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Commit Graph

1993 Commits

Author SHA1 Message Date
John Baldwin
c1f7cf23b1 Use the correct pid when checking to see whether or not the /proc/<pid>
directory itself (rather than any of its contents) is visible to the
current thread.

MFC after:	1 week
PR:		kern/90063
Submitted by:	john of 8192.net
Approved by:	re (kensmith)
2007-10-05 17:37:25 +00:00
Xin LI
3543c1b429 MFp4: Provide a dummy verb "export" to shut up the message
showed up at start when NFS is enabled.

Reported by:	rafan
Approved by:	re (tmpfs blanket)
2007-10-04 17:11:48 +00:00
Xin LI
386c969205 Additional work is still needed before we can claim that tmpfs
is stable enough for production usage.  Warn user upon mount.

Approved by:	re (tmpfs blanket)
2007-10-04 17:08:46 +00:00
Bruce Evans
ed316d339f Remove some of the pessimizations involving writing the fsi sector.
All active fields in fsi are advisory/optional, so we shouldn't do
extra work to make them valid at all times, but instead we write to
the fsi too often (we still do), and we searched for a free cluster
for fsinxtfree too often.

This commit just removes the whole search and its results, so that we
write out our in-core copy of fsinxtfree instead of writing a "fixed"
copy and clobbering our in-core copy.  This saves fixing 3 bugs:
- off-by-1 error for the end of the search, resulting in fsinxtfree
  not actually being adjusted iff only the last cluster is free.
- missing adjustment when no clusters are free.
- off-by-many error for the start of the search.  Starting the search
  at 0 instead of at (the in-core copy of) fsinxtfree did more than
  defeat the reasons for existence of fsinxtfree.  fsinxtfree exists
  mainly to avoid having to start at 0 for just the first search per
  mount, but has the side effect of reducing bias towards allocating
  near cluster 0.  The bias would normally only be generated by the
  first search per mount (if fsinxtfree is not supported), but since
  we also adjusted the in-core copy of fsinxtfree here, we were doing
  extra work to maximize the bias.

Approved by:	re (kensmith)
2007-09-23 14:49:32 +00:00
Craig Rodrigues
00cedf971b Disable multiple ntfs mounts to the same mountpoint.
Eliminates panics due to locking issues.
Idea taken from src/sys/gnu/fs/xfs/FreeBSD/xfs_super.c.

PR:	89966, 92000, 104393
Reported by:	H. Matsuo <hiroshi50000 yahoo co jp>,
		Chris <m2chrischou gmail.com>,
		Andrey V. Elsukov <bu7cher yandex ru>,
		Jan Henrik Sylvester <me janh de>
Approved by:	re (kensmith)
2007-09-21 23:50:15 +00:00
Jeff Roberson
b61ce5b0e6 - Move all of the PS_ flags into either p_flag or td_flags.
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
   previously the sched_lock.  These bugs have existed for some time.
 - Allow swapout to try each thread in a process individually and then
   swapin the whole process if any of these fail.  This allows us to move
   most scheduler related swap flags into td_flags.
 - Keep ki_sflag for backwards compat but change all in source tools to
   use the new and more correct location of P_INMEM.

Reported by:	pho
Reviewed by:	attilio, kib
Approved by:	re (kensmith)
2007-09-17 05:31:39 +00:00
Bruce Evans
c2819440b3 Fix races in msdosfs_lookup() and msdosfs_readdir(). These functions
can easily block in bread(), and then there was nothing to prevent the
static buffer (nambuf_{ptr,len,last_id}) being clobbered by another
thread.

The effects of the bug seem to have been limited to failed lookups and
mangled names in readdir(), since Giant locking provides enough
serialization to prevent concurrent calls to the functions that access
the buffer.  They were very obvious for multiple concurrent tree walks,
especially with a small cluster size.

The bug was introduced in msdosfs_conv.c 1.34 and associated changes,
and is in all releases starting with 5.2.

The fix is to allocate the buffer as a local variable and pass around
pointers to it like "_r" functions in libc do.  Stack use from this
is large but not too large.  This also fixes a memory leak on module
unload.

