pseudofs nodes store their name in a flexible array member, so the node
allocation is sized using the length of the name, including a nul
terminator. pfs_lookup() scans a directory of nodes, comparing names to
find a match. The comparison was incorrect and assumed that all node
names were at least as long as the name being looked up, which of course
isn't true.
I believe the bug is mostly harmless since it cannot result in false
positive or negative matches from the lookup, but it triggers a KASAN
check.
Reported by: pho
Reviewed by: kib, Olivier Certner <olce.freebsd@certner.fr>
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D40692
The pseudo file systems (devfs, fdescfs, procfs, etc.) report total
and available blocks and inodes despite being synthetic with no
underlying storage device to which those values could be applied.
The current code of these file systems tends to report a fixed number
of total blocks but no free blocks, and in the case of procfs,
libprocfs, linsysfs also no free inodes.
This can be irritating in e.g. the "df" output, since 100% of the
resources seem to be in use, but it can also create warnings in
monitoring tools used for capacity management.
This patch makes these file systems return the same value for the
total and free parameters, leading to 0% in use being displayed by
"df". Since there is no resource that can be exhausted, this appears
to be a sensible result.
Reviewed by: mckusick
Differential Revision: https://reviews.freebsd.org/D39442
This will be used later in the linsysfs module to filter out VNETs.
Reviewed by: des
Differential revision: https://reviews.freebsd.org/D39382
MFC after: 1 month
Since 81167243b the size of struct pfs_node is 280 bytes, so the kernel
memory allocator takes memory from 384 bytes sized bucket. However, the
length of the node name is mostly short, e.g., for Linux emulation layer
it is up to 16 bytes. The size of struct pfs_node w/o pfs_name is 152
bytes, i.e., we have 104 bytes left to fit the node name into the 256
bytes-sized bucket.
Reviewed by: des
Differential revision: https://reviews.freebsd.org/D39381
MFC after: 1 month
To quote from a comment above vput_final:
<quote>
* XXX Some filesystems pass in an exclusively locked vnode and strongly depend
* on the lock being held all the way until VOP_INACTIVE. This in particular
* happens with UFS which adds half-constructed vnodes to the hash, where they
* can be found by other code.
</quote>
As is there is no mechanism which allows filesystems to denote that a
vnode is fully initialized, consequently problems like the above are
only found the hard way(tm).
Add rudimentary support for state transitions, which in particular allow
to assert the vnode is not legally unlocked until its fate is decided
(either construction finishes or vgone is called to abort it).
The new field lands in a 1-byte hole, thus it does not grow the struct.
Bump __FreeBSD_version to 1400077
Reviewed by: kib (previous version)
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D37759
This avoids needing to inspect the mount point every time.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D33125
Add a pseudofs node flag 'PFS_AUTODRAIN', which automatically emits sbuf
contents to the caller when the sbuf buffer fills. This is only
permissible if the corresponding PFS node fill function can sleep
whenever it appends to the sbuf.
linprocfs' /proc/self/maps node happens to meet this requirement.
Streaming out the file as it is composed avoids truncating the output
and also avoids preallocating a very large buffer.
Reviewed by: markj; earlier version: emaste, kib, trasz
Differential Revision: https://reviews.freebsd.org/D27047
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.
Approved by: kib (mentor, blanket)
Differential Revision: https://reviews.freebsd.org/D23629
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
The current vnode layout is not smp-friendly by having frequently read data
avoidably sharing cachelines with very frequently modified fields. In
particular v_iflag inspected for VI_DOOMED can be found in the same line with
v_usecount. Instead make it available in the same cacheline as the v_op, v_data
and v_type which all get read all the time.
v_type is avoidably 4 bytes while the necessary data will easily fit in 1.
Shrinking it frees up 3 bytes, 2 of which get used here to introduce a new
flag field with a new value: VIRF_DOOMED.
Reviewed by: kib, jeff
Differential Revision: https://reviews.freebsd.org/D22715
Vast majority of uses the cache are just checking if there is an entry
present on process exit (and evicting it if so). Both checking and
eviction process are very expensive and put the lock protecting it high
up on the profile during poudriere -j 104.
Convert the linked list into a hash. This allows to almost always avoid
taking the lock in the first place (and consequently almost removes it
from the profile). Note only one lock is preserved as a split did not
meaningfully impact contention.
Should the cache be used for something it will still run into contention
issues. The code needs a rewrite, but should someone want to tidy it up
further the following can be done:
1) per-chain locks (or at least an array)
2) hashing by something else than just pid
Sponsored by: The FreeBSD Foundation
of the reverse.
This fixes Linux sysctl(8) binary - it assumes the first two
directory entries are always "." and "..". There might be other
Linux apps affected by this.
NB it might be a good idea to rewrite it using queue(3).
