[Ocfs2-devel] [PATCH] ocfs2: fix issue that ocfs2_setattr() does not deal with new_i_size==i_size
Younger Liu
younger.liu at huawei.com
Fri Jun 28 22:20:05 PDT 2013
On 2013/6/28 12:06, Jeff Liu wrote:
> Thanks for your patch, it indeed fixed a bug. However, your description
> is not correct, please see my inline comments.
>
> On 06/27/2013 03:55 PM, Younger Liu wrote:
>
>> The issue scenario is as following:
>> 1. fallocate a large disk space(eg. 30G) with FALLOC_FL_KEEP_SIZE
>> for a file whose i_size and disk size are 512(or other size).
>> After executing fallocate, i_size file is still 512, and the disk
>> size became to 30G+512;
>
> The file size won't be changed if FALLOC_FL_KEEP_SIZE is specified,
> Pls refer to the man page of fallocate(2) for detail.
>
> Disk size should be changed to reflect this operation, why not?
>
>> 2. ftruncate the file to new_i_size which equal to inode->i_size.
>> After executing ftruncate, disk space does not changes.
>
> This is a real bug that be fixed in this patch.
>
>> In other words, i_size file is still 512, and disk size is
>> 30G+512. But we want disk size to be 512.
>
> Ditto.
>
>> This does not meet our expectations.
>
> ...
>
>>
>> In order to Solving the issue above, we modified ocfs2_setattr(),
>> if attr->ia_size != i_size_read(inode), It calls
>> ocfs2_truncate_file(), and truncate disk space to attr->ia_size.
>
> Right.
>
>>
>> Signed-off-by: Younger Liu <younger.liu at huawei.com>
>> ---
>> fs/ocfs2/alloc.c | 2 +-
>> fs/ocfs2/file.c | 7 ++-----
>> 2 files changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
>> index b8a9d87..19837d4 100644
>> --- a/fs/ocfs2/alloc.c
>> +++ b/fs/ocfs2/alloc.c
>> @@ -7126,7 +7126,7 @@ int ocfs2_truncate_inline(struct inode *inode, struct buffer_head *di_bh,
>> if (end > i_size_read(inode))
>> end = i_size_read(inode);
>>
>> - BUG_ON(start >= end);
>> + BUG_ON(start > end);
>>
>> if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
>> !(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL) ||
>> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
>> index 793c010..2e405e8 100644
>> --- a/fs/ocfs2/file.c
>> +++ b/fs/ocfs2/file.c
>> @@ -476,9 +476,6 @@ static int ocfs2_truncate_file(struct inode *inode,
>>
>> /* lets handle the simple truncate cases before doing any more
>> * cluster locking. */
>
> Above pointless comments should be removed with this change as well.
>
>> - if (new_i_size == le64_to_cpu(fe->i_size))
>> - goto bail;
>> -
>> down_write(&OCFS2_I(inode)->ip_alloc_sem);
>>
>> ocfs2_resv_discard(&osb->osb_la_resmap,
>> @@ -1150,14 +1147,14 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
>> goto bail_unlock_rw;
>> }
>>
>> - if (size_change && attr->ia_size != i_size_read(inode)) {
>> + if (size_change) {
>> status = inode_newsize_ok(inode, attr->ia_size);
>> if (status)
>> goto bail_unlock;
>>
>> inode_dio_wait(inode);
>>
>> - if (i_size_read(inode) > attr->ia_size) {
>> + if (i_size_read(inode) >= attr->ia_size) {
>> if (ocfs2_should_order_data(inode)) {
>> status = ocfs2_begin_ordered_truncate(inode,
>> attr->ia_size);
>
>
> So I also run a quick test to verify this patch, it looks fine.
>
> # dd if=/dev/zero of=/ocfs2/test bs=512 count=1
> 1+0 records in
> 1+0 records out
> 512 bytes (512 B) copied, 0.000150857 s, 3.4 MB/s
>
> # xfs_io -c 'falloc -k 512 3G' /ocfs2/test
> # ls -l /ocfs2/test
> -rw-r--r-- 1 root root 512 Jun 28 11:47 /ocfs2/test
> # df -h
> Filesystem Size Used Avail Use% Mounted on
> ....
> /dev/sdb1 8.0G 3.4G 4.7G 42% /ocfs2
>
> # xfs_io -c 'truncate 512' /ocfs2/test
>
> # df -h
> Filesystem Size Used Avail Use% Mounted on
> .....
> /dev/sdb1 8.0G 363M 7.7G 5% /ocfs2
>
> # ls -l /ocfs2/test
> -rw-r--r-- 1 root root 512 Jun 28 11:47 /ocfs2/test
>
>
> With above bug description problems were fixed, you can
> consider to add:
> Reviewed-by: Jie Liu <jeff.liu at oracle.com>
> Tested-by: Jie Liu <jeff.liu at oracle.com>
>
> -Jeff
>
> .
>
Thanks, I will resent the patch in a moment.
Younger
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