Rather than trying to shoehorn flags into the requested superblock
address, create a separate flags parameter to the ffs_sbget()
function in sys/ufs/ffs/ffs_subr.c. The ffs_sbget() function is
used both in the kernel and in user-level utilities through export
to the sbget() function in the libufs(3) library (see sbget(3)
for details). The kernel uses ffs_sbget() when mounting UFS
filesystems, in the glabel(8) and gjournal(8) GEOM utilities,
and in the standalone library used when booting the system
from a UFS root filesystem.
The ffs_sbget() function reads the superblock located at the byte
offset specified by its sblockloc parameter. The value UFS_STDSB
may be specified for sblockloc to request that the standard
location for the superblock be read.
The two existing options are now flags:
UFS_NOHASHFAIL will note if the check hash is wrong but will still
return the superblock. This is used by the bootstrap code to
give the system a chance to come up so that fsck can be run to
correct the problem.
UFS_NOMSG indicates that superblock inconsistency error messages
should not be printed. It is used by programs like fsck that
want to print their own error message and programs like glabel(8)
that just want to know if a UFS filesystem exists on a partition.
One additional flag is added:
UFS_NOCSUM causes only the superblock itself to be returned, but does
not read in any auxiliary data structures like the cylinder group
summary information. It is used by clients like glabel(8) that
just want to check for possible filesystem types. Using UFS_NOCSUM
skips the superblock checks for csum data which allows superblocks
that have corrupted csum data to be read and used.
The validate_sblock() function checks that the superblock has not
been corrupted in a way that can crash or hang the system. Unless
the UFS_NOMSG flag is specified, it will print out any errors that
it finds. Prior to this commit, validate_sblock() returned as soon
as it found an inconsistency so would print at most one message.
It now does all its checks so when UFS_NOMSG has not been specified
will print out everything that it finds inconsistent.
Sponsored by: The FreeBSD Foundation
Reorder a few checks to ensure fields have been checked before
using them to check other fields.
Add eight new checks mostly checking for non-negative values.
No legitimate superblocks should fail as a result of these changes.
With clang 15, the following -Werror warnings are produced:
sys/ufs/ufs/ufs_dirhash.c:1303:16: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
ufsdirhash_init()
^
void
sys/ufs/ufs/ufs_dirhash.c:1319:18: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
ufsdirhash_uninit()
^
void
This is because ufsdirhash_init() and ufsdirhash_uninit() are declared
with (void) argument lists, but defined with empty argument lists. Make
the definitions match the declarations.
MFC after: 3 days
With clang 15, the following -Werror warning is produced:
sys/ufs/ffs/ffs_snapshot.c:204:7: error: variable 'redo' set but not used [-Werror,-Wunused-but-set-variable]
long redo = 0, snaplistsize = 0;
^
The 'redo' variable is only used when DIAGNOSTIC is defined. Ensure it
is only declared and set in that case.
MFC after: 3 days
With clang 15, the following -Werror warning is produced:
sys/ufs/ufs/ufs_dirhash.c:1252:18: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
ufsdirhash_lowmem()
^
void
This is ufsdirhash_lowmem() is declared with a (void) argument list, but
defined with an empty argument list. Make the definition match the
declaration.
MFC after: 3 days
A better fix to commit 9e1f44d044. Rather than coping with the case
where a backup superblock is used, catch the case when the superblock
is being read in and ensure that the standard one is used rather than
the backup one.
The K&R style in UFS and other places in the tree's days are numbered
as this syntax is removed in C2x proposal N2432:
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2432.pdf
Though running to nearly 6000 lines of diffs this update should cause
no functional change to the code.
Requested by: Warner Losh
MFC after: 2 weeks
Older versions of growfs(8) failed to correctly update fs_dsize.
Filesystems that have been grown fail the test for fs_dsize's correct
value. For now we exclude the fs_dsize test from the requirements.
Reported by: Edward Tomasz Napiera
Tested by: Edward Tomasz Napiera
Tested by: Peter Holm
MFC after: 1 month (with 076002f24d)
Differential Revision: https://reviews.freebsd.org/D35219
The original check verified that if an alternate superblock has not
been selected that the superblock is located in its standard location.
For UFS1 the with a 65536 block size, the first backup superblock
is at the same location as the UFS2 superblock. Since SBLOCK_UFS2
is the first location checked, the first backup is the superblock
that will be used for a UFS1 filesystems with a 65536 block size.
This patch allows the use of the first backup superblock in that
situation.
Reported by: Peter Holm
Tested by: Peter Holm
MFC after: 1 month (with 076002f24d)
Differential Revision: https://reviews.freebsd.org/D35219
The tests for number of cylinder groups (fs_ncg), inodes per cylinder
group (fs_ipg), and the size and layout of the cylinder group summary
information (fs_csaddr and fs_cssize) were overly restrictive and
would exclude some valid filesystems. These updates avoid precluding
valid fiesystems while still detecting rogue values that can crash or
hang the kernel.
Reported by: Chuck Silvers
Tested by: Peter Holm
MFC after: 1 month (with 076002f24d)
Differential Revision: https://reviews.freebsd.org/D35219
Otherwise the mount point could be unmounted meantime.
Reported and tested by: pho
Reviewed by: jah
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D35638
vn_read_from_obj() requires that all pages of a vnode (except the last
partial page) be either completely valid or completely invalid,
but for file systems with block size smaller than PAGE_SIZE,
partially valid pages may exist anywhere in the file.
Do not enable the vn_read_from_obj() path in this case.
Reviewed by: mckusick, kib, markj
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D34836
i_nlink overflow might be transient, i_effnlink indicates the final
value of the link count after all dependencies would be resolved. So if
i_nlink reached the maximum but i_efflink did not, we should be able to
make the link by syncing.
We must sync the whole filesystem to resolve dependencies,
which requires unlocking vnodes locked for VOPs. Use existing
ERELOOKUP/VOP_UNLOCK_PAIR() mechanism to restart the VOP if sync with
unlock was done.
PR: 165392
Reported by: Vsevolod Volkov <vvv@colocall.net>
Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D35514
The "offset" argument to vn_io_fault_pgmove() is supposed to be
the offset within the page, but for ffs we currently use the offset
within the block. When the block size is at least as large as the
page size then these values are the same, but when the page size is
larger than the block size then we need to add the offset of
the block within the page as well.
Sponsored by: Netflix
Reviewed by: mckusick, kib, markj
Differential Revision: https://reviews.freebsd.org/D34835
One of the checks was that the cylinder group size (fs_cgsize)
matched that calculated by CGSIZE(). The value calculated by CGSIZE()
has changed over time as the filesystem has evolved. Thus comparing
the value of CGSIZE() of the current generation filesystem may not
match the size as computed by CGSIZE() that was in effect at the
time an older filesystem was created. Therefore the check for
fs_cgsize is changed to simply ensure that it is not larger than
the filesystem blocksize (fs_bsize).
Reported by: Martin Birgmeier
Tested by: Martin Birgmeier
MFC after: 1 month (with 076002f24d)
PR: 264450
Differential Revision: https://reviews.freebsd.org/D35219
Two bugs have been reported with the UFS/FFS superblock integrity
checks that were added in commit 076002f24d.
The code checked that fs_sblockactualloc was properly set to the
location of the superblock. The fs_sblockactualloc field was an
addition to the superblock in commit dffce2150e on Jan 26 2018
and used a field that was zero in filesystems created before it
was added. The integrity check had to be expanded to accept the
fs_sblockactualloc field being zero so as not to reject filesystems
created before Jan 26 2018.
The integrity check set an upper bound on the value of fs_maxcontig
based on the maximum transfer size supported by the kernel. It
required that fs->fs_maxcontig <= maxphys / fs->fs_bsize. The kernel
variable maxphys defines the maximum transfer size permitted by the
controllers and/or buffering. The fs_maxcontig parameter controls the
maximum number of blocks that the filesystem will read or write in
a single transfer. It is calculated when the filesystem is created
as maxphys / fs_bsize. The bug appeared in the loader because it
uses a maxphys of 128K even when running on a system that supports
larger values. If the filesystem was built on a system that supports
a larger maxphys (1M is typical) it will have configured fs_maxcontig
for that larger system so would fail the test when run with the smaller
maxphys used by the loader. So we bound the upper allowable limit
for fs_maxconfig to be able to at least work with a 1M maxphys on the
smallest block size filesystem: 1M / 4096 == 256. We then use the
limit for fs_maxcontig as fs_maxcontig <= MAX(256, maxphys / fs_bsize).
There is no harm in allowing the mounting of filesystems that make larger
than maxphys I/O requests because those (mostly 32-bit machines) can
(very slowly) handle I/O requests that exceed maxphys.
Thanks to everyone who helped sort out the problems and the fixes.
Reported by: Cy Schubert, David Wolfskill
Diagnosis by: Mark Johnston, John Baldwin
Reviewed by: Warner Losh
Tested by: Cy Schubert, David Wolfskill
MFC after: 1 month (with 076002f24d)
Differential Revision: https://reviews.freebsd.org/D35219
Historically only minimal checks were made of a superblock when it
was read in as it was assumed that fsck would have been run to
correct any errors before attempting to use the filesystem. Recently
several bug reports have been submitted reporting kernel panics
that can be triggered by deliberately corrupting filesystem superblocks,
see Bug 263979 - [meta] UFS / FFS / GEOM crash (panic) tracking
which is tracking the reported corruption bugs.
This change upgrades the checks that are performed. These additional
checks should prevent panics from a corrupted superblock. Although
it appears in only one place, the new code will apply to the kernel
modules and (through libufs) user applications that read in superblocks.
