From e38f7f53c35213b1cbce70eee5de7ced17f40d4a Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 5 Jun 2019 08:04:49 -0700 Subject: vfs: introduce file_modified() helper The combination of file_remove_privs() and file_update_mtime() is quite common in filesystem ->write_iter() methods. Modelled after the helper file_accessed(), introduce file_modified() and use it from generic_remap_file_range_prep(). Note that the order of calling file_remove_privs() before file_update_mtime() in the helper was matched to the more common order by filesystems and not the current order in generic_remap_file_range_prep(). Signed-off-by: Amir Goldstein Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/inode.c | 20 ++++++++++++++++++++ fs/read_write.c | 21 +++------------------ include/linux/fs.h | 2 ++ 3 files changed, 25 insertions(+), 18 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index df6542ec3b88..4348cfb14562 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1899,6 +1899,26 @@ int file_update_time(struct file *file) } EXPORT_SYMBOL(file_update_time); +/* Caller must hold the file's inode lock */ +int file_modified(struct file *file) +{ + int err; + + /* + * Clear the security bits if the process is not being run by root. + * This keeps people from modifying setuid and setgid binaries. + */ + err = file_remove_privs(file); + if (err) + return err; + + if (unlikely(file->f_mode & FMODE_NOCMTIME)) + return 0; + + return file_update_time(file); +} +EXPORT_SYMBOL(file_modified); + int inode_needs_sync(struct inode *inode) { if (IS_SYNC(inode)) diff --git a/fs/read_write.c b/fs/read_write.c index b0fb1176b628..cec7e7b1f693 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1980,25 +1980,10 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, return ret; /* If can't alter the file contents, we're done. */ - if (!(remap_flags & REMAP_FILE_DEDUP)) { - /* Update the timestamps, since we can alter file contents. */ - if (!(file_out->f_mode & FMODE_NOCMTIME)) { - ret = file_update_time(file_out); - if (ret) - return ret; - } + if (!(remap_flags & REMAP_FILE_DEDUP)) + ret = file_modified(file_out); - /* - * Clear the security bits if the process is not being run by - * root. This keeps people from modifying setuid and setgid - * binaries. - */ - ret = file_remove_privs(file_out); - if (ret) - return ret; - } - - return 0; + return ret; } EXPORT_SYMBOL(generic_remap_file_range_prep); diff --git a/include/linux/fs.h b/include/linux/fs.h index e4d382c4342a..79ffa2958bd8 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2177,6 +2177,8 @@ static inline void file_accessed(struct file *file) touch_atime(&file->f_path); } +extern int file_modified(struct file *file); + int sync_inode(struct inode *inode, struct writeback_control *wbc); int sync_inode_metadata(struct inode *inode, int wait); -- cgit v1.2.3