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Date: Thu, 31 Jan 2019 10:47:12 +0900
From: Wang Shilong <wangshilong1991@...il.com>
To: linux-ext4@...r.kernel.org
Cc: linux-fs@...r.kernel.org, linux-xfs@...r.kernel.org,
Wang Shilong <wshilong@....com>,
Andreas Dilger <adilger@...ger.ca>, Li Xi <lixi@....com>
Subject: [RFC PATCH] ext4: add link file support for {GET,SET}XATTR ioctl
From: Wang Shilong <wshilong@....com>
Currently there is no way to change project ID of
symlink file itself, this is important to implement
Directory quota for an existed directory.
For example, for a newly created dir, we could just
set project <ID> and inherit attribute, newly created
symlink file will inherit it automatically.
We implment project changes by GET/SETXATTR ioctl,the
hook function only works for file or dir. To support
symlink file we could do by some ways that i could think of:
1) Add unlocked_ioctl for sys link files.
2) Add FS_IOC_FS[GET|SET]TXATTR_CHILD ioctl which
get/set the xattr of an inode by giving its parent
directory and its dentry name.
This patch try to use the second way to address this problem.
Child share parent @filep for mnt_want_write_file() for
security check which actually try to use sb, and use
for filesystem freeze purpose.
Cc: Andreas Dilger <adilger@...ger.ca>
Cc: Li Xi <lixi@....com>
Signed-off-by: Wang Shilong <wshilong@....com>
---
fs/ext4/ext4.h | 2 +
fs/ext4/ioctl.c | 148 +++++++++++++++++++++++++---------
include/uapi/linux/fs.h | 10 +++
tools/include/uapi/linux/fs.h | 10 +++
4 files changed, 132 insertions(+), 38 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 185a05d3257e..2468c64bb987 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -648,6 +648,8 @@ enum {
#define EXT4_IOC_FSGETXATTR FS_IOC_FSGETXATTR
#define EXT4_IOC_FSSETXATTR FS_IOC_FSSETXATTR
+#define EXT4_IOC_FSGETXATTR_CHILD FS_IOC_FSGETXATTR_CHILD
+#define EXT4_IOC_FSSETXATTR_CHILD FS_IOC_FSSETXATTR_CHILD
#define EXT4_IOC_SHUTDOWN _IOR ('X', 125, __u32)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index d37dafa1d133..0a75cda2dba1 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -20,6 +20,7 @@
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/iversion.h>
+#include <linux/namei.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include <linux/fsmap.h>
@@ -333,9 +334,8 @@ static int ext4_ioctl_setflags(struct inode *inode,
}
#ifdef CONFIG_QUOTA
-static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
+static int ext4_ioctl_setproject(struct inode *inode, __u32 projid)
{
- struct inode *inode = file_inode(filp);
struct super_block *sb = inode->i_sb;
struct ext4_inode_info *ei = EXT4_I(inode);
int err, rc;
@@ -419,7 +419,7 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
return err;
}
#else
-static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
+static int ext4_ioctl_setproject(struct inode *inode, __u32 projid)
{
if (projid != EXT4_DEF_PROJID)
return -EOPNOTSUPP;
@@ -663,6 +663,59 @@ static int ext4_ioctl_check_project(struct inode *inode, struct fsxattr *fa)
