[PATCH] Btrfs: compressed file size ioctl

[PATCH] Btrfs: compressed file size ioctl

[Ulrich Hecht]

Returns a file's size on disk. Had been posted by Chris Ball over a year ago
(http://article.gmane.org/gmane.comp.file-systems.btrfs/2873).  Chris Mason
suggested a couple of improvements back then, which I have implemented in
this version:

- use u64 to return the result
- replaced the loop
	while (1) {
		struct btrfs_ordered_extent *ordered;
		lock_extent(&BTRFS_I(inode)->io_tree, 0, len, GFP_NOFS);
		ordered = btrfs_lookup_first_ordered_extent(inode, len);
		if (BTRFS_I(inode)->delalloc_bytes == 0 && !ordered)
			break;
		unlock_extent(&BTRFS_I(inode)->io_tree, 0, len, GFP_NOFS);
		if (ordered)
			btrfs_put_ordered_extent(ordered);
		btrfs_wait_ordered_range(inode, 0, len);
	}
  with
	btrfs_wait_ordered_range(inode, 0, (u64)-1);
- return the uncompressed size on disk for uncompressed filesystems instead
  of EINVAL

Minimal example:

 #include <sys/ioctl.h>
 #include <fcntl.h>
 #include <stdint.h>
 #include <stdio.h>
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_IOC_COMPR_SIZE   _IOR(BTRFS_IOCTL_MAGIC, 21, uint64_t)
int main(int argc, char **argv)
{
  uint64_t size = -1;
  int d = open(argv[1], O_RDONLY);
  ioctl(d, BTRFS_IOC_COMPR_SIZE, &size);
  printf("%zd\n", size);
  return 0;
}

Signed-off-by: Ulrich Hecht <uli@suse.de>
---
 fs/btrfs/ioctl.c |  103 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/ioctl.h |    1 +
 2 files changed, 104 insertions(+), 0 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 9254b3d..d18401b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1750,6 +1750,107 @@ out_drop_write:
 	return ret;
 }
 
+static long btrfs_ioctl_compsize(struct file *file, void __user *argp)
+{
+	/* This ioctl returns the compressed size of an inode on disk
+	 * by counting the on-disk space used by all of its extents.
+	 */
+	struct inode *inode = fdentry(file)->d_inode;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	u32 nritems;
+	int slot;
+	u64 olen = inode->i_size;
+	u64 len = olen;
+	long ret;
+	u64 compressed_size = 0;
+
+	if (S_ISDIR(inode->i_mode))
+		return -EISDIR;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	path->reada = 2;
+	mutex_lock(&inode->i_mutex);
+
+	/* do any pending delalloc/csum calc on inode, one way or
+	   another, and lock file content */
+	btrfs_wait_ordered_range(inode, 0, (u64)-1);
+
+	/* search for the inode */
+	key.objectid = inode->i_ino;
+	key.type = BTRFS_EXTENT_DATA_KEY;
+	key.offset = 0;
+
+	while (1) {
+		/* note the key will change type as we walk through the tree */
+		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+		if (ret < 0)
+			goto out;
+
+		nritems = btrfs_header_nritems(path->nodes[0]);
+		if (path->slots[0] >= nritems) {
+			ret = btrfs_next_leaf(root, path);
+			if (ret < 0)
+				goto out;
+			if (ret > 0)
+				break;
+			nritems = btrfs_header_nritems(path->nodes[0]);
+		}
+		leaf = path->nodes[0];
+		slot = path->slots[0];
+
+		btrfs_item_key_to_cpu(leaf, &key, slot);
+		if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
+		    key.objectid != inode->i_ino)
+			break;
+
+		if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
+			struct btrfs_file_extent_item *extent;
+			int type;
+			u64 datal = 0;
+
+			extent = btrfs_item_ptr(leaf, slot,
+						struct btrfs_file_extent_item);
+			type = btrfs_file_extent_type(leaf, extent);
+			if (type == BTRFS_FILE_EXTENT_REG) {
+				datal = btrfs_file_extent_num_bytes(leaf,
+								    extent);
+				compressed_size +=
+				  btrfs_file_extent_disk_num_bytes(leaf,
+								   extent);
+			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
+				datal = btrfs_file_extent_ram_bytes(leaf,
+								    extent);
+				compressed_size +=
+				  btrfs_file_extent_inline_item_len(leaf,
+					      btrfs_item_nr(leaf, slot));
+			}
+			btrfs_release_path(root, path);
+		}
+
+		btrfs_release_path(root, path);
+		key.offset++;
+	}
+
+	/* We've succeeded in going through all extents; set the final size. */
+	if (copy_to_user(argp, &compressed_size, sizeof(compressed_size)))
+		ret = -EFAULT;
+	else
+		ret = 0;
+
+out:
+	btrfs_release_path(root, path);
+	unlock_extent(&BTRFS_I(inode)->io_tree, 0, len, GFP_NOFS);
+	mutex_unlock(&inode->i_mutex);
+	btrfs_free_path(path);
+	return ret;
+}
+
 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
 {
 	struct btrfs_ioctl_clone_range_args args;
@@ -2034,6 +2135,8 @@ long btrfs_ioctl(struct file *file, unsigned int
 	case BTRFS_IOC_SYNC:
 		btrfs_sync_fs(file->f_dentry->d_sb, 1);
 		return 0;
+	case BTRFS_IOC_COMPR_SIZE:
+		return btrfs_ioctl_compsize(file, argp);
 	}
 
