lkml.org 
[lkml]   [2000]   [Nov]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Hi Linus,

This patch (against 2.4.0-test10) fixes the O_SYNC/ENOSPC bug. Alan Cox
included a fix for this same bug in 2.2.18pre7 and David Weinehall in
2.0.39final. This bug is listed on Ted's "Linux 2.4 Status / TODO page" as
"Fix Exists But Isnt Merged", "Writing past end of removeable device can
cause data corruption bugs in the future".

More information and source code for small test program here:
http://marc.theaimsgroup.com/?l=linux-kernel&m=96879269024716&w=2

Regards,
Jari Ruusu <jari.ruusu@pp.inet.fi>

--- linux-2.4.0-test10/fs/block_dev.c Wed Oct 4 01:03:11 2000
+++ linux/fs/block_dev.c Sat Nov 4 17:14:19 2000
@@ -30,7 +30,7 @@
ssize_t block, blocks;
loff_t offset;
ssize_t chars;
- ssize_t written;
+ ssize_t written, retval;
struct buffer_head * bhlist[NBUF];
size_t size;
kdev_t dev = inode->i_rdev;
@@ -40,7 +40,7 @@
if (is_read_only(dev))
return -EPERM;

- written = write_error = buffercount = 0;
+ retval = written = write_error = buffercount = 0;
blocksize = BLOCK_SIZE;
if (blksize_size[MAJOR(dev)] && blksize_size[MAJOR(dev)][MINOR(dev)])
blocksize = blksize_size[MAJOR(dev)][MINOR(dev)];
@@ -60,8 +60,10 @@
else
size = INT_MAX;
while (count>0) {
- if (block >= size)
- return written ? written : -ENOSPC;
+ if (block >= size) {
+ retval = -ENOSPC;
+ goto cleanup;
+ }
chars = blocksize - offset;
if (chars > count)
chars=count;
@@ -73,15 +75,19 @@
if (chars != blocksize)
fn = bread;
bh = fn(dev, block, blocksize);
- if (!bh)
- return written ? written : -EIO;
+ if (!bh) {
+ retval = -EIO;
+ goto cleanup;
+ }
if (!buffer_uptodate(bh))
wait_on_buffer(bh);
}
#else
bh = getblk(dev, block, blocksize);
- if (!bh)
- return written ? written : -EIO;
+ if (!bh) {
+ retval = -EIO;
+ goto cleanup;
+ }

if (!buffer_uptodate(bh))
{
@@ -105,7 +111,8 @@
if (!bhlist[i])
{
while(i >= 0) brelse(bhlist[i--]);
- return written ? written : -EIO;
+ retval = -EIO;
+ goto cleanup;
}
}
}
@@ -114,7 +121,8 @@
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
brelse(bh);
- return written ? written : -EIO;
+ retval = -EIO;
+ goto cleanup;
}
};
};
@@ -148,6 +156,7 @@
if (write_error)
break;
}
+ cleanup:
if ( buffercount ){
ll_rw_block(WRITE, buffercount, bufferlist);
for(i=0; i<buffercount; i++){
@@ -157,10 +166,11 @@
brelse(bufferlist[i]);
}
}
- filp->f_reada = 1;
+ if(!retval)
+ filp->f_reada = 1;
if(write_error)
return -EIO;
- return written;
+ return written ? written : retval;
}

ssize_t block_read(struct file * filp, char * buf, size_t count, loff_t *ppos)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-03-22 12:45    [W:0.029 / U:0.992 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site