From: Amir Goldstein <amir73il@gmail.com> mainline inclusion from mainline-v6.8-rc1 commit f567377e406c032fff0799bde4fdf4a977529b84 category: feature bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBHLU4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- include/linux/backing-file.h | 2 ++ fs/backing-file.c | 27 +++++++++++++++++++++++++++ fs/overlayfs/file.c | 23 ++++++----------------- 3 files changed, 35 insertions(+), 17 deletions(-) diff --git a/include/linux/backing-file.h b/include/linux/backing-file.h index 0546d5b1c9f5..3f1fe1774f1b 100644 --- a/include/linux/backing-file.h +++ b/include/linux/backing-file.h @@ -36,5 +36,7 @@ ssize_t backing_file_splice_write(struct pipe_inode_info *pipe, struct file *out, loff_t *ppos, size_t len, unsigned int flags, struct backing_file_ctx *ctx); +int backing_file_mmap(struct file *file, struct vm_area_struct *vma, + struct backing_file_ctx *ctx); #endif /* _LINUX_BACKING_FILE_H */ diff --git a/fs/backing-file.c b/fs/backing-file.c index ddd35c1d6c71..a681f38d84d8 100644 --- a/fs/backing-file.c +++ b/fs/backing-file.c @@ -11,6 +11,7 @@ #include <linux/fs.h> #include <linux/backing-file.h> #include <linux/splice.h> +#include <linux/mm.h> #include "internal.h" @@ -296,6 +297,32 @@ ssize_t backing_file_splice_write(struct pipe_inode_info *pipe, } EXPORT_SYMBOL_GPL(backing_file_splice_write); +int backing_file_mmap(struct file *file, struct vm_area_struct *vma, + struct backing_file_ctx *ctx) +{ + const struct cred *old_cred; + int ret; + + if (WARN_ON_ONCE(!(file->f_mode & FMODE_BACKING)) || + WARN_ON_ONCE(ctx->user_file != vma->vm_file)) + return -EIO; + + if (!file->f_op->mmap) + return -ENODEV; + + vma_set_file(vma, file); + + old_cred = override_creds(ctx->cred); + ret = call_mmap(vma->vm_file, vma); + revert_creds(old_cred); + + if (ctx->accessed) + ctx->accessed(ctx->user_file); + + return ret; +} +EXPORT_SYMBOL_GPL(backing_file_mmap); + static int __init backing_aio_init(void) { backing_aio_cachep = kmem_cache_create("backing_aio", diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 5ca2fab77cc1..63f4b22ee955 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -10,7 +10,6 @@ #include <linux/uio.h> #include <linux/uaccess.h> #include <linux/security.h> -#include <linux/mm.h> #include <linux/fs.h> #include <linux/backing-file.h> #include "overlayfs.h" @@ -412,23 +411,13 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) static int ovl_mmap(struct file *file, struct vm_area_struct *vma) { struct file *realfile = file->private_data; - const struct cred *old_cred; - int ret; - - if (!realfile->f_op->mmap) - return -ENODEV; - - if (WARN_ON(file != vma->vm_file)) - return -EIO; - - vma_set_file(vma, realfile); - - old_cred = ovl_override_creds(file_inode(file)->i_sb); - ret = call_mmap(vma->vm_file, vma); - revert_creds(old_cred); - ovl_file_accessed(file); + struct backing_file_ctx ctx = { + .cred = ovl_creds(file_inode(file)->i_sb), + .user_file = file, + .accessed = ovl_file_accessed, + }; - return ret; + return backing_file_mmap(realfile, vma, &ctx); } static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len) -- 2.39.2