 	return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 424694a..a01ef1e 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -178,4 +178,5 @@ struct btrfs_ioctl_space_args {
 #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
 #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
 				    struct btrfs_ioctl_space_args)
+#define BTRFS_IOC_COMPR_SIZE _IOR(BTRFS_IOCTL_MAGIC, 21, u64)
 #endif
-- 
1.7.1

Re: [PATCH] Btrfs: compressed file size ioctl

[Miao Xie]

On Mon, 26 Jul 2010 17:30:53 +0200, Ulrich Hecht wrote:
[snip]
> +static long btrfs_ioctl_compsize(struct file *file, void __user *argp)
> +{
[snip]
> +
> +	/* search for the inode */
> +	key.objectid = inode->i_ino;
> +	key.type = BTRFS_EXTENT_DATA_KEY;
> +	key.offset = 0;
> +
> +	while (1) {
> +		/* note the key will change type as we walk through the tree */
> +		ret = btrfs_search_slot(NULL, root,&key, path, 0, 0);
> +		if (ret<  0)
> +			goto out;

Why don't you use btrfs_get_extent() to implement it?

Thanks
Miao

> +
> +		nritems = btrfs_header_nritems(path->nodes[0]);
> +		if (path->slots[0]>= nritems) {
> +			ret = btrfs_next_leaf(root, path);
> +			if (ret<  0)
> +				goto out;
> +			if (ret>  0)
> +				break;
> +			nritems = btrfs_header_nritems(path->nodes[0]);
> +		}
> +		leaf = path->nodes[0];
> +		slot = path->slots[0];
> +
> +		btrfs_item_key_to_cpu(leaf,&key, slot);
> +		if (btrfs_key_type(&key)>  BTRFS_EXTENT_DATA_KEY ||
> +		    key.objectid != inode->i_ino)
> +			break;
> +
> +		if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
> +			struct btrfs_file_extent_item *extent;
> +			int type;
> +			u64 datal = 0;
> +
> +			extent = btrfs_item_ptr(leaf, slot,
> +						struct btrfs_file_extent_item);
> +			type = btrfs_file_extent_type(leaf, extent);
> +			if (type == BTRFS_FILE_EXTENT_REG) {
> +				datal = btrfs_file_extent_num_bytes(leaf,
> +								    extent);
> +				compressed_size +=
> +				  btrfs_file_extent_disk_num_bytes(leaf,
> +								   extent);
> +			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
> +				datal = btrfs_file_extent_ram_bytes(leaf,
> +								    extent);
> +				compressed_size +=
> +				  btrfs_file_extent_inline_item_len(leaf,
> +					      btrfs_item_nr(leaf, slot));
> +			}
> +			btrfs_release_path(root, path);
> +		}
> +
> +		btrfs_release_path(root, path);
> +		key.offset++;
> +	}
> +
> +	/* We've succeeded in going through all extents; set the final size. */
> +	if (copy_to_user(argp,&compressed_size, sizeof(compressed_size)))
> +		ret = -EFAULT;
> +	else
> +		ret = 0;
> +
> +out:
> +	btrfs_release_path(root, path);
> +	unlock_extent(&BTRFS_I(inode)->io_tree, 0, len, GFP_NOFS);
> +	mutex_unlock(&inode->i_mutex);
> +	btrfs_free_path(path);
> +	return ret;
> +}
> +
>   static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
>   {
>   	struct btrfs_ioctl_clone_range_args args;
> @@ -2034,6 +2135,8 @@ long btrfs_ioctl(struct file *file, unsigned int
>   	case BTRFS_IOC_SYNC:
>   		btrfs_sync_fs(file->f_dentry->d_sb, 1);
>   		return 0;
> +	case BTRFS_IOC_COMPR_SIZE:
> +		return btrfs_ioctl_compsize(file, argp);
