The option "nonc" disables using of namecache for the created mount,
by default namecache is used. The rationale for the option is that
namecache duplicates the information which is already kept in memory
by tmpfs. Since it believed that namecache scales better than tmpfs,
or will scale better, do not enable the option by default. On the
other hand, smaller machines may benefit from lesser namecache
pressure.
Discussed with: mjg
Tested by: pho (as part of larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
On dotdot lookup and fhtovp operations, it is possible for the file
represented by tmpfs node to be removed after the thread calculated
the pointer. In this case, tmpfs_alloc_vp() accesses freed memory.
Introduce the reference count on the nodes. The allnodes list from
tmpfs mount owns 1 reference, and threads performing unlocked
operations on the node, add one transient reference. Similarly, since
struct tmpfs_mount maintains the list where nodes are enlisted,
refcount it by one reference from struct mount and one reference from
each node on the list. Both nodes and tmpfs_mounts are removed when
refcount goes to zero.
Note that this means that nodes and tmpfs_mounts might survive some
time after the node is deleted or tmpfs_unmount() finished. The
tmpfs_alloc_vp() in these cases returns error either due to node
removal (tn_nlinks == 0) or because of insmntque1(9) error.
Tested by: pho (as part of larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Remove TMPFS_ASSERT_ELOCKED(). Its claims are already stated by other
asserts nearby and by VFS guarantees.
Change TMPFS_ASSERT_LOCKED() and one inlined place to use
ASSERT_VOP_(E)LOCKED() instead of hand-rolled imprecise asserts.
Tested by: pho (as part of the larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Edit comments which explain no longer relevant details, and add
locking annotations to the struct tmpfs_node members.
Tested by: pho (as part of the larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
If tmpfs vnode is only shared locked, tn_status field still needs
updates to note the access time modification. Use the same locking
scheme as for UFS, protect tn_status with the node interlock + shared
vnode lock.
Fix nearby style.
Noted and reviewed by: mjg
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
to UFS, perform updates during syncer scans, which in particular means
that tmpfs now performs scan on sync. Also, this means that a mtime
update may be delayed up to 30 seconds after the write.
The vm_object' OBJ_TMPFS_DIRTY flag for tmpfs swap object is similar
to the OBJ_MIGHTBEDIRTY flag for the vnode object, it indicates that
object could have been dirtied. Adapt fast page fault handler and
vm_object_set_writeable_dirty() to handle OBJ_TMPFS_NODE same as
OBJT_VNODE.
Reported by: Ronald Klop <ronald-lists@klop.ws>
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
- Suspend filesystem for unmount. This prevents new tmpfs nodes from
instantiating, and also ensures that only unmount thread can destroy
nodes.
- Do not start tmpfs node deletion until all vnodes are reclaimed,
which guarantees that no thread can access tmpfs data. For this,
call vflush() in the loop, until the mnt_nvnodelistsize is non-zero.
Note that after mnt_nvnodelistsize becomes 0, insmntque() blocks
insertion of a vnode germ into the mount list of vnodes.
- Fail node allocation when the filesystem is being unmounted. This
is race-free due to the vflush() call in loop. This is mostly
cosmetic, avoiding some more work which might be done until
suspension in unmount is started.
Note that there is currently no way to prevent new vnode instantiation
from readers during the unmount. Due to this, forced unmount might
live-lock if vflush() loop cannot get to the zero vnode count due to
races with readers. The unmount would proceed after the load is
lifted.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
permissions test, forgotten in r164033.
Refactor the permission checks for utimes(2) into vnode helper
function vn_utimes_perm(9), and simplify its code comparing with the
UFS origin, by writing the call to VOP_ACCESSX only once. Use the
helper for UFS(5), tmpfs(5), devfs(5) and msdosfs(5).
Reported by: bde
Reviewed by: bde, trasz
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
in particular, from the tmpfs_lookup VOP method. If LK_NOWAIT is not
specified in the lkflags, the lookup is supposed to return an alive
vnode whenever the underlying node is valid.
Currently, the tmpfs_alloc_vp() returns ENOENT if the vnode attached
to node exists and is being reclaimed. This causes spurious ENOENT
errors from lookup on tmpfs and corresponding random 'No such file'
failures from syscalls working with tmpfs files.
Fix this by waiting for the doomed vnode to be detached from the tmpfs
node if sleepable allocation is requested.
Note that filesystems which use vfs_hash.c, correctly handle the case
due to vfs_hash_get() looping when vget() returns ENOENT for sleepable
requests.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
insmntque() is called. The standard insmntque destructor resets the
vop vector to deadfs one, and calls vgone() on the vnode. As result,
v_object is kept unchanged, which triggers an assertion in the reclaim
code, on instmntque() failure. Also, in this case, OBJ_TMPFS flag on
the backed vm object is not cleared.