return 0;
}
+static void ext4_ioctl_fsgetxattr(struct inode *inode, struct fsxattr *fa,
+ unsigned long arg)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ memset(fa, 0, sizeof(struct fsxattr));
+ fa->fsx_xflags = ext4_iflags_to_xflags(ei->i_flags &
+ EXT4_FL_USER_VISIBLE);
+
+ if (ext4_has_feature_project(inode->i_sb))
+ fa->fsx_projid = (__u32)from_kprojid(&init_user_ns,
+ ei->i_projid);
+}
+
+static int ext4_ioctl_fssetxattr(struct file *filp, struct inode *cinode,
+ struct fsxattr *fa)
+{
+ int err;
+ unsigned int flags;
+ struct ext4_inode_info *ei = EXT4_I(cinode);
+
+ /* Make sure caller has proper permission */
+ if (!inode_owner_or_capable(cinode))
+ return -EACCES;
+
+ if (fa->fsx_xflags & ~EXT4_SUPPORTED_FS_XFLAGS)
+ return -EOPNOTSUPP;
+
+ flags = ext4_xflags_to_iflags(fa->fsx_xflags);
+ if (ext4_mask_flags(cinode->i_mode, flags) != flags)
+ return -EOPNOTSUPP;
+
+ err = mnt_want_write_file(filp);
+ if (err)
+ return err;
+
+ inode_lock(cinode);
+ err = ext4_ioctl_check_project(cinode, fa);
+ if (err)
+ goto out;
+ flags = (ei->i_flags & ~EXT4_FL_XFLAG_VISIBLE) |
+ (flags & EXT4_FL_XFLAG_VISIBLE);
+ err = ext4_ioctl_setflags(cinode, flags);
+ if (err)
+ goto out;
+ err = ext4_ioctl_setproject(cinode, fa->fsx_projid);
+out:
+ inode_unlock(cinode);
+ mnt_drop_write_file(filp);
+
+ return err;
+}
+
long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -1024,56 +1077,75 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct fsxattr fa;
- memset(&fa, 0, sizeof(struct fsxattr));
- fa.fsx_xflags = ext4_iflags_to_xflags(ei->i_flags & EXT4_FL_USER_VISIBLE);
+ ext4_ioctl_fsgetxattr(inode, &fa, arg);
- if (ext4_has_feature_project(inode->i_sb)) {
- fa.fsx_projid = (__u32)from_kprojid(&init_user_ns,
- EXT4_I(inode)->i_projid);
- }
+ if (copy_to_user((struct fsxattr __user *)arg, &fa,
+ sizeof(fa)))
+ return -EFAULT;
+ }
+ case EXT4_IOC_FSGETXATTR_CHILD:
+ {
+ struct fsxattr_child fa;
+ struct dentry *dentry;
- if (copy_to_user((struct fsxattr __user *)arg,
- &fa, sizeof(fa)))
+ if (copy_from_user(&fa, (struct fsxattr_child __user *)arg,
+ sizeof(fa)))
+ return -EFAULT;
+
+ fa.fsxc_name[NAME_MAX] = '\0';
+ inode_lock(file_inode(filp));
+ dentry = lookup_one_len(fa.fsxc_name, file_dentry(filp),
+ strlen(fa.fsxc_name));
+ inode_unlock(file_inode(filp));
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+
+ ext4_ioctl_fsgetxattr(d_inode(dentry), &fa.fsxc_fsx, arg);
+ dput(dentry);
+
+ if (copy_to_user((struct fsxattr_child __user *)arg, &fa,
+ sizeof(fa)))
return -EFAULT;
- return 0;
}
case EXT4_IOC_FSSETXATTR:
{
struct fsxattr fa;
- int err;
if (copy_from_user(&fa, (struct fsxattr __user *)arg,
sizeof(fa)))
return -EFAULT;
- /* Make sure caller has proper permission */
- if (!inode_owner_or_capable(inode))
- return -EACCES;
-
- if (fa.fsx_xflags & ~EXT4_SUPPORTED_FS_XFLAGS)
- return -EOPNOTSUPP;
+ return ext4_ioctl_fssetxattr(filp, inode, &fa);
+ }
+ case EXT4_IOC_FSSETXATTR_CHILD:
+ {
+ struct fsxattr_child fa;
+ struct dentry *dentry;
+ int err;
- flags = ext4_xflags_to_iflags(fa.fsx_xflags);