>   	}
> 
>   	return -ENOTTY;
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 424694a..a01ef1e 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -178,4 +178,5 @@ struct btrfs_ioctl_space_args {
>   #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
>   #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
>   				    struct btrfs_ioctl_space_args)
> +#define BTRFS_IOC_COMPR_SIZE _IOR(BTRFS_IOCTL_MAGIC, 21, u64)
>   #endif

Re: [PATCH] Btrfs: compressed file size ioctl

[Ulrich Hecht]

On Tuesday 27 July 2010, Miao Xie wrote:
> Why don't you use btrfs_get_extent() to implement it?

Because I didn't know about it. :) Thanks, that simplifies things a lot=
=2E

CU
Uli

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[PATCH] Btrfs: compressed file size ioctl

[Ulrich Hecht]

Returns a file's size on disk. Based on a patch by Chris Ball, improved
following suggestions by Chris Mason and Miao Xie.

Minimal example:

 #include <sys/ioctl.h>
 #include <fcntl.h>
 #include <stdint.h>
 #include <stdio.h>
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_IOC_COMPR_SIZE   _IOR(BTRFS_IOCTL_MAGIC, 21, uint64_t)
int main(int argc, char **argv)
{
  uint64_t size = -1;
  int d = open(argv[1], O_RDONLY);
  ioctl(d, BTRFS_IOC_COMPR_SIZE, &size);
  printf("%zd\n", size);
  return 0;
}

Signed-off-by: Ulrich Hecht <uli@suse.de>
---
 fs/btrfs/ioctl.c |   41 +++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/ioctl.h |    1 +
 2 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 9254b3d..29651c9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1750,6 +1750,45 @@ out_drop_write:
 	return ret;
 }
 
+static long btrfs_ioctl_compsize(struct file *file, void __user *argp)
+{
+	/* This ioctl returns the compressed size of an inode on disk
+	 * by counting the on-disk space used by all of its extents.
+	 */
+	struct inode *inode = fdentry(file)->d_inode;
+	struct extent_map *em;
+	u64 len = inode->i_size;
+	u64 compressed_size = 0;
+	u64 offset = 0;
+
+	if (S_ISDIR(inode->i_mode))
+		return -EISDIR;
+	
+	mutex_lock(&inode->i_mutex);
+
+	/* do any pending delalloc/csum calc on inode, one way or
+	   another, and lock file content */
+	btrfs_wait_ordered_range(inode, 0, (u64)-1);
+
+	while (offset < len) {
+		em = btrfs_get_extent(inode, NULL, 0, offset, 1, 0);
+		BUG_ON(IS_ERR(em) || !em);
+		if (em->block_len != (u64)-1)
+			compressed_size += em->block_len;
+		offset += em->len;
+		free_extent_map(em);
+	}
+	mutex_unlock(&inode->i_mutex);
+
+	unlock_extent(&BTRFS_I(inode)->io_tree, 0, len, GFP_NOFS);
+
+	/* We've succeeded in going through all extents; set the final size. */
+	if (copy_to_user(argp, &compressed_size, sizeof(compressed_size)))
+		return -EFAULT;
+	else
+		return 0;
+}
+
 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
 {
 	struct btrfs_ioctl_clone_range_args args;
@@ -2034,6 +2073,8 @@ long btrfs_ioctl(struct file *file, unsigned int
 	case BTRFS_IOC_SYNC:
 		btrfs_sync_fs(file->f_dentry->d_sb, 1);
 		return 0;
+	case BTRFS_IOC_COMPR_SIZE:
+		return btrfs_ioctl_compsize(file, argp);
 	}
 
