msdosfs: fix cluster limit when mounting FAT-16 file systems

The maximum cluster number was calculated based on the number of data
cluters that fit in the givem partition size and the size of the FA

msdosfs: fix cluster limit when mounting FAT-16 file systems

The maximum cluster number was calculated based on the number of data
cluters that fit in the givem partition size and the size of the FAT
area. This limit did not take into account that the highest 10 cluster
numbers are reserved and must not be used for files.

PR: 280347
MFC after: 3 days
Reported by: pho@FreeBSD.org

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msdosfs_remount_ro(): correct vfs_unbusy() loop

PR: 276408
Reported by: John F. Carr
Fixes: 13ccb04589e2c5c840e19b407a59e44cb70ac28e
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

msdosfs_integrity_error(): plug possible busy leak

If taskqueue_enqueue() returned error, unbusy().
Handle parallel calls to msdosfs_integrity_error() by unbusying in
msdosfs_remount_ro() up to pend

msdosfs_integrity_error(): plug possible busy leak

If taskqueue_enqueue() returned error, unbusy().
Handle parallel calls to msdosfs_integrity_error() by unbusying in
msdosfs_remount_ro() up to pending times.

Noted and reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D43482

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sys: Remove $FreeBSD$: one-line .c comment pattern

Remove /^/[*/]\s*\$FreeBSD\$.*\n/

fs/msdosfs: Fix potential panic and size calculations

Some combinations of FAT12 file system parameters could cause a kernel
panic due to an unmapped access if the size of the FAT was larger than
th

fs/msdosfs: Fix potential panic and size calculations

Some combinations of FAT12 file system parameters could cause a kernel
panic due to an unmapped access if the size of the FAT was larger than
the CPU page size. The reason is that FAT12 uses 3 bytes to store
2 FAT pointers, leading to partial FAT pointers at the end of buffers
of a size that is not a multiple of 3.

With a typical page size of 4 KB, this caused the FAT entry at byte
offsets 4095 and 4096 to cross the page boundary, with only the first
page mapped. This was fixed by adjusting the mapping to always cover
both bytes of each FAT entry.

Testing revealed 2 other inconsistencies that are fixed by this commit:

1) The calculation of the size of the data area did not take into
account the fact that the first two data block numbers are reserved
and that the data area starts with block 2. This could cause a
FAT12 file system created with the maximum supported number of
blocks to be incorrectly identified as FAT16.

2) The root directory does not take up space in the data area of a
FAT12 or FAT16 file system, since it is placed into a reserved
area outside of that data area. This commits makes stat() report
the logical size of the root directory, but with 0 blocks allocated
from the data area.

PR: 270587
Reviewed by: mckusick
Differential Revision: https://reviews.freebsd.org/D39386

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fs/msdosfs: add tracking of free root directory entries

This update implements tallying of free directory entries during
create, delete, or rename operations on FAT12 and FAT16 file systems.

Prior

fs/msdosfs: add tracking of free root directory entries

This update implements tallying of free directory entries during
create, delete, or rename operations on FAT12 and FAT16 file systems.

Prior to this change, the total number of root directory entries
was reported as number of inodes, but 0 as the number of free
inodes, causing system health monitoring software to warn about
a suspected disk full issue.

The FAT12 and FAT16 file systems provide a limited number of
root directory entries, e.g. 512 on typical hard disk formats.
The valid range of values is 1 to 65535, but the msdosfs code
will effectively round up "odd" values to the next multiple of 16
(e.g. 513 would allow for 528 root directory entries).

This update implements tracking of directory entries during create,
delete, or rename operations, with initial values determined by
scanning the directory when the file system is mounted.

Total and free directory entries are reported in the f_files and
f_ffree elements of struct statfs, despite differences in semantics
of these values:

- There is no limit on the number of files and directories that can
be created on a FAT file system. Only the root directory of FAT12
and FAT16 file systems is limited, any number of files can still be
created in sub-directories, even when 0 free "inodes" are reported.

- A single file can require 1 to 21 directory entries, depending on
the character set, structure, and length of the name. The DOS 8.3
style file name takes up 1 entry, and if the name does not comply
with the syntax of a DOS 8.3 file name, 1 additional entry is used
for each 13 characters of the file name. Since all these entries
have to be contiguous, it is possible that a file or directory with
a long name can not be created, despite a sufficient total number of
free directory entries.

- Renaming a file can require more directory entries than currently
allocated to store its long name, which may prevent an in-place
update of the name if more entries are needed. This may cause a
rename operation to fail if no contiguous range of free entries for
the new name can be found.

- The volume label is stored in a directory entry. An empty FAT file
system with a volume label will therefore show 1 used "inode" in
df.

- The perceentage of free inodes shown in df or monitoring tools does
only represent the state of the root directory of a FAT12 or FAT16
file system. Neither does a reported value of 0% free inodes does
prevent files from being created in sub-directories, nor does a
value of 50% free inodes guarantee that even a single file with
a "long" name can be created in the root directory (if every other
directory entry is occupied and there are no 2 contiguous entries).

The statfs(2) and df(1) man pages have been updated with a notice
regarding the possibly different semantics of values reported as
total and free inodes for non-Unix file systems.

PR: 270053
Reported by: Ben Woods <woodsb02@freebsd.org>
Approved by: mckusick
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D38987

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Stop cleaning MNT_LOCAL on unmount

There is no point in clearing just this flag. Flags are reset on the
struct mount re-allocation for reuse anyway.

