in the future in a backward compatible (API and ABI) way.
The cap_rights_t represents capability rights. We used to use one bit to
represent one right, but we are running out of spare bits. Currently the new
structure provides place for 114 rights (so 50 more than the previous
cap_rights_t), but it is possible to grow the structure to hold at least 285
rights, although we can make it even larger if 285 rights won't be enough.
The structure definition looks like this:
struct cap_rights {
uint64_t cr_rights[CAP_RIGHTS_VERSION + 2];
};
The initial CAP_RIGHTS_VERSION is 0.
The top two bits in the first element of the cr_rights[] array contain total
number of elements in the array - 2. This means if those two bits are equal to
0, we have 2 array elements.
The top two bits in all remaining array elements should be 0.
The next five bits in all array elements contain array index. Only one bit is
used and bit position in this five-bits range defines array index. This means
there can be at most five array elements in the future.
To define new right the CAPRIGHT() macro must be used. The macro takes two
arguments - an array index and a bit to set, eg.
#define CAP_PDKILL CAPRIGHT(1, 0x0000000000000800ULL)
We still support aliases that combine few rights, but the rights have to belong
to the same array element, eg:
#define CAP_LOOKUP CAPRIGHT(0, 0x0000000000000400ULL)
#define CAP_FCHMOD CAPRIGHT(0, 0x0000000000002000ULL)
#define CAP_FCHMODAT (CAP_FCHMOD | CAP_LOOKUP)
There is new API to manage the new cap_rights_t structure:
cap_rights_t *cap_rights_init(cap_rights_t *rights, ...);
void cap_rights_set(cap_rights_t *rights, ...);
void cap_rights_clear(cap_rights_t *rights, ...);
bool cap_rights_is_set(const cap_rights_t *rights, ...);
bool cap_rights_is_valid(const cap_rights_t *rights);
void cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src);
void cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src);
bool cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little);
Capability rights to the cap_rights_init(), cap_rights_set(),
cap_rights_clear() and cap_rights_is_set() functions are provided by
separating them with commas, eg:
cap_rights_t rights;
cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_FSTAT);
There is no need to terminate the list of rights, as those functions are
actually macros that take care of the termination, eg:
#define cap_rights_set(rights, ...) \
__cap_rights_set((rights), __VA_ARGS__, 0ULL)
void __cap_rights_set(cap_rights_t *rights, ...);
Thanks to using one bit as an array index we can assert in those functions that
there are no two rights belonging to different array elements provided
together. For example this is illegal and will be detected, because CAP_LOOKUP
belongs to element 0 and CAP_PDKILL to element 1:
cap_rights_init(&rights, CAP_LOOKUP | CAP_PDKILL);
Providing several rights that belongs to the same array's element this way is
correct, but is not advised. It should only be used for aliases definition.
This commit also breaks compatibility with some existing Capsicum system calls,
but I see no other way to do that. This should be fine as Capsicum is still
experimental and this change is not going to 9.x.
Sponsored by: The FreeBSD Foundation
allocations under low free-space conditions (-r254995), determine
that old block-preference search order used before -r249782 worked
a bit better. This change reverts to that block-preference search order.
MFC after: 2 weeks
I have 25TB Dell PERC 6 RAID5 array. When it becomes almost
full (10-20GB free), processes which write data to it start
eating 100% CPU and write speed drops below 1MB/sec (normally
to gives 400MB/sec). The revision at which it first became
apparent was http://svnweb.freebsd.org/changeset/base/249782.
The offending change reserved an area in each cylinder group to
store metadata. The new algorithm attempts to save this area for
metadata and allows its use for non-metadata only after all the
data areas have been exhausted. The size of the reserved area
defaults to half of minfree, so the filesystem reports full before
the data area can completely fill. However, in this report, the
filesystem has had minfree reduced to 1% thus forcing the metadata
area to be used for data. As the filesystem approached full, it
had only metadata areas left to allocate. The result was that
every block allocation had to scan summary data for 30,000 cylinder
groups before falling back to searching up to 30,000 metadata areas.
