[PATCH 07/24] elevate writer count for chown and friends

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To: <akpm@...>

Cc: <linux-kernel@...>, <hch@...>, Dave Hansen <haveblue@...>

Subject: [PATCH 07/24] elevate writer count for chown and friends

Date: Monday, September 17, 2007 - 2:27 pm

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	2007-09-17 09:43:59.000000000 -0700
+++ lxc-dave/fs/open.c	2007-09-17 09:43:59.000000000 -0700
@@ -571,12 +571,12 @@ asmlinkage long sys_fchmod(unsigned int 
 
 	audit_inode(NULL, dentry);
 
-	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;
@@ -585,6 +585,8 @@ 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:
@@ -604,13 +606,13 @@ 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)
@@ -620,6 +622,8 @@ 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:
@@ -642,9 +646,6 @@ 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;
@@ -675,7 +676,12 @@ 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;
@@ -695,7 +701,12 @@ 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;
@@ -709,7 +720,12 @@ 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;
@@ -726,9 +742,14 @@ 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);
 	error = chown_common(dentry, user, group);
+	mnt_drop_write(file->f_vfsmnt);
+out_fput:
 	fput(file);
 out:
 	return error;
_
-
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Messages in current thread:

[PATCH 00/24] Read-only bind mounts, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 00/24] Read-only bind mounts, Christoph Hellwig, (Wed Sep 19, 1:44 pm)

Re: [PATCH 00/24] Read-only bind mounts, Andrew Morton, (Wed Sep 19, 5:24 pm)

Re: [PATCH 00/24] Read-only bind mounts, Dave Hansen, (Wed Sep 19, 5:56 pm)

Re: [PATCH 00/24] Read-only bind mounts, Andrew Morton, (Wed Sep 19, 6:06 pm)

Re: [PATCH 00/24] Read-only bind mounts, Miklos Szeredi, (Thu Sep 20, 5:58 am)

Re: [PATCH 00/24] Read-only bind mounts, Serge E. Hallyn, (Wed Sep 19, 10:21 am)

[PATCH 14/24] unix_find_other() elevate write count for touc..., Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 14/24] unix_find_other() elevate write count for ..., Christoph Hellwig, (Wed Sep 19, 1:35 pm)

[PATCH 22/24] do_rmdir(): elevate write count, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 22/24] do_rmdir(): elevate write count, Christoph Hellwig, (Wed Sep 19, 1:39 pm)

[PATCH 21/24] elevate mnt writers for vfs_unlink() callers, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 21/24] elevate mnt writers for vfs_unlink() callers, Christoph Hellwig, (Wed Sep 19, 1:38 pm)

[PATCH 19/24] elevate write count for do_sys_utime() and tou..., Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 19/24] elevate write count for do_sys_utime() and..., Christoph Hellwig, (Wed Sep 19, 1:36 pm)

[PATCH 20/24] sys_mknodat(): elevate write count for vfs_mkn..., Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 20/24] sys_mknodat(): elevate write count for vfs..., Christoph Hellwig, (Wed Sep 19, 1:38 pm)

[PATCH 09/24] elevate mnt writers for callers of vfs_mkdir(), Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 09/24] elevate mnt writers for callers of vfs_mkd..., Christoph Hellwig, (Wed Sep 19, 1:32 pm)

[PATCH 04/24] r/o bind mounts: stub functions, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 04/24] r/o bind mounts: stub functions, Christoph Hellwig, (Wed Sep 19, 1:28 pm)

[PATCH 11/24] elevate write count for link and symlink calls, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 11/24] elevate write count for link and symlink c..., Christoph Hellwig, (Wed Sep 19, 1:33 pm)

[PATCH 06/24] r/o bind mounts: elevate write count for some ..., Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 06/24] r/o bind mounts: elevate write count for s..., Christoph Hellwig, (Wed Sep 19, 1:31 pm)

[PATCH 18/24] elevate write count for do_utimes(), Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 18/24] elevate write count for do_utimes(), Christoph Hellwig, (Wed Sep 19, 1:36 pm)

[PATCH 16/24] nfs: check mnt instead of superblock directly, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 16/24] nfs: check mnt instead of superblock direc..., Christoph Hellwig, (Wed Sep 19, 1:36 pm)

[PATCH 17/24] elevate writer count for do_sys_truncate(), Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 17/24] elevate writer count for do_sys_truncate(), Christoph Hellwig, (Wed Sep 19, 1:36 pm)

[PATCH 15/24] elevate write count over calls to vfs_rename(), Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 15/24] elevate write count over calls to vfs_rena..., Christoph Hellwig, (Wed Sep 19, 1:35 pm)

[PATCH 12/24] elevate mount count for extended attributes, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 12/24] elevate mount count for extended attributes, Christoph Hellwig, (Wed Sep 19, 1:34 pm)

[PATCH 10/24] elevate write count during entire ncp_ioctl(), Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 10/24] elevate write count during entire ncp_ioct..., Christoph Hellwig, (Wed Sep 19, 1:33 pm)

[PATCH 01/24] filesystem helpers for custom 'struct file's, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 01/24] filesystem helpers for custom 'struct file's, Christoph Hellwig, (Wed Sep 19, 1:26 pm)

[PATCH] docuement filesystem helpers for custom 'struct file's, Dave Hansen, (Wed Sep 19, 1:47 pm)

Re: [PATCH] docuement filesystem helpers for custom 'struct ..., Randy Dunlap, (Wed Sep 19, 6:07 pm)

Re: [PATCH] docuement filesystem helpers for custom 'struct ..., Dave Hansen, (Thu Sep 20, 1:25 pm)

Re: [PATCH] docuement filesystem helpers for custom 'struct ..., Christoph Hellwig, (Thu Sep 20, 1:30 pm)

[PATCH 05/24] elevate write count open()'d files, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 05/24] elevate write count open()'d files, Christoph Hellwig, (Wed Sep 19, 1:30 pm)

[PATCH 07/24] elevate writer count for chown and friends, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 07/24] elevate writer count for chown and friends, Christoph Hellwig, (Wed Sep 19, 1:31 pm)

[PATCH 13/24] elevate write count for file_update_time(), Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 13/24] elevate write count for file_update_time(), Christoph Hellwig, (Wed Sep 19, 1:35 pm)

[PATCH 08/24] make access() use mnt check, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 08/24] make access() use mnt check, Christoph Hellwig, (Wed Sep 19, 1:32 pm)

[PATCH 03/24] create cleanup helper svc_msnfs(), Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Jan Engelhardt, (Wed Sep 19, 1:39 pm)

Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Dave Hansen, (Wed Sep 19, 1:45 pm)

Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Trond Myklebust, (Wed Sep 19, 1:54 pm)

Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Christoph Hellwig, (Wed Sep 19, 1:59 pm)

Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Trond Myklebust, (Wed Sep 19, 2:10 pm)

Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Christoph Hellwig, (Wed Sep 19, 1:28 pm)

[PATCH 02/24] rearrange may_open() to be r/o friendly, Dave Hansen, (Mon Sep 17, 2:27 pm)

Re: [PATCH 02/24] rearrange may_open() to be r/o friendly, Christoph Hellwig, (Wed Sep 19, 1:27 pm)

Re: [PATCH 02/24] rearrange may_open() to be r/o friendly, Dave Hansen, (Thu Sep 20, 2:47 pm)


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