linux-stable.git/fs/fuse, branch linux-2.6.16.y

fuse: fix hang on SMP

2007-01-04T00:14:06+00:00

Fuse didn't always call i_size_write() with i_mutex held which caused
rare hangs on SMP/32bit.  This bug has been present since fuse-2.2,
well before being merged into mainline.

The simplest solution is to protect i_size_write() with the
per-connection spinlock.  Using i_mutex for this purpose would require
some restructuring of the code and I'm not even sure it's always safe
to acquire i_mutex in all places i_size needs to be set.

Since most of vmtruncate is already duplicated for other reasons,
duplicate the remaining part as well, making all i_size_write() calls
internal to fuse.

Using i_size_write() was unnecessary in fuse_init_inode(), since this
function is only called on a newly created locked inode.

Reported by a few people over the years, but special thanks to Dana
Henriksen who was persistent enough in helping me debug it.

Adrian Bunk:
Backported to 2.6.16.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Adrian Bunk

[PATCH] fuse: fix oops in fuse_send_readpages()

2006-04-17T20:16:05+00:00

During heavy parallel filesystem activity it was possible to Oops the
kernel.  The reason is that read_cache_pages() could skip pages which
have already been inserted into the cache by another task.
Occasionally this may result in zero pages actually being sent, while
fuse_send_readpages() relies on at least one page being in the
request.

So check this corner case and just free the request instead of trying
to send it.

Reported and tested by Konstantin Isakov.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

[PATCH] fuse: fix bug in negative lookup

2006-03-01T04:53:43+00:00

If negative entries (nodeid == 0) were sent in reply to LOOKUP requests,
two bugs could be triggered:

- looking up a negative entry would return -EIO,

- revaildate on an entry which turned negative would send a FORGET
  request with zero nodeid, which would cause an abort() in the
  library.

The above would only happen if the 'negative_timeout=N' option was used,
otherwise lookups reply -ENOENT, which worked correctly.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: fix bug in aborted fuse_release_end()

2006-02-17T21:59:27+00:00

There's a rather theoretical case of the BUG triggering in
fuse_reset_request():

  - iget() fails because of OOM after a successful CREATE_OPEN request
  - during IO on the resulting RELEASE request the connection is aborted

Fix and add warning to fuse_reset_request().

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: fix request_end() vs fuse_reset_request() race

2006-02-05T19:06:51+00:00

The last fix for this function in fact opened up a much more often
triggering race.

It was uncommented tricky code, that was buggy.  Add comment, make it less
tricky and fix bug.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: fix async read for legacy filesystems

2006-02-01T16:53:09+00:00

While asynchronous reads mean a performance improvement in most cases, if
the filesystem assumed that reads are synchronous, then async reads may
degrade performance (filesystem may receive reads out of order, which can
confuse it's own readahead logic).

With sshfs a 1.5 to 4 times slowdown can be measured.

There's also a need for userspace filesystems to know whether asynchronous
reads are supported by the kernel or not.

To achive these, negotiate in the INIT request whether async reads will be
used and the maximum readahead value.  Update interface version to 7.6

If userspace uses a version earlier than 7.6, then disable async reads, and
set maximum readahead value to the maximum read size, as done in previous
versions.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: fix bitfield race

2006-01-17T07:15:31+00:00

Fix race in setting bitfields of fuse_conn.  Spotted by Andrew Morton.

The two fields ->connected and ->mounted were always changed with the
fuse_lock held.  But other bitfields in the same structure were changed
without the lock.  In theory this could lead to losing the assignment of
even the ones under lock.  The chosen solution is to change these two
fields to be a full unsigned type.  The other bitfields aren't "important"
enough to warrant the extra complexity of full locking or changing them to
bitops.

For all bitfields document why they are safe wrt. concurrent
assignments.

Also make the initialization of the 'num_waiting' atomic counter explicit.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: use asynchronous READ requests for readpages

2006-01-17T07:15:31+00:00

This patch changes fuse_readpages() to send READ requests asynchronously.

This makes it possible for userspace filesystems to utilize the kernel
readahead logic instead of having to implement their own (resulting in double
caching).

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: READ request initialization

2006-01-17T07:15:31+00:00

Add a separate function for filling in the READ request.  This will make it
possible to send asynchronous READ requests as well as synchronous ones.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: move INIT handling to inode.c

2006-01-17T07:15:31+00:00

Now the INIT requests can be completely handled in inode.c and the
fuse_send_init() function need not be global any more.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds