On Thursday 05 May 2011 16:27:57 Josef Bacik wrote: > Looking at this llseek stuff I noticed that default_llseek is the exact same as > generic_file_llseek, so kill default_llseek. I patched this using spatch with > just a simple > > @@ > @@ > > - default_llseek > + generic_file_llseek > > and then I manually removed the default_llseek definitions. I've built and > booted this and it works fine. Thanks, > > Signed-off-by: Josef Bacik <josef@xxxxxxxxxx> Good idea in principle, but you missed the fact that generic_file_llseek checks (offset > inode->i_sb->s_maxbytes), which default_llseek does not. This makes a huge difference on file systems that do not initialize s_maxbytes, leaving it at zero. In particular, it doesn't work for character devices, IIRC they will use whatever s_maxbytes is set for the file system that stores the dentry and for debugfs and other virtual file systems, it is not set at all. The proper fix should be to make sure all file systems set an appropriate s_maxbytes, and then add a special case for character devices to generic_file_llseek. The main reason I didn't do it last year was to avoid possible regressions when missing some other special cases, but please continue to push this once you are sure to have a correct version of the patch. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
