Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765863AbYBOWmd (ORCPT ); Fri, 15 Feb 2008 17:42:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764029AbYBOWho (ORCPT ); Fri, 15 Feb 2008 17:37:44 -0500 Received: from e1.ny.us.ibm.com ([32.97.182.141]:35861 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762301AbYBOWhf (ORCPT ); Fri, 15 Feb 2008 17:37:35 -0500 Subject: [PATCH 08/30] r/o bind mounts: create helper to drop file write access To: linux-kernel@vger.kernel.org Cc: hch@lst.de, miklos@szeredi.hu, akpm@osdl.org, Dave Hansen From: Dave Hansen Date: Fri, 15 Feb 2008 14:37:31 -0800 References: <20080215223721.9E0A088A@kernel> In-Reply-To: <20080215223721.9E0A088A@kernel> Message-Id: <20080215223731.EF3A91FA@kernel> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3509 Lines: 94 If someone decides to demote a file from r/w to just r/o, they can use this same code as __fput(). NFS does just that, and will use this in the next patch. Signed-off-by: Dave Hansen Cc: Erez Zadok Cc: Trond Myklebust Cc: "J Bruce Fields" Acked-by: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Christoph Hellwig --- linux-2.6.git-dave/fs/file_table.c | 19 ++++++++++++++++++- linux-2.6.git-dave/fs/nfsd/nfs4state.c | 3 ++- linux-2.6.git-dave/include/linux/file.h | 1 + 3 files changed, 21 insertions(+), 2 deletions(-) diff -puN fs/file_table.c~create-file_drop_write_access-helper fs/file_table.c --- linux-2.6.git/fs/file_table.c~create-file_drop_write_access-helper 2008-02-15 13:25:46.000000000 -0800 +++ linux-2.6.git-dave/fs/file_table.c 2008-02-15 13:25:46.000000000 -0800 @@ -211,6 +211,23 @@ void fput(struct file *file) EXPORT_SYMBOL(fput); +/** + * 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. + */ +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); +} +EXPORT_SYMBOL_GPL(drop_file_write_access); + /* __fput is called from task context when aio completion releases the last * last use of a struct file *. Do not use otherwise. */ @@ -237,7 +254,7 @@ void __fput(struct file *file) cdev_put(inode->i_cdev); fops_put(file->f_op); if (file->f_mode & FMODE_WRITE) - put_write_access(inode); + drop_file_write_access(file); put_pid(file->f_owner.pid); file_kill(file); file->f_path.dentry = NULL; diff -puN fs/nfsd/nfs4state.c~create-file_drop_write_access-helper fs/nfsd/nfs4state.c --- linux-2.6.git/fs/nfsd/nfs4state.c~create-file_drop_write_access-helper 2008-02-15 13:25:46.000000000 -0800 +++ linux-2.6.git-dave/fs/nfsd/nfs4state.c 2008-02-15 13:25:46.000000000 -0800 @@ -41,6 +41,7 @@ #include #include #include +#include #include #include #include @@ -1239,7 +1240,7 @@ static inline void nfs4_file_downgrade(struct file *filp, unsigned int share_access) { if (share_access & NFS4_SHARE_ACCESS_WRITE) { - put_write_access(filp->f_path.dentry->d_inode); + drop_file_write_access(filp); filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE; } } diff -puN include/linux/file.h~create-file_drop_write_access-helper include/linux/file.h --- linux-2.6.git/include/linux/file.h~create-file_drop_write_access-helper 2008-02-15 13:25:46.000000000 -0800 +++ linux-2.6.git-dave/include/linux/file.h 2008-02-15 13:25:46.000000000 -0800 @@ -61,6 +61,7 @@ extern struct kmem_cache *filp_cachep; extern void __fput(struct file *); extern void fput(struct file *); +extern void drop_file_write_access(struct file *file); struct file_operations; struct vfsmount; _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/