Reviewed by:	kib
Approved by:	re (kensmith)
2007-08-31 22:29:55 +00:00
Xin LI
1f32d0127b MFp4: rework tmpfs_readdir() logic in terms of correctness.
Approved by:	re (tmpfs blanket)
Tested with:	fstest, fsx
2007-08-16 11:00:07 +00:00
John Baldwin
1dc5b1cc56 On 6.x this works:
% mount | grep home
/dev/ad4s1e on /home (ufs, local, noatime, soft-updates)
% mount -u -o atime /home
% mount | grep home
/dev/ad4s1e on /home (ufs, local, soft-updates)

Restore this behavior for on 7.x for the following mount options:
noatime, noclusterr, noclusterw, noexec, nosuid, nosymfollow

In addition, on 7.x, the following are equivalent:
mount -u -o atime /home
mount -u -o nonoatime /home

Ideally, when we introduce new mount options, we should avoid
options starting with "no". :)

Requested by:	jhb
Reported by:	Karol Kwiat <karol.kwiat gmail com>, Scott Hetzel <swhetzel gmail com>
Approved by:	re (bmah)
Proxy commit for:	rodrigc
2007-08-15 17:40:09 +00:00
Xin LI
ad3638ee08 MFp4:
- LK_RETRY prohibits vget() and vn_lock() to return error.
   Remove associated code. [1]
 - Properly use vhold() and vdrop() instead of their unlocked
   versions, we are guaranteed to have the vnode's interlock
   unheld. [1]
 - Fix a pseudo-infinite loop caused by 64/32-bit arithmetic
   with the same way used in modern NetBSD versions. [2]
 - Reorganize tmpfs_readdir to reduce duplicated code.

Submitted by:	kib [1]
Obtained from:	NetBSD [2]
Approved by:	re (tmpfs blanket)
2007-08-10 11:00:30 +00:00
Xin LI
0ae6383d39 MFp4:
- Respect cnflag and don't lock vnode always as LK_EXCLUSIVE [1]
 - Properly lock around tn_vnode to avoid NULL deference
 - Be more careful handling vnodes (*)

(*) This is a WIP
[1] by pjd via howardsu

Thanks kib@ for his valuable VFS related comments.

Tested with:	fsx, fstest, tmpfs regression test set
Found by:	pho's stress2 suite
Approved by:	re (tmpfs blanket)
2007-08-10 05:24:49 +00:00
Bruce Evans
a4e6807c49 In msdosfs_read() and msdosfs_write(), don't check explicitly for
(uio_offset < 0) since this can't happen.  If this happens, then the
general code handles the problem safely (better than before for reading,
returning 0 (EOF) instead of the bogus errno EINVAL, and the same as
before for writing, returning EFBIG).

In msdosfs_read(), don't check for (uio_resid < 0).  msdosfs_write()
already didn't check.

In msdosfs_read(), document in a comment our assumptions that the caller
passed a valid uio_offset and uio_resid.  ffs checks using KASSERT(),
and that is enough sanity checking.  In the same comment, partly document
there is no need to check for the EOVERFLOW case, unlike in ffs where this
case can happen at least in theory.

In msdosfs_write(), add a comment about why the checking of
(uio_resid == 0) is explicit, unlike in ffs.

In msdosfs_write(), check for impossibly large final offsets before
checking if the file size rlimit would be exceeded, so that we don't
have an overflow bug in the rlimit check and are consistent with ffs.
We now return EFBIG instead of EFBIG plus a SIGXFSZ signal if the final
offset would be impossibly large but not so large as to cause overflow.
Overflow normally gave the benign behaviour of no signal.

Approved by:	re (kensmith) (blanket)
2007-08-07 10:35:27 +00:00
Bruce Evans
b7837a91c9 Fix and update the comments about the effect of the read-only flag on writing.
They are still too verbose.

Remove nearby unreachable code for handling symlinks.

Approved by:	re (kensmith) (blanket)
2007-08-07 05:42:10 +00:00
Bruce Evans
e3117f852e Fix some style bugs (don't assume that off_t == int64_t; fix some comments;
remove some parentheses; fix some whitespace errors; fix only one case of
a boolean comparison of a non-boolean).

Improve an error message by quoting ".", and by not printing large positive
values as negative ones.

Approved by:	re (kensmith) (blanket)
2007-08-07 03:59:49 +00:00
Bruce Evans
c0f5121cac Fix some style bugs (don't assume that off_t == int64_t; fix some comments;
remove some parentheses; fix only a couple of whtespace errors).

