Remove OBJT_SWAP_TMPFS. Move tmpfs-specific swap pager bits into
tmpfs_subr.c.
There is no longer any code to directly support tmpfs in sys/vm, most
tmpfs knowledge is shared by non-anon swap object type implementation.
The tmpfs-specific methods are provided by registered tmpfs pager, which
inherits from the swap pager.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30168
This is OBJT_SWAP pager, specialized for tmpfs. Right now, both swap pager
and generic vm code have to explicitly handle swap objects which are tmpfs
vnode v_object, in the special ways. Replace (almost) all such places with
proper methods.
Since VM still needs a notion of the 'swap object', regardless of its
use, add yet another type-classification flag OBJ_SWAP. Set it in
vm_object_allocate() where other type-class flags are set.
This change almost completely eliminates the knowledge of tmpfs from VM,
and opens a way to make OBJT_SWAP_TMPFS loadable from tmpfs.ko.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30070
vfs_cache_lookup() has already done the appropriate VEXEC check, therefore
we must not re-check in VOP_CACHEDLOOKUP.
This fixes O_SEARCH semantics on tmpfs and removes a redundant descent into
VOP_ACCESS() in the common case.
Reported-by: arichardson (via CheriBSD Jenkins CI)
Reviewed-by: kib
MFC-after: 3 days
Differential Revision: https://reviews.freebsd.org/D28401
Otherwise it is dereferenced one extra time at unmount, if it survives
long enough. One way to hold the reference on such node is to keep it
open.
tmpfs_vptocnp() now needs to account for the possibility that unlocked
node was removed from the list.
Reported by: danfe
Tested by: danfe, pho
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Split TMPFS_NODE_ACCCESSED bit into dedicated byte that can be updated
atomically without locks or (locked) atomics.
tn_update_getattr() change also contains unrelated bug fix.
Reported by: lwhsu
PR: 249362
Reviewed by: markj (previous version)
Discussed with: mjg
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26451
Or it could be explained as lockless (for vnode lock) reads. Reads
are performed from the node tn_obj object. Tmpfs regular vnode object
lifecycle is significantly different from the normal OBJT_VNODE: it is
alive as far as ref_count > 0.
Ensure liveness of the tmpfs VREG node and consequently v_object
inside VOP_READ_PGCACHE by referencing tmpfs node in tmpfs_open().
Provide custom tmpfs fo_close() method on file, to ensure that close
is paired with open.
Add tmpfs VOP_READ_PGCACHE that takes advantage of all tmpfs quirks.
It is quite cheap in code size sense to support page-ins for read for
tmpfs even if we do not own tmpfs vnode lock. Also, we can handle
holes in tmpfs node without additional efforts, and do not have
limitation of the transfer size.
Reviewed by: markj
Discussed with and benchmarked by: mjg (previous version)
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26346
Avoid tmpfs mount and node locks when ref count is greater than zero,
which is the case until node is being destroyed by unlink or unmount.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26346
On 64-bit platforms, the two short fields in `struct tmpfs_fid` are padded to
the 64-bit alignment of the long field. This pushes the offsets of the
subsequent fields by 4 bytes and makes `struct tmpfs_fid` bigger than
`struct fid`. `tmpfs_vptofh()` casts a `struct fid *` to `struct tmpfs_fid *`,
causing 4 bytes of adjacent memory to be overwritten when the struct fields are
set. Through several layers of indirection and embedded structs, the adjacent
memory for one particular call to `tmpfs_vptofh()` happens to be the stack
canary for `nfsrvd_compound()`. Half of the canary ends up being clobbered,
going unnoticed until eventually the stack check fails when `nfsrvd_compound()`
returns and a panic is triggered.
Instead of duplicating fields of `struct fid` in `struct tmpfs_fid`, narrow the
struct to cover only the unique fields for tmpfs and assert at compile time
that the struct fits in the allotted space. This way we don't have to
replicate the offsets of `struct fid` fields, we just use them directly.
Reviewed by: kib, mav, rmacklem
Approved by: mav (mentor)
MFC after: 1 week
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D25077
It was generated to be just a jumping off point to tmpfs_itimes.
While here provide a dedicated variant for getattr since we normally don't
expect to need to the update from that caller.
O_SEARCH is defined by POSIX [0] to open a directory for searching, skipping
permissions checks on the directory itself after the initial open(). This is
close to the semantics we've historically applied for O_EXEC on a directory,
which is UB according to POSIX. Conveniently, O_SEARCH on a file is also
explicitly undefined behavior according to POSIX, so O_EXEC would be a fine
choice. The spec goes on to state that O_SEARCH and O_EXEC need not be
distinct values, but they're not defined to be the same value.
This was pointed out as an incompatibility with other systems that had made
its way into libarchive, which had assumed that O_EXEC was an alias for
O_SEARCH.