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21550
Specifically, the following was broken:
$ mount -t procfs procfs /proc
$ ls -l /proc
r351741 reworked readdir slightly to avoid pfs_node/pidhash LOR, but
inadvertently regressed pid == NO_PID; new pfs_lookup_proc() fails for the
obvious reasons, and later pfs_visible_proc doesn't capture the
pid == NO_PID -> return 1 aspect of pfs_visible. We can infact skip this
whole block if we're operating on a directory w/ NO_PID, as it's always
visible.
Reported by: trasz
Reviewed by: mjg
Differential Revision: https://reviews.freebsd.org/D21518
Users of pseudofs (e.g. lindebugfs), should be able to receive
input from command line via commands like "echo 1 > /path/to/file".
Currently this fails because sh tries to truncate the file first and
vop_setattr returns not supported error for this. This patch simply
ignores the error and returns 0 instead.
Reviewed by: imp (mentor), asomers
Approved by: imp (mentor), asomers
MFC after: 1 week
Differential Revision: D20451
- debugfs consumers expect to be able to export names more than 48 characters
- debugfs consumers expect to be able to hold locks across calls and are able
to handle allocation failures
Reviewed by: hps@
MFC after: 1 week
Sponsored by: iX Systems
Differential Revision: https://reviews.freebsd.org/D19256
Directory entries must be padded to maintain alignment; in many
filesystems the padding was not initialized, resulting in stack
memory being copied out to userspace. With the ino64 work there
are also some explicit pad fields in struct dirent. Add a subroutine
to clear these bytes and use it in the in-tree filesystems. The
NFS client is omitted for now as it was fixed separately in r340787.
Reported by: Thomas Barabosch, Fraunhofer FKIE
Reviewed by: kib
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
The d_off field has been added to the dirent structure recently.
Currently filesystems don't support this feature. Support has been
added and tested for zfs, ufs, ext2fs, fdescfs, msdosfs and unionfs.
A stub implementation is available for cd9660, nandfs, udf and
pseudofs but hasn't been tested.
Motivation for this feature: our usecase is for a userspace nfs server
(nfs-ganesha) with zfs. At the moment we cache direntry offsets by
calling lseek once per entry, with this patch we can get the offset
directly from getdirentries(2) calls which provides a significant
speedup.
Submitted by: Jack Halford <jack@gandi.net>
Reviewed by: mckusick, pfg, rmacklem (previous versions)
Sponsored by: Gandi.net
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D17917
by doing most of the work in a new function prison_add_vfs in kern_jail.c
Now a jail-enabled filesystem need only mark itself with VFCF_JAIL, and
the rest is taken care of. This includes adding a jail parameter like
allow.mount.foofs, and a sysctl like security.jail.mount_foofs_allowed.
Both of these used to be a static list of known filesystems, with
predefined permission bits.
Reviewed by: kib
Differential Revision: D14681
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
The previous limit of 24 was somewhat restrictive, and with this change
ceil(log2(sizeof(struct pfs_node))) is the same as before in both the ILP32
and LP64 models, so the malloc zone used for allocations of struct pfs_node
is the same as before.
Approved by: des
changed from %d to a long-width type.
Use uintmax_t casting and %ju to futureproof the format string against
potential changes with either the #define or the implementation-specific
definition for offsetof(..).
fixed size for the name buffer PFS_NAMELEN.
As r318736 was commited (ino64 project) the size of the permanent part
of the struct dirent was changed, so calulate PFS_DELEN properly.
If some process' nodes were accessed using procfs and the process
cannot exit properly at the time modunload event is reported to the
pseudofs-backed filesystem, the assertion in pfs_vncache_unload() is
triggered. Assertion is correct, the cache should be cleaned.
Approved by: des (pseudofs maintainer)
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Owning Giant in the init/uninit is accidental due to the moment where
VFS modules initialization is performed, and is not enforced by the
VFS interface. The Giant lock does not prevent a parallel execution
of the code, it is VFS which implements the proper protocol.
Approved by: des (pseudofs maintainer)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
pfs_visible(). The recursion does not cause deadlock because the sx
implementation does not prefer exclusive waiters over the shared, but
this is an implementation detail.
Reported by: pho, Matthew Bryan <matthew.bryan@isilon.com>
Reviewed by: jhb
Tested by: pho
Approved by: des (pseudofs maintainer)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
compiler interprets this as an undefined behaviour. Instead, ensure
that the sum of uio_offset and uio_resid is below OFF_MAX using the
operation which cannot overflow.
Reported and tested by: pho
Discussed with: bde
Approved by: des (pseudofs maintainer)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
sources from uio. Both uio_offset and offset, and uio_resid and resid
have the same types for some time.
Add check for buflen overflow by comparing the buflen with both offset
and resid (vs. comparing with offset only, as it is currently done).
Reported and tested by: pho
Approved by: des (pseudofs maintainer)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
