From: Dave Hansen <haveblue@us.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
hch@infradead.org, Dave Hansen <haveblue@us.ibm.com>
Subject: [PATCH 07/23] elevate writer count for chown and friends
Date: Wed, 11 Jul 2007 17:17:19 -0700 [thread overview]
Message-ID: <20070712001719.2D60AE0D@kernel> (raw)
In-Reply-To: <20070712001710.654CD9ED@kernel>
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 | 39 ++++++++++++++++++++++++++++++---------
1 file changed, 30 insertions(+), 9 deletions(-)
diff -puN fs/open.c~elevate-writer-count-for-chown-and-friends fs/open.c
--- lxc/fs/open.c~elevate-writer-count-for-chown-and-friends 2007-07-10 12:46:06.000000000 -0700
+++ lxc-dave/fs/open.c 2007-07-10 12:46:06.000000000 -0700
@@ -510,12 +510,12 @@ asmlinkage long sys_fchmod(unsigned int
audit_inode(NULL, inode);
- err = -EROFS;
- if (IS_RDONLY(inode))
+ 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;
@@ -524,6 +524,8 @@ 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:
@@ -543,13 +545,13 @@ asmlinkage long sys_fchmodat(int dfd, co
goto out;
inode = nd.dentry->d_inode;
- error = -EROFS;
- if (IS_RDONLY(inode))
+ error = mnt_want_write(nd.mnt);
+ if (error)
goto dput_and_out;
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)
@@ -559,6 +561,8 @@ 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:
@@ -581,9 +585,6 @@ static int chown_common(struct dentry *
printk(KERN_ERR "chown_common: NULL inode\n");
goto out;
}
- error = -EROFS;
- if (IS_RDONLY(inode))
- goto out;
error = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
goto out;
@@ -613,7 +614,12 @@ 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;
@@ -633,7 +639,12 @@ 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;
@@ -647,7 +658,12 @@ 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);
+ mnt_drop_write(nd.mnt);
+out_release:
path_release(&nd);
out:
return error;
@@ -664,9 +680,14 @@ asmlinkage long sys_fchown(unsigned int
if (!file)
goto out;
+ error = mnt_want_write(file->f_vfsmnt);
+ if (error)
+ goto out_fput;
dentry = file->f_path.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:[~2007-07-12 0:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-12 0:17 [PATCH 00/23] Mount writer count API (read-only bind mounts prep) Dave Hansen
2007-07-12 0:17 ` [PATCH 01/23] rearrange may_open() to be r/o friendly Dave Hansen
2007-07-12 0:17 ` [PATCH 02/23] create cleanup helper svc_msnfs() Dave Hansen
2007-07-12 0:17 ` [PATCH 03/23] filesystem helpers for custom 'struct file's Dave Hansen
2007-07-12 0:17 ` [PATCH 04/23] r/o bind mounts: stub functions Dave Hansen
2007-07-12 0:17 ` [PATCH 05/23] elevate write count open()'d files Dave Hansen
2007-07-12 0:17 ` [PATCH 06/23] r/o bind mounts: elevate write count for some ioctls Dave Hansen
2007-07-12 0:17 ` Dave Hansen [this message]
2007-07-12 0:17 ` [PATCH 08/23] make access() use mnt check Dave Hansen
2007-07-12 0:17 ` [PATCH 09/23] elevate mnt writers for callers of vfs_mkdir() Dave Hansen
2007-07-12 0:17 ` [PATCH 10/23] elevate write count during entire ncp_ioctl() Dave Hansen
2007-07-12 0:17 ` [PATCH 11/23] elevate write count for link and symlink calls Dave Hansen
2007-07-12 0:17 ` [PATCH 12/23] elevate mount count for extended attributes Dave Hansen
2007-07-12 0:17 ` [PATCH 13/23] elevate write count for file_update_time() Dave Hansen
2007-07-12 0:17 ` [PATCH 14/23] mount_is_safe(): add comment Dave Hansen
2007-07-12 0:17 ` [PATCH 15/23] unix_find_other() elevate write count for touch_atime() Dave Hansen
2007-07-12 0:17 ` [PATCH 16/23] elevate write count over calls to vfs_rename() Dave Hansen
2007-07-12 0:17 ` [PATCH 17/23] nfs: check mnt instead of superblock directly Dave Hansen
2007-07-12 0:17 ` [PATCH 18/23] elevate writer count for do_sys_truncate() Dave Hansen
2007-07-12 0:17 ` [PATCH 19/23] elevate write count for do_utimes() Dave Hansen
2007-07-12 0:17 ` [PATCH 20/23] elevate write count for do_sys_utime() and touch_atime() Dave Hansen
2007-07-12 0:17 ` [PATCH 21/23] sys_mknodat(): elevate write count for vfs_mknod/create() Dave Hansen
2007-07-12 0:17 ` [PATCH 22/23] elevate mnt writers for vfs_unlink() callers Dave Hansen
2007-07-12 0:17 ` [PATCH 23/23] do_rmdir(): elevate write count Dave Hansen
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