Reported by: Robert Morris and Neeraj
Reviewed by: kib
Tested by: Peter Holm
PR: 263979
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D35219
This is needed for in-kernel copy of the code, where allocation might
happen after fs_fmod is cleared in ffs_sbput() but before the write.
Reported by: markj
Reviewed by: chs, markj
PR: 263765
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D35149
Copy in-memory struct fs to the superblock buffer under the UFS mutex.
Reviewed by: chs, markj
PR: 263765
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D35149
Right now it is incidentally declared in sys/lockf.h, which will be
corrected shortly.
Reviewed by: markj, rmacklem
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D34756
All softdep processing is supposed to be completed by
softdep_flushfiles() and no more deps are supposed to be created after
that, but if a pending trim completes after softdep_flushfiles() and
before softdep_unmount() then the blkfree that is performed by
ffs_blkfree_trim_task() will create a dep when none should exist, and
if softdep_unmount() is called before that dep is freed then the
kernel will panic. Prevent this by waiting for trims to complete
earlier in the unmount process, in ffs_flushfiles(), so that any deps
will be freed and any modified CG buffers will be flushed by the final
fsync of the devvp in ffs_flushfiles() as intended.
Reviewed by: mckusick, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D34806
Commit 0455cc7104 broke snapshotting for ffs. In that commit,
ffs_mount() was changed so the namei() lookup for a disk device happens
before ffs_snapshot(). This caused the issue where namei() would lookup
the snapshot file and fail because the file doesn't exist. Even if it did
exist, taking a snapshot would still fail since it's not a disk device.
Fix this by taking a snapshot of the filesystem as-is and return without
altering ro/rw or any other attributes that are passed in.
Reported by: pho
Reviewed by: mckusick
Fixes: 0455cc7104 ("ffs_mount(): return early if namei() fails to lookup disk device")
Differential Revision: https://reviews.freebsd.org/D34562
With soft updates enabled, an INVARIANTS panic is hit in ffs_unmount().
The problem occurs in ffs_mount() when upgrading a mount from ro->rw.
During a mount update, the soft update code gets set up but doesn't get
cleaned up if namei() fails when looking up the disk device.
Avoid this scenario by looking up the disk device first and bail early
if the namei() lookup fails.
PR: 256511
MFC After: 2 weeks
Reviewed by: mckusick, kib
Differential Revision: https://reviews.freebsd.org/D30870
When allocating new vnode, we need to lock it exclusively before
making it externally visible. Since other threads cannot observe the
vnode yet, current lock order cannot create LoR conditions.
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D34126
when the vnode is doomed after relock. The mere fact that the vnode is
doomed does not prevent us from doing UFS operations on it while it is
still belongs to UFS, which is determined by non-NULL v_data. Not
finishing some operations, e.g. not syncing the inode block only because
the vnode started reclamation, is not correct.
Add macro IS_UFS() which incapsulates the v_data != NULL, and use it
instead of VN_IS_DOOMED() for places where the operation completion is
important.
Reviewed by: markj, mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D34072
When a filesystem is mounted all of its associated snapshots must
be activated. It first allocates a snapshot lock (snaplk) that will
be shared by all the snapshot vnodes associated with the filesystem.
As part of each snapshot file activation, it must replace its own
ufs vnode lock with the snaplk. In this way acquiring the snaplk
gives exclusive access to all the snapshots for the filesystem.
A write to a ufs vnode first acquires the ufs vnode lock for the
file to be written then acquires the snaplk. Once it has the snaplk,
it can check all the snapshots to see if any of them needs to make
a copy of the block that is about to be written. This ffs_copyonwrite()
code path establishes the ufs vnode followed by snaplk locking
order.
When a filesystem is unmounted it has to release all of its snapshot
vnodes. Part of doing the release is to revert the snapshot vnode
from using the snaplk to using its original vnode lock. While holding
the snaplk, the vnode lock has to be acquired, the vnode updated
to reference it, then the snaplk released. Acquiring the vnode lock
while holding the snaplk violates the ufs vnode then snaplk order.
Because the vnode lock is unused, using LK_EXCLUSIVE | LK_NOWAIT
to acquire it will always succeed and the LK_NOWAIT prevents the
reverse lock order from being recorded.
This change was made in January 2021 (173779b98f) to avoid an LOR
violation in ffs_snapshot_unmount(). The same LOR issue was recently
found again when removing a snapshot in ffs_snapremove() which must
also revert the snaplk to the original vnode lock as part of freeing it.
The unwind in ffs_snapremove() deals with the case in which the
snaplk is held as a recursive lock holding multiple references.
Specifically an equal number of references are made on the vnode
lock. This change factors out the lock reversion operations into a
new function revert_snaplock() which handles both the recursive
locks and avoids the LOR. The new revert_snaplock() function is
then used in both ffs_snapshot_unmount() and in ffs_snapremove().
