move virtrng_remove to .devexit.text
[linux-2.6.git] / fs / block_dev.c
index b3c1eff..9cf4b92 100644 (file)
 #include <linux/module.h>
 #include <linux/blkpg.h>
 #include <linux/buffer_head.h>
+#include <linux/pagevec.h>
 #include <linux/writeback.h>
 #include <linux/mpage.h>
 #include <linux/mount.h>
 #include <linux/uio.h>
 #include <linux/namei.h>
 #include <linux/log2.h>
+#include <linux/kmemleak.h>
 #include <asm/uaccess.h>
 #include "internal.h"
 
@@ -75,7 +77,7 @@ int set_blocksize(struct block_device *bdev, int size)
                return -EINVAL;
 
        /* Size cannot be smaller than the size supported by the device */
-       if (size < bdev_hardsect_size(bdev))
+       if (size < bdev_logical_block_size(bdev))
                return -EINVAL;
 
        /* Don't change the size if it is same as current */
@@ -105,7 +107,7 @@ EXPORT_SYMBOL(sb_set_blocksize);
 
 int sb_min_blocksize(struct super_block *sb, int size)
 {
-       int minsize = bdev_hardsect_size(sb->s_bdev);
+       int minsize = bdev_logical_block_size(sb->s_bdev);
        if (size < minsize)
                size = minsize;
        return sb_set_blocksize(sb, size);
@@ -174,6 +176,164 @@ blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
                                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);
+}
+
+/*
+ * Write out and wait upon all the dirty data associated with a block
+ * device via its mapping.  Does not take the superblock lock.
+ */
+int sync_blockdev(struct block_device *bdev)
+{
+       return __sync_blockdev(bdev, 1);
+}
+EXPORT_SYMBOL(sync_blockdev);
+
+/*
+ * Write out and wait upon all dirty data associated with this
+ * device.   Filesystem data as well as the underlying block
+ * device.  Takes the superblock lock.
+ */
+int fsync_bdev(struct block_device *bdev)
+{
+       struct super_block *sb = get_super(bdev);
+       if (sb) {
+               int res = sync_filesystem(sb);
+               drop_super(sb);
+               return res;
+       }
+       return sync_blockdev(bdev);
+}
+EXPORT_SYMBOL(fsync_bdev);
+
+/**
+ * freeze_bdev  --  lock a filesystem and force it into a consistent state
+ * @bdev:      blockdevice to lock
+ *
+ * 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
+ * unfreeze process can unfreeze the frozen filesystem actually when multiple
+ * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
+ * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
+ * actually.
+ */
+struct super_block *freeze_bdev(struct block_device *bdev)
+{
+       struct super_block *sb;
+       int error = 0;
+
+       mutex_lock(&bdev->bd_fsfreeze_mutex);
+       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;
+       }
+
+       sb = get_active_super(bdev);
+       if (!sb)
+               goto out;
+       if (sb->s_flags & MS_RDONLY) {
+               deactivate_locked_super(sb);
+               mutex_unlock(&bdev->bd_fsfreeze_mutex);
+               return sb;
+       }
+
+       sb->s_frozen = SB_FREEZE_WRITE;
+       smp_wmb();
+
+       sync_filesystem(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;
+                       deactivate_locked_super(sb);
+                       bdev->bd_fsfreeze_count--;
+                       mutex_unlock(&bdev->bd_fsfreeze_mutex);
+                       return ERR_PTR(error);
+               }
+       }
+       up_write(&sb->s_umount);
+
+ out:
+       sync_blockdev(bdev);
+       mutex_unlock(&bdev->bd_fsfreeze_mutex);
+       return sb;      /* thaw_bdev releases s->s_umount */
+}
+EXPORT_SYMBOL(freeze_bdev);
+
+/**
+ * thaw_bdev  -- unlock filesystem
+ * @bdev:      blockdevice to unlock
+ * @sb:                associated superblock
+ *
+ * Unlocks the filesystem and marks it writeable again after freeze_bdev().
+ */
+int thaw_bdev(struct block_device *bdev, struct super_block *sb)
+{
+       int error = -EINVAL;
+
+       mutex_lock(&bdev->bd_fsfreeze_mutex);
+       if (!bdev->bd_fsfreeze_count)
+               goto out_unlock;
+
+       error = 0;
+       if (--bdev->bd_fsfreeze_count > 0)
+               goto out_unlock;
+
+       if (!sb)
+               goto out_unlock;
+
+       BUG_ON(sb->s_bdev != bdev);
+       down_write(&sb->s_umount);
+       if (sb->s_flags & MS_RDONLY)
+               goto out_deactivate;
+
+       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);
+
+out_deactivate:
+       if (sb)
+               deactivate_locked_super(sb);
+out_unlock:
+       mutex_unlock(&bdev->bd_fsfreeze_mutex);
+       return 0;
+}
+EXPORT_SYMBOL(thaw_bdev);
+
 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
 {
        return block_write_full_page(page, blkdev_get_block, wbc);
@@ -267,7 +427,6 @@ static void bdev_destroy_inode(struct inode *inode)
 {
        struct bdev_inode *bdi = BDEV_I(inode);
 
-       bdi->bdev.bd_inode_backing_dev_info = NULL;
        kmem_cache_free(bdev_cachep, bdi);
 }
 
@@ -278,7 +437,6 @@ static void init_once(void *foo)
 
        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
@@ -345,6 +503,11 @@ void __init bdev_cache_init(void)
        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 */
 }
 
@@ -406,6 +569,16 @@ struct block_device *bdget(dev_t dev)
 
 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;
@@ -947,7 +1120,7 @@ EXPORT_SYMBOL(revalidate_disk);
 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;
@@ -964,7 +1137,7 @@ EXPORT_SYMBOL(check_disk_change);
 
 void bd_set_size(struct block_device *bdev, loff_t size)
 {
-       unsigned bsize = bdev_hardsect_size(bdev);
+       unsigned bsize = bdev_logical_block_size(bdev);
 
        bdev->bd_inode->i_size = size;
        while (bsize < PAGE_CACHE_SIZE) {
@@ -1237,6 +1410,33 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 }
 
 /*
+ * 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.
  */
@@ -1268,7 +1468,7 @@ const struct file_operations def_blk_fops = {
        .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,
        .unlocked_ioctl = block_ioctl,