Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932332AbZJUTWL (ORCPT ); Wed, 21 Oct 2009 15:22:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932273AbZJUTWK (ORCPT ); Wed, 21 Oct 2009 15:22:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42011 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755260AbZJUTVr (ORCPT ); Wed, 21 Oct 2009 15:21:47 -0400 From: Valerie Aurora To: Jan Blunck , Alexander Viro , Christoph Hellwig , Andy Whitcroft , Scott James Remnant , Sandu Popa Marius , Jan Rekorajski , "J. R. Okajima" , Arnd Bergmann , Vladimir Dronnikov , Felix Fietkau Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 40/41] union-mount: Make truncate work in all its glorious UNIX variations Date: Wed, 21 Oct 2009 12:19:38 -0700 Message-Id: <1256152779-10054-41-git-send-email-vaurora@redhat.com> In-Reply-To: <1256152779-10054-40-git-send-email-vaurora@redhat.com> References: <1256152779-10054-1-git-send-email-vaurora@redhat.com> <1256152779-10054-2-git-send-email-vaurora@redhat.com> <1256152779-10054-3-git-send-email-vaurora@redhat.com> <1256152779-10054-4-git-send-email-vaurora@redhat.com> <1256152779-10054-5-git-send-email-vaurora@redhat.com> <1256152779-10054-6-git-send-email-vaurora@redhat.com> <1256152779-10054-7-git-send-email-vaurora@redhat.com> <1256152779-10054-8-git-send-email-vaurora@redhat.com> <1256152779-10054-9-git-send-email-vaurora@redhat.com> <1256152779-10054-10-git-send-email-vaurora@redhat.com> <1256152779-10054-11-git-send-email-vaurora@redhat.com> <1256152779-10054-12-git-send-email-vaurora@redhat.com> <1256152779-10054-13-git-send-email-vaurora@redhat.com> <1256152779-10054-14-git-send-email-vaurora@redhat.com> <1256152779-10054-15-git-send-email-vaurora@redhat.com> <1256152779-10054-16-git-send-email-vaurora@redhat.com> <1256152779-10054-17-git-send-email-vaurora@redhat.com> <1256152779-10054-18-git-send-email-vaurora@redhat.com> <1256152779-10054-19-git-send-email-vaurora@redhat.com> <1256152779-10054-20-git-send-email-vaurora@redhat.com> <1256152779-10054-21-git-send-email-vaurora@redhat.com> <1256152779-10054-22-git-send-email-vaurora@redhat.com> <1256152779-10054-23-git-send-email-vaurora@redhat.com> <1256152779-10054-24-git-send-email-vaurora@redhat.com> <1256152779-10054-25-git-send-email-vaurora@redhat.com> <1256152779-10054-26-git-send-email-vaurora@redhat.com> <1256152779-10054-27-git-send-email-vaurora@redhat.com> <1256152779-10054-28-git-send-email-vaurora@redhat.com> <1256152779-10054-29-git-send-email-vaurora@redhat.com> <1256152779-10054-30-git-send-email-vaurora@redhat.com> <1256152779-10054-31-git-send-email-vaurora@redhat.com> <1256152779-10054-32-git-send-email-vaurora@redhat.com> <1256152779-10054-33-git-send-email-vaurora@redhat.com> <1256152779-10054-34-git-send-email-vaurora@redhat.com> <1256152779-10054-35-git-send-email-vaurora@redhat.com> <1256152779-10054-36-git-send-email-vaurora@redhat.com> <1256152779-10054-37-git-send-email-vaurora@redhat.com> <1256152779-10054-38-git-send-email-vaurora@redhat.com> <1256152779-10054-39-git-send-email-vaurora@redhat.com> <1256152779-10054-40-git-send-email-vaurora@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8532 Lines: 299 Implement truncate(), ftruncate(), and open(O_TRUNC) for union mounts. This moves the union_copyup() in do_filp_open() down below may_open() - this way you don't copy up a file you don't even have permission to open. may_open() now takes a nameidata * because it may have to do a union_copyup() internally if O_TRUNC is specified. It's a trivial change, all callers were just doing "may_open(&nd.path, ...)" anyway. It kinda sucks, but may_open() auto-magically doing a truncate also sucks (may open? may