Messages in this thread | | | Date | Wed, 25 May 2011 15:07:23 -0700 | From | Sunil Mushran <> | Subject | Re: [PATCH 1/3] fs: add SEEK_HOLE and SEEK_DATA flags V4 |
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On 05/25/2011 01:46 PM, Josef Bacik wrote: > On 05/25/2011 03:45 PM, Andreas Dilger wrote: >> Most of the filesystem-specific ->llseek() methods don't do any error >> checking on "origin" because this is handled at the sys_llseek() level, >> and hasn't changed in many years. >> >> I assume this patch is also dependent upon the "remove default_llseek()" >> patch, so that the implementation of SEEK_DATA and SEEK_HOLE can be done >> in only generic_file_llseek()? >> >> Finally, while looking through the various ->llseek() methods I notice >> that many filesystems return "i_size" for SEEK_END, which clearly does >> not make sense for filesystems like ext3/ext4 htree, btrfs, etc that >> use hash keys instead of byte offsets for doing directory traversal. >> The comment at generic_file_llseek() is that it is intended for use by >> regular files. >> >> Should the ext4_llseek() code be changed to return 0x7ffffffff for the >> SEEK_END value? That makes more sense compared to values returned for >> SEEK_CUR so that an application can compare the current "offset" with >> the final value for a progress bar. > So maybe we make SEEK_DATA/SEEK_HOLE only work on regular files and not > directories? Sunil what does solaris do? Thanks,
In Solaris the size of the directory appears to be equal to the number of entries and the offset is the file#, so to speak. SEEK_DATA returns the current offset and SEEK_HOLE the last one.
Just to be clear, I am not a Solaris expert. I just happen to have access to it. ;)
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