Messages in this thread | | | Date | Sat, 27 Aug 2011 10:30:32 +0200 | From | Marco Stornelli <> | Subject | Re: [PATCH] xfstests 255: add a seek_data/seek_hole tester |
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Il 26/08/2011 16:41, Zach Brown ha scritto: >>> Hole: a range of the file that contains no data or is made up >>> entirely of NULL (zero) data. Holes include preallocated ranges of >>> files that have not had actual data written to them. > >> No for me. A hole is made up of zero data? It's a strange definition >> for me. > > It's a very natural definition for me. It mirrors the behaviour of > read() of sparse data inside i_size that file system authors already > have to consider. > > It's also a reminder for people that this interface is about avoiding > reading zeros. Systems that track contents can do this for files that > had tons of zeros written. The data is there but the app is > specifically asking us to skip it by using SEEK_DATA. > > - z >
I think we need to consider a hole and "data not present/not written yet" as two different cases even they are related. For example, if I do an fallocate without keep size option, then I do a read, I have the same behavior of sparse data inside i_size, but the blocks are allocated so no sparse data in this case. Simply there are no difference from app point of view.
Marco
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