Provide the tmpfs insmntque() destructor which properly clears
OBJ_TMPFS flag and resets v_object.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
u_long. Before this change it was of type int for syscalls, but prototypes
in sys/stat.h and documentation for chflags(2) and fchflags(2) (but not
for lchflags(2)) stated that it was u_long. Now some related functions
use u_long type for flags (strtofflags(3), fflagstostr(3)).
- Make path argument of type 'const char *' for consistency.
Discussed on: arch
Sponsored by: The FreeBSD Foundation
Use file name hash as a tree key, handle duplicate keys. Both VOP_LOOKUP
and VOP_READDIR operations utilize same tree for search. Directory
entry offset (cookie) is either file name hash or incremental id in case
of hash collisions (duplicate-cookies). Keep sorted per directory list
of duplicate-cookie entries to facilitate cookie number allocation.
Don't fail if previous VOP_READDIR() offset is no longer valid, start
with next dirent instead. Other file system handle it similarly.
Workaround race prone tn_readdir_last[pn] fields update.
Add tmpfs_dir_destroy() to free all dirents.
Set NFS cookies in tmpfs_dir_getdents(). Return EJUSTRETURN from
tmpfs_dir_getdents() instead of hard coded -1.
Mark directory traversal routines static as they are no longer
used outside of tmpfs_subr.c
Since r230208 update mounts were allowed if the list of mount options
contained the "export" option. This is not correct as tmpfs doesn't
really support updating all options.
Reviewed by: kevlo, trociny
- Don't deduct wired pages from total usable counts because it does not
make any sense. To make things worse, on systems where swap size is
smaller than physical memory and use a lot of wired pages (e.g. ZFS),
tmpfs can suddenly have free space of 0 because of this;
- Count cached pages as available; [1]
- Don't count inactive pages as available, technically we could but that
might be too aggressive; [1]
[1] Suggested by kib@
MFC after: 1 week
object's size field. Previously, that field was always zero, even
when the object tn_reg.tn_aobj contained numerous pages.
Apply style fixes to tmpfs_reg_resize().
In collaboration with: kib
Right now unionfs only allows filesystems to be mounted on top of
another if it supports whiteouts. Even though I have sent a patch to
daichi@ to let unionfs work without it, we'd better also add support for
whiteouts to tmpfs.
This patch implements .vop_whiteout and makes necessary changes to
lookup() and readdir() to take them into account. We must also make sure
that when adding or removing a file, we honour the componentname's
DOWHITEOUT and ISWHITEOUT, to prevent duplicate filenames.
MFC after: 1 month
the VFS. Now all the VFS_* functions and relating parts don't want the
context as long as it always refers to curthread.
In some points, in particular when dealing with VOPs and functions living
in the same namespace (eg. vflush) which still need to be converted,
pass curthread explicitly in order to retain the old behaviour.
Such loose ends will be fixed ASAP.
While here fix a bug: now, UFS_EXTATTR can be compiled alone without the
UFS_EXTATTR_AUTOSTART option.
VFS KPI is heavilly changed by this commit so thirdy parts modules needs
to be recompiled. Bump __FreeBSD_version in order to signal such
situation.
both node pointer and name component. This does the right thing for
hardlinks to the same node in the same directory.
Submitted by: Yoshihiro Ota <ota j email ne jp>
PR: kern/131356
MFC after: 2 weeks
and bcmp are not the same thing. 'man bcmp' states that the return is
"non-zero" if the two byte strings are not identical. Where as,
'man memcmp' states that the return is the "difference between the
first two differing bytes (treated as unsigned char values" if the
two byte strings are not identical.
So provide a proper memcmp(9), but it is a C implementation not a tuned
assembly implementation. Therefore bcmp(9) should be preferred over memcmp(9).
filesystem-specific vnode data to the struct vnode. Provide the
default implementation for the vop_advlock and vop_advlockasync.
Purge the locks on the vnode reclaim by using the lf_purgelocks().
The default implementation is augmented for the nfs and smbfs.
In the nfs_advlock, push the Giant inside the nfs_dolock.
Before the change, the vop_advlock and vop_advlockasync have taken the
unlocked vnode and dereferenced the fs-private inode data, racing with
with the vnode reclamation due to forced unmount. Now, the vop_getattr
under the shared vnode lock is used to obtain the inode size, and
later, in the lf_advlockasync, after locking the vnode interlock, the
VI_DOOMED flag is checked to prevent an operation on the doomed vnode.
