This allows ffs_fsync() to break out of a loop that might otherwise
be infinite on kernels compiled without the SOFTUPDATES option.
The observed symptom was a system hang at the first unmount attempt.
the SF_IMMUTABLE flag to prevent writing. Instead put in explicit
checking for the SF_SNAPSHOT flag in the appropriate places. With
this change, it is now possible to rename and link to snapshot files.
It is also possible to set or clear any of the owner, group, or
other read bits on the file, though none of the write or execute
bits can be set. There is also an explicit test to prevent the
setting or clearing of the SF_SNAPSHOT flag via chflags() or
fchflags(). Note also that the modify time cannot be changed as
it needs to accurately reflect the time that the snapshot was taken.
Submitted by: Robert Watson <rwatson@FreeBSD.org>
with the new snapshot code.
Update addaliasu to correctly implement the semantics of the old
checkalias function. When a device vnode first comes into existence,
check to see if an anonymous vnode for the same device was created
at boot time by bdevvp(). If so, adopt the bdevvp vnode rather than
creating a new vnode for the device. This corrects a problem which
caused the kernel to panic when taking a snapshot of the root
filesystem.
Change the calling convention of vn_write_suspend_wait() to be the
same as vn_start_write().
Split out softdep_flushworklist() from softdep_flushfiles() so that
it can be used to clear the work queue when suspending filesystem
operations.
Access to buffers becomes recursive so that snapshots can recursively
traverse their indirect blocks using ffs_copyonwrite() when checking
for the need for copy on write when flushing one of their own indirect
blocks. This eliminates a deadlock between the syncer daemon and a
process taking a snapshot.
Ensure that softdep_process_worklist() can never block because of a
snapshot being taken. This eliminates a problem with buffer starvation.
Cleanup change in ffs_sync() which did not synchronously wait when
MNT_WAIT was specified. The result was an unclean filesystem panic
when doing forcible unmount with heavy filesystem I/O in progress.
Return a zero'ed block when reading a block that was not in use at
the time that a snapshot was taken. Normally, these blocks should
never be read. However, the readahead code will occationally read
them which can cause unexpected behavior.
Clean up the debugging code that ensures that no blocks be written
on a filesystem while it is suspended. Snapshots must explicitly
label the blocks that they are writing during the suspension so that
they do not cause a `write on suspended filesystem' panic.
Reorganize ffs_copyonwrite() to eliminate a deadlock and also to
prevent a race condition that would permit the same block to be
copied twice. This change eliminates an unexpected soft updates
inconsistency in fsck caused by the double allocation.
Use bqrelse rather than brelse for buffers that will be needed
soon again by the snapshot code. This improves snapshot performance.
attribute data size.
o Fortunately it turned out to be an unused constant left over from an
earlier implementation, and is therefore being removed so as not to
confuse casual observers.
Submitted by: mbendiks@eunet.no
the gating of system calls that cause modifications to the underlying
filesystem. The gating can be enabled by any filesystem that needs
to consistently suspend operations by adding the vop_stdgetwritemount
to their set of vnops. Once gating is enabled, the function
vfs_write_suspend stops all new write operations to a filesystem,
allows any filesystem modifying system calls already in progress
to complete, then sync's the filesystem to disk and returns. The
function vfs_write_resume allows the suspended write operations to
begin again. Gating is not added by default for all filesystems as
for SMP systems it adds two extra locks to such critical kernel
paths as the write system call. Thus, gating should only be added
as needed.
Details on the use and current status of snapshots in FFS can be
found in /sys/ufs/ffs/README.snapshot so for brevity and timelyness
is not included here. Unless and until you create a snapshot file,
these changes should have no effect on your system (famous last words).
in mount.h instead of ffs_extern.h. The correct solution is to use
an indirect function pointer so that the kernel does not have to be
built with options FFS, but that will be left for another day.
advance preparation for them to get migrated into place so that
subsequent changes in utilities will not fail to compile for lack
of up-to-date header files in /usr/include.
after the acquisition of any advisory locks. This fix corrects a case
in which a process tries to open a file with a non-blocking exclusive
lock. Even if it fails to get the lock it would still truncate the
file even though its open failed. With this change, the truncation
is done only after the lock is successfully acquired.