- if (ext4_mask_flags(inode->i_mode, flags) != flags)
- return -EOPNOTSUPP;
+ if (copy_from_user(&fa, (struct fsxattr_child __user *)arg,
+ sizeof(fa)))
+ return -EFAULT;
- err = mnt_want_write_file(filp);
- if (err)
- return err;
+ fa.fsxc_name[NAME_MAX] = '\0';
+ inode_lock(file_inode(filp));
+ dentry = lookup_one_len(fa.fsxc_name, file_dentry(filp),
+ strlen(fa.fsxc_name));
+ inode_unlock(file_inode(filp));
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ /* this didn't work since child will share
+ * parent @filp to use mnt_want_write_file()
+ */
+ if (file_inode(filp)->i_sb != d_inode(dentry)->i_sb) {
+ err = -EXDEV;
+ goto errout;
+ }
- inode_lock(inode);
- err = ext4_ioctl_check_project(inode, &fa);
- if (err)
- goto out;
- flags = (ei->i_flags & ~EXT4_FL_XFLAG_VISIBLE) |
- (flags & EXT4_FL_XFLAG_VISIBLE);
- err = ext4_ioctl_setflags(inode, flags);
- if (err)
- goto out;
- err = ext4_ioctl_setproject(filp, fa.fsx_projid);
-out:
- inode_unlock(inode);
- mnt_drop_write_file(filp);
+ err = ext4_ioctl_fssetxattr(filp, d_inode(dentry),
+ &fa.fsxc_fsx);
+errout:
+ dput(dentry);
return err;
}
case EXT4_IOC_SHUTDOWN:
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 121e82ce296b..e8f54126da2e 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -118,6 +118,14 @@ struct fsxattr {
unsigned char fsx_pad[8];
};
+/*
+ * Structure for FS_IOC_FSGETXATTR_CHILD and FS_IOC_FSSETXATTR_CHILD.
+ */
+struct fsxattr_child {
+ struct fsxattr fsxc_fsx;
+ unsigned char fsxc_name[NAME_MAX + 1]; /* child filename */
+};
+
/*
* Flags for the fsx_xflags field
*/
@@ -209,6 +217,8 @@ struct fsxattr {
#define FS_IOC32_SETVERSION _IOW('v', 2, int)
#define FS_IOC_FSGETXATTR _IOR('X', 31, struct fsxattr)
#define FS_IOC_FSSETXATTR _IOW('X', 32, struct fsxattr)
+#define FS_IOC_FSGETXATTR_CHILD _IOR('X', 33, struct fsxattr_child)
+#define FS_IOC_FSSETXATTR_CHILD _IOW('X', 34, struct fsxattr_child)
#define FS_IOC_GETFSLABEL _IOR(0x94, 49, char[FSLABEL_MAX])
#define FS_IOC_SETFSLABEL _IOW(0x94, 50, char[FSLABEL_MAX])
diff --git a/tools/include/uapi/linux/fs.h b/tools/include/uapi/linux/fs.h
index 121e82ce296b..e8f54126da2e 100644
--- a/tools/include/uapi/linux/fs.h
+++ b/tools/include/uapi/linux/fs.h
@@ -118,6 +118,14 @@ struct fsxattr {
unsigned char fsx_pad[8];
};
+/*
+ * Structure for FS_IOC_FSGETXATTR_CHILD and FS_IOC_FSSETXATTR_CHILD.
+ */
+struct fsxattr_child {
+ struct fsxattr fsxc_fsx;
+ unsigned char fsxc_name[NAME_MAX + 1]; /* child filename */
+};
+
/*
* Flags for the fsx_xflags field
*/
@@ -209,6 +217,8 @@ struct fsxattr {
#define FS_IOC32_SETVERSION _IOW('v', 2, int)
#define FS_IOC_FSGETXATTR _IOR('X', 31, struct fsxattr)
#define FS_IOC_FSSETXATTR _IOW('X', 32, struct fsxattr)
+#define FS_IOC_FSGETXATTR_CHILD _IOR('X', 33, struct fsxattr_child)
+#define FS_IOC_FSSETXATTR_CHILD _IOW('X', 34, struct fsxattr_child)
#define FS_IOC_GETFSLABEL _IOR(0x94, 49, char[FSLABEL_MAX])
#define FS_IOC_SETFSLABEL _IOW(0x94, 50, char[FSLABEL_MAX])
--
2.20.1
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