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OpenCloudOS-Kernel
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ovl: take mnt_want_write() for work/index dir setup 

There are several write operations on upper fs not covered by
mnt_want_write():

- test set/remove OPAQUE xattr
- test create O_TMPFILE
- set ORIGIN xattr in ovl_verify_origin()
- cleanup of index entries in ovl_indexdir_cleanup()

Some of these go way back, but this patch only applies over the
v4.14 re-factoring of ovl_fill_super().

Cc: <stable@vger.kernel.org> #v4.14
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2018-01-03 18:54:41 +02:00 committed by Miklos Szeredi
parent f81678173c
commit 2ba9d57e65
1 changed files with 17 additions and 8 deletions
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25
fs/overlayfs/super.c
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@ -521,10 +521,6 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
bool retried = false;
bool locked = false;
err = mnt_want_write(mnt);
if (err)
goto out_err;
inode_lock_nested(dir, I_MUTEX_PARENT);
locked = true;
@ -589,7 +585,6 @@ retry:
goto out_err;
}
out_unlock:
mnt_drop_write(mnt);
if (locked)
inode_unlock(dir);
@ -930,12 +925,17 @@ out:
static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
{
struct vfsmount *mnt = ofs->upper_mnt;
struct dentry *temp;
int err;
err = mnt_want_write(mnt);
if (err)
return err;
ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false);
if (!ofs->workdir)
return 0;
goto out;
/*
* Upper should support d_type, else whiteouts are visible. Given
@ -945,7 +945,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
*/
err = ovl_check_d_type_supported(workpath);
if (err < 0)
return err;
goto out;
/*
* We allowed this configuration and don't want to break users over
@ -969,6 +969,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
if (err) {
ofs->noxattr = true;
pr_warn("overlayfs: upper fs does not support xattr.\n");
err = 0;
} else {
vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);
}
@ -980,7 +981,9 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n");
}
return 0;
out:
mnt_drop_write(mnt);
return err;
}
static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
@ -1027,8 +1030,13 @@ out:
static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe,
struct path *upperpath)
{
struct vfsmount *mnt = ofs->upper_mnt;
int err;
err = mnt_want_write(mnt);
if (err)
return err;
/* Verify lower root is upper root origin */
err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry,
false, true);
@ -1056,6 +1064,7 @@ static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe,
pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n");
out:
mnt_drop_write(mnt);
return err;
}