Approved by:	re (kensmith) (blanket)
2007-08-07 03:43:28 +00:00
Bruce Evans
2d7c6b2724 Fix some style bugs (mainly some whitespace errors).
Approved by:	re (kensmith) (blanket)
2007-08-07 03:38:36 +00:00
Bruce Evans
b6d0381e7e Fix some style bugs (some whitespace errors only).
Approved by:	re (kensmith) (blanket)
2007-08-07 03:22:10 +00:00
Bruce Evans
d2bb66bacd Sort includes.
Remove rotted banal comment attached to includes.

Approved by:	re (kensmith) (blanket)
2007-08-07 02:28:33 +00:00
Bruce Evans
6becd1c855 Sort includes.
Remove banal comments attached to includes.

Approved by:	re (kensmith) (blanket)
2007-08-07 02:27:35 +00:00
Bruce Evans
5696c6e0b2 Sort includes.
Remove banal comments before includes.  Remove rotted banal comments attached
to includes.

Approved by:	re (kensmith) (blanket)
2007-08-07 02:20:37 +00:00
Bruce Evans
9b0802c90b Remove unused include(s).
Remove banal comments before includes.

Approved by:	re (kensmith) (blanket)
2007-08-07 02:11:16 +00:00
Bruce Evans
a878a31c13 Remove unused include(s).
Approved by:	re (kensmith) (blanket)
2007-08-07 02:08:06 +00:00
Bruce Evans
eba34270fa Include <sys/mutex.h> and its prerequisite <sys/lock.h> instead of
depending on namespace pollution in <sys/buf.h> and/or <sys/vnode.h>

Approved by:	re (kensmith) (blanket)
2007-08-07 01:40:27 +00:00
Bruce Evans
1103771d95 Include <sys/mutex.h>'s prerequisite <sys/lock.h> instead of depending on
namespace pollution in <sys/vnode.h>.

Sort the include of <sys/mutex.h> instead of unsorting it after
<sys/vnode.h> and depending on the pollution there.

Approved by:	re (kensmith) (blanket)
2007-08-07 01:37:59 +00:00
Bruce Evans
6fd81fc7a6 Remove unused include(s).
Approved by:	re (kensmith) (blanket)
2007-08-07 01:07:16 +00:00
Bruce Evans
8d61a735c6 Silently fix up the estimated next free cluster number from the fsinfo
sector, instead of failing the whole mount if it is garbage.  Fields
in the fsinfo sector are only advisory, so there are better sanity
checks than this, and we already silently fix up the only other advisory
field in the fsinfo (the free cluster count).

This wasn't handled quite right in rev.1.92, 1.117, or in NetBSD.  1.92
also failed the whole mount for the non-garbage magic value 0xffffffff
1.117 fixed this well enough in practice since garbage values shouldn't
occur in practice, but left the error handling larger and more convoluted
than necessary.  Now we handle the magic value as a special case of
fixing up all out of bounds values.

Also fix up the estimated next free cluster number when there is no
fsinfo sector.  We were using 0, but CLUST_FIRST is safer.

Approved by:	re (kensmith)
2007-08-05 12:58:34 +00:00
Bruce Evans
3726942956 Oops, fix the fix for the i/o size of the fsinfo block. Its log
message explained why the size is 1 sector, but the code used a
size of 1 cluster.

I/o sizes larger than necessary may cause serious coherency problems
in the buffer cache.  Here I think there were only minor efficiency
problems, since a too-large fsinfo buffer could only get far enough
to overlap buffers for the same vnode (the device vnode), so mappings
are coherent at the page level although not at the buffer level, and
the former is probably enough due to our limited use of the fsinfo
buffer.

Approved by:	re (kensmith)
2007-08-03 23:13:50 +00:00
Xin LI
fb7557140e MFp4 - Refine locking to eliminate some potential race/panics:
- Copy before testing a pointer.  This closes a race window.
 - Use msleep with the node interlock instead of tsleep.
 - Do proper locking around access to tn_vpstate.
 - Assert vnode VOP lock for dir_{atta,de}tach to capture
   inconsistent locking.