Obtained from: BSD/OS
the system would panic when a user's inode quota was exceeded (see
PR 18959 for details). This fixes that problem.
PR: 18959
Submitted by: Jason Godsey <jason@unixguy.fidalgo.net>
check to see if it has been committed to disk. If it has never
been written, it can be freed immediately. For short lived files
this change allows the same inode to be reused repeatedly.
Similarly, when upgrading a fragment to a larger size, if it
has never been claimed by an inode on disk, it too can be freed
immediately making it available for reuse often in the next slowly
growing block of the same file.
if an FFS partition returns EOPNOTSUPP, as it just means extended
attributes weren't enabled on that partition. Prevents spurious
warning per-partition at shutdown.
<sys/bio.h>.
<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.
Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.
Still a few bogus uses of struct buf to track down.
Repocopy by: peter
provide locking over extended attribute operations, requiring that
individual operations be atomic. Allowing non-zero starting offsets
permits applications/etc to put themselves at risk for inconsistent
behavior. As VOP_SETEXTATTR already prohibited non-zero write offsets,
this makes sense.
Suggested by: Andreas Gruenbacher <a.gruenbacher@bestbits.at>
reset their grace timer as their ownership crossed the soft limit
threshhold. Thus if they had been over their limit in the past,
they were suddenly penalized as if they had been over their limit
ever since. The fix is to check when root gives away files, that
when the receiving user crosses their soft limit, their grace timer
is reset. See the PR report for a detailed method of reproducing
the bug.
PR: kern/17128
Submitted by: Andre Albsmeier <andre.albsmeier@mchp.siemens.de>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
chances of consistency with other file/directory meta-data in a
write. In the current set of extended attribute applications,
this does not hurt much. This should be discussed again later when
it comes time to optimize performance of attributes.
o Include an inode generation number in the per-attribute header
information. This allows consistency verification to catch when
a crash occurs, or an inode is recycled while attributes are not
properly configured. For now, an irritating error message is
displayed when an inconsistency occurs. At some point, may introduce
an ``extattrctl check ...'' which catches these before attributes
are enabled. Not today. If you get this message, it means you
somehow managed to get your attribute backing file out of synch
with the file system. When this occurs, attribute not found is
returned (== undefined). Writes will overwrite the value there
correcting the problem. Might want to think about introducing
a new errno or two to handle this kind of situation.
Discussed with: kris
o Put back in {} removed during over-zealous cleanup of gratuitous
debugging output during preparation for the commit. Due to the
missing {}, writes on extended attributes always silently failed.
Doh.
o Don't unlock the target vnode if it's the backing vnode, as we
don't lock the target vnode if it's the backing vnode.
Exceptions:
Vinum untouched. This means that it cannot be compiled.
Greg Lehey is on the case.
CCD not converted yet, casts to struct buf (still safe)
atapi-cd casts to struct buf to examine B_PHYS
(name, value) pairs to be associated with inodes. This support is
used for ACLs, MAC labels, and Capabilities in the TrustedBSD
security extensions, which are currently under development.
In this implementation, attributes are backed to data vnodes in the
style of the quota support in FFS. Support for FFS extended
attributes may be enabled using the FFS_EXTATTR kernel option
(disabled by default). Userland utilities and man pages will be
committed in the next batch. VFS interfaces and man pages have
been in the repo since 4.0-RELEASE and are unchanged.
o ufs/ufs/extattr.h: UFS-specific extattr defines
o ufs/ufs/ufs_extattr.c: bulk of support routines
o ufs/{ufs,ffs,mfs}/*.[ch]: hooks and extattr.h includes
o contrib/softupdates/ffs_softdep.c: extattr.h includes
o conf/options, conf/files, i386/conf/LINT: added FFS_EXTATTR
o coda/coda_vfsops.c: XXX required extattr.h due to ufsmount.h
(This should not be the case, and will be fixed in a future commit)
Currently attributes are not supported in MFS. This will be fixed.
Reviewed by: adrian, bp, freebsd-fs, other unthanked souls
Obtained from: TrustedBSD Project
