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 <u...@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 > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html