X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fblock_dev.c;h=6dcee88c2e5d275fe7df4b3e82caa52375779a74;hb=274a24c16fa97a1fc67437b191274db2286c7ac3;hp=8ebbfdf708c24c9d70bc4cc88e8266202d56ec06;hpb=d3374825ce57ba2214d375023979f6197ccc1385;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/block_dev.c b/fs/block_dev.c index 8ebbfdf..6dcee88 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -18,12 +18,14 @@ #include #include #include +#include #include #include #include #include #include #include +#include #include #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 +176,165 @@ 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) { + sb->s_frozen = SB_FREEZE_TRANS; + up_write(&sb->s_umount); + 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_unfrozen; + + 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; + } + } + +out_unfrozen: + sb->s_frozen = SB_UNFROZEN; + smp_wmb(); + wake_up(&sb->s_wait_unfrozen); + + 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); @@ -243,10 +404,28 @@ static loff_t block_llseek(struct file *file, loff_t offset, int origin) * 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, struct dentry *dentry, 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, NULL); + if (error == -EOPNOTSUPP) + error = 0; + + mutex_lock(&bd_inode->i_mutex); + + return error; } +EXPORT_SYMBOL(blkdev_fsync); /* * pseudo-fs @@ -267,7 +446,6 @@ 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); } @@ -278,13 +456,14 @@ 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 INIT_LIST_HEAD(&bdev->bd_holder_list); #endif inode_init_once(&ei->vfs_inode); + /* Initialize mutex for freeze. */ + mutex_init(&bdev->bd_fsfreeze_mutex); } static inline void __bd_forget(struct inode *inode) @@ -343,6 +522,11 @@ 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 */ } @@ -404,6 +588,16 @@ 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; @@ -945,7 +1139,7 @@ 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; @@ -962,7 +1156,7 @@ 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) { @@ -1073,8 +1267,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) 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) { @@ -1234,6 +1428,47 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) return blkdev_ioctl(bdev, mode, cmd, 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. + */ +static int blkdev_releasepage(struct page *page, gfp_t wait) +{ + struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; + + if (super && super->s_op->bdev_try_to_free_page) + return super->s_op->bdev_try_to_free_page(super, page, wait); + + return try_to_free_buffers(page); +} + static const struct address_space_operations def_blk_aops = { .readpage = blkdev_readpage, .writepage = blkdev_writepage, @@ -1241,6 +1476,7 @@ static const struct address_space_operations def_blk_aops = { .write_begin = blkdev_write_begin, .write_end = blkdev_write_end, .writepages = generic_writepages, + .releasepage = blkdev_releasepage, .direct_IO = blkdev_direct_IO, }; @@ -1251,9 +1487,9 @@ 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, + .fsync = blkdev_fsync, .unlocked_ioctl = block_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = compat_blkdev_ioctl,