Messages in this thread | | | Date | Sat, 20 Aug 2011 11:41:31 +0200 | From | Marco Stornelli <> | Subject | Re: [PATCH 1/4] fs: add SEEK_HOLE and SEEK_DATA flags |
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Hi,
Il 28/06/2011 17:33, Josef Bacik ha scritto: > This just gets us ready to support the SEEK_HOLE and SEEK_DATA flags. Turns out > using fiemap in things like cp cause more problems than it solves, so lets try > and give userspace an interface that doesn't suck. We need to match solaris > here, and the definitions are > > *o* If /whence/ is SEEK_HOLE, the offset of the start of the > next hole greater than or equal to the supplied offset > is returned. The definition of a hole is provided near > the end of the DESCRIPTION. > > *o* If /whence/ is SEEK_DATA, the file pointer is set to the > start of the next non-hole file region greater than or > equal to the supplied offset. >
I'm implementing the SEEK_DATA/SEEK_HOLE management for pramfs and I've got some doubts about the right behavior:
1) when we use SEEK_DATA/SEEK_HOLE, the offset used in lseek means always the offset from the start of the file, right?
2) in case of a file with hole at the beginning and data at the end, if I do lseek(fd, 0, SEEK_HOLE) I should receive the end of the file because the idea is to search the *next* hole and we have always a virtual hole at the end of the file, right?
3) about the last sentence of point 2), is it always true even if we have a case of block allocation beyond the end of file (fallocate with keep size option)?
Thanks.
Regards,
Marco
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