From: Dave Hansen Acked-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton --- fs/open.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff -puN fs/open.c~r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate fs/open.c --- a/fs/open.c~r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate +++ a/fs/open.c @@ -244,21 +244,21 @@ static long do_sys_truncate(const char _ if (!S_ISREG(inode->i_mode)) goto dput_and_out; - error = vfs_permission(&nd, MAY_WRITE); + error = mnt_want_write(nd.mnt); if (error) goto dput_and_out; - error = -EROFS; - if (IS_RDONLY(inode)) - goto dput_and_out; + error = vfs_permission(&nd, MAY_WRITE); + if (error) + goto mnt_drop_write_and_out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - goto dput_and_out; + goto mnt_drop_write_and_out; error = get_write_access(inode); if (error) - goto dput_and_out; + goto mnt_drop_write_and_out; /* * Make sure that there are no leases. get_write_access() protects @@ -276,6 +276,8 @@ static long do_sys_truncate(const char _ put_write_and_out: put_write_access(inode); +mnt_drop_write_and_out: + mnt_drop_write(nd.mnt); dput_and_out: path_release(&nd); out: _