Reviewed by: kib
Tested by: Peter Holm
MFC after: 2 weeks
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D33946
When the kernel is requested to mount a filesystem with a bad superblock
check hash, it would set the flag in the superblock requesting that the
fsck(8) program be run. The flag is only written to disk as part of a
superblock update. Since the superblock always has its check hash updated
when it is written to disk, the problem for which the flag has been set
will no longer exist. Hence, it is counter-productive to set the flag
as it will just cause an unnecessary run of fsck if it ever gets written.
Sponsored by: Netflix
The code here tries to be smart and zeroes out both di_db and di_ib with
a single bzero call, thereby overrunning the di_db subobject. This is
fine on most architectures, if a little dodgy. However, on CHERI, the
compiler can optionally restrict the bounds on pointers to subobjects to
just that subobject, in order to mitigate intra-object buffer overflows,
and this is enabled in CheriBSD's pure-capability kernels.
Instead, use separate bzero calls for each array, and let the compiler
optimise it as it sees fit; even if it's not generating inline zeroing
code, Clang will happily optimise two consecutive bzero's to a single
larger call.
Reviewed by: mckusick
Differential Revision: https://reviews.freebsd.org/D33651
Shortlinks occupy the space of both di_db and di_ib when used. However,
everywhere that wants to read or write a shortlink takes a pointer do
di_db and promptly runs off the end of it into di_ib. This is fine on
most architectures, if a little dodgy. However, on CHERI, the compiler
can optionally restrict the bounds on pointers to subobjects to just
that subobject, in order to mitigate intra-object buffer overflows, and
this is enabled in CheriBSD's pure-capability kernels.
Instead, clean this up by inserting a union such that a new di_shortlink
can be added with the right size and element type, avoiding the need to
cast and allowing the use of the DIP macro to access the field. This
also mirrors how the ext2fs code implements extents support, with the
exact same structure other than having a uint32_t i_data[] instead of a
char di_shortlink[].
Reviewed by: mckusick, jhb
Differential Revision: https://reviews.freebsd.org/D33650
The cookies argument is only used by the NFS server. NFSv2 defines the
cookie as 32 bits on the wire, but NFSv3 increased it to 64 bits. Our
VOP_READDIR, however, has always defined it as u_long, which is 32 bits
on some architectures. Change it to 64 bits on all architectures. This
doesn't matter for any in-tree file systems, but it matters for some
FUSE file systems that use 64-bit directory cookies.
PR: 260375
Reviewed by: rmacklem
Differential Revision: https://reviews.freebsd.org/D33404
The mntfs vnode lock should be before topology, as established in
ffs_mountfs(). Extend the locked region in ffs_unmount().
Reported and reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D33013
Normally a UFS/FFS filesystem with a bad check hash can only be
mounted read only. With this commit the mount(8) -f (force) option
can be used to force a read-write mount of a UFS/FFS filesystem with
a bad check hash. Conveniently the filesystem will proceed to
update its on-disk superblock with a corrected check hash.
Sponsored by: Netflix
When reading UFS/FFS superblocks that have check hashes, both the kernel
and libufs print an error message if the check hash is incorrect. This
commit adds the ability to request that the error message not be made.
It is intended for use by programs like fsck that wants to print its
own error message and by kernel subsystems like glabel that just wants
to check for possible filesystem types.
This capability will be used in followup commits.
Sponsored by: Netflix
The STDSB macro is passed to the ffs_sbget() routine to fetch a
UFS/FFS superblock "from the stadard place". It was identically defined
in lib/libufs/libufs.h, stand/libsa/ufs.c, sys/ufs/ffs/ffs_extern.h,
and sys/ufs/ffs/ffs_subr.c. Delete it from these four files and
define it instead in sys/ufs/ffs/fs.h. All existing uses of this macro
already include sys/ufs/ffs/fs.h so no include changes need to be made.
No functional change intended.
Sponsored by: Netflix
It is not, and the lock is not needed there
Reported and tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D32761
Require devvp locked for mntfs_freevp(), to have it locked around
vgone(). Make that true for ffs, which is the only consumer of
the interface.
Reported and tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D32761
Mark variables as __diagused for invariant-only vars
Reviewed by: imp, mjg
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D32577
These began to become obsolete in d6d64f0f2c (r137739) and the deal
was later sealed in 003e18aef4 (r137801) when vfs.fifofs.fops was
dropped and vop-bypass for pipes became mandatory.
PR: 225934
Suggested by: markj
Reviewe by: kib, markj
Differential Revision: https://reviews.freebsd.org/D32270
The fsckpid mount option was introduced in 927a12ae16 along with a
couple sysctl's to support SU+J with snapshots. However, those sysctl's
were never used and eventually removed in f2620e9ceb.
There are no in-tree consumers of this mount option.
Reviewed by: mckusick, kib
Differential Revision: https://reviews.freebsd.org/D32015
while using a UFS snapshot.
