Re: [PATCH v6] ceph: do not dencrypt the dentry name twice for readdir

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 3/9/22 9:43 PM, Xiubo Li wrote:

On 3/9/22 9:05 PM, Jeff Layton wrote:
On Wed, 2022-03-09 at 20:25 +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>
---

V6:
- Remove CEPH_ENCRYPTED_LONG_SNAP_NAME_MAX macro and use the NAME_MAX
   instead, since we are limiting the max length of snapshot name to
   240, which is NAME_MAX - 2 * sizeof('_') - sizeof(<inode#>).

V5:
- fix typo of CEPH_ENCRYPTED_LONG_SNAP_NAME_MAX macro
- release the rde->dentry in destroy_reply_info



  fs/ceph/dir.c        | 59 +++++++++++++++++++++-----------------------
  fs/ceph/inode.c      |  7 ++++++
  fs/ceph/mds_client.c |  2 ++
  fs/ceph/mds_client.h |  1 +
  4 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 6df2a91af236..19321a1f7399 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)
@@ -369,14 +368,6 @@ 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? */
@@ -528,31 +519,39 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
              }
          }
      }
+
+    dentry_name = kmalloc(NAME_MAX, GFP_KERNEL);
+    if (!dentry_name) {
+        err = -ENOMEM;
+        ceph_mdsc_put_request(dfi->last_readdir);
+        dfi->last_readdir = NULL;
+        goto out;
+    }
+
      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;
+

It's buggy here.

In case the the dir_emit() just fails, the rde->dentry has been set to NULL, but the file->f_pos won't set to next rde, so when the next readdir comes, we will his this bug.

Since will put all the rde->dentry in the 'destroy_reply_info()' when releasing the req, so this is not needed.

I will remove the above two line and test it locally.

The relevant logs:


266272 <7>[10027.239390] ceph:  filldir stopping us...
266273 <7>[10027.240437] ceph:  readdir 00000000fae918a2 file 000000008c9cfe7f pos ff7f38e60000002 266274 <7>[10027.240448] ceph:  readdir frag 0 num 1024 pos ff7f38e60000002 chunk first ff4001b50000002 266275 <7>[10027.240493] ceph:  readdir (1022/1024) -> ff7f38e60000002 'adcaba' 000000009240ec06

After this the xfstest passed and also the fsstress test.

xfstest for generic/006:

[root@lxbceph1 xfstests]# ./check generic/006
FSTYP         -- ceph
PLATFORM      -- Linux/x86_64 lxbceph1 5.17.0-rc6+
MKFS_OPTIONS  -- 10.72.47.117:40437:/testB
MOUNT_OPTIONS -- -o test_dummy_encryption,name=admin,nowsync,copyfrom,rasize=4096 -o context=system_u:object_r:root_t:s0 10.72.47.117:40437:/testB /mnt/kcephfs.B

generic/006 49s ... 22s
Ran: generic/006
Passed all 1 tests

[root@lxbceph1 xfstests]# ./check generic/006
FSTYP         -- ceph
PLATFORM      -- Linux/x86_64 lxbceph1 5.17.0-rc6+
MKFS_OPTIONS  -- 10.72.47.117:40437:/testB
MOUNT_OPTIONS -- -o test_dummy_encryption,name=admin,nowsync,copyfrom,rasize=4096 -o context=system_u:object_r:root_t:s0 10.72.47.117:40437:/testB /mnt/kcephfs.B

generic/006 22s ... 27s
Ran: generic/006
Passed all 1 tests


fsstress test:

2/994: dread - d5/d15/d58/deb/f131 zero size
2/995: creat d5/d15/d4e/f144 x:0 0 0
2/996: symlink d5/d15/d2d/d63/dbd/l145 0
2/997: unlink d5/d15/d2d/da2/db8/d1b/l4d 0
2/998: dwrite d5/d15/f3b [4194304,4194304] 0
2/999: readlink d5/d15/d2d/da2/db8/d21/dc7/d133/l108 0
+ rm -rf -- ./tmp.PBIQVJ10zf

I will send the V7.

Thanks

- Xiubo


Thanks.

- XIubo


+        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)) {
              /*
@@ -566,8 +565,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
              goto out;
          }
  -        /* Reset the lengths to their original allocated vals */
-        oname.len = olen;
          ctx->pos++;
      }
  @@ -625,8 +622,8 @@ 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 b573a0f33450..19e5275eae1c 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1909,6 +1909,7 @@ 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);
@@ -1969,6 +1970,12 @@ 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);
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 8d704ddd7291..215a52169a1a 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -733,6 +733,8 @@ static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
            kfree(rde->inode.fscrypt_auth);
          kfree(rde->inode.fscrypt_file);
+        dput(rde->dentry);
+        rde->dentry = NULL;
      }
      free_pages((unsigned long)info->dir_entries, get_order(info->dir_buf_size));
  }
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;
Testing this on top of wip-fscrypt, I hit the new BUG_ON you added
immediately with xfstest generic/006. I haven't sat down to work out the
cause though:

