From 83f936c75e3689a63253d89c47a4d239c56d7410 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 14 Mar 2014 12:02:47 -0400 Subject: [PATCH] mark struct file that had write access grabbed by open() new flag in ->f_mode - FMODE_WRITER. Set by do_dentry_open() in case when it has grabbed write access, checked by __fput() to decide whether it wants to drop the sucker. Allows to stop bothering with mnt_clone_write() in alloc_file(), along with fewer special_file() checks. Signed-off-by: Al Viro --- fs/file_table.c | 37 ++++--------------------------------- fs/namespace.c | 4 +--- fs/open.c | 9 ++++----- include/linux/fs.h | 2 ++ 4 files changed, 11 insertions(+), 41 deletions(-) diff --git a/fs/file_table.c b/fs/file_table.c index ee20658a0647..ce1504fec5a1 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -177,43 +177,12 @@ struct file *alloc_file(struct path *path, fmode_t mode, file->f_mapping = path->dentry->d_inode->i_mapping; file->f_mode = mode; file->f_op = fop; - - /* - * These mounts don't really matter in practice - * for r/o bind mounts. They aren't userspace- - * visible. We do this for consistency, and so - * that we can do debugging checks at __fput() - */ - if ((mode & FMODE_WRITE) && !special_file(path->dentry->d_inode->i_mode)) { - WARN_ON(mnt_clone_write(path->mnt)); - } if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) i_readcount_inc(path->dentry->d_inode); return file; } EXPORT_SYMBOL(alloc_file); -/** - * drop_file_write_access - give up ability to write to a file - * @file: the file to which we will stop writing - * - * This is a central place which will give up the ability - * to write to @file, along with access to write through - * its vfsmount. - */ -static void drop_file_write_access(struct file *file) -{ - struct vfsmount *mnt = file->f_path.mnt; - struct dentry *dentry = file->f_path.dentry; - struct inode *inode = dentry->d_inode; - - if (special_file(inode->i_mode)) - return; - - put_write_access(inode); - __mnt_drop_write(mnt); -} - /* the real guts of fput() - releasing the last reference to file */ static void __fput(struct file *file) @@ -248,8 +217,10 @@ static void __fput(struct file *file) put_pid(file->f_owner.pid); if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) i_readcount_dec(inode); - if (file->f_mode & FMODE_WRITE) - drop_file_write_access(file); + if (file->f_mode & FMODE_WRITER) { + put_write_access(inode); + __mnt_drop_write(mnt); + } file->f_path.dentry = NULL; file->f_path.mnt = NULL; file->f_inode = NULL; diff --git a/fs/namespace.c b/fs/namespace.c index a66aff5bd3fe..20e8696c31a7 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -414,9 +414,7 @@ EXPORT_SYMBOL_GPL(mnt_clone_write); */ int __mnt_want_write_file(struct file *file) { - struct inode *inode = file_inode(file); - - if (!(file->f_mode & FMODE_WRITE) || special_file(inode->i_mode)) + if (!(file->f_mode & FMODE_WRITER)) return __mnt_want_write(file->f_path.mnt); else return mnt_clone_write(file->f_path.mnt); diff --git a/fs/open.c b/fs/open.c index ebef0c5fa10c..dcefb2f02d10 100644 --- a/fs/open.c +++ b/fs/open.c @@ -670,6 +670,7 @@ static int do_dentry_open(struct file *f, put_write_access(inode); goto cleanup_file; } + f->f_mode |= FMODE_WRITER; } f->f_mapping = inode->i_mapping; @@ -715,11 +716,9 @@ static int do_dentry_open(struct file *f, cleanup_all: fops_put(f->f_op); - if (f->f_mode & FMODE_WRITE) { - if (!special_file(inode->i_mode)) { - put_write_access(inode); - __mnt_drop_write(f->f_path.mnt); - } + if (f->f_mode & FMODE_WRITER) { + put_write_access(inode); + __mnt_drop_write(f->f_path.mnt); } cleanup_file: path_put(&f->f_path); diff --git a/include/linux/fs.h b/include/linux/fs.h index e80659ed78fc..d9d88a0b456e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -125,6 +125,8 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset, /* File needs atomic accesses to f_pos */ #define FMODE_ATOMIC_POS ((__force fmode_t)0x8000) +/* Write access to underlying fs */ +#define FMODE_WRITER ((__force fmode_t)0x10000) /* File was opened by fanotify and shouldn't generate fanotify events */ #define FMODE_NONOTIFY ((__force fmode_t)0x1000000) -- 2.25.1