From 585d3bc06f4ca57f975a5a1f698f65a45ea66225 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 25 Feb 2009 10:44:19 +0100 Subject: fs: move bdev code out of buffer.c Move some block device related code out from buffer.c and put it in block_dev.c. I'm trying to move non-buffer_head code out of buffer.c Signed-off-by: Al Viro --- fs/block_dev.c | 146 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) (limited to 'fs/block_dev.c') diff --git a/fs/block_dev.c b/fs/block_dev.c index b3c1efff5e1d..8c3c6899ccf3 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -174,6 +175,151 @@ blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, iov, offset, nr_segs, blkdev_get_blocks, NULL); } +/* + * 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) +{ + int ret = 0; + + if (bdev) + ret = filemap_write_and_wait(bdev->bd_inode->i_mapping); + return ret; +} +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 = fsync_super(sb); + drop_super(sb); + return res; + } + return sync_blockdev(bdev); +} + +/** + * 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 + * 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 > 0) { + bdev->bd_fsfreeze_count++; + sb = get_super(bdev); + 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); + } + } + } + + sync_blockdev(bdev); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + + return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */ +} +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 = 0; + + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (!bdev->bd_fsfreeze_count) { + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return -EINVAL; + } + + bdev->bd_fsfreeze_count--; + if (bdev->bd_fsfreeze_count > 0) { + if (sb) + drop_super(sb); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return 0; + } + + 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); + } + + up(&bdev->bd_mount_sem); + 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); -- cgit v1.3-8-gc7d7 From 47e4491b40df73c3b117e3d80b31b5b512a4b19f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 1 Apr 2009 07:07:16 -0400 Subject: Cleanup after commit 585d3bc06f4ca57f975a5a1f698f65a45ea66225 fsync_bdev() export and a bunch of stubs for !CONFIG_BLOCK case had been left behind Signed-off-by: Al Viro --- fs/block_dev.c | 1 + fs/buffer.c | 1 - include/linux/buffer_head.h | 12 ------------ include/linux/fs.h | 12 ++++++++++++ 4 files changed, 13 insertions(+), 13 deletions(-) (limited to 'fs/block_dev.c') diff --git a/fs/block_dev.c b/fs/block_dev.c index 8c3c6899ccf3..f45dbc18dd17 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -204,6 +204,7 @@ int fsync_bdev(struct block_device *bdev) } return sync_blockdev(bdev); } +EXPORT_SYMBOL(fsync_bdev); /** * freeze_bdev -- lock a filesystem and force it into a consistent state diff --git a/fs/buffer.c b/fs/buffer.c index a2fd743d97cb..b71e52925c83 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -3281,7 +3281,6 @@ EXPORT_SYMBOL(cont_write_begin); EXPORT_SYMBOL(end_buffer_read_sync); EXPORT_SYMBOL(end_buffer_write_sync); EXPORT_SYMBOL(file_fsync); -EXPORT_SYMBOL(fsync_bdev); EXPORT_SYMBOL(generic_block_bmap); EXPORT_SYMBOL(generic_cont_expand_simple); EXPORT_SYMBOL(init_buffer); diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index f19fd9045ea0..fc91665d39d0 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -332,22 +332,10 @@ extern int __set_page_dirty_buffers(struct page *page); static inline void buffer_init(void) {} static inline int try_to_free_buffers(struct page *page) { return 1; } -static inline int sync_blockdev(struct block_device *bdev) { return 0; } static inline int inode_has_buffers(struct inode *inode) { return 0; } static inline void invalidate_inode_buffers(struct inode *inode) {} static inline int remove_inode_buffers(struct inode *inode) { return 1; } static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; } -static inline void invalidate_bdev(struct block_device *bdev) {} - -static inline struct super_block *freeze_bdev(struct block_device *sb) -{ - return NULL; -} - -static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb) -{ - return 0; -} #endif /* CONFIG_BLOCK */ #endif /* _LINUX_BUFFER_HEAD_H */ diff --git a/include/linux/fs.h b/include/linux/fs.h index 3d7bd5447ca3..674134725597 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1886,6 +1886,18 @@ extern int fsync_super(struct super_block *); extern int fsync_no_super(struct block_device *); #else static inline void bd_forget(struct inode *inode) {} +static inline int sync_blockdev(struct block_device *bdev) { return 0; } +static inline void invalidate_bdev(struct block_device *bdev) {} + +static inline struct super_block *freeze_bdev(struct block_device *sb) +{ + return NULL; +} + +static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb) +{ + return 0; +} #endif extern const struct file_operations def_blk_fops; extern const struct file_operations def_chr_fops; -- cgit v1.3-8-gc7d7