The fix is to give up on saving the metadata areas once the free
space reserve drops below 2%. The effect of this change is to use
the old algorithm of just accepting the first available block that
we find. Since most filesystems use the default 5% minfree, this
will have no effect on their operation. For those that want to push
to the limit, they will get their crappy block placements quickly.
Submitted by: Dmitry Sivachenko
Fix Tested by: Dmitry Sivachenko
PR: kern/181226
MFC after: 2 weeks
and CIFS file attributes as BSD stat(2) flags.
This work is intended to be compatible with ZFS, the Solaris CIFS
server's interaction with ZFS, somewhat compatible with MacOS X,
and of course compatible with Windows.
The Windows attributes that are implemented were chosen based on
the attributes that ZFS already supports.
The summary of the flags is as follows:
UF_SYSTEM: Command line name: "system" or "usystem"
ZFS name: XAT_SYSTEM, ZFS_SYSTEM
Windows: FILE_ATTRIBUTE_SYSTEM
This flag means that the file is used by the
operating system. FreeBSD does not enforce any
special handling when this flag is set.
UF_SPARSE: Command line name: "sparse" or "usparse"
ZFS name: XAT_SPARSE, ZFS_SPARSE
Windows: FILE_ATTRIBUTE_SPARSE_FILE
This flag means that the file is sparse. Although
ZFS may modify this in some situations, there is
not generally any special handling for this flag.
UF_OFFLINE: Command line name: "offline" or "uoffline"
ZFS name: XAT_OFFLINE, ZFS_OFFLINE
Windows: FILE_ATTRIBUTE_OFFLINE
This flag means that the file has been moved to
offline storage. FreeBSD does not have any special
handling for this flag.
UF_REPARSE: Command line name: "reparse" or "ureparse"
ZFS name: XAT_REPARSE, ZFS_REPARSE
Windows: FILE_ATTRIBUTE_REPARSE_POINT
This flag means that the file is a Windows reparse
point. ZFS has special handling code for reparse
points, but we don't currently have the other
supporting infrastructure for them.
UF_HIDDEN: Command line name: "hidden" or "uhidden"
ZFS name: XAT_HIDDEN, ZFS_HIDDEN
Windows: FILE_ATTRIBUTE_HIDDEN
This flag means that the file may be excluded from
a directory listing if the application honors it.
FreeBSD has no special handling for this flag.
The name and bit definition for UF_HIDDEN are
identical to the definition in MacOS X.
UF_READONLY: Command line name: "urdonly", "rdonly", "readonly"
ZFS name: XAT_READONLY, ZFS_READONLY
Windows: FILE_ATTRIBUTE_READONLY
This flag means that the file may not written or
appended, but its attributes may be changed.
ZFS currently enforces this flag, but Illumos
developers have discussed disabling enforcement.
The behavior of this flag is different than MacOS X.
MacOS X uses UF_IMMUTABLE to represent the DOS
readonly permission, but that flag has a stronger
meaning than the semantics of DOS readonly permissions.
UF_ARCHIVE: Command line name: "uarch", "uarchive"
ZFS_NAME: XAT_ARCHIVE, ZFS_ARCHIVE
Windows name: FILE_ATTRIBUTE_ARCHIVE
The UF_ARCHIVED flag means that the file has changed and
needs to be archived. The meaning is same as
the Windows FILE_ATTRIBUTE_ARCHIVE attribute, and
the ZFS XAT_ARCHIVE and ZFS_ARCHIVE attribute.
msdosfs and ZFS have special handling for this flag.
i.e. they will set it when the file changes.
sys/param.h: Bump __FreeBSD_version to 1000047 for the
addition of new stat(2) flags.
chflags.1: Document the new command line flag names
(e.g. "system", "hidden") available to the
user.
ls.1: Reference chflags(1) for a list of file flags
and their meanings.
strtofflags.c: Implement the mapping between the new
command line flag names and new stat(2)
flags.
chflags.2: Document all of the new stat(2) flags, and
explain the intended behavior in a little
more detail. Explain how they map to
Windows file attributes.
