From dd20908a8a06b22c171f6c3fcdbdbd65bed07505 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 14 Mar 2014 10:56:20 -0400 Subject: don't bother with {get,put}_write_access() on non-regular files it's pointless and actually leads to wrong behaviour in at least one moderately convoluted case (pipe(), close one end, try to get to another via /proc/*/fd and run into ETXTBUSY). Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- fs/file_table.c | 4 ++-- fs/open.c | 26 +++++++------------------- 2 files changed, 9 insertions(+), 21 deletions(-) diff --git a/fs/file_table.c b/fs/file_table.c index 5b24008ea4f6..79ecae62209a 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -209,10 +209,10 @@ static void drop_file_write_access(struct file *file) struct dentry *dentry = file->f_path.dentry; struct inode *inode = dentry->d_inode; - put_write_access(inode); - if (special_file(inode->i_mode)) return; + + put_write_access(inode); if (file_check_writeable(file) != 0) return; __mnt_drop_write(mnt); diff --git a/fs/open.c b/fs/open.c index b9ed8b25c108..2ed7325f713e 100644 --- a/fs/open.c +++ b/fs/open.c @@ -641,23 +641,12 @@ out: static inline int __get_file_write_access(struct inode *inode, struct vfsmount *mnt) { - int error; - error = get_write_access(inode); + int error = get_write_access(inode); if (error) return error; - /* - * Do not take mount writer counts on - * special files since no writes to - * the mount itself will occur. - */ - if (!special_file(inode->i_mode)) { - /* - * Balanced in __fput() - */ - error = __mnt_want_write(mnt); - if (error) - put_write_access(inode); - } + error = __mnt_want_write(mnt); + if (error) + put_write_access(inode); return error; } @@ -690,12 +679,11 @@ static int do_dentry_open(struct file *f, path_get(&f->f_path); inode = f->f_inode = f->f_path.dentry->d_inode; - if (f->f_mode & FMODE_WRITE) { + if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) { error = __get_file_write_access(inode, f->f_path.mnt); if (error) goto cleanup_file; - if (!special_file(inode->i_mode)) - file_take_write(f); + file_take_write(f); } f->f_mapping = inode->i_mapping; @@ -742,7 +730,6 @@ static int do_dentry_open(struct file *f, cleanup_all: fops_put(f->f_op); if (f->f_mode & FMODE_WRITE) { - put_write_access(inode); if (!special_file(inode->i_mode)) { /* * We don't consider this a real @@ -750,6 +737,7 @@ cleanup_all: * because it all happenend right * here, so just reset the state. */ + put_write_access(inode); file_reset_write(f); __mnt_drop_write(f->f_path.mnt); } -- cgit v1.2.3-59-g8ed1b