pfs_vncache_free() that removes pvd from the list, while it is not yet
put on the list.
Prevent the invalid removal from the list by clearing pvd_next and
pvd_prev for the newly allocated pvd, and only move pfs_vncache list
head when the pvd was at the head.
Suggested and approved by: des
MFC after: 2 weeks
may need to lock arbitrary vnodes, causing either lock order reversal or
recursive vnode lock acquisition.
Tested by: pho
Approved by: des
MFC after: 2 weeks
do pfs_vncache_alloc() for the same pfs_node and pid. In this case, we
could end up with two vnodes for the pair. Recheck the cache under the
locked pfs_vncache_mutex after all sleeping operations are done [1].
This case mostly cannot happen now because pseudofs uses exclusive vnode
locking for lookup. But it does drop the vnode lock for dotdot lookups,
and Marcus' pseudofs_vptocnp implementation is vulnerable too.
Do not call free() on the struct pfs_vdata after insmntque() failure,
because vp->v_data points to the structure, and pseudofs_reclaim()
frees it by the call to pfs_vncache_free().
Tested by: pho [1]
Approved by: des
MFC after: 2 weeks
to add more V* constants, and the variables changed by this patch were often
being assigned to mode_t variables, which is 16 bit.
Approved by: rwatson (mentor)
initialize the vattr structure in VOP_GETATTR() with VATTR_NULL(),
vattr_null() or by zeroing it. Remove these to allow preinitialization
of fields work in vn_stat(). This is needed to get birthtime initialized
correctly.
Submitted by: Jaakko Heinonen <jh saunalahti fi>
Discussed on: freebsd-fs
MFC after: 1 month
namespace in order to handle lockmgr fields in a controlled way instead
than spreading all around bogus stubs:
- VN_LOCK_AREC() allows lock recursion for a specified vnode
- VN_LOCK_ASHARE() allows lock sharing for a specified vnode
In FFS land:
- BUF_AREC() allows lock recursion for a specified buffer lock
- BUF_NOREC() disallows recursion for a specified buffer lock
Side note: union_subr.c::unionfs_node_update() is the only other function
directly handling lockmgr fields. As this is not simple to fix, it has
been left behind as "sole" exception.
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.
KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.
Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
Remove this argument and pass curthread directly to underlying
VOP_LOCK1() VFS method. This modify makes the code cleaner and in
particular remove an annoying dependence helping next lockmgr() cleanup.
KPI results, obviously, changed.
Manpage and FreeBSD_version will be updated through further commits.
As a side note, would be valuable to say that next commits will address
a similar cleanup about VFS methods, in particular vop_lock1 and
vop_unlock.
Tested by: Diego Sardina <siarodx at gmail dot com>,
Andrea Di Pasquale <whyx dot it at gmail dot com>
directory itself (rather than any of its contents) is visible to the
current thread.
MFC after: 1 week
PR: kern/90063
Submitted by: john of 8192.net
Approved by: re (kensmith)
The pfs_info mutex is only needed to lock pi_unrhdr. Everything else
in struct pfs_info is modified only while Giant is held (during
vfs_init() / vfs_uninit()); add assertions to that effect.
Simplify pfs_destroy somewhat.
Remove superfluous arguments from pfs_fileno_{alloc,free}(), and the
assertions which were added in the previous commit to ensure they were
consistent.
Assert that Giant is held while the vnode cache is initialized and
destroyed. Also assert that the cache is empty when it is destroyed.
Rename the vnode cache mutex for consistency.
Fix a long-standing bug in pfs_getattr(): it would uncritically return
the node's pn_fileno as st_ino. This would result in st_ino being 0
if the node had not previously been visited by readdir(), and also in
an incorrect st_ino for process directories and any files contained
therein. Correct this by abstracting the fileno manipulations
previously done in pfs_readdir() into a new function, pfs_fileno(),
which is used by both pfs_getattr() and pfs_readdir().
specific nodes when the process exits)
Move the vnode-cache-walking loop which was duplicated in pfs_exit() and
pfs_disable() into its own function, pfs_purge(), which looks for vnodes
marked as dead and / or belonging to the specified pfs_node and reclaims
them. Note that this loop is still extremely inefficient.
