Re: [patch 5/6][RFC] Introduce FIBMAP64

2007-10-29 Thread Chris Mason
On Fri, 26 Oct 2007 16:37:37 -0700
Mike Waychison <[EMAIL PROTECTED]> wrote:

> Introduce FIBMAP64.  This is the same as FIBMAP, but takes a u64.

If we're adding new ioctls, I'd rather see the FIEMAP stuff go
in, a quick search found discussions but has it died off?

-chris
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[patch 5/6][RFC] Introduce FIBMAP64

2007-10-26 Thread Mike Waychison
Introduce FIBMAP64.  This is the same as FIBMAP, but takes a u64.

This new routine requires filesystems to implement bmap64 if they want to 
support > 2^31 blocks in a logical file.  We do this to give time for 
filesystems to be properly audited.

Signed-off-by: Mike Waychison <[EMAIL PROTECTED]>

 fs/compat_ioctl.c  |2 ++
 fs/ioctl.c |   34 +-
 include/linux/fs.h |7 +++
 3 files changed, 42 insertions(+), 1 deletion(-)

Index: linux-2.6.23/fs/ioctl.c
===
--- linux-2.6.23.orig/fs/ioctl.c2007-10-26 15:28:28.0 -0700
+++ linux-2.6.23/fs/ioctl.c 2007-10-26 16:16:28.0 -0700
@@ -44,11 +44,24 @@ static int do_fibmap(struct address_spac
 sector_t *phys_block)
 {
struct inode *inode = mapping->host;
+   sector_t (*bmap)(struct address_space *, sector_t);
 
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
-   if (!mapping->a_ops->bmap)
+
+   if (mapping->a_ops->bmap64) {
+   /* Filesystem has bmap path audited for 64bit. */
+   bmap = mapping->a_ops->bmap64;
+   } else if (mapping->a_ops->bmap) {
+   bmap = mapping->a_ops->bmap;
+   /* Need to verify that the input looks sane when sector_t is
+* 64bit and the filesystem has only been audited for 32bit. */
+   if ((s32)block < 0)
+   return -EFBIG;
+   } else {
+   /* no FIBMAP support */
return -EINVAL;
+   }
 
lock_kernel();
/* Avoid races with truncate */
@@ -95,6 +108,25 @@ static int file_ioctl(struct file *filp,
res = phys_block;
return put_user(res, p);
}
+   case FIBMAP64:
+   {
+   struct address_space *mapping = filp->f_mapping;
+   sector_t phys_block;
+   u64 block;
+
+   if ((error = get_user(block, p)) != 0)
+   return error;
+
+   /* Make sure that the logical block fits in sector_t */
+   if ((sector_t)-1 < block)
+   return -EFBIG;
+
+   error = do_fibmap(mapping, block, &phys_block);
+   if (error)
+   return error;
+
+   return put_user(block, p);
+   }
case FIGETBSZ:
return put_user(inode->i_sb->s_blocksize, p);
case FIONREAD:
Index: linux-2.6.23/include/linux/fs.h
===
--- linux-2.6.23.orig/include/linux/fs.h2007-10-26 15:25:47.0 
-0700
+++ linux-2.6.23/include/linux/fs.h 2007-10-26 15:29:00.0 -0700
@@ -220,6 +220,7 @@ extern int dir_notify_enable;
 #define BMAP_IOCTL 1   /* obsolete - kept for compatibility */
 #define FIBMAP_IO(0x00,1)  /* bmap access */
 #define FIGETBSZ   _IO(0x00,2) /* get the block size used for bmap */
+#define FIBMAP64   _IO(0x00,3) /* bmap access - 64 bit sector numbers */
 
 #defineFS_IOC_GETFLAGS _IOR('f', 1, long)
 #defineFS_IOC_SETFLAGS _IOW('f', 2, long)
@@ -423,6 +424,12 @@ struct address_space_operations {
int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
/* Unfortunately this kludge is needed for FIBMAP. Don't use it */
sector_t (*bmap)(struct address_space *, sector_t);
+   /*
+* Version of bmap for filesystems that can safely handle 64bit
+* sector_t.  Once all filesystems are converted to this, we can drop
+* bmap().
+*/
+   sector_t (*bmap64)(struct address_space *, sector_t);
void (*invalidatepage) (struct page *, unsigned long);
int (*releasepage) (struct page *, gfp_t);
ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
Index: linux-2.6.23/fs/compat_ioctl.c
===
--- linux-2.6.23.orig/fs/compat_ioctl.c 2007-10-26 15:25:47.0 -0700
+++ linux-2.6.23/fs/compat_ioctl.c  2007-10-26 15:29:00.0 -0700
@@ -2506,6 +2506,7 @@ COMPATIBLE_IOCTL(FIONREAD)  /* This is a
 /* 0x00 */
 COMPATIBLE_IOCTL(FIBMAP)
 COMPATIBLE_IOCTL(FIGETBSZ)
+COMPATIBLE_IOCTL(FIBMAP64)
 /* 0x03 -- HD/IDE ioctl's used by hdparm and friends.
  * Some need translations, these do not.
  */
@@ -3597,6 +3598,7 @@ asmlinkage long compat_sys_ioctl(unsigne
 
case FIBMAP:
case FIGETBSZ:
+   case FIBMAP64:
case FIONREAD:
if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
break;

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