On Thu, 2022-03-03 at 11:26 +0800, xiubli@xxxxxxxxxx wrote:
> From: Xiubo Li <xiubli@xxxxxxxxxx>
>
> For the readdir request the dentries will be pasred and dencrypted
> in ceph_readdir_prepopulate(). And in ceph_readdir() we could just
> get the dentry name from the dentry cache instead of parsing and
> dencrypting them again. This could improve performance.
>
> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
> ---
> fs/ceph/crypto.h | 8 +++++
> fs/ceph/dir.c | 74 +++++++++++++++++++++++---------------------
> fs/ceph/inode.c | 15 +++++++++
> fs/ceph/mds_client.h | 1 +
> 4 files changed, 63 insertions(+), 35 deletions(-)
>
> diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
> index 1e08f8a64ad6..9a00c60b8535 100644
> --- a/fs/ceph/crypto.h
> +++ b/fs/ceph/crypto.h
> @@ -83,6 +83,14 @@ static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa)
> */
> #define CEPH_NOHASH_NAME_MAX (189 - SHA256_DIGEST_SIZE)
>
> +/*
> + * The encrypted long snap name will be in format of
> + * "_${ENCRYPTED-LONG-SNAP-NAME}_${INODE-NUM}". And will set the max longth
> + * to sizeof('_') + NAME_MAX + sizeof('_') + max of sizeof(${INO}) + extra 7
> + * bytes to align the total size to 8 bytes.
> + */
> +#define CEPH_ENCRPTED_LONG_SNAP_NAME_MAX (1 + 255 + 1 + 16 + 7)
> +
Maybe CEPH_ENCRYPTED_LONG_SNAP_NAME_MAX instead?
> void ceph_fscrypt_set_ops(struct super_block *sb);
>
> void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc);
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 4da59810b036..fa3da3b29130 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -316,8 +316,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
> int err;
> unsigned frag = -1;
> struct ceph_mds_reply_info_parsed *rinfo;
> - struct fscrypt_str tname = FSTR_INIT(NULL, 0);
> - struct fscrypt_str oname = FSTR_INIT(NULL, 0);
> + char *dentry_name = NULL;
>
> dout("readdir %p file %p pos %llx\n", inode, file, ctx->pos);
> if (dfi->file_info.flags & CEPH_F_ATEND)
> @@ -345,10 +344,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
> ctx->pos = 2;
> }
>
> - err = fscrypt_prepare_readdir(inode);
> - if (err)
> - goto out;
> -
> spin_lock(&ci->i_ceph_lock);
> /* request Fx cap. if have Fx, we don't need to release Fs cap
> * for later create/unlink. */
> @@ -369,14 +364,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
> spin_unlock(&ci->i_ceph_lock);
> }
>
> - err = ceph_fname_alloc_buffer(inode, &tname);
> - if (err < 0)
> - goto out;
> -
> - err = ceph_fname_alloc_buffer(inode, &oname);
> - if (err < 0)
> - goto out;
> -
> /* proceed with a normal readdir */
> more:
> /* do we have the correct frag content buffered? */
> @@ -528,42 +515,59 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
> }
> }
> }
> +
> + dentry_name = kmalloc(CEPH_ENCRPTED_LONG_SNAP_NAME_MAX, GFP_KERNEL);
> + if (!dentry_name) {
> + err = -ENOMEM;
> + ceph_mdsc_put_request(dfi->last_readdir);
> + dfi->last_readdir = NULL;
> + goto out;
> + }
> +
If this happens (or an earlier error), all of the dentry references will
leak. I think you probably need to move the cleanup into
destroy_reply_info().
