From: "Yan, Zheng" <zheng.z.yan@intel.com>
To: kedacomkernel <kedacomkernel@gmail.com>
Cc: sage <sage@inktank.com>, ceph-devel <ceph-devel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH V2 2/2] ceph: Implement writev/pwritev for sync operation.
Date: Sat, 07 Sep 2013 09:26:14 +0800 [thread overview]
Message-ID: <522A80B6.6080405@intel.com> (raw)
In-Reply-To: <201309061648267673903@gmail.com>
On 09/06/2013 04:48 PM, kedacomkernel 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.
>
> V2:
> -using struct iov_iter replace clone iovs in ceph_sync_write.
>
> Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
> ---
> fs/ceph/file.c | 314 ++++++++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 234 insertions(+), 80 deletions(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 1c28c52..8dcde64 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -547,17 +547,19 @@ 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);
> @@ -571,59 +573,55 @@ 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++) {
why not use iov iterator here? I think it makes the code simpler. For example,
below line can be changed to "while (iov_iter_count(i))".
> + void __user *data = iov[i].iov_base;
> + size_t left;
>
> - snapc = ci->i_snap_realm->cached_context;
> - vino = ceph_vino(inode);
> - req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
> - vino, pos, &len, num_ops,
> - CEPH_OSD_OP_WRITE, flags, snapc,
> - ci->i_truncate_seq, ci->i_truncate_size,
> - false);
> - if (IS_ERR(req))
> - return PTR_ERR(req);
> + left = min(count, iov[i].iov_len);
> +more:
> + page_align = (unsigned long)data & ~PAGE_MASK;
> + len = left;
> +
> + snapc = ci->i_snap_realm->cached_context;
> + vino = ceph_vino(inode);
> + req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
> + vino, pos, &len, num_ops,
> + CEPH_OSD_OP_WRITE, flags, snapc,
> + ci->i_truncate_seq,
> + ci->i_truncate_size,
> + false);
> + if (IS_ERR(req)) {
> + ret = PTR_ERR(req);
> + goto out;
> + }
>
> - /* write from beginning of first page, regardless of io alignment */
> - page_align = file->f_flags & O_DIRECT ? buf_align : io_align;
> - num_pages = calc_pages_for(page_align, len);
> - if (file->f_flags & O_DIRECT) {
> + num_pages = calc_pages_for(page_align, len);
> pages = ceph_get_direct_page_vector(data, num_pages, false);
> if (IS_ERR(pages)) {
> ret = PTR_ERR(pages);
> @@ -635,61 +633,215 @@ more:
> * may block.
> */
> truncate_inode_pages_range(inode->i_mapping, pos,
> - (pos+len) | (PAGE_CACHE_SIZE-1));
> - } else {
> + (pos+len) | (PAGE_CACHE_SIZE-1));
> + osd_req_op_extent_osd_data_pages(req, 0, pages, len, page_align,
> + false, false);
> +
> + /* BUG_ON(vino.snap != CEPH_NOSNAP); */
> + ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
> +
> + ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
> + if (!ret)
> + ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
> +
> + ceph_put_page_vector(pages, num_pages, false);
> +
> +out:
> + ceph_osdc_put_request(req);
> + if (ret == 0) {
> + pos += len;
> + written += len;
> + left -= len;
> + count -= len;
> + data += len;
> + if (left)
> + goto more;
we can get rid of this "goto" if using iov iterator
> +
> + ret = written;
> + if (pos > i_size_read(inode))
> + check_caps = ceph_inode_set_size(inode, pos);
> + if (check_caps)
> + ceph_check_caps(ceph_inode(inode),
> + CHECK_CAPS_AUTHONLY,
> + NULL);
> + } else {
> + if (ret != -EOLDSNAPC && written > 0)
> + ret = written;
> + break;
> + }
> + }
> +
> + if (ret > 0)
> + iocb->ki_pos = pos;
> + return ret;
> +}
> +
> +
> +/*
> + * 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 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);
> + struct ceph_snap_context *snapc;
> + struct ceph_vino vino;
> + struct ceph_osd_request *req;
> + int num_ops = 1;
> + struct page **pages;
> + int num_pages;
> + u64 len;
> + int written = 0;
> + int flags;
> + int check_caps = 0;
> + int ret;
> + struct timespec mtime = CURRENT_TIME;
> + loff_t pos = iocb->ki_pos;
> + struct iov_iter i;
> +
> + if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
> + return -EROFS;
> +
> + dout("sync_write on file %p %lld~%u\n", file, pos, (unsigned)count);
> +
> + 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 + 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 |
> + CEPH_OSD_FLAG_ACK;
> +
> + iov_iter_init(&i, iov, nr_segs, count, 0);
> +
> + while (i.count) {
please call iov_iter_count()
> + void __user *data;
> + size_t left;
> +
> + left = i.count;
> +more:
> + len = left;
> +
> + snapc = ci->i_snap_realm->cached_context;
> + vino = ceph_vino(inode);
> + req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
> + vino, pos, &len, num_ops,
> + CEPH_OSD_OP_WRITE, flags, snapc,
> + ci->i_truncate_seq,
> + ci->i_truncate_size,
> + false);
> + if (IS_ERR(req)) {
> + ret = PTR_ERR(req);
