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do_add_mount(): lift lock_mount/unlock_mount into callers 

preparation to finish_automount() fix (next commit)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-01-11 10:14:09 -05:00
parent bb6d3fb354
commit 8f11538ebe
1 changed files with 24 additions and 23 deletions
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47
fs/namespace.c
View File

@ -2697,45 +2697,32 @@ static int do_move_mount_old(struct path *path, const char *old_name)
/*
* add a mount into a namespace's mount tree
*/
static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags)
static int do_add_mount(struct mount *newmnt, struct mountpoint *mp,
struct path *path, int mnt_flags)
{
struct mountpoint *mp;
struct mount *parent;
int err;
struct mount *parent = real_mount(path->mnt);
mnt_flags &= ~MNT_INTERNAL_FLAGS;
mp = lock_mount(path);
if (IS_ERR(mp))
return PTR_ERR(mp);
parent = real_mount(path->mnt);
err = -EINVAL;
if (unlikely(!check_mnt(parent))) {
/* that's acceptable only for automounts done in private ns */
if (!(mnt_flags & MNT_SHRINKABLE))
goto unlock;
return -EINVAL;
/* ... and for those we'd better have mountpoint still alive */
if (!parent->mnt_ns)
goto unlock;
return -EINVAL;
}
/* Refuse the same filesystem on the same mount point */
err = -EBUSY;
if (path->mnt->mnt_sb == newmnt->mnt.mnt_sb &&
path->mnt->mnt_root == path->dentry)
goto unlock;
return -EBUSY;
err = -EINVAL;
if (d_is_symlink(newmnt->mnt.mnt_root))
goto unlock;
return -EINVAL;
newmnt->mnt.mnt_flags = mnt_flags;
err = graft_tree(newmnt, parent, mp);
unlock:
unlock_mount(mp);
return err;
return graft_tree(newmnt, parent, mp);
}
static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags);
@ -2748,6 +2735,7 @@ static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint,
unsigned int mnt_flags)
{
struct vfsmount *mnt;
struct mountpoint *mp;
struct super_block *sb = fc->root->d_sb;
int error;
@ -2768,7 +2756,13 @@ static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint,
mnt_warn_timestamp_expiry(mountpoint, mnt);
error = do_add_mount(real_mount(mnt), mountpoint, mnt_flags);
mp = lock_mount(mountpoint);
if (IS_ERR(mp)) {
mntput(mnt);
return PTR_ERR(mp);
}
error = do_add_mount(real_mount(mnt), mp, mountpoint, mnt_flags);
unlock_mount(mp);
if (error < 0)
mntput(mnt);
return error;
@ -2830,6 +2824,7 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
int finish_automount(struct vfsmount *m, struct path *path)
{
struct mount *mnt = real_mount(m);
struct mountpoint *mp;
int err;
/* The new mount record should have at least 2 refs to prevent it being
* expired before we get a chance to add it
@ -2842,7 +2837,13 @@ int finish_automount(struct vfsmount *m, struct path *path)
goto fail;
}
err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
mp = lock_mount(path);
if (IS_ERR(mp)) {
err = PTR_ERR(mp);
goto fail;
}
err = do_add_mount(mnt, mp, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
unlock_mount(mp);
if (!err)
return 0;
fail: