This is required to avoid data corruption bugs, where a getattr slices
itself within a setattr operation, and sets the size to the stall value
it got from the filesystem. That value is smaller than the one set by
setattr, and the call to uvm_vnp_setsize() trigged a spurious truncate.
The result is a chunk of zeroed data in the file.
Such a situation can easily happen when the ioflush thread issue a
VOP_FSYNC/puffs_vnop_sync/flushvncache/dosetattrn while andother process
do a sys_stat/VOP_GETATTR/puffs_vnop_getattr.
This mutex on size operation can be removed the day we decide VOP_GETATTR
has to operated on a locked vnode, since the other operations that touch
size already require that.
- Enable VOP tmpfs_whiteout().
- Support ISWHITEOUT in tmpfs_alloc_file().
- Support DOWHITEOUT in tmpfs_remove() and tmpfs_rmdir().
- Make rmdir on a directory containing whiteouts working.
Should fix PR #35112 (tmpfs doesn't play well with unionfs).
Fixes PR kern/36681. tmpfs now survives dirconc, all our vfs/tmpfs
tests and rename races in atf, and a bunch of hand-written tests
that I'd commit if atf didn't find them highly indigestible.
ok dholland
- union_close() has to lock/unlock the lower vnode.
- union_fsync() has to call spec_fsync() for the union vnode.
- union_strategy() must allow writes to devices on the lower file system.
- union_bwrite() was completely missing.
as zero. Make it advertise one (no_trunc == true).
Names longer than NAME_MAX (255) will never pass namei() btw.
Fixes PR #43670 (msdosfs claims support for filenames longer than {NAME_MAX},
but fails)
#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif
This should fix cross-build problems, but I can't really test
that now, so I am not re-enabling the inclusion of v7fs support
in makefs.
sys/stdarg.h and expect compiler to provide proper builtins, defaulting
to the GCC interface. lint still has a special fallback.
Reduce abuse of _BSD_VA_LIST_ by defining __va_list by default and
derive va_list as required by standards.
Renaming a file of any non-directory type over another file of any
other non-directory type is OK -- they need not match as long as
neither is a directory, so loosen the kassert to reflect this.
XXX Need to write test cases for this.
ok dholland, rmind
filesystem in which format extended attribute shall be listed.
There are currently two formats:
- NUL-terminated strings, used for listxattr(2), this is the default.
- one byte length-pprefixed, non NUL-terminated strings, used for
extattr_list_file(2), which is obtanined by setting the
EXTATTR_LIST_PREFIXLEN flag to VOP_LISTEXTATTR(9)
This approach avoid the need for converting the list back and forth, except
in libperfuse, since FUSE uses NUL-terminated strings, and the kernel may
have requested EXTATTR_LIST_PREFIXLEN.
ubc_zerorange(struct uvm_object *, off_t, size_t, int) changing
the first argument to an uvm_object and adding a flags argument.
Modify tmpfs_reg_resize() to zero the backing store (aobj) instead
of the vnode. Ubc_purge() no longer panics when unmounting tmpfs.
Keep uvm_vnp_zerorange() until the next kernel version bump.
- Reorganize locking in UVM and provide extra serialisation for pmap(9).
New lock order: [vmpage-owner-lock] -> pmap-lock.
- Simplify locking in some pmap(9) modules by removing P->V locking.
- Use lock object on vmobjlock (and thus vnode_t::v_interlock) to share
the locks amongst UVM objects where necessary (tmpfs, layerfs, unionfs).
- Rewrite and optimise x86 TLB shootdown code, make it simpler and cleaner.
Add TLBSTATS option for x86 to collect statistics about TLB shootdowns.
- Unify /dev/mem et al in MI code and provide required locking (removes
kernel-lock on some ports). Also, avoid cache-aliasing issues.
Thanks to Andrew Doran and Joerg Sonnenberger, as their initial patches
formed the core changes of this branch.
cycle (destruction part). Perform link counting in tmpfs_dir_attach()
and tmpfs_dir_detach(), instead of alloc/free and arbitrary places.
Fixes PR/44285, PR/44288, PR/44657 and likely PR/42484.
- Fix the race between the lookup and inode destruction. Fixes PR/43167
and its duplicates PR/40088, PR/40757.
- Improve tmpfs_rename() locking a little, fix kqueue event notifications
and also fix PR/43617. Add simplistic tmpfs_parentcheck_p(); to be
expanded and used for further rename() locking fixes.
- Cache directory entry "hint" in the tmpfs node, add tmpfs_dir_cached(),
and thus avoid unnecessary lookup in tmpfs_remove() and tmpfs_rmdir().
- Set correct _PC_FILESIZEBITS value in tmpfs_pathconf(). Fixes PR/43576.
- Few minor fixes.
manu