Suggested by:	kib
Submitted by:	delphij
Reviewed by:	Howard Su
Approved by:	re (tmpfs blanket)
2007-08-03 06:24:31 +00:00
Pawel Jakub Dawidek
57fd3d5572 When we do open, we should lock the vnode exclusively. This fixes few races:
- fifo race, where two threads assign v_fifoinfo,
- v_writecount modifications,
- v_object modifications,
- and probably more...

Discussed with:	kib, ups
Approved by:	re (rwatson)
2007-07-26 16:58:09 +00:00
Xin LI
f62e5595fd MFp4: Force 64-bit arithmatic when caculating the maximum file size.
This fixes tmpfs caculations on 32-bit systems equipped with more than
4GB swap.

Reported by:	Craig Boston <craig xfoil gank org>
PR:		kern/114870
Approved by:	re (tmpfs blanket)
2007-07-24 17:14:53 +00:00
Bruce Evans
4eb3abf0a5 Make using msdosfs as the root file system sort of work:
o Initialize ownerships and permissions.  They were garbage (0) for
  root mounts since vfs_mountroot_try() doesn't ask for them to be set
  and msdosfs's old incomplete code to set them was removed.  The
  garbage happened to give the correct ownerships root:wheel, but it
  gave permissions 000 so init could not be execed.  Use the macros
  for root: wheel and 0755.  (The removed code gave 0:0 and 0777.  0755
  is more normal and secure, thought wrong for /tmp.)

o Check the readonly flag for initial (non-MNT_UPDATE) mounts in the
  correct place, as in ffs.  For root mounts, it is only passed in
  mp->mnt_flags, since vfs_mountroot_try() only passes it as a flag
  and nothing translates the flag to the "ro" option string.  msdosfs
  only looked for it in the string, so it gave a rw mount for root
  mounts without even clearing the flag in mp->mnt_flags, so the final
  state was inconsistent.  Checking the flag only in mp->mnt_flags
  works for initial userland mounts too.  The MNT_UPDATE case is
  messier.

The main point that should work but doesn't is fsck of msdosfs root
while it is mounted ro.  This needs mainly MNT_RELOAD support to work.
It should be possible to run fsck -p and succeed provided the fs is
consistent, not just for msdosfs, but this fails because fsck -p always
tries to open the device rw.  The hack that allows open for writing
in ffs is not implemented in msdosfs, since without MNT_RELOAD support
writing could only be harmful.  So fsck must be turned off to use
msdosfs as root.  This is quite dangerous, since msdosfs is still missing
actually using its fs-dirty flag internally, so it is happy to mount
dirty fileystems rw.

Unrelated changes:
- Fix missing error handling for MNT_UPDATE from rw to ro.
- Catch up with renaming msdos to msdosfs in a string.

Approved by:	re (kensmith)
2007-07-23 07:10:17 +00:00
Xin LI
7280082944 MFp4: When swapping is not enabled, allow creating files by taking
physical memory pages into account for tm_maxfilesize.

Reported by:	Dominique Goncalves <dominique.goncalves gmail.com>
Submitted by:	Howard Su
Approved by:	re (tmpfs blanket)
2007-07-23 06:54:58 +00:00
Bruce Evans
6b6c5f5ef9 Implement vfs clustering for msdosfs.
This gives a very large speedup for small block sizes (in my tests,
about 5 times for write and 3 times for read with a block size of 512,
if clustering is possible) and a moderate speedup for the moderatatly
large block sizes that should be used on non-small media (4K is the
best size in most cases, and the speedup for that is about 1.3 times
for write and 1.2 times for read).  mmap() should benefit from clustering
like read()/write(), but the current implementation of vm only supports
clustering (at least for getpages) if the fs block size is >= PAGE SIZE.

msdosfs is now only slightly slower than ffs with soft updates for
writing and slightly faster for reading when both use their best block
sizes.  Writing is slower for msdosfs because of more sync writes.
Reading is faster for msdosfs because indirect blocks interfere with
clustering in ffs.

The changes in msdosfs_read() and msdosfs_write() are simpler merges
of corresponding code in ffs (after fixing some style bugs in ffs).
msdosfs_bmap() needs fs-specific code.  This implementation loops
calling a lower level bmap function to do the hard parts.  This is a
bit inefficient, but is efficient enough since msdsfs_bmap() is only
called when there is physical i/o to do.