The implementation of the lf_purgelocks() is submitted by dfr.
Reported by: kris
Tested by: kris, pho
Discussed with: jeff, dfr
MFC after: 2 weeks
strees2 suite, to quote his letter, this change:
1. It removes the tn_lookup_dirent stuff. I think this cannot be fixed,
because nothing protects vnode/tmpfs node between lookup is done, and
actual operation is performed, in the case the vnode lock is dropped.
At least, this is the case with the from vnode for rename.
For now, we do the linear lookup in the parent node. This has its own
drawbacks. Not mentioning speed (that could be fixed by using hash), the
real problem is the situation where several hardlinks exist in the dvp.
But, I think this is fixable.
2. The patch restores the VV_ROOT flag on the root vnode after it became
reclaimed and allocated again. This fixes MPASS assertion at the start
of the tmpfs_lookup() reported by many.
Submitted by: kib
- LK_RETRY prohibits vget() and vn_lock() to return error.
Remove associated code. [1]
- Properly use vhold() and vdrop() instead of their unlocked
versions, we are guaranteed to have the vnode's interlock
unheld. [1]
- Fix a pseudo-infinite loop caused by 64/32-bit arithmetic
with the same way used in modern NetBSD versions. [2]
- Reorganize tmpfs_readdir to reduce duplicated code.
Submitted by: kib [1]
Obtained from: NetBSD [2]
Approved by: re (tmpfs blanket)
- Respect cnflag and don't lock vnode always as LK_EXCLUSIVE [1]
- Properly lock around tn_vnode to avoid NULL deference
- Be more careful handling vnodes (*)
(*) This is a WIP
[1] by pjd via howardsu
Thanks kib@ for his valuable VFS related comments.
Tested with: fsx, fstest, tmpfs regression test set
Found by: pho's stress2 suite
Approved by: re (tmpfs blanket)
- Copy before testing a pointer. This closes a race window.
- Use msleep with the node interlock instead of tsleep.
- Do proper locking around access to tn_vpstate.
- Assert vnode VOP lock for dir_{atta,de}tach to capture
inconsistent locking.
Suggested by: kib
Submitted by: delphij
Reviewed by: Howard Su
Approved by: re (tmpfs blanket)
- Plug memory leak.
- Respect underlying vnode's properties rather than assuming that
the user want root:wheel + 0755. Useful for using tmpfs(5) for
/tmp.
- Use roundup2 and howmany macros instead of rolling our own version.
- Try to fix fsx -W -R foo case.
- Instead of blindly zeroing a page, determine whether we need a pagein
order to prevent data corruption.
- Fix several bugs reported by Coverity.
Submitted by: Mingyan Guo <guomingyan gmail com>, Howard Su, delphij
Coverity ID: CID 2550, 2551, 2552, 2557
Approved by: re (tmpfs blanket)
- Remove unnecessary NULL checks after M_WAITOK allocations.
- Use VOP_ACCESS instead of hand-rolled suser_cred()
calls. [1]
- Use malloc(9) KPI to allocate memory for string. The
optimization taken from NetBSD is not valid for FreeBSD
because our malloc(9) already act that way. [2]
Requested by: rwatson [1]
Submitted by: Howard Su [2]
Approved by: re (tmpfs blanket)
- Remove tmpfs_zone_xxx KPI, the uma(9) wrapper, since
they does not bring any value now.
- Use |= instead of = when applying VV_ROOT flag.
- Remove tm_avariable_nodes list. Use uma to hold the
released nodes.
- init/destory interlock mutex of node when init/fini
instead of ctor/dtor.
- Change memory computing using u_int to fix negative
value in 2G mem machine.
- Remove unnecessary bzero's
- Rely uma logic to make file id allocation harder to
guess.
- Fix some unsigned/signed related things. Make sure
we respect -o size=xxxx
- Use wire instead of hold a page.
- Pass allocate_zero to obtain zeroed pages upon first
use.
Submitted by: Howard Su
Approved by: re (tmpfs blanket, kensmith)
Please note that, this is currently considered as an
experimental feature so there could be some rough
edges. Consult http://wiki.freebsd.org/TMPFS for
more information.
For now, connect tmpfs to build on i386 and amd64
architectures only. Please let us know if you have
success with other platforms.
This work was developed by Julio M. Merino Vidal
for NetBSD as a SoC project; Rohit Jalan ported it
from NetBSD to FreeBSD. Howard Su and Glen Leeder
are worked on it to continue this effort.
Obtained from: NetBSD via p4
Submitted by: Howard Su (with some minor changes)
Approved by: re (kensmith)