The UFS filesystem supports snapshots. Each snapshot is a file whose
contents are a frozen image of the disk partition on which the filesystem
resides. Each time an existing block in the filesystem is modified,
the filesystem checks whether that block was in use at the time that
the snapshot was taken. If so, and if it has not already been copied,
a new block is allocated from among the blocks that were not in use
at the time that the snapshot was taken and placed in the snapshot file
to replace the entry that has not yet been copied. The previous contents
of the block are copied to the newly allocated snapshot file block,
and the write to the original is then allowed to proceed.
The block allocation is done using the usual UFS_BALLOC() routine
which allocates the needed block in the snapshot and returns a
buffer that is set up to write data into the newly allocated block.
In usual filesystem operation, the contents for the new block is
copied from user space into the buffer and the buffer is then written
to the file using bwrite(), bawrite(), or bdwrite(). In the case of a
snapshot the new block must be filled from the disk block that is about
to be rewritten. The snapshot routine has a function readblock() that
it uses to read the `about to be rewritten' disk block.
/*
* Read the specified block into the given buffer.
*/
static int
readblock(snapvp, bp, lbn)
struct vnode *snapvp;
struct buf *bp;
ufs2_daddr_t lbn;
{
struct inode *ip;
struct bio *bip;
struct fs *fs;
ip = VTOI(snapvp);
fs = ITOFS(ip);
bip = g_alloc_bio();
bip->bio_cmd = BIO_READ;
bip->bio_offset = dbtob(fsbtodb(fs, blkstofrags(fs, lbn)));
bip->bio_data = bp->b_data;
bip->bio_length = bp->b_bcount;
bip->bio_done = NULL;
g_io_request(bip, ITODEVVP(ip)->v_bufobj.bo_private);
bp->b_error = biowait(bip, "snaprdb");
g_destroy_bio(bip);
return (bp->b_error);
}
When the underlying disk fails, its GEOM module is removed.
Subsequent attempts to access it should return the ENXIO error.
The functionality of checking for the lost disk and returning
ENXIO is handled by the g_vfs_strategy() routine:
void
g_vfs_strategy(struct bufobj *bo, struct buf *bp)
{
struct g_vfs_softc *sc;
struct g_consumer *cp;
struct bio *bip;
cp = bo->bo_private;
sc = cp->geom->softc;
/*
* If the provider has orphaned us, just return ENXIO.
*/
mtx_lock(&sc->sc_mtx);
if (sc->sc_orphaned || sc->sc_enxio_active) {
mtx_unlock(&sc->sc_mtx);
bp->b_error = ENXIO;
bp->b_ioflags |= BIO_ERROR;
bufdone(bp);
return;
}
sc->sc_active++;
mtx_unlock(&sc->sc_mtx);
bip = g_alloc_bio();
bip->bio_cmd = bp->b_iocmd;
bip->bio_offset = bp->b_iooffset;
bip->bio_length = bp->b_bcount;
bdata2bio(bp, bip);
if ((bp->b_flags & B_BARRIER) != 0) {
bip->bio_flags |= BIO_ORDERED;
bp->b_flags &= ~B_BARRIER;
}
if (bp->b_iocmd == BIO_SPEEDUP)
bip->bio_flags |= bp->b_ioflags;
bip->bio_done = g_vfs_done;
bip->bio_caller2 = bp;
g_io_request(bip, cp);
}
Only after checking that the device is present does it construct
the "bio" request and call g_io_request(). When readblock()
constructs its own "bio" request and calls g_io_request() directly
it panics with "consumer not attached in g_io_request" when the
underlying device no longer exists.
The fix is to have readblock() call g_vfs_strategy() rather than
constructing its own "bio" request:
/*
* Read the specified block into the given buffer.
*/
static int
readblock(snapvp, bp, lbn)
struct vnode *snapvp;
struct buf *bp;
ufs2_daddr_t lbn;
{
struct inode *ip;
struct fs *fs;
ip = VTOI(snapvp);
fs = ITOFS(ip);
bp->b_iocmd = BIO_READ;
bp->b_iooffset = dbtob(fsbtodb(fs, blkstofrags(fs, lbn)));
bp->b_iodone = bdone;
g_vfs_strategy(&ITODEVVP(ip)->v_bufobj, bp);
bufwait(bp);
return (bp->b_error);
}
Here it uses the buffer that will eventually be written to the disk.
The g_vfs_strategy() routine uses four parts of the buffer: b_bcount,
b_iocmd, b_iooffset, and b_data.
The b_bcount field is already correctly set for the buffer. It is
safe to set the b_iocmd and b_iooffset fields as they are set
correctly when the later write is done. The write path will also
clear the B_DONE flag that our use of the buffer will set. The
b_iodone callback has to be set to bdone() which will do just
notification that the I/O is done in bufdone(). The rest of
bufdone() includes things like processing the softdeps associated
with the buffer should not be done until the buffer has been
written. Bufdone() will set b_iodone back to NULL after using it,
so the full bufdone() processing will be done when the buffer is
written. The final change from the previous version of readblock()
is that it used the b_data for the destination of the read while
g_vfs_strategy() uses the bdata2bio() function to take advantage
of VMIO when it is available.