Add a comment in pfs_vncache_alloc() explaining why we have to purge the
vnode from the vnode cache before returning, in case anyone should be
tempted to remove the call to cache_purge().
Move the special handling for pfstype_root nodes into pfs_fileno_alloc()
and pfs_fileno_free() (the root node's fileno must always be 2). This
also fixes a bug where pfs_fileno_free() would reclaim the root node's
fileno, triggering a panic in the unr code, as that fileno was never
allocated from unr to begin with.
When destroying a pfs_node, release its fileno and purge it from the
vnode cache. I wish we could put off the call to pfs_purge() until
after the entire tree had been destroyed, but then we'd have vnodes
referencing freed pfs nodes. This probably doesn't matter while we're
still under Giant, but might become an issue later.
When destroying a pseudofs instance, destroy the tree before tearing
down the fileno allocator.
In pfs_mount(), acquire the mountpoint interlock when required.
MFC after: 3 weeks
late stages of unmount). On failure, the vnode is recycled.
Add insmntque1(), to allow for file system specific cleanup when
recycling vnode on failure.
Change getnewvnode() to no longer call insmntque(). Previously,
embryonic vnodes were put onto the list of vnode belonging to a file
system, which is unsafe for a file system marked MPSAFE.
Change vfs_hash_insert() to no longer lock the vnode. The caller now
has that responsibility.
Change most file systems to lock the vnode and call insmntque() or
insmntque1() after a new vnode has been sufficiently setup. Handle
failed insmntque*() calls by propagating errors to callers, possibly
after some file system specific cleanup.
Approved by: re (kensmith)
Reviewed by: kib
In collaboration with: kib
function which is called from pfs_destroy() before the node is reclaimed.
Modify pfs_create_{dir,file,link}() to accept a pointer to a destructor
function in addition to the usual attr / fill / vis pointers.
This breaks both the programming and binary interfaces between pseudofs
and its consumers. It is believed that there are no pseudofs consumers
outside the source tree, so that the impact of this change is minimal.
Submitted by: Aniruddha Bohra <bohra@cs.rutgers.edu>
one byte less than needed.
This is a RELENG_x_y candidate, since it fixes a problem with Oracle 10.
Noticed by: Dmitry Ganenko <dima@apk-inform.com>
Testcase by: Dmitry Ganenko <dima@apk-inform.com>
Reviewed by: des
Submitted by: rdivacky
Sponsored by: Google SoC 2006
MFC after: 1 week
mount(2) system call:
* Add cmount hook to fdescfs and pseudofs (and, by extension, procfs and
linprocfs). This (mostly) restores the ability to mount these
filesystems using the old mount(2) system call (see below for the
rest of the fix).
* Remove not-NULL check for the data argument from the mount(2) entry
point. Per the mount(2) man page, it is up to the individual
filesystem being mounted to verify data. Or, in the case of procfs,
etc. the filesystem is free to ignore the data parameter if it does
not use it. Enforcing data to be not-NULL in the mount(2) system call
entry point prevented passing NULL to filesystems which ignored the
data pointer value. Apparently, passing NULL was common practice
in such cases, as even our own mount_std(8) used to do it in the
pre-nmount(2) world.
All userland programs in the tree were converted to nmount(2) long ago,
but I've found at least one external program which broke due to this
(presumably unintentional) mount(2) API change. One could argue that
external programs should also be converted to nmount(2), but then there
isn't much point in keeping the mount(2) interface for backward
compatibility if it isn't backward compatible.
- Reorder the events in exit(2) slightly so that we trigger the S_EXIT
stop event earlier. After we have signalled that, we set P_WEXIT and
then wait for any processes with a hold on the vmspace via PHOLD to
release it. PHOLD now KASSERT()'s that P_WEXIT is clear when it is
invoked, and PRELE now does a wakeup if P_WEXIT is set and p_lock drops
to zero.
- Change proc_rwmem() to require that the processing read from has its
vmspace held via PHOLD by the caller and get rid of all the junk to
screw around with the vmspace reference count as we no longer need it.
- In ptrace() and pseudofs(), treat a process with P_WEXIT set as if it
doesn't exist.
- Only do one PHOLD in kern_ptrace() now, and do it earlier so it covers
FIX_SSTEP() (since on alpha at least this can end up calling proc_rwmem()
to clear an earlier single-step simualted via a breakpoint). We only
do one to avoid races. Also, by making the EINVAL error for unknown
requests be part of the default: case in the switch, the various
switch cases can now just break out to return which removes a _lot_ of
duplicated PRELE and proc unlocks, etc. Also, it fixes at least one bug
where a LWP ptrace command could return EINVAL with the proc lock still
held.
- Changed the locking for ptrace_single_step(), ptrace_set_pc(), and
ptrace_clear_single_step() to always be called with the proc lock
held (it was a mixed bag previously). Alpha and arm have to drop
the lock while the mess around with breakpoints, but other archs
avoid extra lock release/acquires in ptrace(). I did have to fix a
couple of other consumers in kern_kse and a few other places to
hold the proc lock and PHOLD.
Tested by: ps (1 mostly, but some bits of 2-4 as well)
MFC after: 1 week
associated with the passed in pfs_node. If it does return a pointer, it
keeps the process locked. This allows a lot of places that were calling
pfind() again right after pfs_visible() to not have to do that and avoids
races since we don't drop the proc lock just to turn around and lock it
again. This will become more important with future changes to fix races
between procfs/ptrace and exit(2). Also, removed a duplicate pfs_visible()
call in pfs_getextattr().
Reviewed by: des
MFC after: 1 week
these filesystems will support shared locks until they are explicitly
modified to do so. Careful review must be done to ensure that this
is safe for each individual filesystem.
Sponsored by: Isilon Systems, Inc.
as suggested by Matt's comment. Also fix some style and paranoia issues.
The entire function could benefit from review by a VFS guru.
MFC after: 6 weeks
Since we used an sbuf of size resid to accumulate dirents, we would end
up returning one byte short when we had enough dirents to fill or exceed
the size of the sbuf (the last byte being lost to bogus NUL termination)
causing the next call to return EINVAL due to an unaligned offset. This
went undetected for a long time because I did most of my testing in
single-user mode, where there are rarely enough processes to fill the
4096-byte buffer ls(1) uses. The most common symptom of this bug is that
tab completion of /proc or /compat/linux/proc does not work properly when
many processes are running.
Also, a check near the top would return EINVAL if resid was smaller than
PFS_DELEN, even if it was 0, which is frequently the case and perfectly
allowable. Change the test so that it returns 0 if resid is 0.
MFC after: 2 weeks
the filesystem. Check that rather than VI_XLOCK.
- VOP_INACTIVE should no longer drop the vnode lock.
- The vnode lock is required around calls to vrecycle() and vgone().
Sponsored by: Isilon Systems, Inc.
initializations but we did have lofty goals and big ideals.
Adjust to more contemporary circumstances and gain type checking.
Replace the entire vop_t frobbing thing with properly typed
structures. The only casualty is that we can not add a new
VOP_ method with a loadable module. History has not given
us reason to belive this would ever be feasible in the the
first place.
Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc.
Give coda correct prototypes and function definitions for
all vop_()s.
Generate a bit more data from the vnode_if.src file: a
struct vop_vector and protype typedefs for all vop methods.
Add a new vop_bypass() and make vop_default be a pointer
to another struct vop_vector.
Remove a lot of vfs_init since vop_vector is ready to use
from the compiler.
Cast various vop_mumble() to void * with uppercase name,
for instance VOP_PANIC, VOP_NULL etc.
Implement VCALL() by making vdesc_offset the offsetof() the
relevant function pointer in vop_vector. This is disgusting
but since the code is generated by a script comparatively
safe. The alternative for nullfs etc. would be much worse.
Fix up all vnode method vectors to remove casts so they
become typesafe. (The bulk of this is generated by scripts)
returning incompletely initialized processes. This problem was
eliminated by kern_proc.c:1.215, which causes pfind() not to
return processes in the PRS_NEW state.
check whether p_ucred is NULL or not in pfs_getattr() before
dereferencing the credential, and return ENOENT if there wasn't one.
This is a symptom of a larger problem, wherein pfind() can return
references to incompletely initialized processes, and we instead ought
to not return them, or check the process state before acting on the
process.
Reported by: kris
Discussed with: tjr, others