This defines compatibility O_SEARCH/FSEARCH (equivalent to O_EXEC and FEXEC
respectively) and expands our UB for O_EXEC on a directory. O_EXEC on a
directory is checked in vn_open_vnode already, so for completeness we add a
NOEXECCHECK when O_SEARCH has been specified on the top-level fd and do not
re-check that when descending in namei.
[0] https://pubs.opengroup.org/onlinepubs/9699919799/
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23247
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
Both of these features are not needed by many consumers and result in avoidable
reads which in turn puts them on profiles due to cache-line ping ponging.
On top of that the current lockgmr entry point is slower than necessary
single-threaded. As an attempted clean up preparing for other changes,
provide new routines which don't support any of the aforementioned features.
With these patches in place vop_stdlock and vop_stdunlock disappear from
flamegraphs during -j 104 buildkernel.
Reviewed by: jeff (previous version)
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D22665
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
Top-level kern_renameat() increases the writecount on the mount point,
which, together with tmpfs unmount suspending the mount, already
ensures that unmount cannot proceed while rename unlocks and relocks
all operated vnodes.
Remove vfs_busy() call from tmpfs_rename() which was done while
holding a vnode lock, creating the deadlock. The only intent of the
busy operation seems to be the prevention of unmount, which is already
ensured.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
flag and use the same system.
This enables further fault locking improvements by allowing more faults to
proceed with a shared lock.
Reviewed by: kib
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D22116
Current implementation of vnode_create_vobject() and
vnode_destroy_vobject() is written so that it prepared to handle the
vm object destruction for live vnode. Practically, no filesystems use
this, except for some remnants that were present in UFS till today.
One of the consequences of that model is that each filesystem must
call vnode_destroy_vobject() in VOP_RECLAIM() or earlier, as result
all of them get rid of the v_object in reclaim.
Move the call to vnode_destroy_vobject() to vgonel() before
VOP_RECLAIM(). This makes v_object stable: either the object is NULL,
or it is valid vm object till the vnode reclamation. Remove code from
vnode_create_vobject() to handle races with the parallel destruction.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21412
In particular, this fixes atimes still changing for ro tmpfs.
tmpfs_set_status() gains tmpfs_mount * argument.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D19737
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
This will enable callers to take const paths as part of syscall
decleration improvements.
Where doing so is easy and non-distruptive carry the const through
implementations. In UFS the value is passed to an interface that must
take non-const values. In ZFS, const poisoning would touch code shared
with upstream and it's not worth adding diffs.
Bump __FreeBSD_version for external API consumers.
Reviewed by: kib (prior version)
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D17805
pathconf(2) and fpathconf(2) both return a long. The kern_[f]pathconf()
functions now accept a pointer to a long value rather than modifying
td_retval directly. Instead, the system calls explicitly store the
returned long value in td_retval[0].
Requested by: bde
Reviewed by: kib
Sponsored by: Chelsio Communications
On the one hand, FIFOs should respect other variables not supported by
the fifofs vnode operation (such as _PC_NAME_MAX, _PC_LINK_MAX, etc.).
These values are fs-specific and must come from a fs-specific method.
On the other hand, filesystems that support FIFOs are required to
support _PC_PIPE_BUF on directory vnodes that can contain FIFOs.
Given this latter requirement, once the fs-specific VOP_PATHCONF
method supports _PC_PIPE_BUF for directories, it is also suitable for
FIFOs permitting a single VOP_PATHCONF method to be used for both
FIFOs and non-FIFOs.
To that end, retire all of the FIFO-specific pathconf methods from
filesystems and change FIFO-specific vnode operation switches to use
the existing fs-specific VOP_PATHCONF method. For fifofs, set it's
VOP_PATHCONF to VOP_PANIC since it should no longer be used.
While here, move _PC_PIPE_BUF handling out of vop_stdpathconf() so that
only filesystems supporting FIFOs will report a value. In addition,
only report a valid _PC_PIPE_BUF for directories and FIFOs.
Discussed with: bde
Reviewed by: kib (part of a larger patch)
MFC after: 1 month
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D12572
Add a new TMPFS_LINK_MAX to use in place of LINK_MAX for link overflow
checks and pathconf() reporting. Rather than storing a full 64-bit
link count, just use a plain int and use INT_MAX as TMPFS_LINK_MAX.
Discussed with: bde
Reviewed by: kib (part of a larger patch)
Sponsored by: Chelsio Communications
Having all filesystems fall through to default values isn't always correct
and these values can vary for different filesystem implementations. Most
of these changes just use the existing default values with a few exceptions:
- Don't report CHOWN_RESTRICTED for ZFS since it doesn't do the exact
permissions check this claims for chown().
- Use NANDFS_NAME_LEN for NAME_MAX for nandfs.
- Don't report a LINK_MAX of 0 on smbfs. Now fail with EINVAL to
indicate hard links aren't supported.
Requested by: bde (though perhaps not this exact implementation)
Reviewed by: kib (earlier version)
MFC after: 1 month
Sponsored by: Chelsio Communications
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.
