> On Jul 11, 2018, at 4:20 AM, Sujay Jayakar <sujaya...@dropbox.com> wrote: > > Hi all, > > I'm trying to write file's contents, resource fork, and extended attributes > durably on both HFS+ and APFS. My current approach is to use `write` and > `fsetxattr` to the write to the file and then `fcntl(fd, F_FULLFSYNC)` > afterwards. Is this sufficient? >
yes. > Looking at the HFS+ source, I was able to find that... > Regular files have their content synced on `F_FULLSYNC`, as expected [1]. > All files' resource forks are synced immediately on `fsetxattr` [2]. > It looks like we skip syncing data on directory nodes [3]. If an xattr on a > directory is large enough to be in an extent, does this skip waiting on its > blocks to be flushed? > What about extended attributes, both inline and extent-based? They are synchronous writes. resource forks are seperately sync'ed in fsetxattr because they behave slightly differently than all other extended attributes. > > Next, what guarantees do we have for resource forks and extended attributes > with `F_FULLSYNC` on APFS? same as HFS. > > Thanks, > Sujay > > [1] > https://github.com/apple/darwin-xnu/blob/xnu-2782.1.97/bsd/hfs/hfs_vnops.c#L3011 > > <https://github.com/apple/darwin-xnu/blob/xnu-2782.1.97/bsd/hfs/hfs_vnops.c#L3011> > [2] > https://github.com/apple/darwin-xnu/blob/xnu-2782.1.97/bsd/hfs/hfs_xattr.c#L926 > > <https://github.com/apple/darwin-xnu/blob/xnu-2782.1.97/bsd/hfs/hfs_xattr.c#L926> > [3] > https://github.com/apple/darwin-xnu/blob/xnu-2782.1.97/bsd/hfs/hfs_vnops.c#L2896 > > <https://github.com/apple/darwin-xnu/blob/xnu-2782.1.97/bsd/hfs/hfs_vnops.c#L2896> > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Filesystem-dev mailing list (Filesystem-dev@lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/filesystem-dev/vivek_verma%40apple.com > > This email sent to vivek_ve...@apple.com
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