From: majianpeng <majianpeng@gmail.com>
To: "Yan, Zheng" <ukernel@gmail.com>
Cc: sage <sage@inktank.com>, "Yan, Zheng" <zheng.z.yan@intel.com>,
ceph-devel <ceph-devel@vger.kernel.org>
Subject: Re: Re: [PATCH V4 1/2] ceph: Implement readv/preadv for sync operation.
Date: Sun, 22 Sep 2013 11:00:11 +0800 [thread overview]
Message-ID: <201309221100079637870@gmail.com> (raw)
In-Reply-To: CAAM7YAkCQ1Jkd9B=C4mZT0109=-LXPcBYSo34j2EA4QMsmky5Q@mail.gmail.com
>On Thu, Sep 12, 2013 at 1:25 PM, majianpeng <majianpeng@gmail.com> wrote:
>> For readv/preadv sync-operatoin, ceph only do the first iov.
>> It don't think other iovs.Now implement this.
>>
>> V4:
>> modify one bug.
>> V3:
>> modify some bug.
>> V2:
>> -add generic_segment_checks
>> -using struct iov_iter replace cloning the iovs.
>> -return previous successfully copied if ceph_copy_page_vector_to_user
>> met error.
>>
>>
>> Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
>> Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
>> ---
>> fs/ceph/file.c | 157 ++++++++++++++++++++++++++++++++++++++-------------------
>> 1 file changed, 106 insertions(+), 51 deletions(-)
>>
>> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
>> index 3de8982..bc7fa52 100644
>> --- a/fs/ceph/file.c
>> +++ b/fs/ceph/file.c
>> @@ -408,51 +408,94 @@ more:
>> *
>> * If the read spans object boundary, just do multiple reads.
>> */
>> -static ssize_t ceph_sync_read(struct file *file, char __user *data,
>> - unsigned len, loff_t *poff, int *checkeof)
>> +static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i,
>> + int *checkeof)
>> {
>> + struct file *file = iocb->ki_filp;
>> struct inode *inode = file_inode(file);
>> struct page **pages;
>> - u64 off = *poff;
>> + u64 off = iocb->ki_pos;
>> int num_pages, ret;
>>
>> - dout("sync_read on file %p %llu~%u %s\n", file, off, len,
>> + dout("sync_read on file %p %llu~%u %s\n", file, off,
>> + (unsigned)iocb->ki_left,
>> (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
>> -
>> - if (file->f_flags & O_DIRECT) {
>> - num_pages = calc_pages_for((unsigned long)data, len);
>> - pages = ceph_get_direct_page_vector(data, num_pages, true);
>> - } else {
>> - num_pages = calc_pages_for(off, len);
>> - pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
>> - }
>> - if (IS_ERR(pages))
>> - return PTR_ERR(pages);
>> -
>> /*
>> * flush any page cache pages in this range. this
>> * will make concurrent normal and sync io slow,
>> * but it will at least behave sensibly when they are
>> * in sequence.
>> */
>> - ret = filemap_write_and_wait(inode->i_mapping);
>> + ret = filemap_write_and_wait_range(inode->i_mapping, off,
>> + off + iocb->ki_left);
>> if (ret < 0)
>> - goto done;
>> -
>> - ret = striped_read(inode, off, len, pages, num_pages, checkeof,
>> - file->f_flags & O_DIRECT,
>> - (unsigned long)data & ~PAGE_MASK);
>> + return ret;
>>
>> - if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
>> - ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
>> - if (ret >= 0)
>> - *poff = off + ret;
>> + if (file->f_flags & O_DIRECT) {
>> + while (iov_iter_count(i)) {
>> + void __user *data = i->iov[0].iov_base + i->iov_offset;
>> + size_t len = i->iov[0].iov_len - i->iov_offset;
>> +
>> + num_pages = calc_pages_for((unsigned long)data, len);
>> + pages = ceph_get_direct_page_vector(data,
>> + num_pages, true);
>> + if (IS_ERR(pages))
>> + return PTR_ERR(pages);
>> +
>> + ret = striped_read(inode, off, len,
>> + pages, num_pages, checkeof,
>> + 1, (unsigned long)data & ~PAGE_MASK);
