claim(bdev, filp);
- if (res)
- goto out_blkdev_put;
+ if (whole) {
+ if (res == 0)
+ bd_finish_claiming(bdev, whole, filp);
+ else
+ bd_abort_claiming(whole, filp);
}
- return 0;
-
- out_blkdev_put:
- blkdev_put(bdev, filp->f_mode);
return res;
}
}
/*
+ * Write data to the block device. Only intended for the block device itself
+ * and the raw driver which basically is a fake block device.
+ *
+ * Does not take i_mutex for the write and thus is not for general purpose
+ * use.
+ */
+ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct file *file = iocb->ki_filp;
+ ssize_t ret;
+
+ BUG_ON(iocb->ki_pos != pos);
+
+ ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
+ if (ret > 0 || ret == -EIOCBQUEUED) {
+ ssize_t err;
+
+ err = generic_write_sync(file, pos, ret);
+ if (err < 0 && ret > 0)
+ ret = err;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(blkdev_aio_write);
+
+/*
* Try to release a page associated with block device when the system
* is under memory pressure.
*/
static const struct address_space_operations def_blk_aops = {
.readpage = blkdev_readpage,
- .readpages = blkdev_readpages,
.writepage = blkdev_writepage,
.sync_page = block_sync_page,
.write_begin = blkdev_write_begin,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = generic_file_aio_read,
- .aio_write = generic_file_aio_write_nolock,
+ .aio_write = blkdev_aio_write,
.mmap = generic_file_mmap,
- .fsync = block_fsync,
+ .fsync = blkdev_fsync,
.unlocked_ioctl = block_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = compat_blkdev_ioctl,
*/
struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
{
- struct block_device *bdev;
- int error = 0;
+ struct block_device *bdev, *whole;
+ int error;
bdev = lookup_bdev(path);
if (IS_ERR(bdev))
return bdev;
+ whole = bd_start_claiming(bdev, holder);
+ if (IS_ERR(whole)) {
+ bdput(bdev);
+ return whole;
+ }
+
error = blkdev_get(bdev, mode);
if (error)
- return ERR_PTR(error);
+ goto out_abort_claiming;
+
error = -EACCES;
if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
- goto blkdev_put;
- error = bd_claim(bdev, holder);
- if (error)
- goto blkdev_put;
+ goto out_blkdev_put;
+ bd_finish_claiming(bdev, whole, holder);
return bdev;
-
-blkdev_put:
+
+out_blkdev_put:
blkdev_put(bdev, mode);
+out_abort_claiming:
+ bd_abort_claiming(whole, holder);
return ERR_PTR(error);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff