>Hi,
>
>Thank you for the patch.
>
>On 09/03/2013 04:52 PM, majianpeng wrote:
>> For writev/pwritev sync-operatoin, ceph only do the first iov.
>> It don't think other iovs.Now implement this.
>> I divided the write-sync-operation into two functions.One for
>> direct-write,other for none-direct-sync-write.This is because for
>> none-direct-sync-write we can merge iovs to one.But for direct-write,
>> we can't merge iovs.
>>
>> Signed-off-by: Jianpeng Ma <majianpeng@xxxxxxxxx>
>> ---
>> fs/ceph/file.c | 328 +++++++++++++++++++++++++++++++++++++++++++--------------
>> 1 file changed, 248 insertions(+), 80 deletions(-)
>>
>> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
>> index 7d6a3ee..42c97b3 100644
>> --- a/fs/ceph/file.c
>> +++ b/fs/ceph/file.c
>> @@ -533,17 +533,19 @@ static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
>> }
>> }
>>
>> +
>> /*
>> - * Synchronous write, straight from __user pointer or user pages (if
>> - * O_DIRECT).
>> + * Synchronous write, straight from __user pointer or user pages.
>> *
>> * If write spans object boundary, just do multiple writes. (For a
>> * correct atomic write, we should e.g. take write locks on all
>> * objects, rollback on failure, etc.)
>> */
>> -static ssize_t ceph_sync_write(struct file *file, const char __user *data,
>> - size_t left, loff_t pos, loff_t *ppos)
>> +static ssize_t
>> +ceph_sync_direct_write(struct kiocb *iocb, const struct iovec *iov,
>> + unsigned long nr_segs, size_t count)
>> {
>> + struct file *file = iocb->ki_filp;
>> struct inode *inode = file_inode(file);
>> struct ceph_inode_info *ci = ceph_inode(inode);
>> struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
>> @@ -557,59 +559,55 @@ static ssize_t ceph_sync_write(struct file *file, const char __user *data,
>> int written = 0;
>> int flags;
>> int check_caps = 0;
>> - int page_align, io_align;
>> - unsigned long buf_align;
>> - int ret;
>> + int page_align;
>> + int ret, i;
>> struct timespec mtime = CURRENT_TIME;
>> - bool own_pages = false;
>> + loff_t pos = iocb->ki_pos;
>>
>> if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
>> return -EROFS;
>>
>> - dout("sync_write on file %p %lld~%u %s\n", file, pos,
>> - (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
>> + dout("sync_direct_write on file %p %lld~%u\n", file, pos,
>> + (unsigned)count);
>>
>> - ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
>> + ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + count);
>> if (ret < 0)
>> return ret;
>>
>> ret = invalidate_inode_pages2_range(inode->i_mapping,
>> pos >> PAGE_CACHE_SHIFT,
>> - (pos + left) >> PAGE_CACHE_SHIFT);
>> + (pos + count) >> PAGE_CACHE_SHIFT);
>> if (ret < 0)
>> dout("invalidate_inode_pages2_range returned %d\n", ret);
>>
>> flags = CEPH_OSD_FLAG_ORDERSNAP |
>> CEPH_OSD_FLAG_ONDISK |
>> CEPH_OSD_FLAG_WRITE;
>> - if ((file->f_flags & (O_SYNC|O_DIRECT)) == 0)
>> - flags |= CEPH_OSD_FLAG_ACK;
>> - else
>> - num_ops++; /* Also include a 'startsync' command. */
>> + num_ops++; /* Also include a 'startsync' command. */
>>
>> - /*
>> - * we may need to do multiple writes here if we span an object
>> - * boundary. this isn't atomic, unfortunately. :(
>> - */
>> -more:
>> - io_align = pos & ~PAGE_MASK;
>> - buf_align = (unsigned long)data & ~PAGE_MASK;
>> - len = left;
>> + for (i = 0; i < nr_segs && count; i++) {
>
>POSIX requires that write syscall is atomic. I means we should allocate a single OSD request
>for all buffer segments that belong to the same object.
>
I think we could not.
For direct write, we use ceph_get_direct_page_vector to get pages.
Given iov1 and iov2 are in the same object. But we can't make the pages of iov1/2 to join together.
Because for ceph page_vector,it only record the offset of first page.
Or am i missing something?
Maybe we can use ceph pagelist but it will copy data.
Thanks!
Jianpeng Ma
>Regards
>Yan, Zheng
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