From: Jeff Layton <jlayton@kernel.org>
To: ceph-devel@vger.kernel.org
Cc: lhenriques@suse.de, xiubli@redhat.com,
linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
dhowells@redhat.com
Subject: [RFC PATCH v7 14/24] ceph: make ceph_msdc_build_path use ref-walk
Date: Fri, 25 Jun 2021 09:58:24 -0400 [thread overview]
Message-ID: <20210625135834.12934-15-jlayton@kernel.org> (raw)
In-Reply-To: <20210625135834.12934-1-jlayton@kernel.org>
Encryption potentially requires allocation, at which point we'll need to
be in a non-atomic context. Convert ceph_msdc_build_path to take dentry
spinlocks and references instead of using rcu_read_lock to walk the
path.
This is slightly less efficient, and we may want to eventually allow
using RCU when the leaf dentry isn't encrypted.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/mds_client.c | 35 +++++++++++++++++++----------------
1 file changed, 19 insertions(+), 16 deletions(-)
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 08710b347c07..5b7872a61ad7 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2396,7 +2396,8 @@ static inline u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
int stop_on_nosnap)
{
- struct dentry *temp;
+ struct dentry *cur;
+ struct inode *inode;
char *path;
int pos;
unsigned seq;
@@ -2413,34 +2414,35 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
path[pos] = '\0';
seq = read_seqbegin(&rename_lock);
- rcu_read_lock();
- temp = dentry;
+ cur = dget(dentry);
for (;;) {
- struct inode *inode;
+ struct dentry *temp;
- spin_lock(&temp->d_lock);
- inode = d_inode(temp);
+ spin_lock(&cur->d_lock);
+ inode = d_inode(cur);
if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
dout("build_path path+%d: %p SNAPDIR\n",
- pos, temp);
- } else if (stop_on_nosnap && inode && dentry != temp &&
+ pos, cur);
+ } else if (stop_on_nosnap && inode && dentry != cur &&
ceph_snap(inode) == CEPH_NOSNAP) {
- spin_unlock(&temp->d_lock);
+ spin_unlock(&cur->d_lock);
pos++; /* get rid of any prepended '/' */
break;
} else {
- pos -= temp->d_name.len;
+ pos -= cur->d_name.len;
if (pos < 0) {
- spin_unlock(&temp->d_lock);
+ spin_unlock(&cur->d_lock);
break;
}
- memcpy(path + pos, temp->d_name.name, temp->d_name.len);
+ memcpy(path + pos, cur->d_name.name, cur->d_name.len);
}
+ temp = cur;
spin_unlock(&temp->d_lock);
- temp = READ_ONCE(temp->d_parent);
+ cur = dget_parent(temp);
+ dput(temp);
/* Are we at the root? */
- if (IS_ROOT(temp))
+ if (IS_ROOT(cur))
break;
/* Are we out of buffer? */
@@ -2449,8 +2451,9 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
path[pos] = '/';
}
- base = ceph_ino(d_inode(temp));
- rcu_read_unlock();
+ inode = d_inode(cur);
+ base = inode ? ceph_ino(inode) : 0;
+ dput(cur);
if (read_seqretry(&rename_lock, seq))
goto retry;
--
2.31.1
next prev parent reply other threads:[~2021-06-25 13:59 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 13:58 [RFC PATCH v7 00/24] ceph+fscrypt: context, filename and symlink support Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 01/24] vfs: export new_inode_pseudo Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 02/24] fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode Jeff Layton
2021-07-11 17:40 ` Eric Biggers
2021-07-12 11:55 ` Jeff Layton
2021-07-12 14:22 ` Eric Biggers
2021-07-12 14:32 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 03/24] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size Jeff Layton
2021-07-11 17:43 ` Eric Biggers
2021-06-25 13:58 ` [RFC PATCH v7 04/24] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2021-07-11 17:44 ` Eric Biggers
2021-06-25 13:58 ` [RFC PATCH v7 05/24] ceph: preallocate inode for ops that may create one Jeff Layton
2021-07-07 3:37 ` Xiubo Li
2021-07-07 12:05 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 06/24] ceph: parse new fscrypt_auth and fscrypt_file fields in inode traces Jeff Layton
2021-07-07 3:53 ` Xiubo Li
2021-07-07 12:09 ` Jeff Layton
2021-07-07 12:46 ` Xiubo Li
2021-07-07 10:47 ` Luis Henriques
2021-07-07 11:19 ` Xiubo Li
2021-07-07 12:19 ` Jeff Layton
2021-07-07 14:32 ` Luis Henriques
2021-07-07 14:56 ` Luis Henriques
2021-07-08 2:56 ` Xiubo Li
2021-07-08 11:26 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 07/24] ceph: add fscrypt_* handling to caps.c Jeff Layton
2021-07-07 7:20 ` Xiubo Li
2021-07-07 12:02 ` Jeff Layton
2021-07-07 12:47 ` Xiubo Li
2021-07-11 23:00 ` Eric Biggers
2021-07-12 13:22 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 08/24] ceph: add ability to set fscrypt_auth via setattr Jeff Layton
2021-07-07 8:11 ` Xiubo Li
2021-07-07 12:10 ` Jeff Layton
2021-07-07 10:47 ` Luis Henriques
2021-07-07 12:25 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 09/24] ceph: crypto context handling for ceph Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 10/24] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 11/24] ceph: add routine to create fscrypt context prior to RPC Jeff Layton
2021-07-07 10:48 ` Luis Henriques
2021-07-07 12:29 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 12/24] ceph: add fscrypt ioctls Jeff Layton
2021-07-08 7:30 ` Xiubo Li
2021-07-08 11:26 ` Jeff Layton
2021-07-08 11:32 ` Xiubo Li
2021-06-25 13:58 ` [RFC PATCH v7 13/24] ceph: decode alternate_name in lease info Jeff Layton
2021-06-25 13:58 ` Jeff Layton [this message]
2021-06-25 13:58 ` [RFC PATCH v7 15/24] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2021-07-11 22:53 ` Eric Biggers
2021-07-12 12:36 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 16/24] ceph: send altname in MClientRequest Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 17/24] ceph: properly set DCACHE_NOKEY_NAME flag in lookup Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 18/24] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 19/24] ceph: add helpers for converting names for userland presentation Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 20/24] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 21/24] ceph: add support to readdir for encrypted filenames Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 22/24] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 23/24] ceph: make ceph_get_name decrypt filenames Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 24/24] ceph: add a new ceph.fscrypt.auth vxattr Jeff Layton
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