On 5/12/23 22:13, 胡玮文 wrote:

On Thu, May 11, 2023 at 11:03:34AM +0800, xiubli@redhat.com wrote:

...

From: Xiubo Li xiubli@redhat.com

We need to save the 'f_ra.ra_pages' to expand the readahead window later.

Cc: stable@vger.kernel.org Fixes: 49870056005c ("ceph: convert ceph_readpages to ceph_readahead") URL: https://lore.kernel.org/ceph-devel/20230504082510.247-1-sehuww@mail.scut.edu... URL: https://www.spinics.net/lists/ceph-users/msg76183.html Cc: Hu Weiwen sehuww@mail.scut.edu.cn Signed-off-by: Xiubo Li xiubli@redhat.com

---

fs/ceph/addr.c | 43 ++++++++++++++++++++++++++++++++----------- fs/ceph/super.h | 13 +++++++++++++ 2 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 3b20873733af..db55fce13324 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -404,18 +404,27 @@ static int ceph_init_request(struct netfs_io_request *rreq, struct file *file) { struct inode *inode = rreq->inode; int got = 0, want = CEPH_CAP_FILE_CACHE;

• struct ceph_netfs_request_data *priv; int ret = 0;

if (rreq->origin != NETFS_READAHEAD) return 0;

• priv = kzalloc(sizeof(*priv), GFP_NOFS);
• if (!priv)

• return -ENOMEM;
  

• if (file) { struct ceph_rw_context *rw_ctx; struct ceph_file_info *fi = file->private_data;

rw_ctx = ceph_find_rw_context(fi);

• if (rw_ctx)
  

• if (rw_ctx) {
  

• 	kfree(priv);
  return 0;
  

This is not working. When reaching here by read() system call, we always have non-null rw_ctx. (As I read the code and also verified with gdb) ceph_add_rw_context() is invoked in ceph_read_iter().

This should work:

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index e1bf90059112..d3e37e01c3d0 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -444,13 +444,14 @@ static int ceph_init_request(struct netfs_io_request *rreq, struct file *file)                 struct ceph_rw_context *rw_ctx;                 struct ceph_file_info *fi = file->private_data;

+               priv->file_ra_pages = file->f_ra.ra_pages; +               priv->file_ra_disabled = file->f_mode & FMODE_RANDOM; +                 rw_ctx = ceph_find_rw_context(fi);                 if (rw_ctx) { -                       kfree(priv); +                       rreq->netfs_priv = priv;                         return 0;                 } -               priv->file_ra_pages = file->f_ra.ra_pages; -               priv->file_ra_disabled = !!(file->f_mode & FMODE_RANDOM);         }

/*

Thanks

- Xiubo

...

• }
  

• priv->file_ra_pages = file->f_ra.ra_pages;
  

• priv->file_ra_disabled = !!(file->f_mode & FMODE_RANDOM);
  

'!!' is not needed. From coding-style.rst: "When using bool types the !! construction is not needed, which eliminates a class of bugs".

Thanks Hu Weiwen

...

} /* @@ -425,27 +434,39 @@ static int ceph_init_request(struct netfs_io_request *rreq, struct file *file) ret = ceph_try_get_caps(inode, CEPH_CAP_FILE_RD, want, true, &got); if (ret < 0) { dout("start_read %p, error getting cap\n", inode);

• return ret;
  

• goto out;
  

  }

if (!(got & want)) { dout("start_read %p, no cache cap\n", inode);

• return -EACCES;
  

• ret = -EACCES;
  

• goto out;
  

• }
• if (ret == 0) {

• ret = -EACCES;
  

• goto out;
  

  }

• if (ret == 0)

• return -EACCES;
  

• rreq->netfs_priv = (void *)(uintptr_t)got;
• return 0;

• priv->caps = got;
• rreq->netfs_priv = priv;

+out:

• if (ret)

• kfree(priv);
  

• return ret; }

static void ceph_netfs_free_request(struct netfs_io_request *rreq) {

• struct ceph_inode_info *ci = ceph_inode(rreq->inode);
• int got = (uintptr_t)rreq->netfs_priv;

• struct ceph_netfs_request_data *priv = rreq->netfs_priv;
• if (!priv)

• return;
  

• if (got)

• ceph_put_cap_refs(ci, got);
  

• ceph_put_cap_refs(ceph_inode(rreq->inode), priv->caps);
• kfree(priv);
• rreq->netfs_priv = NULL; }

const struct netfs_request_ops ceph_netfs_ops = { diff --git a/fs/ceph/super.h b/fs/ceph/super.h index a226d36b3ecb..1233f53f6e0b 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -470,6 +470,19 @@ struct ceph_inode_info { #endif }; +struct ceph_netfs_request_data {

• int caps;
• /*

• * Maximum size of a file readahead request.
  

• * The posix_fadvise could update the bdi's default ra_pages.
  

• */
  

• unsigned int file_ra_pages;
• /* Set it if posix_fadvise disables file readahead entirely */
• bool file_ra_disabled;

+};

• static inline struct ceph_inode_info * ceph_inode(const struct inode *inode) {

-- 2.40.0