> + goto out;
> + }
> +
> + /*
> + * write from beginning of first page,
> + * regardless of io alignment
> + */
> + num_pages = (len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
> +
> pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
> if (IS_ERR(pages)) {
> ret = PTR_ERR(pages);
> goto out;
> }
> - ret = ceph_copy_user_to_page_vector(pages, data, pos, len);
> + if (len <= i.iov[0].iov_len - i.iov_offset) {
> + data = i.iov[0].iov_base + i.iov_offset;
> + ret = ceph_copy_user_to_page_vector(pages,
> + data, 0, len);
> +
> + if (ret > 0)
> + iov_iter_advance(&i, ret);
> + } else {
> + int l, k = 0, copyed = 0;
> + size_t tmp = len;
> +
> + while (tmp) {
> + data = i.iov[0].iov_base + i.iov_offset;
> + l = i.iov[0].iov_len - i.iov_offset;
> +
> + if (tmp < l) {
> + ret = ceph_copy_user_to_page_vector(&pages[k],
> + data,
> + copyed,
> + tmp);
> + if (ret > 0)
> + iov_iter_advance(&i, ret);
> + break;
> + } else if (l) {
> + ret = ceph_copy_user_to_page_vector(&pages[k],
> + data,
> + copyed,
> + l);
> + if (ret < 0)
> + break;
> + iov_iter_advance(&i, ret);
> + copyed += ret;
> + tmp -= ret;
> + k = calc_pages_for(0, copyed + 1) - 1;
> + }
> + }
> + }
I think using iov_iter_copy_from_user() will simplify the code. something like:
for (n = 0; n < num_pages; n++) {
size_t l = min(len, PAGE_SIZE);
ret = iov_iter_copy_from_user(pages[n], &i, 0, l);
if (ret > 0) {
iov_iter_advance(&i, ret);
copyed += ret;
}
if (ret < l)
break;
}
Regards
Yan, Zheng
> +
> if (ret < 0) {
> ceph_release_page_vector(pages, num_pages);
> goto out;
> }
>
> - if ((file->f_flags & O_SYNC) == 0) {
> - /* get a second commit callback */
> - req->r_unsafe_callback = ceph_sync_write_unsafe;
> - req->r_inode = inode;
> - own_pages = true;
> - }
> - }
> - osd_req_op_extent_osd_data_pages(req, 0, pages, len, page_align,
> - false, own_pages);
> + /* get a second commit callback */
> + req->r_unsafe_callback = ceph_sync_write_unsafe;
> + req->r_inode = inode;
>
> - /* BUG_ON(vino.snap != CEPH_NOSNAP); */
> - ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
> + osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
> + false, true);
>
> - ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
> - if (!ret)
> - ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
> + /* BUG_ON(vino.snap != CEPH_NOSNAP); */
> + ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
>
> - if (file->f_flags & O_DIRECT)
> - ceph_put_page_vector(pages, num_pages, false);
> - else if (file->f_flags & O_SYNC)
> - ceph_release_page_vector(pages, num_pages);
> + ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
> + if (!ret)
> + ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
>
> out:
> - ceph_osdc_put_request(req);
> - if (ret == 0) {
> - pos += len;
> - written += len;
> - left -= len;
> - data += len;
> - if (left)
> - goto more;
> -
> - ret = written;
> - *ppos = pos;
> - if (pos > i_size_read(inode))
> - check_caps = ceph_inode_set_size(inode, pos);
> - if (check_caps)
> - ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
> - NULL);
> - } else if (ret != -EOLDSNAPC && written > 0) {
> - ret = written;
> + ceph_osdc_put_request(req);
> + if (ret == 0) {
> + pos += len;
> + written += len;
> + left -= len;
> + if (left)
> + goto more;
> +
> + ret = written;
> + if (pos > i_size_read(inode))
> + check_caps = ceph_inode_set_size(inode, pos);
> + if (check_caps)
> + ceph_check_caps(ceph_inode(inode),
> + CHECK_CAPS_AUTHONLY,
> + NULL);
> + } else {
> + if (ret != -EOLDSNAPC && written > 0)
> + ret = written;
> + break;
> + }
> }
> +
> + if (ret > 0)
> + iocb->ki_pos = pos;
> return ret;
> }
>
> @@ -844,11 +996,13 @@ retry_snap:
> inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
>
> if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
> - (iocb->ki_filp->f_flags & O_DIRECT) ||
> - (fi->flags & CEPH_F_SYNC)) {
> + (file->f_flags & O_DIRECT) || (fi->flags & CEPH_F_SYNC)) {
> mutex_unlock(&inode->i_mutex);
> - written = ceph_sync_write(file, iov->iov_base, count,
> - pos, &iocb->ki_pos);
> + if (file->f_flags & O_DIRECT)
> + written = ceph_sync_direct_write(iocb, iov,
> + nr_segs, count);
> + else
> + written = ceph_sync_write(iocb, iov, nr_segs, count);
> if (written == -EOLDSNAPC) {
> dout("aio_write %p %llx.%llx %llu~%u"
> "got EOLDSNAPC, retrying\n",
>
prev parent reply other threads:[~2013-09-07 1:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-06 8:48 [PATCH V2 2/2] ceph: Implement writev/pwritev for sync operation kedacomkernel
2013-09-07 1:26 ` Yan, Zheng [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=522A80B6.6080405@intel.com \
--to=zheng.z.yan@intel.com \
--cc=ceph-devel@vger.kernel.org \
--cc=kedacomkernel@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=sage@inktank.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).