Approved by:	re (hrs)
2007-07-20 17:06:57 +00:00
Bruce Evans
d34b0a1bac Clean up before implementing vfs clustering for msdosfs:
In msdosfs_read(), mainly reorder the main loop to the same order as in
ffs_read().

In msdosfs_write() and extendfile(), use vfs_bio_clrbuf() instead of
clrbuf().  I think this just just a bogus optimization, but ffs always
does it and msdosfs already did it in one place, and it is what I've
tested.

In msdosfs_write(), merge good bits from a comment in ffs_write(), and
fix 1 style bug.

In the main comment for msdosfs_pcbmap(), improve wording and catch
up with 13 years of changes in the function.  This comment belongs in
VOP_BMAP.9 but that doesn't exist.

In msdosfs_bmap(), return EFBIG if the requested cluster number is out
of bounds instead of blindly truncating it, and fix many style bugs.

Approved by:	re (hrs)
2007-07-20 16:21:47 +00:00
Robert Watson
825eaf3470 Make sure we release the control vnode in Coda:
We allocate coda_ctlvp when /coda is mounted, but never release it.
During the unmount this vnode was marked as UNMOUNTING and when venus
is started a second time the system would hang, possibly waiting for
the old vnode to disappear.

So now we call vrele on the control vnode when file system is unmounted
to drop the reference we got during the mount. I'm pretty sure it is
also necessary to not skip the handling in coda_inactive for the control
vnode, it seems like that is the place we actually get rid of the vnode
once the refcount has dropped to 0.

Submitted by:	Jan Harkes <jaharkes at cs dot cmu dot edu>
Approved by:	re (kensmith)
2007-07-20 11:14:51 +00:00
Xin LI
c5be778305 MFp4: Rework on tmpfs's mapped read/write procedures. This
should finally fix fsx test case.

The printf's added here would be eventually turned into
assertions.

Submitted by:	Mingyan Guo (mostly)
Approved by:	re (tmpfs blanket)
2007-07-19 03:34:50 +00:00
Robert Watson
00f05dc847 Complete repo-copy and move of Coda from src/sys/coda to src/sys/fs/coda
by removing files from src/sys/coda, and updating include paths in the
new location, kernel configuration, and  Makefiles.  In one case add
$FreeBSD$.

Discussed with:		anderson, Jan Harkes <jaharkes@cs.cmu.edu>
Approved by:		re (kensmith)
Repo-copy madness:	simon
2007-07-12 21:04:58 +00:00
Robert Watson
d21e51d059 Forced commit to recognize repo-copy of Coda files from src/sys/coda to
src/sys/fs/coda.

Discussed with:         anderson, Jan Harkes <jaharkes@cs.cmu.edu>
Approved by:            re (kensmith)
Repo-copy madness:      simon
2007-07-12 20:40:38 +00:00
Bruce Evans
93fe42b62f Round up the FAT block size to a multiple of the sector size so that i/o
to the FAT is possible.

Make the FAT block size less arbitrary before it is rounded up:
- for FAT12, default to 3*512 instead of to 3 sectors.  The magic 3 is
  the default number of 512-byte FAT sectors on a floppy drive.  That
  many sectors is too many if the sector size is larger.
- for !FAT12, default to PAGE_SIZE instead of to 4096.  Remove
  MSDOSFS_DFLTBSIZE since it only obfuscated this 4096.

For reading the BPB, use a block size of 8192 instead of 2048 so that
sector sizes up to 8192 can work.  We should try several sizes, or just
try the maximum supported size (MAXBSIZE = 64K).  I use 8192 because
that is enough for DVD-RW's (even 2048 is enough) and 8192 has been
tested a lot in use by ffs.

This completes fixing msdosfs for some large sector sizes (up to 8K
for read and 64K for write).  Microsoft documents support for sector
sizes up to 4K in mdosfs.  ffs is currently limited to 8K for both
read and write.

Approved by:	re (kensmith)
Approved by:	nyan (several years ago)
2007-07-12 17:17:47 +00:00
Bruce Evans
fd7c4230b2 Fix some bugs involving the fsinfo block (many remain unfixed). This is
part of fixing msdosfs for large sector sizes.  One of the fixed bugs
was fatal for large sector sizes.

