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Re: [PATCH][RFC] fs: Add new pre-allocation ioctls to vfs for compatibil

To: Mark Fasheh <mfasheh@xxxxxxxx>
Subject: Re: [PATCH][RFC] fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls
From: Ankit Jain <me@xxxxxxxxxxxxx>
Date: Thu, 18 Dec 2008 15:14:09 +0530
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>, Christoph Hellwig <hch@xxxxxxxxxxxxx>, linux-fsdevel@xxxxxxxxxxxxxxx, joel.becker@xxxxxxxxxx, ocfs2-devel@xxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, xfs-masters@xxxxxxxxxxx, xfs@xxxxxxxxxxx
In-reply-to: <20081217202815.GE8791@xxxxxxxxxxxxx>
References: <49460F88.2080408@xxxxxxxxxxxxx> <20081217202815.GE8791@xxxxxxxxxxxxx>
User-agent: Thunderbird 2.0.0.18 (X11/20081112)
Mark Fasheh wrote:
>> 2. Should the corresponding ioctls be removed from ocfs2?
> 
> Well, a small amount of the code in fs/ocfs2/ioctl.c can certainly go away.
> Shouldn't we be talking about doing the same for xfs too?

Yep. I'll cook up cleanup patches for these two and post them.

-Ankit

> 
> 
>> Signed-off-by: Ankit Jain <me@xxxxxxxxxxxxx>
>> ---
>>  fs/ioctl.c             |   37 +++++++++++++++++++++++++++
>>  fs/open.c              |   51 ++++++++++++++++++-------------------
>>  include/linux/falloc.h |   19 ++++++++++++++
>>  include/linux/fs.h     |    2 +
>>  4 files changed, 83 insertions(+), 26 deletions(-)
>>
>> diff --git a/fs/ioctl.c b/fs/ioctl.c
>> index 43e8b2c..5e565c8 100644
>> --- a/fs/ioctl.c
>> +++ b/fs/ioctl.c
>> @@ -15,6 +15,7 @@
>>  #include <linux/uaccess.h>
>>  #include <linux/writeback.h>
>>  #include <linux/buffer_head.h>
>> +#include <linux/falloc.h>
>>  
>>  #include <asm/ioctls.h>
>>  
>> @@ -346,6 +347,37 @@ EXPORT_SYMBOL(generic_block_fiemap);
>>  
>>  #endif  /*  CONFIG_BLOCK  */
>>  
>> +/*
>> + * This provides compatibility with legacy XFS pre-allocation ioctls
>> + * which predate the fallocate syscall.
>> + *
>> + * Only the l_start, l_len and l_whence fields of the 'struct space_resv'
>> + * are used here, rest are ignored.
>> + */
>> +static int ioctl_preallocate(struct file *filp, unsigned long arg)
>> +{
>> +    struct inode *inode = filp->f_path.dentry->d_inode;
>> +    struct space_resv sr;
>> +
>> +    if (copy_from_user(&sr, (struct space_resv __user *) arg, sizeof(sr)))
>> +            return -EFAULT;
>> +
>> +    switch (sr.l_whence) {
>> +    case SEEK_SET:
>> +            break;
>> +    case SEEK_CUR:
>> +            sr.l_start += filp->f_pos;
>> +            break;
>> +    case SEEK_END:
>> +            sr.l_start += i_size_read(inode);
>> +            break;
>> +    default:
>> +            return -EINVAL;
>> +    }
>> +
>> +    return do_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
>> +}
>> +
>>  static int file_ioctl(struct file *filp, unsigned int cmd,
>>              unsigned long arg)
>>  {
>> @@ -361,6 +393,11 @@ static int file_ioctl(struct file *filp, unsigned int 
>> cmd,
>>              return put_user(inode->i_sb->s_blocksize, p);
>>      case FIONREAD:
>>              return put_user(i_size_read(inode) - filp->f_pos, p);
>> +    case F_IOC_RESVSP:
>> +    case F_IOC_RESVSP64:
>> +    case F_IOC_UNRESVSP:
>> +    case F_IOC_UNRESVSP64:
>> +            return ioctl_preallocate(filp, arg);
> 
> This patch is not implementing proper support for F_IOC_UNRESVSP and
> F_IOC_UNRESVSP64, so why are you catching those here? To be more clear,
> those are used for freeing space in a file ("puching holes"), which
> fallocate is not set up to do right now.
>       --Mark
> 
> --
> Mark Fasheh

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