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Maxim Sobolev
afe1dec742
Check that once fsync(2), fdatasync(2), or a write(2) with O_SYNC or O_DSYNC returns, the new data, the file size and every block pointer leading to the data are on disk. The cases append a block, fill a hole, append the first block that needs an indirect block and append below an existing indirect block. Two more append after another write left a new direct block unsynced, which with soft updates cuts the size and the later pointers of an inode written meanwhile. With O_SYNC and O_DSYNC on soft updates, those also check that the open already made the unsynced block durable. Each case runs on UFS without soft updates, with soft updates and with SU+J. The file systems live on md(4) and the checks read the inode, the indirect block and the data block straight from the device with libufs right after the synchronous call returns. There is no cache in front of the disk device, so this shows what would survive a crash at that moment without having to crash anything. Sponsored by: Sippy Software, Inc. Reviewed by: pho Tested by: pho Differential Revision: https://reviews.freebsd.org/D60134 MFC after: 1 month
Note: If you modify these files, please keep hier(7) updated!
These files are used to create empty file hierarchies for building the
system into. Some notes about working with them are placed here to try
and keep them in good working order.
a) The files use 4 space indentation, and other than in the header
comments, should not contain any tabs. An indentation of 4 is
preferable to the standard indentation of 8 because the indentation
of levels in these files can become quite deep causing the line to
overflow 80 characters.
This also matches with the files generated when using the
mtree -c option, which was implemented that way for the same reason.
b) Only directories should be listed here.
c) The listing should be kept in filename sorted order.
d) Sanity checking changes to these files can be done by following
this procedure (the sed -e is ugly, but fixing mtree -c to
not emit the trailing white space would be even uglier):
mkdir /tmp/MTREE
mtree -deU -f BSD.X.dist -p /tmp/MTREE
mtree -bcdjn -F freebsd9 -k uname,gname,mode -p /tmp/MTREE | \
sed -e 's/ *$//' >BSD.X.new
diff -u BSD.X.dist BSD.X.new
rm -r /tmp/MTREE
Note that you will get some differences about /set lines,
and uname= gname= on certain directory areas, mainly man page
sections. This is caused by mtree not having a look ahead
mechanism for making better selections for these as it
traverses the hierarchy.
The BSD.X.new file should NOT be committed, as it will be missing
the correct header, and important keywords like ``nochange''.
Simply use the diff for a sanity check to make sure things are in
the correct order and correctly indented.
e) Further sanity checking of the system builds with DESTDIR=/someplace
are more complicated, but can often catch missing entries in these
files. I tend to run this more complete sanity check shortly after
the target date for a new release is announced.
If you want details on it bug me about it via email to
[email protected].