1. The fsinfo block has size 512, but it was misunderstood and declared
   as having size 1024, with nothing in the second 512 bytes except a
   signature at the end.  The second 512 bytes actually normally (if
   the file system was created by Windows) consist of a second boot
   sector which is normally (in WinXP) empty except for a signature --
   the normal layout is one boot sector, one fsinfo sector, another
   boot sector, then these 3 sectors duplicated.  However, other
   layouts are valid.  newfs_msdos produces a valid layout with one
   boot sector, one fsinfo sector, then these 2 sectors duplicated.
   The signature check for the extra part of the fsinfo was thus
   normally checking the signature in either the second boot sector
   or the first boot sector in the copy, and thus accidentally
   succeeding.  The extra signature check would just fail for weirder
   layouts with 512-byte sectors, and for normal layouts with any other
   sector size.

   Remove the extra bytes and the extra signature check.

2. Old versions did i/o to the fsinfo block using size 1024, with the
   second half only used for the extra signature check on read.  This
   was harmless for sector size 512, and worked accidentally for sector
   size 1024.  The i/o just failed for larger sector sizes.

   The version being fixed did i/o to the fsinfo block using size
   fsi_size(pmp) = (1024 << ((pmp)->pm_BlkPerSec >> 2)).  This
   expression makes no sense.  It happens to work for sector small
   sector sizes, but for sector size 32K it gives the preposterous
   value of 64M and thus causes panics.  A sector size of 32768 is
   necessary for at least some DVD-RW's (where the minimum write size
   is 32768 although the minimum read size is 2048).

   Now that the size of the fsinfo block is 512, it always fits in
   one sector so there is no need for a macro to express it.  Just
   use the sector size where the old code uses 1024.

Approved by:	re (kensmith)
Approved by:	nyan (several years ago for a different version of (2))
2007-07-12 16:09:07 +00:00
Robert Watson
26e3bc3a96 Fix ioctls on the control vnode: ioctls on a character device fail with
ENOTTY.  Make the control vnode a regular file so that ioctls are passed
through to our kernel module.

Submitted by:	Jan Harkes <jaharkes@cs.cmu.edu>
Approved by:	re (kensmith)
2007-07-11 21:34:41 +00:00
Robert Watson
0e3ce855cc Avoid a panic in insmntque when we pass a NULL mount: this reenables
some previously disabled code which according to the comment caused a
problem during shutdown.  But even that is still better than
triggering a kernel panic whenever venus is started.

Submitted by:	Jan Harkes <jaharkes@cs.cmu.edu>
Approved by:	re (kensmith)
2007-07-11 21:33:46 +00:00
Robert Watson
74d326ada8 Replace CODA_OPEN with CODA_OPEN_BY_FD: coda_open was disabled because
we can't open container files by device/inode number pair anymore.
Replace the CODA_OPEN upcall with CODA_OPEN_BY_FD, where venus returns
an open file descriptor for the container file.  We can then grab a
reference on the vnode coda_psdev.c:vc_nb_write and use this vnode for
further accesses to the container file.

Submitted by:	Jan Harkes <jaharkes@cs.cmu.edu>
Approved by:	re (kensmith)
2007-07-11 21:32:08 +00:00
Robert Watson
934030b2c9 Resolve Coda mount failing because Coda failed to match the device
operations.  But we don't have to, if we find the coda_mntinfo structure
for this device in our linked list, we know the device is good.

Submitted by:	Jan Harkes <jaharkes@cs.cmu.edu>
Approved by:	re (kensmith)
2007-07-11 21:21:55 +00:00
Robert Watson
7263babb85 Avoid crash when opening Coda device: when allocating coda_mntinfo, we
need to initialize dev so that we can actually find the allocated
coda_mntinfo structure later on.

Submitted by:	Jan Harkes <jaharkes@cs.cmu.edu>
Approved by:	re (kensmith)
2007-07-11 20:39:53 +00:00
Xin LI
8d9a89a3a0 MFp4: Make use of the kernel unit number allocation facility
for tmpfs nodes.

Submitted by:	Mingyan Guo <guomingyan gmail com>
Approved by:	re (tmpfs blanket)
2007-07-11 14:26:27 +00:00
Bruce Evans
8e55bfaf4b Don't use almost perfectly pessimal cluster allocation. Allocation
of the the first cluster in a file (and, if the allocation cannot be
continued contiguously, for subsequent clusters in a file) was randomized
in an attempt to leave space for contiguous allocation of subsequent
clusters in each file when there are multiple writers.  This reduced
internal fragmentation by a few percent, but it increased external
fragmentation by up to a few thousand percent.

