Messages in this thread | | | From | Peter Chubb <> | Date | Tue, 14 May 2002 12:58:33 +1000 | Subject | Re: [PATCH] remove 2TB block device limit |
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>>>>> "Andrew" == Andrew Morton <akpm@zip.com.au> writes:
Andrew> Peter Chubb wrote: >> ... Christoph> - why is the get_block block argument a sector_t? It Christoph> presents a logical filesystem block which usually is larger Christoph> than the sector, not to mention that for the usual Christoph> blocksize == PAGE_SIZE case a ulong is enough as that is Christoph> the same size the pagecache limit triggers. >> For filesystems that *can* handle logical filesystem blocks beyond >> the 2^32 limit (i.e., that use >32bit offsets in their on-disc >> format), the get_block() argument has to be > 32bits long. At the >> moment that's only JFS and XFS, but reiserfs version 4 looks as if >> it might go that way. We'll need this especially when the >> pagecache limit is gone.
Andrew> I think Christoph's point is that a pagecache index is not a Andrew> sector number. We agree that we need to plan for taking it to Andrew> 64 bits, but it should be something different. Like Andrew> pageindex_t, or whatever.
I'll let Christoph speak for himself, but my point is that get_block() is an interface exported from the filesystem. It should be possible to specify any logical block number that the filesystem supports. That the current VM system on 32-bit machines will never request a block beyond 2^32 is a (one-day-soon-to-be-removed) current limitation.
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