The mbp->b_resid is used to track if all the nested buffers have been issued
and reported back. When the last buffer calls in, mbp->b_resid becomes zero
and biodone(mbp) is called. This is fine as long as there are no errors.
If a read-error does occure in one of the nested buffers, the mbp->b_error is
set and on its call to biodone(mbp), with mbp->b_resid is zero, physio()
panics since it asserts that IF an error is set on a buffer, there should be a
residual amount of data left to transfered.
The patch fixes this case by setting mbp->b_resid back to mbp->b_bcount on
mbp->b_error just before biodone(mbp).
This behaviour is consistent with normal buffer issueing. It either succeeds
or doesn't succeed.
if the buffer was read with intention to modify but the caller changed its mind.
This error could lead to snapshot corruption when a buffer with B_COWDONE set
resides on the freelist and we create a new snapshot.
PR kern/16942 panic with softdep and quotas
PR kern/19565 panic: softdep_write_inodeblock: indirect pointer #1 mismatch
PR kern/26274 softdep panic: allocdirect_merge: ...
PR kern/26374 Long delay before non-root users can write to softdep partitions
PR kern/28621 1.6.x "vp != NULL" panic in ffs_softdep.c:4653 while unmounting a softdep (+quota) filesystem
PR kern/29513 FFS+Softdep panic with unfsck-able file-corruption
PR kern/31544 The ffs softdep code appears to fail to write dirty bits to disk
PR kern/31981 stopping scsi disk can cause panic (softdep)
PR kern/32116 kernel panic in softdep (assertion failure)
PR kern/32532 softdep_trackbufs deadlock
PR kern/37191 softdep: locking against myself
PR kern/40474 Kernel panic after remounting raid root with softdep
Retire softdep, pass 2. As discussed and later formally announced on the
mailing lists.
case is not possible. The buffer length has changed and the rounded size
may not have, essentially changing the transaction size. Reported by
various users and in PR 39898.
This changes the order of hook processing as the copy-on-write handlers
are called after the journal processing. This makes more sense as the
journal overwrite is logically part of the disk IO.
Add Wasabi System's WAPBL (Write Ahead Physical Block Logging)
journaling code. Originally written by Darrin B. Jewell while
at Wasabi and updated to -current by Antti Kantee, Andy Doran,
Greg Oster and Simon Burge.
OK'd by core@, releng@.
queue, if it's being flushed. But in this case, we'll also have B_VFLUSH.
While there fix checkfreelist() so that it can be used to check that a
buffer is not in the free lists.
its not on a free list.
Also change buf_init() to not automatically mark buffers `busy' since this
only makes sense for bufcache buffers.
Mark all buf_init'd buffers 'busy' on the places where they ought to be
flagged as such to not confuse the buffer cache.
Fixes PR 38923.
run through copy-on-write. Call fscow_run() with valid data where possible.
The LP_UFSCOW hack is no longer needed to protect ffs_copyonwrite() against
endless recursion.
- Add a flag B_MODIFY to bread(), breada() and breadn(). If set the caller
intends to modify the buffer returned.
- Always run copy-on-write on buffers returned from ffs_balloc().
- Add new function ffs_getblk() that gets a buffer, assigns a new blkno,
may clear the buffer and runs copy-on-write. Process possible errors
from getblk() or fscow_run(). Part of PR kern/38664.
Welcome to 4.99.63
Reviewed by: YAMAMOTO Takashi <yamt@netbsd.org>
error-out the master buffer.
The old setup was undeterministic since a later sheduled nested buffer
could clear the error again since there is no B_ERROR flag anymore. It also
would discard the error the nested buffer returned.
buf_memcalc is used by bootstrap as well. fix NULL dereference for them.
- limit kva usage for each cache to 20% of vm_map. XXX a bit arbitrary.
- add a comment.
- Lock processes, credentials, filehead etc correctly.
- Acquire a read hold on sysctl_treelock if only doing a query.
- Don't wire down the output buffer. It doesn't work correctly and the code
regularly does long term sleeps with it held - it's not worth it.
- Don't hold locks other than sysctl_lock while doing copyout().
- Drop sysctl_lock while doing copyout / allocating memory in a few places.
- Don't take kernel_lock for sysctl.
- Fix a number of bugs spotted along the way
Buffers run through copy-on-write are marked B_COWDONE. This condition
is valid until the buffer has run through bwrite() and gets cleared from
biodone().
Welcome to 4.99.39.
Reviewed by: YAMAMOTO Takashi <yamt@netbsd.org>