Differential revision: https://reviews.freebsd.org/D32150
Reviewed by: kib, chs
MFC after: 1 week
Sponsored by: Netflix
Each vnode has an embedded lock that controls access to its contents.
However vnodes describing a UFS snapshot all share a single snapshot
lock to coordinate their access and update. As part of creating a
new UFS snapshot, it has to have its individual vnode lock replaced
with the filesystem's snapshot lock.
The lock order for regular vnodes with respect to buffer locks is that
they must first acquire the vnode lock, then a buffer lock. The order
for the snapshot lock is reversed: a buffer lock must be acquired before
the snapshot lock.
When creating a new snapshot, the snapshot file must retain its vnode
lock until it has allocated all the blocks that it needs before
switching to the snapshot lock. This update moves one final piece of
the initial snapshot block allocation so that it is done before the
newly created snapshot is switched to use the snapshot lock.
Reported by: Witness code
MFC after: 1 week
Sponsored by: Netflix
Instead do protective check for the local flags and do not interpret
EBUSY specially if we did not request trylock mode for bread().
Reviewed by: mckusick
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Inode type could migrate between snapshot and regular types while the
vnode is unlocked. Recalculate flags specific for snapshot after relock.
Reviewed by: mckusick
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
ufs_rename() calls ufs_checkpath() to ensure that the target directory
is not a child of the source. If not, rename would create a loop.
For instance:
source->X1->X2->target
and if source moved under target, we get corrupted filesystem.
Suppose that we initially have
source->X1 .... and X2->target
where X1 is not on path from root to X2. Then ufs_checkpath() accepts
the inodes, but there is nothing preventing parallel rename of X2 to become
under X1, after checkpath finished.
Ensure stability of ufs_checkpath() result by taking a per-mount sx in
ufs_rename right before ufs_checkpath() and till the end.
Reviewed by: chs, mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
During forcible unmount after a disk failure there is a bug that
causes one or more indirdep dependency structures to fail to be
deallocated. Until we manage to track down why they fail to get
cleaned up, this code tracks them down and eliminates them so that
the unmount can succeed.
Reported by: Peter Holm
Help from: kib
Reviewed by: Chuck Silvers
Tested by: Peter Holm
MFC after: 7 days
Sponsored by: Netflix
The soft updates diagnotic code keeps a list for each type of soft
update dependency. When a new block is allocated for a file it is
initially tracked by a "newblk" dependency. The "newblk" dependency
eventually becomes either an "allocdirect" dependency or an "indiralloc"
dependency. The diagnotic code failed to move the "newblk" from the list
of "newblk"s to its new type list.
No functional change intended.
Reviewed by: Chuck Silvers (as part of a larger change)
Tested by: Peter Holm (as part of a larger change)
Sponsored by: Netflix
Now that dounmount() supports a dedicated taskqueue, we can simply call
it with MNT_DEFERRED directly from the failing context. This also
avoids blocking taskqueue_thread with a potentially-expensive unmount
operation.
Reviewed by: kib, mckusick
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D31016
In certain emergency cases such as media failure or removal, UFS will
initiate a forced unmount in order to prevent dirty buffers from
accumulating against the no-longer-usable filesystem. The presence
of a stacked filesystem such as nullfs or unionfs above the UFS mount
will prevent this forced unmount from succeeding.
This change addreses the situation by allowing stacked filesystems to
be recursively unmounted on a taskqueue thread when the MNT_RECURSE
flag is specified to dounmount(). This call will block until all upper
mounts have been removed unless the caller specifies the MNT_DEFERRED
flag to indicate the base filesystem should also be unmounted from the
taskqueue.
To achieve this, the recently-added vfs_pin_from_vp()/vfs_unpin() KPIs
have been combined with the existing 'mnt_uppers' list used by nullfs
and renamed to vfs_register_upper_from_vp()/vfs_unregister_upper().
The format of the mnt_uppers list has also been changed to accommodate
filesystems such as unionfs in which a given mount may be stacked atop
more than one lower mount. Additionally, management of lower FS
reclaim/unlink notifications has been split into a separate list
managed by a separate set of KPIs, as registration of an upper FS no
longer implies interest in these notifications.
Reviewed by: kib, mckusick
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D31016
This effectively causes syncing of the mount point from softdep_prealloc(),
softdep_prerename(), and softdep_prelink(). Typically it avoids the need
for journal suspension at this point, at all.
Suggested and reviewed by: mckusick
Discussed with: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D30041
We call into softdep_prerename() and softdep_prelink() when there is
low free space in the journal. Functions sync all vnodes participating
in the VOP, in the hope that this would reduce journal utilization. But
if the vnodes are already synced, doing sync would only spend writes,
journal is filled not due to the records from modifications of our
vnodes.
Remember original seqc numbers for vnodes, and only initiate syncs when
seqc changed.
