[PATCH 15/23] vfs: Teach fallocate, and filp_close 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.om>
---
fs/open.c | 22 +++++++++++++++++-----
1 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/open.c b/fs/open.c
index d0b2433..83d6369 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -398,19 +398,22 @@ SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
goto out;
if (!(file->f_mode & FMODE_WRITE))
goto out_fput;
+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out_fput;
/*
* Revalidate the write permissions, in case security policy has
* changed since the files were opened.
*/
ret = security_file_permission(file, MAY_WRITE);
if (ret)
- goto out_fput;
+ goto out_unlock;

inode = file->f_path.dentry->d_inode;

ret = -ESPIPE;
if (S_ISFIFO(inode->i_mode))
- goto out_fput;
+ goto out_unlock;

ret = -ENODEV;
/*
@@ -418,18 +421,20 @@ SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
* for directories or not.
*/
if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
- goto out_fput;
+ goto out_unlock;

ret = -EFBIG;
/* Check for wrap through zero too */
if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
- goto out_fput;
+ goto out_unlock;

if (inode->i_op->fallocate)
ret = inode->i_op->fallocate(inode, mode, offset, len);
else
ret = -EOPNOTSUPP;

+out_unlock:
+ file_hotplug_read_unlock(file);
out_fput:
fput(file);
out:
@@ -1101,18 +1106,25 @@ SYSCALL_DEFINE2(creat, const char __user *, pathname, int, mode)
*/
int filp_close(struct file *filp, fl_owner_t id)
{
- int retval = 0;
+ int retval;

if (!file_count(filp)) {
printk(KERN_ERR "VFS: Close: file count is 0\n");
return 0;
}

+ retval = -EIO;
+ if (!file_hotplug_read_trylock(filp))
+ goto out_fput;
+
+ retval = 0;
if (filp->f_op && filp->f_op->flush)
retval = filp->f_op->flush(filp, id);

dnotify_flush(filp, id);
locks_remove_posix(filp, id);
+ file_hotplug_read_unlock(filp);
+out_fput:
fput(filp);
return retval;
}
--
1.6.3.1.54.g99dd.dirty