Tflush handling was wrong, we cannot respond to the old
request if we have not actually removed the req from the
in progress block queue.
when reads are issued concurrently, we have to set b->len
before the block is inserted into the inprogress list.
otherwise findblock() is unable to find it and no requests
can be queued on the block. this caused the same offset
to be downloaded multiple times.
set the errstr in getrange() so in case of an error, we dont
get some random previous error string.
as the Fgrp can be shared with other processes, we have to
recheck the fd index after locking the Fgrp in fdclose()
to make sure not to read beyond the bounds of the fd array.
using the user buffer has a race where the user can modify
the buffer from another process before it is copied into the cache.
this allows poisoning the cache for every file where the user
has read access.
instead, we update the cache from kernel memory.
*after* writing, the directory tree gets alphabetically sorted for
path table. this causes data to not be in the same order as it was
written causing seeks when taring up the filesystem.
so instead write the files in alphabetical order as well to better
match the directory sorting.
data on the disk is layed out sequentially and directory information
is at the end of the disk. we want to keep data and metadata separated
so that reading large sequential files will not evict the directory
information from the cache causing long seeks.
for that, we tag the clusters (an 8th for metadata, and the rest
for data) and getbuf() will only evict clusters of the same tag.
doing tests taring up 9front.iso shows the following:
lowering the cluster size back to 128k avoids over half the
reads. 837888 sectors read for 512k vs. 347712 sectors with
128k cluster size.
foo.c includes bar/bar.h, which includes "baz.h"; it wants bar/baz.h
meanwhile, it also includes meh/quux.h, which includes "baz.h"; it wants meh/baz.h
Wnode gets two new counters: txcount and txerror
and actrate pointer that will be between minrate
and maxrate.
driver should use actrate instead of maxrate for
transmission when it can provide error feedback.
when a driver detects a transmission failed, it calls
wifitxfail() with the original packet. wifitxfail() then
reduces wn->actrate.
every 256th packet, we optimistically increase wn->actrate
before transmitting.
- reject files smaller or equal to two bytes, they are bogus
- fix out of bounds access in shargs() when n <= 2
- only copy the bytes read into line buffer
- use nil for pointers instead of 0
imagereclaim(), pagereclaim():
- move imagereclaim() and pagereclaim() declarations to portfns.h
- consistently use ulong type for page counts
- name number of pages to free "pages" instead of "min"
- check for pages == 0 on entry
freepages():
- move pagechaindone() call to wakeup newpage() consumers inside
palloc critical section.
putimage():
- use long type for refcount