Reviewed by: mckusick
Discussed with: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D30041
so call it only in SU+J case
Reviewed by: mckusick
Discussed with: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D30041
Make sure we return an error if no input was specified, since
SYSCTL_IN() will report success in that case.
Reported by: KMSAN
Reviewed by: mckusick
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30586
Instead of requiring all implementations of vfs_quotactl to unbusy
the mount for Q_QUOTAON and Q_QUOTAOFF, add an "mp_busy" in/out param
to VFS_QUOTACTL(9). The implementation may then indicate to the caller
whether it needed to unbusy the mount.
Also, add stbool.h to libprocstat modules which #define _KERNEL
before including sys/mount.h. Otherwise they'll pull in sys/types.h
before defining _KERNEL and therefore won't have the bool definition
they need for mp_busy.
Reviewed By: kib, markj
Differential Revision: https://reviews.freebsd.org/D30556
Parts of libprocstat like to pretend they're kernel components for the
sake of including mount.h, and including sys/types.h in the _KERNEL
case doesn't fix the build for some reason. Revert both the
VFS_QUOTACTL() change and the follow-up "fix" for now.
Instead of requiring all implementations of vfs_quotactl to unbusy
the mount for Q_QUOTAON and Q_QUOTAOFF, add an "mp_busy" in/out param
to VFS_QUOTACTL(9). The implementation may then indicate to the caller
whether it needed to unbusy the mount.
Reviewed By: kib, markj
Differential Revision: https://reviews.freebsd.org/D30218
At this point the directory's vnode lock is held, so blocking while
waiting for free pages makes the system more susceptible to deadlock in
low memory conditions. This is particularly problematic on NUMA systems
as UMA currently implements a strict first-touch policy.
ufsdirhash_build() already uses M_NOWAIT for other allocations and
already handled failures for the block array allocation, so just convert
to M_NOWAIT.
PR: 253992
Reviewed by: markj, mckusick, vangyzen
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29045
The original filesystem release (4.2BSD) had no embedded sysmlinks.
Historically symbolic links were just a different type of file, so
the content of the symbolic link was contained in a single disk block
fragment. We observed that most symbolic links were short enough that
they could fit in the area of the inode that normally holds the block
pointers. So we created embedded symlinks where the content of the
link was held in the inode's pointer area thus avoiding the need to
seek and read a data fragment and reducing the pressure on the block
cache. At the time we had only UFS1 with 32-bit block pointers,
so the test for a fastlink was:
di_size < (NDADDR + NIADDR) * sizeof(daddr_t)
(where daddr_t would be ufs1_daddr_t today).
When embedded symlinks were added, a spare field in the superblock
with a known zero value became fs_maxsymlinklen. New filesystems
set this field to (NDADDR + NIADDR) * sizeof(daddr_t). Embedded
symlinks were assumed when di_size < fs->fs_maxsymlinklen. Thus
filesystems that preceeded this change always read from blocks
(since fs->fs_maxsymlinklen == 0) and newer ones used embedded
symlinks if they fit. Similarly symlinks created on pre-embedded
symlink filesystems always spill into blocks while newer ones will
embed if they fit.
At the same time that the embedded symbolic links were added, the
on-disk directory structure was changed splitting the former
u_int16_t d_namlen into u_int8_t d_type and u_int8_t d_namlen.
Thus fs_maxsymlinklen <= 0 (as used by the OFSFMT() macro) can
be used to distinguish old directory formats. In retrospect that
should have just been an added flag, but we did not realize we
needed to know about that change until it was already in production.
Code was split into ufs/ffs so that the log structured filesystem could
use ufs functionality while doing its own disk layout. This meant
that no ffs superblock fields could be used in the ufs code. Thus
ffs superblock fields that were needed in ufs code had to be copied
to fields in the mount structure. Since ufs_readlink needed to know
if a link was embedded, fs_maxlinklen gets copied to mnt_maxsymlinklen.
The kernel panic that arose to making this fix was triggered when a
disk error created an inode of type symlink with no allocated data
blocks but a large size. When readlink was called the uiomove was
attempted which segment faulted.
static int
ufs_readlink(ap)
struct vop_readlink_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct inode *ip = VTOI(vp);
doff_t isize;
isize = ip->i_size;
if ((isize < vp->v_mount->mnt_maxsymlinklen) ||
DIP(ip, i_blocks) == 0) { /* XXX - for old fastlink support */
return (uiomove(SHORTLINK(ip), isize, ap->a_uio));
}
return (VOP_READ(vp, ap->a_uio, 0, ap->a_cred));
}
The second part of the "if" statement that adds
DIP(ip, i_blocks) == 0) { /* XXX - for old fastlink support */
is problematic. It never appeared in BSD released by Berkeley because
as noted above mnt_maxsymlinklen is 0 for old format filesystems, so
will always fall through to the VOP_READ as it should. I had to dig
back through `git blame' to find that Rodney Grimes added it as
part of ``The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.''
He must have brought it across from an earlier FreeBSD. Unfortunately
the source-control logs for FreeBSD up to the merger with the
AT&T-blessed 4.4BSD-Lite conversion were destroyed as part of the
agreement to let FreeBSD remain unencumbered, so I cannot pin-point
where that line got added on the FreeBSD side.
The one change needed here is that mnt_maxsymlinklen is declared as
an `int' and should be changed to be `u_int64_t'.
This discovery led us to check out the code that deletes symbolic
links. Specifically
if (vp->v_type == VLNK &&
(ip->i_size < vp->v_mount->mnt_maxsymlinklen ||
datablocks == 0)) {
if (length != 0)
panic("ffs_truncate: partial truncate of symlink");
bzero(SHORTLINK(ip), (u_int)ip->i_size);
ip->i_size = 0;
DIP_SET(ip, i_size, 0);
UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
if (needextclean)
goto extclean;
return (ffs_update(vp, waitforupdate));
}
Here too our broken symlink inode with no data blocks allocated
and a large size will segment fault as we are incorrectly using the
test that we have no data blocks to decide that it is an embdedded
symbolic link and attempting to bzero past the end of the inode.
The test for datablocks == 0 is unnecessary as the test for
ip->i_size < vp->v_mount->mnt_maxsymlinklen will do the right
thing in all cases.
The test for datablocks == 0 was added by David Greenman in this commit:
Author: David Greenman <dg@FreeBSD.org>
Date: Tue Aug 2 13:51:05 1994 +0000
Completed (hopefully) the kernel support for old style "fastlinks".
Notes:
svn path=/head/; revision=1821
I am guessing that he likely earlier added the incorrect test in the
ufs_readlink code.
I asked David if he had any recollection of why he made this change.
Amazingly, he still had a recollection of why he had made a one-line
change more than twenty years ago. And unsurpisingly it was because
he had been stuck between a rock and a hard place.
FreeBSD was up to 1.1.5 before the switch to the 4.4BSD-Lite code
base. Prior to that, there were three years of development in all
areas of the kernel, including the filesystem code, from the combined
set of people including Bill Jolitz, Patchkit contributors, and
FreeBSD Project members. The compatibility issue at hand was caused
by the FASTLINKS patches from Curt Mayer. In merging in the 4.4BSD-Lite
changes David had to find a way to provide compatibility with both
the changes that had been made in FreeBSD 1.1.5 and with 4.4BSD-Lite.
He felt that these changes would provide compatibility with both systems.
In his words:
``My recollection is that the 'FASTLINKS' symlinks support in
FreeBSD-1.x, as implemented by Curt Mayer, worked differently than
4.4BSD. He used a spare field in the inode to duplicately store the
length. When the 4.4BSD-Lite merge was done, the optimized symlinks
support for existing filesystems (those that were initialized in
FreeBSD-1.x) were broken due to the FFS on-disk structure of
4.4BSD-Lite differing from FreeBSD-1.x. My commit was needed to
restore the backward compatibility with FreeBSD-1.x filesystems.
I think it was the best that could be done in the somewhat urgent
circumstances of the post Berkeley-USL settlement. Also, regarding
Rod's massive commit with little explanation, some context: John
Dyson and I did the initial re-port of the 4.4BSD-Lite kernel to
the 386 platform in just 10 days. It was by far the most intense
hacking effort of my life. In addition to the porting of tons of
FreeBSD-1 code, I think we wrote more than 30,000 lines of new code
in that time to deal with the missing pieces and architectural
changes of 4.4BSD-Lite. We didn't make many notes along the way.
There was a lot of pressure to get something out to the rest of the
developer community as fast as possible, so detailed discrete commits
didn't happen - it all came as a giant wad, which is why Rod's
commit message was worded the way it was.''
Reported by: Chuck Silvers
Tested by: Chuck Silvers
History by: David Greenman Lawrence
MFC after: 1 week
Sponsored by: Netflix
The trunc_dependencies() issue was reported by Alexander Lochmann
<alexander.lochmann@tu-dortmund.de>, who found the problem by performing
lock analysis using LockDoc, see https://doi.org/10.1145/3302424.3303948.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
When quotas are enabled with the quotaon(8) command, it sets the
MNT_QUOTA flag in the mount structure mnt_flag field. The mount
structure holds a cached copy of the filesystem statfs structure
in mnt_stat that includes a copy of the mnt_flag field in
mnt_stat.f_flags. The mnt_stat structure may not be updated for
hours. Since the mount command requests mount details using the
MNT_NOWAIT option, it gets the mount's mnt_stat statfs structure
whose f_flags field does not yet show the MNT_QUOTA flag being set
in mnt_flag.
The fix is to have quotaon(8) set the MNT_QUOTA flag in both mnt_flag
and in mnt_stat.f_flags so that it will be immediately visible to
callers of statfs(2).
Reported by: Christos Chatzaras
Tested by: Christos Chatzaras
PR: 254682
MFC after: 3 days
Sponsored by: Netflix
