Re: [PATCH 1/2 v2] fs: add SEEK_HOLE and SEEK_DATA flags

From: Valdis . Kletnieks
Date: Wed May 04 2011 - 15:31:49 EST


On Wed, 04 May 2011 13:58:39 EDT, Josef Bacik said:

> +#define SEEK_HOLE 3 /* seek to the closest hole */
> +#define SEEK_DATA 4 /* seek to the closest data */

Comments here need nearest/next fixing as well - otherwise the ext[34] crew may
actually implement the commented semantics. ;)

Other than that, patch 1/2 looks OK to me (not that there's much code to
review), and 2/2 *seems* sane and implement the "next" semantics, though I only
examined the while/if structure and am assuming the btrfs innards are done
correctly. In particular, that 'while (1)' looks like it can be painful for a
sufficiently large and fragmented file (think a gigabyte file in 4K chunks,
producing a million extents), but I'll let a btrfs expert analyse that
performance issue ;)

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