Use simple sequential allocation instead.  Actually maintain the fsinfo
sequence index for this.  The read and write of this index from/to
disk still have many non-critical bugs, but we now write an index that
has something to do with our allocations instead of being modified
garbage.  If there is no fsinfo on the disk, then we maintain the index
internally and don't go near the bugs for writing it.

Allocating the first free cluster gives a layout that is almost as good
(better in some cases), but takes too much CPU if the FAT is large and
the first free cluster is not near the beginning.

The effect of this change for untar and tar of a slightly reduced copy
of /usr/src on a new file system was:

Before (msdosfs 4K-clusters):
untar:  459.57 real              untar from cached file (actually a pipe)
tar:    342.50 real              tar from uncached tree to /dev/zero
Before (ffs2 soft updates 4K-blocks 4K-frags)
untar:   39.18 real
tar:     29.94 real
Before (ffs2 soft updates 16K-blocks 2K-frags)
untar:   31.35 real
tar:     18.30 real

After (msdosfs 4K-clusters):
untar    54.83 real
tar      16.18 real

All of these times can be improved further.

With multiple concurrent writers or readers (especially readers), the
improvement is smaller, but I couldn't find any case where it is
negative.  342 seconds for tarring up about 342 MB on a ~47MB/S partition
is just hard to unimprove on.  (This operation would take about 7.3
seconds with reasonably localized allocation and perfect read-ahead.)
However, for active file systems, 342 seconds is closer to normal than
the 16+ seconds above or the 11 seconds with other changes (best I've
measured -- won easily by msdosfs!).  E.g., my active /usr/src on ffs1
is quite old and fragmented, so reading to prepare for the above
benchmark takes about 6 times longer than reading back the fresh copies
of it.

Approved by:	re (kensmith)
2007-07-10 13:20:24 +00:00
Xin LI
1df86a323d MFp4:
- Plug memory leak.
 - Respect underlying vnode's properties rather than assuming that
   the user want root:wheel + 0755.  Useful for using tmpfs(5) for
   /tmp.
 - Use roundup2 and howmany macros instead of rolling our own version.
 - Try to fix fsx -W -R foo case.
 - Instead of blindly zeroing a page, determine whether we need a pagein
   order to prevent data corruption.
 - Fix several bugs reported by Coverity.

Submitted by:	Mingyan Guo <guomingyan gmail com>, Howard Su, delphij
Coverity ID:	CID 2550, 2551, 2552, 2557
Approved by:	re (tmpfs blanket)
2007-07-08 15:56:12 +00:00
Konstantin Belousov
de10ffa527 Since rev. 1.199 of sys/kern/kern_conf.c, the thread that calls
destroy_dev() from d_close() cdev method would self-deadlock.
devfs_close() bump device thread reference counter, and destroy_dev()
sleeps, waiting for si_threadcount to reach zero for cdev without
d_purge method.

destroy_dev_sched() could be used instead from d_close(), to
schedule execution of destroy_dev() in another context. The
destroy_dev_sched_drain() function can be used to drain the scheduled
calls to destroy_dev_sched(). Similarly, drain_dev_clone_events() drains
the events clone to make sure no lingering devices are left after
dev_clone event handler deregistered.

make_dev_credf(MAKEDEV_REF) function should be used from dev_clone
event handlers instead of make_dev()/make_dev_cred() to ensure that created
device has reference counter bumped before cdev mutex is dropped inside
make_dev().

Reviewed by:	tegge (early versions), njl (programming interface)
Debugging help and testing by:	Peter Holm
Approved by:	re (kensmith)
2007-07-03 17:42:37 +00:00
Xin LI
9b258fca27 MFp4:
- Remove unnecessary NULL checks after M_WAITOK allocations.
 - Use VOP_ACCESS instead of hand-rolled suser_cred()
   calls. [1]
 - Use malloc(9) KPI to allocate memory for string.  The
   optimization taken from NetBSD is not valid for FreeBSD
   because our malloc(9) already act that way. [2]

Requested by:	rwatson [1]
Submitted by:	Howard Su [2]
Approved by:	re (tmpfs blanket)
2007-06-29 05:23:15 +00:00