>> + ceph_put_page_vector(pages, num_pages, true);
>> +
>> + if (ret <= 0)
>> + break;
>> + off += ret;
>> + iov_iter_advance(i, ret);
>> + if (ret < len)
>> + break;
>> + }
>> + } else {
>> + size_t len = iocb->ki_left;
>>
>> -done:
>> - if (file->f_flags & O_DIRECT)
>> - ceph_put_page_vector(pages, num_pages, true);
>> - else
>> + num_pages = calc_pages_for(off, len);
>> + pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
>> + if (IS_ERR(pages))
>> + return PTR_ERR(pages);
>> + ret = striped_read(inode, off, len, pages,
>> + num_pages, checkeof, 0, 0);
>> + if (ret > 0) {
>> + int l, k = 0;
>> + size_t left = len = ret;
>> +
>> + while (left) {
>> + void __user *data = i->iov[0].iov_base
>> + + i->iov_offset;
>> + l = min(i->iov[0].iov_len - i->iov_offset,
>> + left);
>> +
>> + ret = ceph_copy_page_vector_to_user(&pages[k],
>> + data, off,
>> + l);
>> + if (ret > 0) {
>> + iov_iter_advance(i, ret);
>> + left -= ret;
>> + off += ret;
>> + k = calc_pages_for(iocb->ki_pos,
>> + len - left + 1) - 1;
>> + BUG_ON(k >= num_pages && left);
>> + } else
>> + break;
>> + }
>> + }
>> ceph_release_page_vector(pages, num_pages);
>> + }
>> +
>> + if (off > iocb->ki_pos) {
>> + ret = off - iocb->ki_pos;
>> + iocb->ki_pos = off;
>> + iocb->ki_left -= ret;
>> + }
>> +
>> dout("sync_read result %d\n", ret);
>> return ret;
>> }
>> @@ -647,55 +690,67 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
>> {
>> struct file *filp = iocb->ki_filp;
>> struct ceph_file_info *fi = filp->private_data;
>> - loff_t *ppos = &iocb->ki_pos;
>> - size_t len = iov->iov_len;
>> + size_t len = 0;
>> struct inode *inode = file_inode(filp);
>> struct ceph_inode_info *ci = ceph_inode(inode);
>> - void __user *base = iov->iov_base;
>> ssize_t ret;
>> int want, got = 0;
>> int checkeof = 0, read = 0;
>>
>> dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
>> inode, ceph_vinop(inode), pos, (unsigned)len, inode);
>> -again:
>> +
>> + ret = generic_segment_checks(iov, &nr_segs, &len, VERIFY_WRITE);
>> + if (ret)
>> + return ret;
>> +
>> if (fi->fmode & CEPH_FILE_MODE_LAZY)
>> want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
>> else
>> want = CEPH_CAP_FILE_CACHE;
>> ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
>> if (ret < 0)
>> - goto out;
>> + return ret;
>> +
>> dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
>> inode, ceph_vinop(inode), pos, (unsigned)len,
>> ceph_cap_string(got));
>>
>> if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
>> (iocb->ki_filp->f_flags & O_DIRECT) ||
>> - (fi->flags & CEPH_F_SYNC))
>> + (fi->flags & CEPH_F_SYNC)) {
>> + struct iov_iter i;
>> +
>> + iocb->ki_left = len;
>> + iov_iter_init(&i, iov, nr_segs, len, 0);
>> +again:
>> /* hmm, this isn't really async... */
>> - ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
>> - else
>> + ret = ceph_sync_read(iocb, &i, &checkeof);
>> +
>> + if (checkeof && ret >= 0) {
>> + int statret = ceph_do_getattr(inode,
>> + CEPH_STAT_CAP_SIZE);
>
>It's wrong to move getattr to here. because getattr while holding Fr
>cap can cause hang.
>
>Regards
>Yan, Zheng
>
Hi,
Can you explain in detail?
Thanks!
Jianpeng Ma
next prev parent reply other threads:[~2013-09-22 3:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-12 5:25 [PATCH V4 1/2] ceph: Implement readv/preadv for sync operation majianpeng
2013-09-12 5:38 ` Yan, Zheng
2013-09-22 2:04 ` Yan, Zheng
2013-09-22 3:00 ` majianpeng [this message]
2013-09-22 4:17 ` Yan, Zheng
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