Reviewed by: mckusick
Sponsored by: The FreeBSD

Stop cleaning MNT_LOCAL on unmount

There is no point in clearing just this flag. Flags are reset on the
struct mount re-allocation for reuse anyway.

Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D37966

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mntfs: change mntfs_allocvp API to relock on its own

Reviewed by: kib
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D37759

Tree-wide replacement of VOP_UNLOCK + vrele combo with vput

No functional changes.

vfs: NDFREE(&nd, NDF_ONLY_PNBUF) -> NDFREE_PNBUF(&nd)

msdosfs: Fix mounting when the device sector size is >512B

HugeSectors * BytesPerSec should be computed before converting
HugeSectors to a DEV_BSIZE-based count.

Fixes: ba2c98389b78 ("msdosfs: sani

msdosfs: Fix mounting when the device sector size is >512B

HugeSectors * BytesPerSec should be computed before converting
HugeSectors to a DEV_BSIZE-based count.

Fixes: ba2c98389b78 ("msdosfs: sanity check sector count from BPB")
Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D34264

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msdosfs: use mntfs vnode for pm_devvp

to prevent races with devfs VCHR vnode reclamation, same as it was
done for UFS.

Reported by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC a

msdosfs: use mntfs vnode for pm_devvp

to prevent races with devfs VCHR vnode reclamation, same as it was
done for UFS.

Reported by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D33721

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msdosfs: add msdosfs_integrity_error()

A function to remount the filesystem from rw to ro on integrity error.
The work is performed in taskqueue to allow the call to be done from
almost arbitrary co

msdosfs: add msdosfs_integrity_error()

A function to remount the filesystem from rw to ro on integrity error.
The work is performed in taskqueue to allow the call to be done from
almost arbitrary context where erronous state was detected.

Tested by: pho
Reviewed by: markj, mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D33721

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msdosfs: sanity check sector count from BPB

We use sector count to size the FAT inuse bitset. If sector count is
corrupted, kernel might be tricked into doing unbound allocation.
Ensure that the se

msdosfs: sanity check sector count from BPB

We use sector count to size the FAT inuse bitset. If sector count is
corrupted, kernel might be tricked into doing unbound allocation.
Ensure that the sector count does not exceed the actual volume size.

In collaboration with: pho
Reviewed by: markj, mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D33721

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mountmsdosfs(): some style

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D33721

vfs: remove the unused thread argument from NDINIT*

See b4a58fbf640409a1 ("vfs: remove cn_thread")

Bump __FreeBSD_version to 1400043.

msdosfs: add doscheckpath lock

Similar to the UFS revision 8df4bc48c89a130207

Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: http

msdosfs: add doscheckpath lock

Similar to the UFS revision 8df4bc48c89a130207

Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31464

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msdosfs deget(): add locking flags argument

LK_EXCLUSIVE must be passed always, some consumers need the ability to
specify LK_NOWAIT

Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD F

msdosfs deget(): add locking flags argument

LK_EXCLUSIVE must be passed always, some consumers need the ability to
specify LK_NOWAIT

Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31464

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Make MAXPHYS tunable. Bump MAXPHYS to 1M.

Replace MAXPHYS by runtime variable maxphys. It is initialized from
MAXPHYS by default, but can be also adjusted with the tunable kern.maxphys.

Make b_pag

Make MAXPHYS tunable. Bump MAXPHYS to 1M.

Replace MAXPHYS by runtime variable maxphys. It is initialized from
MAXPHYS by default, but can be also adjusted with the tunable kern.maxphys.

Make b_pages[] array in struct buf flexible. Size b_pages[] for buffer
cache buffers exactly to atop(maxbcachebuf) (currently it is sized to
atop(MAXPHYS)), and b_pages[] for pbufs is sized to atop(maxphys) + 1.
The +1 for pbufs allow several pbuf consumers, among them vmapbuf(),
to use unaligned buffers still sized to maxphys, esp. when such
buffers come from userspace (*). Overall, we save significant amount
of otherwise wasted memory in b_pages[] for buffer cache buffers,
while bumping MAXPHYS to desired high value.

Eliminate all direct uses of the MAXPHYS constant in kernel and driver
sources, except a place which initialize maxphys. Some random (and
arguably weird) uses of MAXPHYS, e.g. in linuxolator, are converted
straight. Some drivers, which use MAXPHYS to size embeded structures,
get private MAXPHYS-like constant; their convertion is out of scope
for this work.

Changes to cam/, dev/ahci, dev/ata, dev/mpr, dev/mpt, dev/mvs,
dev/siis, where either submitted by, or based on changes by mav.

Suggested by: mav (*)
Reviewed by: imp, mav, imp, mckusick, scottl (intermediate versions)
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D27225

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msdosfs: suspend around unmount or remount rw->ro.

This also eliminates unsafe use of VFS_SYNC(MNT_WAIT).

Requested by: mckusick
Discussed with: imp
Tested by: pho (previous version)
Sponsored by:

msdosfs: suspend around unmount or remount rw->ro.

This also eliminates unsafe use of VFS_SYNC(MNT_WAIT).

Requested by: mckusick
Discussed with: imp
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D27269

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msdosfs: Add trivial support for suspension.

Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D27269

msdosfs(5): Fix debug-only format string

No functional change; MSDOSFS_DEBUG isn't a real build option, so this isn't
covered by LINT kernels.

MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

vfs: drop the error parameter from vn_isdisk, introduce vn_isdisk_error

Most consumers pass NULL.

Merge ^/head r364264 through r364278.