[PATCH 16/23] vfs: Teach fstatfs, fstatfs64, ftruncate, fchdir, fchmod, fchown to use file_hotplug_lock

Eric W. Biederman
2009-06-03T18:17:43Z

From: Eric W. Biederman <ebiederm@maxwell.arastra.com>

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/open.c | 47 +++++++++++++++++++++++++++++++++++++++++------
1 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/fs/open.c b/fs/open.c
index 83d6369..354646b 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -167,9 +167,14 @@ SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
file = fget(fd);
if (!file)
goto out;
+ error = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out_putf;
error = vfs_statfs_native(file->f_path.dentry, &tmp);
if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
error = -EFAULT;
+ file_hotplug_read_unlock(file);
+out_putf:
fput(file);
out:
return error;
@@ -188,9 +193,14 @@ SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user
file = fget(fd);
if (!file)
goto out;
+ error = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out_putf;
error = vfs_statfs64(file->f_path.dentry, &tmp);
if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
error = -EFAULT;
+ file_hotplug_read_unlock(file);
+out_putf:
fput(file);
out:
return error;
@@ -309,6 +319,10 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
if (!file)
goto out;

+ error = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out_putf;
+
/* explicitly opened as large or we are on 64-bit box */
if (file->f_flags & O_LARGEFILE)
small = 0;
@@ -317,16 +331,16 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
inode = dentry->d_inode;
error = -EINVAL;
if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
- goto out_putf;
+ goto out_unlock;

error = -EINVAL;
/* Cannot ftruncate over 2^31 bytes without large file support */
if (small && length > MAX_NON_LFS)
- goto out_putf;
+ goto out_unlock;

error = -EPERM;
if (IS_APPEND(inode))
- goto out_putf;
+ goto out_unlock;

error = locks_verify_truncate(inode, file, length);
if (!error)
@@ -334,6 +348,9 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
ATTR_MTIME|ATTR_CTIME);
if (!error)
error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file);
+
+out_unlock:
+ file_hotplug_read_unlock(file);
out_putf:
fput(file);
out:
@@ -560,15 +577,21 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd)
if (!file)
goto out;

+ error = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out_putf;
+
inode = file->f_path.dentry->d_inode;

error = -ENOTDIR;
if (!S_ISDIR(inode->i_mode))
- goto out_putf;
+ goto out_unlock;

error = inode_permission(inode, MAY_EXEC | MAY_ACCESS);
if (!error)
set_fs_pwd(current->fs, &file->f_path);
+out_unlock:
+ file_hotplug_read_unlock(file);
out_putf:
fput(file);
out:
@@ -612,6 +635,10 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode)
if (!file)
goto out;

+ err = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out_putf;
+
dentry = file->f_path.dentry;
inode = dentry->d_inode;

@@ -619,7 +646,7 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode)

err = mnt_want_write_file(file);
if (err)
- goto out_putf;
+ goto out_unlock;
mutex_lock(&inode->i_mutex);
if (mode == (mode_t) -1)
mode = inode->i_mode;
@@ -628,6 +655,8 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode)
err = notify_change(dentry, &newattrs);
mutex_unlock(&inode->i_mutex);
mnt_drop_write(file->f_path.mnt);
+out_unlock:
+ file_hotplug_read_unlock(file);
out_putf:
fput(file);
out:
@@ -766,13 +795,19 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
if (!file)
goto out;

+ error = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out_fput;
+
error = mnt_want_write_file(file);
if (error)
- goto out_fput;
+ goto out_unlock;
dentry = file->f_path.dentry;
audit_inode(NULL, dentry);
error = chown_common(dentry, user, group);
mnt_drop_write(file->f_path.mnt);
+out_unlock:
+ file_hotplug_read_unlock(file);
out_fput:
fput(file);
out:
--
1.6.3.1.54.g99dd.dirty