truncate, too!). XXX - Only copy up the bytes that won't be truncated. XXX - Re-organize code. may_open() especially blah. XXX - truncate() implemented as in-kernel file open and ftruncate() XXX - Split up into smaller pieces Signed-off-by: Valerie Aurora --- fs/namei.c | 22 +++++---- fs/nfsctl.c | 6 +- fs/open.c | 124 ++++++++++++++++++++-------------------------------- include/linux/fs.h | 2 +- 4 files changed, 64 insertions(+), 90 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index a8d3acf..e3e8e98 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2115,8 +2115,9 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode, return error; } -int may_open(struct path *path, int acc_mode, int flag) +int may_open(struct nameidata *nd, int acc_mode, int flag) { + struct path *path = &nd->path; struct dentry *dentry = path->dentry; struct inode *inode = dentry->d_inode; int error; @@ -2188,6 +2189,9 @@ int may_open(struct path *path, int acc_mode, int flag) if (!error) error = security_path_truncate(path, 0, ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); + /* XXX don't copy up file data */ + if (is_unionized(path->dentry, path->mnt)) + error = union_copyup(nd, flag /* XXX not used */); if (!error) { vfs_dq_init(inode); @@ -2234,7 +2238,7 @@ out_unlock: if (error) return error; /* Don't check for write permission, don't truncate */ - return may_open(&nd->path, 0, flag & ~O_TRUNC); + return may_open(nd, 0, flag & ~O_TRUNC); } /* @@ -2309,12 +2313,6 @@ struct file *do_filp_open(int dfd, const char *pathname, &nd, flag); if (error) return ERR_PTR(error); - if (unlikely(flag & FMODE_WRITE)) { - /* Check for union, etc. in union_copyup */ - error = union_copyup(&nd, flag /* XXX not used */); - if (error) - return ERR_PTR(error); - } goto ok; } @@ -2452,12 +2450,18 @@ ok: if (error) goto exit; } - error = may_open(&nd.path, acc_mode, flag); + error = may_open(&nd, acc_mode, flag); if (error) { if (will_write) mnt_drop_write(nd.path.mnt); goto exit; } + /* Okay, all permissions go, now copy up */ + if (!(flag & O_CREAT) && (flag & FMODE_WRITE)) { + error = union_copyup(&nd, flag /* XXX not used */); + if (error) + goto exit; + } filp = nameidata_to_filp(&nd, open_flag); if (IS_ERR(filp)) ima_counts_put(&nd.path, diff --git a/fs/nfsctl.c b/fs/nfsctl.c index 8f9a205..e3b733e 100644 --- a/fs/nfsctl.c +++ b/fs/nfsctl.c @@ -38,10 +38,10 @@ static struct file *do_open(char *name, int flags) return ERR_PTR(error); if (flags == O_RDWR) - error = may_open(&nd.path, MAY_READ|MAY_WRITE, - FMODE_READ|FMODE_WRITE); + error = may_open(&nd, MAY_READ|MAY_WRITE, + FMODE_READ|FMODE_WRITE); else - error = may_open(&nd.path, MAY_WRITE, FMODE_WRITE); + error = may_open(&nd, MAY_WRITE, FMODE_WRITE); if (!error) return dentry_open(nd.path.dentry, nd.path.mnt, flags, diff --git a/fs/open.c b/fs/open.c index 3df5a1b..a1da3a0 100644 --- a/fs/open.c +++ b/fs/open.c @@ -223,69 +223,69 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, return err; } -static long do_sys_truncate(const char __user *pathname, loff_t length) +static int __do_ftruncate(struct file *file, unsigned long length, int small) { - struct path path; - struct inode *inode; + struct inode * inode; + struct dentry *dentry; int error; error = -EINVAL; - if (length < 0) /* sorry, but loff_t says... */ + if (length < 0) goto out; + /* explicitly opened as large or we are on 64-bit box */ + if (file->f_flags & O_LARGEFILE) + small = 0; - error = user_path(pathname, &path); - if (error) + dentry = file->f_path.dentry; + inode = dentry->d_inode; + error = -EINVAL; + if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) goto out; - inode = path.dentry->d_inode; - - /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ - error = -EISDIR; - if (S_ISDIR(inode->i_mode)) - goto dput_and_out; error = -EINVAL; - if (!S_ISREG(inode->i_mode)) - goto dput_and_out; - - error = mnt_want_write(path.mnt); - if (error) - goto dput_and_out; + /* Cannot ftruncate over 2^31 bytes without large file support */ + if (small && length > MAX_NON_LFS) - error = inode_permission(inode, MAY_WRITE); - if (error) - goto mnt_drop_write_and_out; + goto out; error = -EPERM; if (IS_APPEND(inode)) - goto mnt_drop_write_and_out; + goto out; - error = get_write_access(inode); - if (error) - goto mnt_drop_write_and_out; + error = locks_verify_truncate(inode, file, length); + if (!error) + error = security_path_truncate(&file->f_path, length, + ATTR_MTIME|ATTR_CTIME); + if (!error) + /* Already copied up for union, opened with write */ + error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file); +out: + return error; +} - /* - * Make sure that there are no leases. get_write_access() protects - * against the truncate racing with a lease-granting setlease(). - */ - error = break_lease(inode, FMODE_WRITE); - if (error) - goto put_write_and_out; +static long do_sys_truncate(const char __user *pathname, loff_t length) +{ + struct file *file; + char *tmp; + int error; - error = locks_verify_truncate(inode, NULL, length); - if (!error) - error = security_path_truncate(&path, length, 0); - if (!error) { - vfs_dq_init(inode); - error = do_truncate(path.dentry, length, 0, NULL); - } + error = -EINVAL; + if (length < 0) /* sorry, but loff_t says... */ + return error; -put_write_and_out: - put_write_access(inode); -mnt_drop_write_and_out: - mnt_drop_write(path.mnt); -dput_and_out: - path_put(&path); -out: + tmp = getname(pathname); + if (IS_ERR(tmp)) + return PTR_ERR(tmp); + + file = filp_open(tmp, O_RDWR | O_LARGEFILE, 0); + putname(tmp); + + if (IS_ERR(file)) + return PTR_ERR(file); + + error = __do_ftruncate(file, length, 0); + + fput(file); return error; } @@ -297,46 +297,16 @@ SYSCALL_DEFINE2(truncate, const char __user *, path, unsigned long, length) static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) { - struct inode * inode; - struct dentry *dentry; struct file * file; int error; - error = -EINVAL; - if (length < 0) - goto out; error = -EBADF; file = fget(fd); if (!file) goto out; - /* explicitly opened as large or we are on 64-bit box */ - if (file->f_flags & O_LARGEFILE) - small = 0; + error = __do_ftruncate(file, length, small); - dentry = file->f_path.dentry; - inode = dentry->d_inode; - error = -EINVAL; - if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) - goto out_putf; - - error = -EINVAL; - /* Cannot ftruncate over 2^31 bytes without large file support */ - if (small && length > MAX_NON_LFS) - goto out_putf; - - error = -EPERM; - if (IS_APPEND(inode)) - goto out_putf; - - error = locks_verify_truncate(inode, file, length); - if (!error) - error = security_path_truncate(&file->f_path, length, - ATTR_MTIME|ATTR_CTIME); - if (!error) - /* Already copied up for union, opened with write */ - error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file); -out_putf: fput(file); out: return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index 38fb113..8eb0e0e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2134,7 +2134,7 @@ extern void free_write_pipe(struct file *); extern struct file *do_filp_open(int dfd, const char *pathname, int open_flag, int mode, int acc_mode); -extern int may_open(struct path *, int, int); +extern int may_open(struct nameidata *, int, int); extern int kernel_read(struct file *, loff_t, char *, unsigned long); extern struct file * open_exec(const char *); -- 1.6.3.3 -- 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/