summaryrefslogtreecommitdiffstats
path: root/kernel/fs/namespace.c
diff options
context:
space:
mode:
authorYunhong Jiang <yunhong.jiang@linux.intel.com>2017-03-08 23:13:28 -0800
committerYunhong Jiang <yunhong.jiang@linux.intel.com>2017-03-08 23:36:15 -0800
commit52f993b8e89487ec9ee15a7fb4979e0f09a45b27 (patch)
treed65304486afe0bea4a311c783c0d72791c8c0aa2 /kernel/fs/namespace.c
parentc189ccac5702322ed843fe17057035b7222a59b6 (diff)
Upgrade to 4.4.50-rt62
The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it to 4.4.50-rt62. The command to achieve it is: a) Clone a git repo from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git b) Get the diff between this two changesets: git diff 640eca2901f3435e616157b11379d3223a44b391 705619beeea1b0b48219a683fd1a901a86fdaf5e where the two commits are: [yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only 640eca2901f3435e616157b11379d3223a44b391 640eca2901f3 v4.4.6-rt14 localversion-rt [yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only 705619beeea1b0b48219a683fd1a901a86fdaf5e 705619beeea1 Linux 4.4.50-rt62 localversion-rt c) One patch has been backported thus revert the patch before applying. filterdiff -p1 -x scripts/package/Makefile ~/tmp/v4.4.6-rt14-4.4.50-rt62.diff |patch -p1 --dry-run Upstream status: backport Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01 Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Diffstat (limited to 'kernel/fs/namespace.c')
-rw-r--r--kernel/fs/namespace.c75
1 files changed, 54 insertions, 21 deletions
diff --git a/kernel/fs/namespace.c b/kernel/fs/namespace.c
index 62588bfcd..c09f16efd 100644
--- a/kernel/fs/namespace.c
+++ b/kernel/fs/namespace.c
@@ -747,26 +747,50 @@ static struct mountpoint *lookup_mountpoint(struct dentry *dentry)
return NULL;
}
-static struct mountpoint *new_mountpoint(struct dentry *dentry)
+static struct mountpoint *get_mountpoint(struct dentry *dentry)
{
- struct hlist_head *chain = mp_hash(dentry);
- struct mountpoint *mp;
+ struct mountpoint *mp, *new = NULL;
int ret;
- mp = kmalloc(sizeof(struct mountpoint), GFP_KERNEL);
- if (!mp)
+ if (d_mountpoint(dentry)) {
+mountpoint:
+ read_seqlock_excl(&mount_lock);
+ mp = lookup_mountpoint(dentry);
+ read_sequnlock_excl(&mount_lock);
+ if (mp)
+ goto done;
+ }
+
+ if (!new)
+ new = kmalloc(sizeof(struct mountpoint), GFP_KERNEL);
+ if (!new)
return ERR_PTR(-ENOMEM);
+
+ /* Exactly one processes may set d_mounted */
ret = d_set_mounted(dentry);
- if (ret) {
- kfree(mp);
- return ERR_PTR(ret);
- }
- mp->m_dentry = dentry;
- mp->m_count = 1;
- hlist_add_head(&mp->m_hash, chain);
- INIT_HLIST_HEAD(&mp->m_list);
+ /* Someone else set d_mounted? */
+ if (ret == -EBUSY)
+ goto mountpoint;
+
+ /* The dentry is not available as a mountpoint? */
+ mp = ERR_PTR(ret);
+ if (ret)
+ goto done;
+
+ /* Add the new mountpoint to the hash table */
+ read_seqlock_excl(&mount_lock);
+ new->m_dentry = dentry;
+ new->m_count = 1;
+ hlist_add_head(&new->m_hash, mp_hash(dentry));
+ INIT_HLIST_HEAD(&new->m_list);
+ read_sequnlock_excl(&mount_lock);
+
+ mp = new;
+ new = NULL;
+done:
+ kfree(new);
return mp;
}
@@ -1561,11 +1585,12 @@ void __detach_mounts(struct dentry *dentry)
struct mount *mnt;
namespace_lock();
+ lock_mount_hash();
mp = lookup_mountpoint(dentry);
if (IS_ERR_OR_NULL(mp))
goto out_unlock;
- lock_mount_hash();
+ event++;
while (!hlist_empty(&mp->m_list)) {
mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
@@ -1574,9 +1599,9 @@ void __detach_mounts(struct dentry *dentry)
}
else umount_tree(mnt, UMOUNT_CONNECTED);
}
- unlock_mount_hash();
put_mountpoint(mp);
out_unlock:
+ unlock_mount_hash();
namespace_unlock();
}
@@ -1965,9 +1990,7 @@ retry:
namespace_lock();
mnt = lookup_mnt(path);
if (likely(!mnt)) {
- struct mountpoint *mp = lookup_mountpoint(dentry);
- if (!mp)
- mp = new_mountpoint(dentry);
+ struct mountpoint *mp = get_mountpoint(dentry);
if (IS_ERR(mp)) {
namespace_unlock();
mutex_unlock(&dentry->d_inode->i_mutex);
@@ -1986,7 +2009,11 @@ retry:
static void unlock_mount(struct mountpoint *where)
{
struct dentry *dentry = where->m_dentry;
+
+ read_seqlock_excl(&mount_lock);
put_mountpoint(where);
+ read_sequnlock_excl(&mount_lock);
+
namespace_unlock();
mutex_unlock(&dentry->d_inode->i_mutex);
}
@@ -2405,8 +2432,10 @@ static int do_new_mount(struct path *path, const char *fstype, int flags,
mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV;
}
if (type->fs_flags & FS_USERNS_VISIBLE) {
- if (!fs_fully_visible(type, &mnt_flags))
+ if (!fs_fully_visible(type, &mnt_flags)) {
+ put_filesystem(type);
return -EPERM;
+ }
}
}
@@ -3056,9 +3085,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
touch_mnt_namespace(current->nsproxy->mnt_ns);
/* A moved mount should not expire automatically */
list_del_init(&new_mnt->mnt_expire);
+ put_mountpoint(root_mp);
unlock_mount_hash();
chroot_fs_refs(&root, &new);
- put_mountpoint(root_mp);
error = 0;
out4:
unlock_mount(old_mp);
@@ -3240,6 +3269,10 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
if (mnt->mnt.mnt_sb->s_iflags & SB_I_NOEXEC)
mnt_flags &= ~(MNT_LOCK_NOSUID | MNT_LOCK_NOEXEC);
+ /* Don't miss readonly hidden in the superblock flags */
+ if (mnt->mnt.mnt_sb->s_flags & MS_RDONLY)
+ mnt_flags |= MNT_LOCK_READONLY;
+
/* Verify the mount flags are equal to or more permissive
* than the proposed new mount.
*/
@@ -3266,7 +3299,7 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
struct inode *inode = child->mnt_mountpoint->d_inode;
/* Only worry about locked mounts */
- if (!(mnt_flags & MNT_LOCKED))
+ if (!(child->mnt.mnt_flags & MNT_LOCKED))
continue;
/* Is the directory permanetly empty? */
if (!is_empty_dir_inode(inode))