> for (; i < rinfo->dir_nr; i++) {
> struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
> - struct ceph_fname fname = { .dir = inode,
> - .name = rde->name,
> - .name_len = rde->name_len,
> - .ctext = rde->altname,
> - .ctext_len = rde->altname_len };
> - u32 olen = oname.len;
> -
> - err = ceph_fname_to_usr(&fname, &tname, &oname, NULL);
> - if (err) {
> - pr_err("%s unable to decode %.*s, got %d\n", __func__,
> - rde->name_len, rde->name, err);
> - goto out;
> - }
> + struct dentry *dn = rde->dentry;
> + int name_len;
>
> BUG_ON(rde->offset < ctx->pos);
> BUG_ON(!rde->inode.in);
> + BUG_ON(!rde->dentry);
>
> ctx->pos = rde->offset;
> - dout("readdir (%d/%d) -> %llx '%.*s' %p\n",
> - i, rinfo->dir_nr, ctx->pos,
> - rde->name_len, rde->name, &rde->inode.in);
>
> - if (!dir_emit(ctx, oname.name, oname.len,
> + spin_lock(&dn->d_lock);
> + memcpy(dentry_name, dn->d_name.name, dn->d_name.len);
> + name_len = dn->d_name.len;
> + spin_unlock(&dn->d_lock);
> +
> + dentry_name[name_len] = '\0';
> + dout("readdir (%d/%d) -> %llx '%s' %p\n",
> + i, rinfo->dir_nr, ctx->pos, dentry_name, &rde->inode.in);
> +
> + dput(dn);
> + rde->dentry = NULL;
> +
> + if (!dir_emit(ctx, dentry_name, name_len,
> ceph_present_ino(inode->i_sb, le64_to_cpu(rde->inode.in->ino)),
> le32_to_cpu(rde->inode.in->mode) >> 12)) {
> dout("filldir stopping us...\n");
> +
> + /*
> + * dput the rest dentries. Must do this before
> + * releasing the request.
> + */
> + for (++i; i < rinfo->dir_nr; i++) {
> + rde = rinfo->dir_entries + i;
> + dput(rde->dentry);
> + rde->dentry = NULL;
> + }
> +
> err = 0;
> ceph_mdsc_put_request(dfi->last_readdir);
> dfi->last_readdir = NULL;
> goto out;
> }
>
> - /* Reset the lengths to their original allocated vals */
> - oname.len = olen;
> ctx->pos++;
> }
>
> @@ -621,8 +625,8 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
> err = 0;
> dout("readdir %p file %p done.\n", inode, file);
> out:
> - ceph_fname_free_buffer(inode, &tname);
> - ceph_fname_free_buffer(inode, &oname);
> + if (dentry_name)
> + kfree(dentry_name);
> return err;
> }
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index e5a9838981ba..d0719feed792 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -1902,6 +1902,7 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
> goto out;
> }
>
> + rde->dentry = NULL;
> dname.name = oname.name;
> dname.len = oname.len;
> dname.hash = full_name_hash(parent, dname.name, dname.len);
> @@ -1962,6 +1963,12 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
> goto retry_lookup;
> }
>
> + /*
> + * ceph_readdir will use the dentry to get the name
> + * to avoid doing the dencrypt again there.
> + */
> + rde->dentry = dget(dn);
> +
> /* inode */
> if (d_really_is_positive(dn)) {
> in = d_inode(dn);
> @@ -2024,6 +2031,14 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
> dput(dn);
> }
> out:
> + if (err) {
> + for (; i >= 0; i--) {
> + struct ceph_mds_reply_dir_entry *rde;
> +
> + rde = rinfo->dir_entries + i;
> + dput(rde->dentry);
> + }
> + }
> if (err == 0 && skipped == 0) {
> set_bit(CEPH_MDS_R_DID_PREPOPULATE, &req->r_req_flags);
> req->r_readdir_cache_idx = cache_ctl.index;
> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> index 0dfe24f94567..663d7754d57d 100644
> --- a/fs/ceph/mds_client.h
> +++ b/fs/ceph/mds_client.h
> @@ -96,6 +96,7 @@ struct ceph_mds_reply_info_in {
> };
>
> struct ceph_mds_reply_dir_entry {
> + struct dentry *dentry;
> char *name;
> u8 *altname;
> u32 name_len;
--
Jeff Layton <jlayton@xxxxxxxxxx>