[  286.647758] ------------[ cut here ]------------
[  286.652281] kernel BUG at fs/ceph/dir.c:535!
[  286.654487] invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
[  286.656188] CPU: 4 PID: 2073 Comm: find Tainted: G E     5.17.0-rc6+ #170 [  286.658393] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014
[  286.660775] RIP: 0010:ceph_readdir+0x1271/0x1d90 [ceph]
[  286.662412] Code: 25 c8 48 8b 95 d0 fa ff ff 4d 89 e9 45 89 f0 4c 89 f9 48 c7 c6 00 76 32 c1 48 c7 c7 b0 ec 38 c1 e8 c4 10 6d c8 e9 b8 fb ff ff <0f> 0b 48 89 ea b9 02 00 00 00 48 c1 ea 20 89 d0 31 e8 39 d5 0f 44
[  286.667755] RSP: 0018:ffff8881156ffce0 EFLAGS: 00010246
[  286.669225] RAX: 0000000000000000 RBX: ffff8881648b5e50 RCX: ffffffffc12d25c1 [  286.671209] RDX: dffffc0000000000 RSI: ffffffff8a40007c RDI: ffff8881648b5e50 [  286.673269] RBP: 0000000000000000 R08: ffffffffc12d2523 R09: 0000000000000000 [  286.675577] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8881156ffeb0 [  286.677013] R13: ffff8881156ffeb8 R14: ffff8881648b5e78 R15: 0ff7caa620000002 [  286.678277] FS:  00007fb446008800(0000) GS:ffff88841d400000(0000) knlGS:0000000000000000
[  286.679781] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  286.680800] CR2: 0000564c99ee90e8 CR3: 0000000117e16000 CR4: 00000000003506e0
[  286.682005] Call Trace:
[  286.682472]  <TASK>
[  286.682837]  ? __fdget_pos+0x71/0x80
[  286.683484]  ? __handle_mm_fault+0x17e0/0x1c20
[  286.684245]  ? ceph_d_revalidate+0x7e0/0x7e0 [ceph]
[  286.685265]  ? down_write_killable+0xc7/0x130
[  286.686202]  ? __down_interruptible+0x1d0/0x1d0
[  286.686965]  iterate_dir+0x107/0x2e0
[  286.687584]  __x64_sys_getdents64+0xe2/0x1b0
[  286.688360]  ? filldir+0x270/0x270
[  286.693689]  ? __ia32_sys_getdents+0x1a0/0x1a0
[  286.698465]  ? lockdep_hardirqs_on_prepare+0x129/0x220
[  286.703362]  ? syscall_enter_from_user_mode+0x21/0x70
[  286.708261]  do_syscall_64+0x3b/0x90
[  286.712819]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  286.717584] RIP: 0033:0x7fb44617afd7
[  286.722128] Code: 19 fb ff 4c 89 e0 5b 5d 41 5c c3 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 21 0e 12 00 f7 d8 64 89 02 48 [  286.733041] RSP: 002b:00007ffec9342038 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 [  286.738408] RAX: ffffffffffffffda RBX: 0000564c99e51380 RCX: 00007fb44617afd7 [  286.743834] RDX: 0000000000010000 RSI: 0000564c99e51380 RDI: 0000000000000004 [  286.749041] RBP: 0000564c99e51354 R08: 0000000000000003 R09: 0000000000000001 [  286.754147] R10: 0000000000000fff R11: 0000000000000293 R12: fffffffffffffe98 [  286.759581] R13: 0000000000000000 R14: 0000564c99e51350 R15: 00000000000010fe
[  286.764698]  </TASK>
[  286.769321] Modules linked in: ceph(E) libceph(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) bridge(E) stp(E) llc(E) ip_set(E) rfkill(E) nf_tables(E) nfnetlink(E) cachefiles(E) fscache(E) netfs(E) sunrpc(E) iTCO_wdt(E) intel_pmc_bxt(E) iTCO_vendor_support(E) intel_rapl_msr(E) joydev(E) i2c_i801(E) virtio_balloon(E) i2c_smbus(E) intel_rapl_common(E) lpc_ich(E) fuse(E) zram(E) ip_tables(E) xfs(E) crct10dif_pclmul(E) crc32_pclmul(E) crc32c_intel(E) ghash_clmulni_intel(E) serio_raw(E) virtio_gpu(E) virtio_dma_buf(E) drm_shmem_helper(E) virtio_console(E) drm_kms_helper(E) virtio_net(E) cec(E) virtio_blk(E) net_failover(E) failover(E) drm(E) qemu_fw_cfg(E)
[  286.811123] ---[ end trace 0000000000000000 ]---
[  286.826446] RIP: 0010:ceph_readdir+0x1271/0x1d90 [ceph]
[  286.858765] Code: 25 c8 48 8b 95 d0 fa ff ff 4d 89 e9 45 89 f0 4c 89 f9 48 c7 c6 00 76 32 c1 48 c7 c7 b0 ec 38 c1 e8 c4 10 6d c8 e9 b8 fb ff ff <0f> 0b 48 89 ea b9 02 00 00 00 48 c1 ea 20 89 d0 31 e8 39 d5 0f 44
[  286.873795] RSP: 0018:ffff8881156ffce0 EFLAGS: 00010246
[  286.888083] RAX: 0000000000000000 RBX: ffff8881648b5e50 RCX: ffffffffc12d25c1 [  286.906391] RDX: dffffc0000000000 RSI: ffffffff8a40007c RDI: ffff8881648b5e50 [  286.922678] RBP: 0000000000000000 R08: ffffffffc12d2523 R09: 0000000000000000 [  286.938922] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8881156ffeb0 [  286.954630] R13: ffff8881156ffeb8 R14: ffff8881648b5e78 R15: 0ff7caa620000002 [  286.970468] FS:  00007fb446008800(0000) GS:ffff88841d400000(0000) knlGS:0000000000000000
[  286.977032] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  286.990098] CR2: 0000564c99ee90e8 CR3: 0000000117e16000 CR4: 00000000003506e0





[Index of Archives]     [CEPH Users]     [Ceph Large]     [Ceph Dev]     [Information on CEPH]     [Linux BTRFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux