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| author | Jeff Layton <jlayton@redhat.com> | 2016-07-01 09:39:20 -0400 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2016-07-28 03:00:39 +0200 |
| commit | 14fb9c9efe3570459b6bddd76a990140917237ad (patch) | |
| tree | daf8c348ec9487c5d3466dbb00b39dbf28e562e4 /fs | |
| parent | 5b484a513149f53613d376a9d1cd0391de099fb4 (diff) | |
| download | linux-14fb9c9efe3570459b6bddd76a990140917237ad.tar.bz2 | |
ceph: allow dentry_lease_is_valid to work under RCU walk
Under rcuwalk, we need to take extra care when dereferencing d_parent.
We want to do that once and pass a pointer to dentry_lease_is_valid.
Also, we must ensure that that function can handle the case where we're
racing with d_release. Check whether "di" is NULL under the d_lock, and
just return 0 if so.
Finally, we still need to kick off a renewal job if the lease is getting
close to expiration. If that's the case, then just drop out of rcuwalk
mode since that could block.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ceph/dir.c | 41 |
1 files changed, 26 insertions, 15 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 904dc671580f..60dcca163ba0 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -1133,7 +1133,8 @@ void ceph_invalidate_dentry_lease(struct dentry *dentry) * Check if dentry lease is valid. If not, delete the lease. Try to * renew if the least is more than half up. */ -static int dentry_lease_is_valid(struct dentry *dentry) +static int dentry_lease_is_valid(struct dentry *dentry, unsigned int flags, + struct inode *dir) { struct ceph_dentry_info *di; struct ceph_mds_session *s; @@ -1141,12 +1142,11 @@ static int dentry_lease_is_valid(struct dentry *dentry) u32 gen; unsigned long ttl; struct ceph_mds_session *session = NULL; - struct inode *dir = NULL; u32 seq = 0; spin_lock(&dentry->d_lock); di = ceph_dentry(dentry); - if (di->lease_session) { + if (di && di->lease_session) { s = di->lease_session; spin_lock(&s->s_gen_ttl_lock); gen = s->s_cap_gen; @@ -1159,12 +1159,19 @@ static int dentry_lease_is_valid(struct dentry *dentry) valid = 1; if (di->lease_renew_after && time_after(jiffies, di->lease_renew_after)) { - /* we should renew */ - dir = d_inode(dentry->d_parent); - session = ceph_get_mds_session(s); - seq = di->lease_seq; - di->lease_renew_after = 0; - di->lease_renew_from = jiffies; + /* + * We should renew. If we're in RCU walk mode + * though, we can't do that so just return + * -ECHILD. + */ + if (flags & LOOKUP_RCU) { + valid = -ECHILD; + } else { + session = ceph_get_mds_session(s); + seq = di->lease_seq; + di->lease_renew_after = 0; + di->lease_renew_from = jiffies; + } } } } @@ -1224,12 +1231,16 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags) } else if (d_really_is_positive(dentry) && ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) { valid = 1; - } else if (dentry_lease_is_valid(dentry) || - dir_lease_is_valid(dir, dentry)) { - if (d_really_is_positive(dentry)) - valid = ceph_is_any_caps(d_inode(dentry)); - else - valid = 1; + } else { + valid = dentry_lease_is_valid(dentry, flags, dir); + if (valid == -ECHILD) + return valid; + if (valid || dir_lease_is_valid(dir, dentry)) { + if (d_really_is_positive(dentry)) + valid = ceph_is_any_caps(d_inode(dentry)); + else + valid = 1; + } } if (!valid) { |