From: Dave Hansen <haveblue@us.ibm.com>
To: viro@ftp.linux.org.uk
Cc: serue@us.ibm.com, linux-kernel@vger.kernel.org,
Dave Hansen <haveblue@us.ibm.com>
Subject: [RFC][PATCH 09/27] elevate writer count for chown and friends
Date: Wed, 12 Jul 2006 11:17:16 -0700 [thread overview]
Message-ID: <20060712181716.05BDA4FD@localhost.localdomain> (raw)
In-Reply-To: <20060712181709.5C1A4353@localhost.localdomain>
chown/chmod,etc... don't call permission in the same way
that the normal "open for write" calls do. They still
write to the filesystem, so bump the write count during
these operations.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---
lxc-dave/fs/open.c | 38 +++++++++++++++++++++++++++++++++-----
1 files changed, 33 insertions(+), 5 deletions(-)
diff -puN fs/open.c~C-elevate-writers-chown-and-friends fs/open.c
--- lxc/fs/open.c~C-elevate-writers-chown-and-friends 2006-07-12 11:09:17.000000000 -0700
+++ lxc-dave/fs/open.c 2006-07-12 11:09:26.000000000 -0700
@@ -644,9 +644,12 @@ asmlinkage long sys_fchmod(unsigned int
err = -EROFS;
if (IS_RDONLY(inode))
goto out_putf;
+ err = mnt_want_write(file->f_vfsmnt);
+ if (err)
+ goto out_putf;
err = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
- goto out_putf;
+ goto out_drop_write;
mutex_lock(&inode->i_mutex);
if (mode == (mode_t) -1)
mode = inode->i_mode;
@@ -655,6 +658,8 @@ asmlinkage long sys_fchmod(unsigned int
err = notify_change(dentry, &newattrs);
mutex_unlock(&inode->i_mutex);
+out_drop_write:
+ mnt_drop_write(file->f_vfsmnt);
out_putf:
fput(file);
out:
@@ -674,13 +679,16 @@ asmlinkage long sys_fchmodat(int dfd, co
goto out;
inode = nd.dentry->d_inode;
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ goto dput_and_out;
error = -EROFS;
if (IS_RDONLY(inode))
- goto dput_and_out;
+ goto out_drop_write;
error = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
- goto dput_and_out;
+ goto out_drop_write;
mutex_lock(&inode->i_mutex);
if (mode == (mode_t) -1)
@@ -690,6 +698,8 @@ asmlinkage long sys_fchmodat(int dfd, co
error = notify_change(nd.dentry, &newattrs);
mutex_unlock(&inode->i_mutex);
+out_drop_write:
+ mnt_drop_write(nd.mnt);
dput_and_out:
path_release(&nd);
out:
@@ -715,7 +725,7 @@ static int chown_common(struct dentry *
error = -EROFS;
if (IS_RDONLY(inode))
goto out;
- error = -EPERM;
+ error = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
goto out;
newattrs.ia_valid = ATTR_CTIME;
@@ -744,7 +754,12 @@ asmlinkage long sys_chown(const char __u
error = user_path_walk(filename, &nd);
if (error)
goto out;
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ goto out_release;
error = chown_common(nd.dentry, user, group);
+ mnt_drop_write(nd.mnt);
+out_release:
path_release(&nd);
out:
return error;
@@ -764,7 +779,12 @@ asmlinkage long sys_fchownat(int dfd, co
error = __user_walk_fd(dfd, filename, follow, &nd);
if (error)
goto out;
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ goto out_release;
error = chown_common(nd.dentry, user, group);
+ mnt_drop_write(nd.mnt);
+out_release:
path_release(&nd);
out:
return error;
@@ -778,7 +798,11 @@ asmlinkage long sys_lchown(const char __
error = user_path_walk_link(filename, &nd);
if (error)
goto out;
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ goto out_release;
error = chown_common(nd.dentry, user, group);
+out_release:
path_release(&nd);
out:
return error;
@@ -794,10 +818,14 @@ asmlinkage long sys_fchown(unsigned int
file = fget(fd);
if (!file)
goto out;
-
+ error = mnt_want_write(file->f_vfsmnt);
+ if (error)
+ goto out_fput;
dentry = file->f_dentry;
audit_inode(NULL, dentry->d_inode);
error = chown_common(dentry, user, group);
+ mnt_drop_write(file->f_vfsmnt);
+out_fput:
fput(file);
out:
return error;
_
next prev parent reply other threads:[~2006-07-12 18:25 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-12 18:17 [RFC][PATCH 00/27] Mount writer count and read-only bind mounts (v4) Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 01/27] prepare for write access checks: collapse if() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 02/27] r/o bind mount prepwork: move open_namei()'s vfs_create() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 03/27] unlink: monitor i_nlink Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 04/27] reintroduce list of vfsmounts over superblock Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 05/27] Add vfsmount writer count Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 06/27] record when sb_writer_count elevated for inode Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 07/27] kill open files traverse on remount ro Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 08/27] increment sb writer count when nlink hits zero Dave Hansen
2006-07-12 18:17 ` Dave Hansen [this message]
2006-07-12 18:17 ` [RFC][PATCH 10/27] elevate mnt writers for callers of vfs_mkdir() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 11/27] elevate write count during entire ncp_ioctl() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 12/27] sys_symlinkat() elevate write count around vfs_symlink() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 13/27] elevate mount count for extended attributes Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 14/27] sys_linkat(): elevate write count around vfs_link() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 15/27] mount_is_safe(): add comment Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 16/27] unix_find_other() elevate write count for touch_atime() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 17/27] elevate write count over calls to vfs_rename() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 18/27] tricky: elevate write count files are open()ed Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 19/27] elevate writer count for do_sys_truncate() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 21/27] elevate write count for do_sys_utime() and touch_atime() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 20/27] elevate write count for do_utimes() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 22/27] sys_mknodat(): elevate write count for vfs_mknod/create() Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 23/27] elevate mnt writers for vfs_unlink() callers Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 25/27] elevate writer count for custom 'struct file' Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 24/27] do_rmdir(): elevate write count Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 26/27] Originally from: Herbert Poetzl <herbert@13thfloor.at> Dave Hansen
2006-07-12 18:17 ` [RFC][PATCH 27/27] honor r/w changes at do_remount() time Dave Hansen
2006-07-13 7:04 ` [RFC][PATCH 00/27] Mount writer count and read-only bind mounts (v4) Ram Pai
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