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| author | Al Viro <viro@zeniv.linux.org.uk> | 2019-10-29 16:50:19 +0300 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2019-10-30 00:29:54 +0300 |
| commit | aa8dd816732b2bab28c54bc4d2ccf3fc8a6e0892 (patch) | |
| tree | 0805d90f6214b72791f9ca0cd12cc85b1dd6d3fa | |
| parent | ea60ed6fcf29eebc78f2ce91491e6309ee005a01 (diff) | |
| download | linux-aa8dd816732b2bab28c54bc4d2ccf3fc8a6e0892.tar.xz | |
ceph: fix RCU case handling in ceph_d_revalidate()
For RCU case ->d_revalidate() is called with rcu_read_lock() and
without pinning the dentry passed to it. Which means that it
can't rely upon ->d_inode remaining stable; that's the reason
for d_inode_rcu(), actually.
Make sure we don't reload ->d_inode there.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
| -rw-r--r-- | fs/ceph/dir.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 4ca0b8ff9a72..d17a789fd856 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -1553,36 +1553,37 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags) { int valid = 0; struct dentry *parent; - struct inode *dir; + struct inode *dir, *inode; if (flags & LOOKUP_RCU) { parent = READ_ONCE(dentry->d_parent); dir = d_inode_rcu(parent); if (!dir) return -ECHILD; + inode = d_inode_rcu(dentry); } else { parent = dget_parent(dentry); dir = d_inode(parent); + inode = d_inode(dentry); } dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry, - dentry, d_inode(dentry), ceph_dentry(dentry)->offset); + dentry, inode, ceph_dentry(dentry)->offset); /* always trust cached snapped dentries, snapdir dentry */ if (ceph_snap(dir) != CEPH_NOSNAP) { dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry, - dentry, d_inode(dentry)); + dentry, inode); valid = 1; - } else if (d_really_is_positive(dentry) && - ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) { + } else if (inode && ceph_snap(inode) == CEPH_SNAPDIR) { valid = 1; } else { valid = dentry_lease_is_valid(dentry, flags); 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)); + if (inode) + valid = ceph_is_any_caps(inode); else valid = 1; } |