From: Jeff Layton <jlayton@kernel.org>
To: ceph-devel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
ebiggers@kernel.org
Subject: [RFC PATCH v2 13/18] ceph: make ceph_msdc_build_path use ref-walk
Date: Fri, 4 Sep 2020 12:05:32 -0400 [thread overview]
Message-ID: <20200904160537.76663-14-jlayton@kernel.org> (raw)
In-Reply-To: <20200904160537.76663-1-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 4107dc64cc8c..e3dc061252d4 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2327,7 +2327,8 @@ 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;
@@ -2344,34 +2345,35 @@ 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;
+ cur = dget(temp->d_parent);
spin_unlock(&temp->d_lock);
- temp = READ_ONCE(temp->d_parent);
+ dput(temp);
/* Are we at the root? */
- if (IS_ROOT(temp))
+ if (IS_ROOT(cur))
break;
/* Are we out of buffer? */
@@ -2380,8 +2382,9 @@ 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;
--
2.26.2
next prev parent reply other threads:[~2020-09-04 16:07 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 16:05 [RFC PATCH v2 00/18] ceph+fscrypt: context, filename and symlink support Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 01/18] vfs: export new_inode_pseudo Jeff Layton
2020-09-08 3:38 ` Eric Biggers
2020-09-08 11:27 ` Jeff Layton
2020-09-08 22:31 ` Eric Biggers
2020-09-09 10:47 ` Jeff Layton
2020-09-09 16:12 ` Eric Biggers
2020-09-09 16:51 ` Jeff Layton
2020-09-09 18:49 ` Eric Biggers
2020-09-09 19:24 ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 02/18] fscrypt: drop unused inode argument from fscrypt_fname_alloc_buffer Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 03/18] fscrypt: export fscrypt_d_revalidate Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 04/18] fscrypt: add fscrypt_new_context_from_inode Jeff Layton
2020-09-08 3:48 ` Eric Biggers
2020-09-08 11:29 ` Jeff Layton
2020-09-08 12:29 ` Jeff Layton
2020-09-08 22:34 ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 05/18] fscrypt: don't balk when inode is already marked encrypted Jeff Layton
2020-09-08 3:52 ` Eric Biggers
2020-09-08 12:54 ` Jeff Layton
2020-09-08 23:08 ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 06/18] fscrypt: move nokey_name conversion to separate function and export it Jeff Layton
2020-09-08 3:55 ` Eric Biggers
2020-09-08 12:50 ` Jeff Layton
2020-09-08 22:53 ` Eric Biggers
2020-09-09 16:02 ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 07/18] lib: lift fscrypt base64 conversion into lib/ Jeff Layton
2020-09-08 3:59 ` Eric Biggers
2020-09-08 12:51 ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 08/18] ceph: add fscrypt ioctls Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 09/18] ceph: crypto context handling for ceph Jeff Layton
2020-09-08 4:29 ` Eric Biggers
2020-09-08 16:14 ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 10/18] ceph: preallocate inode for ops that may create one Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 11/18] ceph: add routine to create context prior to RPC Jeff Layton
2020-09-08 4:43 ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 12/18] ceph: set S_ENCRYPTED bit if new inode has encryption.ctx xattr Jeff Layton
2020-09-08 4:57 ` Eric Biggers
2020-09-09 12:20 ` Jeff Layton
2020-09-09 15:53 ` Jeff Layton
2020-09-09 16:33 ` Eric Biggers
2020-09-09 17:19 ` Jeff Layton
2020-09-04 16:05 ` Jeff Layton [this message]
2020-09-04 16:05 ` [RFC PATCH v2 14/18] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2020-09-08 5:06 ` Eric Biggers
2020-09-09 12:24 ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 15/18] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2020-09-08 5:12 ` Eric Biggers
2020-09-09 12:26 ` Jeff Layton
2020-09-09 16:18 ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 16/18] ceph: add support to readdir for encrypted filenames Jeff Layton
2020-09-08 5:34 ` Eric Biggers
2020-09-09 13:02 ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 17/18] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 18/18] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2020-09-04 16:11 ` Jeff Layton
2020-09-08 5:43 ` Eric Biggers
2020-09-08 5:54 ` [RFC PATCH v2 00/18] ceph+fscrypt: context, filename and symlink support Eric Biggers
2020-09-08 12:09 ` Jeff Layton
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