 	return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 424694a..a01ef1e 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -178,4 +178,5 @@ struct btrfs_ioctl_space_args {
 #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
 #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
 				    struct btrfs_ioctl_space_args)
+#define BTRFS_IOC_COMPR_SIZE _IOR(BTRFS_IOCTL_MAGIC, 21, u64)
 #endif
-- 
1.7.1

Re: [PATCH] Btrfs: compressed file size ioctl

[liubo]

On 07/29/2010 07:27 PM, Ulrich Hecht wrote:
> Returns a file's size on disk. Based on a patch by Chris Ball, improved
> following suggestions by Chris Mason and Miao Xie.
>
> Minimal example:
>
>  #include <sys/ioctl.h>
>  #include <fcntl.h>
>  #include <stdint.h>
>  #include <stdio.h>
>  #define BTRFS_IOCTL_MAGIC 0x94
>  #define BTRFS_IOC_COMPR_SIZE   _IOR(BTRFS_IOCTL_MAGIC, 21, uint64_t)
> int main(int argc, char **argv)
> {
>   uint64_t size = -1;
>   int d = open(argv[1], O_RDONLY);
>   ioctl(d, BTRFS_IOC_COMPR_SIZE, &size);
>   printf("%zd\n", size);
>   return 0;
> }
>
> Signed-off-by: Ulrich Hecht <uli@suse.de>
> ---
>  fs/btrfs/ioctl.c |   41 +++++++++++++++++++++++++++++++++++++++++
>  fs/btrfs/ioctl.h |    1 +
>  2 files changed, 42 insertions(+), 0 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 9254b3d..29651c9 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -1750,6 +1750,45 @@ out_drop_write:
>  	return ret;
>  }
>  
> +static long btrfs_ioctl_compsize(struct file *file, void __user *argp)
> +{
> +	/* This ioctl returns the compressed size of an inode on disk
> +	 * by counting the on-disk space used by all of its extents.
> +	 */
> +	struct inode *inode = fdentry(file)->d_inode;
> +	struct extent_map *em;
> +	u64 len = inode->i_size;
> +	u64 compressed_size = 0;
> +	u64 offset = 0;
> +
> +	if (S_ISDIR(inode->i_mode))
> +		return -EISDIR;
> +	
> +	mutex_lock(&inode->i_mutex);
> +
> +	/* do any pending delalloc/csum calc on inode, one way or
> +	   another, and lock file content */
> +	btrfs_wait_ordered_range(inode, 0, (u64)-1);
> +
> +	while (offset < len) {
> +		em = btrfs_get_extent(inode, NULL, 0, offset, 1, 0);
> +		BUG_ON(IS_ERR(em) || !em);
> +		if (em->block_len != (u64)-1)
> +			compressed_size += em->block_len;
> +		offset += em->len;
> +		free_extent_map(em);
> +	}
> +	mutex_unlock(&inode->i_mutex);
> +
> +	unlock_extent(&BTRFS_I(inode)->io_tree, 0, len, GFP_NOFS);
> +
> +	/* We've succeeded in going through all extents; set the final size. */
> +	if (copy_to_user(argp, &compressed_size, sizeof(compressed_size)))
> +		return -EFAULT;
> +	else
>   

BTW, this "else" can be dropped. :-)

