|From:||Andrew Morton <akpm-AT-linux-foundation.org>|
|To:||Hugh Dickins <hughd-AT-google.com>|
|Subject:||Re: [PATCH v5 0/10] fs: Introduce new flag(FALLOC_FL_COLLAPSE_RANGE) for fallocate|
|Date:||Tue, 25 Feb 2014 15:41:28 -0800|
|Cc:||Namjae Jeon <linkinjeon-AT-gmail.com>, Matthew Wilcox <matthew-AT-wil.cx>, "Theodore Ts'o" <tytso-AT-mit.edu>, Dave Chinner <david-AT-fromorbit.com>, Stephen Rothwell <sfr-AT-canb.auug.org.au>, viro-AT-zeniv.linux.org.uk, bpm-AT-sgi.com, adilger.kernel-AT-dilger.ca, jack-AT-suse.cz, mtk.manpages-AT-gmail.com, lczerner-AT-redhat.com, linux-fsdevel-AT-vger.kernel.org, xfs-AT-oss.sgi.com, linux-ext4-AT-vger.kernel.org, linux-kernel-AT-vger.kernel.org, linux-mm-AT-kvack.org, Namjae Jeon <namjae.jeon-AT-samsung.com>|
On Tue, 25 Feb 2014 15:23:35 -0800 (PST) Hugh Dickins <email@example.com> wrote: > On Tue, 25 Feb 2014, Dave Chinner wrote: > > On Tue, Feb 25, 2014 at 02:16:01PM +1100, Stephen Rothwell wrote: > > > On Mon, 24 Feb 2014 11:57:10 +1100 Dave Chinner <firstname.lastname@example.org> wrote: > > > > > > > > > Namjae Jeon (10): > > > > > fs: Add new flag(FALLOC_FL_COLLAPSE_RANGE) for fallocate > > > > > xfs: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate > > > > > > > > I've pushed these to the following branch: > > > > > > > > git://oss.sgi.com/xfs/xfs.git xfs-collapse-range > > > > > > > > And so they'll be in tomorrow's linux-next tree. > > > > > > > > > ext4: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate > > > > > > > > I've left this one alone for the ext4 guys to sort out. > > > > > > So presumably that xfs tree branch is now completely stable and so Ted > > > could just merge that branch into the ext4 tree as well and put the ext4 > > > part on top of that in his tree. > > > > Well, for some definition of stable. Right now it's just a topic > > branch that is merged into the for-next branch, so in theory it is > > still just a set of pending changes in a branch in a repo that has > > been pushed to linux-next for testing. > > > > That said, I don't see that branch changing unless we find bugs in > > the code or a problem with the API needs fixing, at which point I > > would add more commits to it and rebase the for-next branch that you > > are pulling into the linux-next tree. > > > > Realistically, I'm waiting for Lukas to repost his other pending > > fallocate changes (the zero range changes) so I can pull the VFS and > > XFS bits of that into the XFS tree and I can test them together > > before I'll call the xfs-collapse-range stable and ready to be > > merged into some other tree... > > ... > > Emphasis on "might": I expect it's impossible, given your current > approach, but something to be on guard against is unmap_mapping_range() > failing to find and unmap a pte, because the page is mapped at the > "wrong" place in the vma, resulting in BUG_ON(page_mapped(page)) > in __delete_from_page_cache(). It should be well tested with non-linear mappings please. It *should* be OK, but... > > ... > > FALLOC_FL_COLLAPSE_RANGE: I'm a little sad at the name COLLAPSE, > but probably seven months too late to object. It surprises me that > you're doing all this work to deflate a part of the file, without > the obvious complementary work to inflate it - presumably all those > advertisers whose ads you're cutting out, will come back to us soon > to ask for inflation, so that they have somewhere to reinsert them ;) Yes, I was wondering that. Why not simply "move these blocks from here to there". -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to email@example.com. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"firstname.lastname@example.org"> email@example.com </a>
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