Patch FIOFLUSH

Patch FIOFLUSH

[Ross Biro]

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Here's a patch against 2.4.18 that allows user space to flush a file 
from both the buffer cache and the page cache.  The reason for flushing 
a file from the caches is to the read the file again to verify it made 
it to more permanent storage correctly.  Someone may want to add 
similiar code to 2.5.

    Ross


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diff -urdbB linux-2.4.18-58/fs/ioctl.c linux-2.4.18-59/fs/ioctl.c
--- linux-2.4.18-58/fs/ioctl.c	Fri Feb  9 11:29:44 2001
+++ linux-2.4.18-59/fs/ioctl.c	Thu May  1 09:52:18 2003
@@ -39,6 +39,13 @@
 			return put_user(inode->i_sb->s_blocksize, (int *) arg);
 		case FIONREAD:
 			return put_user(inode->i_size - filp->f_pos, (int *) arg);
+
+                case FIOFLUSH:
+                        write_inode_now(inode, 1);
+                        invalidate_inode_buffers(inode);
+                        invalidate_inode_pages(inode);
+                        return 0;
+
 	}
 	if (filp->f_op && filp->f_op->ioctl)
 		return filp->f_op->ioctl(inode, filp, cmd, arg);
diff -urdbB linux-2.4.18-58/include/asm/ioctls.h linux-2.4.18-59/include/asm/ioctls.h
--- linux-2.4.18-58/include/asm-i386/ioctls.h	Fri Jul 24 11:10:16 1998
+++ linux-2.4.18-59/include/asm-i386/ioctls.h	Thu May  1 09:53:51 2003
@@ -32,6 +32,7 @@
 #define TIOCGSOFTCAR	0x5419
 #define TIOCSSOFTCAR	0x541A
 #define FIONREAD	0x541B
+#define FIOFLUSH	_IO('F', 1) /* flush a file out of the caches */
 #define TIOCINQ		FIONREAD
 #define TIOCLINUX	0x541C
 #define TIOCCONS	0x541D

Re: Patch FIOFLUSH

[Christoph Hellwig]

On Wed, May 21, 2003 at 10:28:03AM -0700, Ross Biro wrote:
> 
> Here's a patch against 2.4.18 that allows user space to flush a file 
> from both the buffer cache and the page cache.  The reason for flushing 
> a file from the caches is to the read the file again to verify it made 
> it to more permanent storage correctly.  Someone may want to add 
> similiar code to 2.5.

This came up at SGI some time ago and the right solution is _not_ a new
ioctl but fadvise(..., POSIX_FADV_DONTNEED).   I'll submit a clean backport
once 2.4.21 is out (if that will ever happen)

Re: Patch FIOFLUSH

[Marc-Christian Petersen]

On Wednesday 21 May 2003 19:38, Christoph Hellwig wrote:

Hi Christoph,

> This came up at SGI some time ago and the right solution is _not_ a new
> ioctl but fadvise(..., POSIX_FADV_DONTNEED).   I'll submit a clean backport
could you please send it to me even 2.4.21 is not out? Thank you.

> once 2.4.21 is out (if that will ever happen)
ROTFL! :-)

ciao, Marc