Different filesystems behave differently
with respect to flags, so warn the
application developer to take care when
using them.
zfs_vnops.c: Add support for getting and setting the
UF_ARCHIVE, UF_READONLY, UF_SYSTEM, UF_HIDDEN,
UF_REPARSE, UF_OFFLINE, and UF_SPARSE flags.
All of these flags are implemented using
attributes that ZFS already supports, so
the on-disk format has not changed.
ZFS currently doesn't allow setting the
UF_REPARSE flag, and we don't really have
the other infrastructure to support reparse
points.
msdosfs_denode.c,
msdosfs_vnops.c: Add support for getting and setting
UF_HIDDEN, UF_SYSTEM and UF_READONLY
in MSDOSFS.
It supported SF_ARCHIVED, but this has been
changed to be UF_ARCHIVE, which has the same
semantics as the DOS archive attribute instead
of inverse semantics like SF_ARCHIVED.
After discussion with Bruce Evans, change
several things in the msdosfs behavior:
Use UF_READONLY to indicate whether a file
is writeable instead of file permissions, but
don't actually enforce it.
Refuse to change attributes on the root
directory, because it is special in FAT
filesystems, but allow most other attribute
changes on directories.
Don't set the archive attribute on a directory
when its modification time is updated.
Windows and DOS don't set the archive attribute
in that scenario, so we are now bug-for-bug
compatible.
smbfs_node.c,
smbfs_vnops.c: Add support for UF_HIDDEN, UF_SYSTEM,
UF_READONLY and UF_ARCHIVE in SMBFS.
This is similar to changes that Apple has
made in their version of SMBFS (as of
smb-583.8, posted on opensource.apple.com),
but not quite the same.
We map SMB_FA_READONLY to UF_READONLY,
because UF_READONLY is intended to match
the semantics of the DOS readonly flag.
The MacOS X code maps both UF_IMMUTABLE
and SF_IMMUTABLE to SMB_FA_READONLY, but
the immutable flags have stronger meaning
than the DOS readonly bit.
stat.h: Add definitions for UF_SYSTEM, UF_SPARSE,
UF_OFFLINE, UF_REPARSE, UF_ARCHIVE, UF_READONLY
and UF_HIDDEN.
The definition of UF_HIDDEN is the same as
the MacOS X definition.
Add commented-out definitions of
UF_COMPRESSED and UF_TRACKED. They are
defined in MacOS X (as of 10.8.2), but we
do not implement them (yet).
ufs_vnops.c: Add support for getting and setting
UF_ARCHIVE, UF_HIDDEN, UF_OFFLINE, UF_READONLY,
UF_REPARSE, UF_SPARSE, and UF_SYSTEM in UFS.
Alphabetize the flags that are supported.
These new flags are only stored, UFS does
not take any action if the flag is set.
Sponsored by: Spectra Logic
Reviewed by: bde (earlier version)
collision between a rename and an open system call for the same
target file. Here, rename releases its vnode references, waits for
the open to finish, and then restarts by reacquiring its needed
vnode locks. In this case, rename was unlocking but failing to
release its reference to one of its held vnodes. The effect was
that even after all the actual references to the vnode had gone,
the vnode still showed active references. For files that had been
removed, their space was not reclaimed until the filesystem was
forcibly unmounted.
This bug manifested itself in the Postgres server which would
leak/lose hundreds of files per day amounting to many gigabytes of
disk space. This bug required shutting down Postgres, forcibly
unmounting its filesystem, remounting its filesystem and restarting
Postgres every few days to recover the lost space.
Reported by: Dan Thomas and Palle Girgensohn
Bug-fix by: kib
Tested by: Dan Thomas and Palle Girgensohn
MFC after: 2 weeks
persist much longer than previously. Historically we had at most 100
entries; now the count may reach a million. With the increased count
we spent far too much time looking them up in the grossly undersized
newblk hash table. Configure the newblk hash table to accurately reflect
the number of entries that it must index.
Reviewed by: kib
Tested by: Peter Holm
MFC after: 2 weeks
we need to collect the highest level of allocation for each of the
different soft update dependency structures. This change collects these
statistics and makes them available using `sysctl debug.softdep.highuse'.
Reviewed by: kib
Tested by: Peter Holm
MFC after: 2 weeks
block copy, when copying the superblock into the snapshot. UFS1 does
not align superblock on the block boundary, and bcopy runs off the end
of the buffer.
Reported by: Andre Albsmeier <Andre.Albsmeier@siemens.com>
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
vfs_busy(mp);
vfs_write_suspend(mp);
which are problematic if other thread starts unmount between two
calls. The unmount starts a write, while vfs_write_suspend() drain
writers. On the other hand, unmount drains busy references, causing
the deadlock.
Add a flag argument to vfs_write_suspend and require the callers of it
to specify VS_SKIP_UNMOUNT flag, when the call is performed not in the
mount path, i.e. the covered vnode is not locked. The suspension is
not attempted if VS_SKIP_UNMOUNT is specified and unmount is in
progress.
Reported and tested by: Andreas Longwitz <longwitz@incore.de>
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Revert the simplification of the i_gen calculation.
It is still a good idea to avoid zero values and for the case
of old filesystems there is probably no advantage in using
the complete 32 bits anyways.
Discussed with: bde
MFC after: 4 weeks
Further simplify the i_gen calculation for older disks.
Having a zero here is not really a problem and this is more
similar to what is done in newfs_random().
Reported by: Xin Li
MFC after: 4 weeks
defined by <sys/dirent.h>
Always start parsing at DIRBLKSIZ aligned offset, skip first entries if
uio_offset is not DIRBLKSIZ aligned. Return EINVAL if buffer is too
small for single entry.
Preallocate buffer for cookies. Cookies will be replaced with d_off
field in struct dirent at later point.
Skip entries with zero inode number.
Stop mangling dirent in ufs_extattr_iterate_directory().
Reviewed by: kib
Sponsored by: Google Summer Of Code 2011
In UFS, i_gen is a random generated value and there is not way for
it to be negative. Actually, the value of i_gen is just used to
match bit patterns and it is of not consequence if the values are
signed or not.
Following other filesystems, set it to unsigned and use it as such,
Discussed by: mckusick
Reviewed by: mckusick (previous version)
MFC after: 4 weeks
- Use a shared bufobj lock in getblk() and inmem().
- Convert softdep's lk to rwlock to match the bufobj lock.
- Move INFREECNT to b_flags and protect it with the buf lock.
- Remove unnecessary locking around bremfree() and BKGRDINPROG.
Sponsored by: EMC / Isilon Storage Division
Discussed with: mckusick, kib, mdf
an error. One could argue that returning a buffer even when it is
not valid is incorrect, but bread has always returned a buffer
valid or not.
Reviewed by: kib
MFC after: 2 weeks
the return value is NULL. Based on the returned flags, the
return value should never be inspected in the case where NULL
is returned, but it is good coding practice not to return a
pointer to freed memory.
Found by: Coverity Scan, CID 1006096
Reviewed by: kib
MFC after: 2 weeks
- Don't insert BKGRDMARKER bufs into the splay or dirty/clean buf lists.
No consumers need to find them there and it complicates the tree.
These flags are all FFS specific and could be moved out of the buf
cache.
- Use pbgetvp() and pbrelvp() to associate the background and journal
bufs with the vp. Not only is this much cheaper it makes more sense
for these transient bufs.
- Fix the assertions in pbget* and pbrel*. It's not safe to check list
pointers which were never initialized. Use the BX flags instead. We
also check B_PAGING in reassignbuf() so this should cover all cases.
Discussed with: kib, mckusick, attilio
Sponsored by: EMC / Isilon Storage Division
in the pagedep and inodedep hash tables. An entry in the table is
skipped because 'pagedep_hash' and 'inodedep_hash' hold the size
of the hash tables - 1.
The chance that this would have any operational failure is extremely
unlikely. These funtions only need to find a single entry and are
only called when there are too many entries. The chance that they
would fail because all the entries are on the single skipped hash
chain are remote.
Submitted by: Pedro Martelletto
Reviewed by: kib
MFC after: 2 weeks
running time for a full fsck. It also reduces the random access time
for large files and speeds the traversal time for directory tree walks.
The key idea is to reserve a small area in each cylinder group
immediately following the inode blocks for the use of metadata,
specifically indirect blocks and directory contents. The new policy
is to preferentially place metadata in the metadata area and
everything else in the blocks that follow the metadata area.
The size of this area can be set when creating a filesystem using
newfs(8) or changed in an existing filesystem using tunefs(8).
Both utilities use the `-k held-for-metadata-blocks' option to
specify the amount of space to be held for metadata blocks in each
cylinder group. By default, newfs(8) sets this area to half of
minfree (typically 4% of the data area).
This work was inspired by a paper presented at Usenix's FAST '13:
www.usenix.org/conference/fast13/ffsck-fast-file-system-checker
Details of this implementation appears in the April 2013 of ;login:
www.usenix.org/publications/login/april-2013-volume-38-number-2.
A copy of the April 2013 ;login: paper can also be downloaded
from: www.mckusick.com/publications/faster_fsck.pdf.
Reviewed by: kib
Tested by: Peter Holm
MFC after: 4 weeks
we need to call ufs_checkpath() to walk from our new location to
the root of the filesystem to ensure that we do not encounter
ourselves along the way. Until now, we accomplished this by reading
the ".." entries of each directory in our path until we reached
the root (or encountered an error). This change tries to avoid the
I/O of reading the ".." entries by first looking them up in the
name cache and only doing the I/O when the name cache lookup fails.
Reviewed by: kib
Tested by: Peter Holm
MFC after: 4 weeks
cluster_write() and cluster_wbuild() functions. The flags to be
allowed are a subset of the GB_* flags for getblk().
Sponsored by: The FreeBSD Foundation
Tested by: pho
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.
The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
- VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
- VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
- VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
- VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
(in order to avoid visibility of implementation details)
- The read-mode operations are added:
VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
sys/mutex.h in consumers directly to cater its inlining functions
using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
the compat layer because the name clash between FreeBSD and solaris
versions must be avoided.
At this purpose zfs redefines the vm_object locking functions
directly, isolating the FreeBSD components in specific compat stubs.
The KPI results heavilly broken by this commit. Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).
Sponsored by: EMC / Isilon storage division
Reviewed by: jeff
Reviewed by: pjd (ZFS specific review)
Discussed with: alc
Tested by: pho
Current dqflush() panics when a dquot with with non-zero refcount is
encountered. The situation is possible, because quotas are turned off
before softdep workitem queue if flushed, due to the quota file writes
might create softdep workitems.
Make the encountering an active dquot in dqflush() not fatal, return
the error from quotaoff() instead. Ignore the quotaoff() failures
when ffs_flushfiles() is called in the course of softdep_flushfiles()
loop, until the last iteration. At the last loop, the quotas must be
closed, and because SU workitems should be already flushed, the
references to dquot are gone.
Sponsored by: The FreeBSD Foundation
Reported and tested by: pho
Reviewed by: mckusick
MFC after: 2 weeks
The order is inode buffer lock -> snaplk -> cg buffer lock, reversing
the order causes deadlocks.
Inode block must not be written while cg block buffer is owned. The
FFS copy on write needs to allocate a block to copy the content of the
inode block, and the cylinder group selected for the allocation might
be the same as the owned cg block. The reserved block detection code
in the ffs_copyonwrite() and ffs_bp_snapblk() is unable to detect the
situation, because the locked cg buffer is not exposed to it.
In order to maintain the dependency between initialized inode block
and the cg_initediblk pointer, look up the inode buffer in
non-blocking mode. If succeeded, brelse cg block, initialize the inode
block and write it. After the write is finished, reread cg block and
update the cg_initediblk.
If inode block is already locked by another thread, let the another
thread initialize it. If another thread raced with us after we
started writing inode block, the situation is detected by an update of
cg_initediblk. Note that double-initialization of the inode block is
harmless, the block cannot be used until cg_initediblk is incremented.
Sponsored by: The FreeBSD Foundation
In collaboration with: pho
Reviewed by: mckusick
MFC after: 1 month
X-MFC-note: after r246877
When a cylinder group runs short of inodes, a new block for inodes is
allocated, zero'ed, and written to the disk. The zero'ed inodes must
be on the disk before the cylinder group can be updated to claim them.
If the cylinder group claiming the new inodes were written before the
zero'ed block of inodes, the system could crash with the filesystem in
an unrecoverable state.
Rather than adding a soft updates dependency to ensure that the new
inode block is written before it is claimed by the cylinder group
map, we just do a barrier write of the zero'ed inode block to ensure
that it will get written before the updated cylinder group map can
be written. This change should only slow down bulk loading of newly
created filesystems since that is the primary time that new inode
blocks need to be created.
Reported by: Robert Watson
Reviewed by: kib
Tested by: Peter Holm
function, implementing the sysctl vfs.ffs.set_bufoutput (not used in
the tree yet).
- The current directory vnode dereference is unsafe since fd_cdir
could be changed and unreferenced, lock the filedesc around and vref
the fd_cdir.
- The VTOI() conversion of the fd_cdir is unsafe without first
checking that the vnode is indeed from an FFS mount, otherwise
the code dereferences a random memory.
- The cdir could be reclaimed from under us, lock it around the
checks.
- The type of the fp vnode might be not a disk, or it might have
changed while the thread was in flight, check the type.
Reviewed and tested by: mckusick
MFC after: 2 weeks
has gone below zero after the blocks in its inode are freed is a
no-op which the compiler fails to warn about because of the use of
the DIP macro. Change the sanity check to compare the number of
blocks being freed against the value i_blocks. If the number of
blocks being freed exceeds i_blocks, just set i_blocks to zero.
Reported by: Pedro Giffuni (pfg@)
MFC after: 2 weeks
mount, which means that is must not be called while the snaplock is
owned. The vfs_write_resume(9) does call the function as the
VFS_SUSP_CLEAN() method, which is too early and falls into the region
still protected by snaplock.
Add yet another flag for the vfs_write_resume_flags() to avoid calling
suspension cleanup handler after the suspend is lifted, and use it in
the ffs_snapshot() call to vfs_write_resume.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
the write start, by adding a variation of the vfs_write_resume(9)
which accepts flags.
Use the new function to prevent a deadlock between parallel suspension
and snapshotting a UFS mount. The ffs_snapshot() code performed
vfs_write_resume() followed by vn_start_write() while owning the
snaplock. If the suspension intervene between resume and
vn_start_write(), the deadlock occured after the suspending thread
tried to lock the snaplock, most typically during the write in the
ffs_copyonwrite().
Reported and tested by: Andreas Longwitz <longwitz@incore.de>
Reviewed by: mckusick
MFC after: 2 weeks
X-MFC-note: make the vfs_write_resume(9) function a macro after the MFC,
in HEAD
When kern_yield() was introduced with the possibility to specify
a new priority, the behaviour changed by not lowering priority at all
in the consumers, making the yielding mechanism highly ineffective for
high priority kthreads like bufdaemon, syncer, vlrudaemon, etc.
There are no evidences that consumers could bear with such change in
semantic and this situation could finally lead to bugs similar to the
ones fixed in r244240.
Re-specify userland pri for kthreads involved.
Tested by: pho
Reviewed by: kib, mdf
MFC after: 1 week