Thanks,
liubo

> +		return 0;
> +}
> +
>  static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
>  {
>  	struct btrfs_ioctl_clone_range_args args;
> @@ -2034,6 +2073,8 @@ long btrfs_ioctl(struct file *file, unsigned int
>  	case BTRFS_IOC_SYNC:
>  		btrfs_sync_fs(file->f_dentry->d_sb, 1);
>  		return 0;
> +	case BTRFS_IOC_COMPR_SIZE:
> +		return btrfs_ioctl_compsize(file, argp);
>  	}
>  
>  	return -ENOTTY;
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 424694a..a01ef1e 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -178,4 +178,5 @@ struct btrfs_ioctl_space_args {
>  #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
>  #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
>  				    struct btrfs_ioctl_space_args)
> +#define BTRFS_IOC_COMPR_SIZE _IOR(BTRFS_IOCTL_MAGIC, 21, u64)
>  #endif
>   

Re: [PATCH] Btrfs: compressed file size ioctl

[Miao Xie]

On Thu, 29 Jul 2010 13:27:09 +0200, Ulrich Hecht wrote:
> +static long btrfs_ioctl_compsize(struct file *file, void __user *argp)
> +{
> +	/* This ioctl returns the compressed size of an inode on disk
> +	 * by counting the on-disk space used by all of its extents.
> +	 */
> +	struct inode *inode = fdentry(file)->d_inode;
> +	struct extent_map *em;
> +	u64 len = inode->i_size;
> +	u64 compressed_size = 0;
> +	u64 offset = 0;
> +
> +	if (S_ISDIR(inode->i_mode))
> +		return -EISDIR;
> +	
> +	mutex_lock(&inode->i_mutex);
> +
> +	/* do any pending delalloc/csum calc on inode, one way or
> +	   another, and lock file content */
> +	btrfs_wait_ordered_range(inode, 0, (u64)-1);
> +
> +	while (offset<  len) {
> +		em = btrfs_get_extent(inode, NULL, 0, offset, 1, 0);

I think you need use lock_extent()/unlock_extent() to enclose
btrfs_get_extent(), but I didn't find lock_extent().

Thanks
Miao

> +		BUG_ON(IS_ERR(em) || !em);
> +		if (em->block_len != (u64)-1)
> +			compressed_size += em->block_len;
> +		offset += em->len;
> +		free_extent_map(em);
> +	}
> +	mutex_unlock(&inode->i_mutex);
> +
> +	unlock_extent(&BTRFS_I(inode)->io_tree, 0, len, GFP_NOFS);
> +
> +	/* We've succeeded in going through all extents; set the final size. */
> +	if (copy_to_user(argp,&compressed_size, sizeof(compressed_size)))
> +		return -EFAULT;
> +	else
> +		return 0;
> +}
> +
>   static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
>   {
>   	struct btrfs_ioctl_clone_range_args args;
> @@ -2034,6 +2073,8 @@ long btrfs_ioctl(struct file *file, unsigned int
>   	case BTRFS_IOC_SYNC:
>   		btrfs_sync_fs(file->f_dentry->d_sb, 1);
>   		return 0;
> +	case BTRFS_IOC_COMPR_SIZE:
> +		return btrfs_ioctl_compsize(file, argp);
>   	}
> 
>   	return -ENOTTY;
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 424694a..a01ef1e 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -178,4 +178,5 @@ struct btrfs_ioctl_space_args {
>   #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
>   #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
>   				    struct btrfs_ioctl_space_args)
> +#define BTRFS_IOC_COMPR_SIZE _IOR(BTRFS_IOCTL_MAGIC, 21, u64)
>   #endif

Re: [PATCH] Btrfs: compressed file size ioctl

[Ulrich Hecht]

On Monday 02 August 2010, Miao Xie wrote:
> I think you need use lock_extent()/unlock_extent() to enclose
> btrfs_get_extent(), but I didn't find lock_extent().

Yeah, I think that was missing in the original patch as well. Hope the=20
latest iteration is OK.

CU
Uli

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