fix typos in comments.

fix typos in word "request(s)".

miscelaneous -> miscellaneous in comment.

branches: 1.22.14;
make the env stuff visible.

make this compile again, and simplify.

branches: 1.20.10; 1.20.14; 1.20.16;
- Fix same vnodes associated with multiple cookies
The scheme used to retreive known nodes on lookup was flawed, as it only
used parent and name. This produced a different cookie for the same file
if it was renamed, when looking up ../ or when dealing with multiple files
associated with the same name through link(2).

We therefore abandon the use of node name and introduce hashed lists of
inodes. This causes a huge rewrite of reclaim code, which do not attempt
to keep parents allocated until all their children are reclaimed

- Fix race conditions in reclaim
There are a few situations where we issue multiple FUSE operations for
a PUFFS operation. On reclaim, we therefore have to wait for all FUSE
operation to complete, not just the current exchanges. We do this by
introducing node reference count with node_ref() and node_rele().

- Detect data loss caused by FAF
VOP_PUTPAGES causes FAF writes where the kernel does not check the
operation result. At least issue a warning on error.

- Enjoy FAF shortcut on setattr
No need to wait for the result if the kernel does not want it. There is
however an exception for setattr that touch the size, we need to wait
for completion because we have other operations queued for after the
resize.

- Fix fchmod() on write-open file
fchmod() on a node open with write privilege will send setattr with both mode and size set. This confuses some FUSE filesystem. Therefore we send two FUSE operations, one for mode, and one for size.

- Remove node TTL handling for netbsd-5 for simplicity sake. The code
still builds on netbsd-5 but does not have the node TTL feature anymore.
It works fine with kernel support on netbsd-6.

Add placeholder so that we can later add allbacks without breaking the ABI

branches: 1.18.2;
Add a FUSE trace facility, with statistics collection. This should help
tracking bugs and performance issues

branches: 1.17.2;
- Fix the confusion between fileno (opaque FUSE reference) and inode
numbers. fileno must be used when exchanging FUSE messages.
- Do not use kernel name cache anymore, as it caused modification from
other machines to be invisible.
- Honour name and attribute cache directive from FUSE filesystem

Serialize access to file size. We already have such a thing in the
kernel, where it fixes race for PUFFS filesystems, but we need it again
in perfused since FUSE filesystems are allowed to reorder requests.

The huge issue is in the asyncrhonous SETATTR sent by fsync. It is
followed by a syncrhnous FSYNC, so if the filesystem does not reorder
requests, once the FSYNC returns, we are confident the SETATTR is done.
But since FUSE can reorder, we need to implement sync in perfused.

simplify and eliminate non literal string formats.

- fix warn/err confusiog
- fix debugging printf
- add func arguments to simple formats

Use SOCK_SEQPACKET in perfuse if available. This fix file operations hangs
where the FUSE filesyste replied to an operation and got an ENOBUFS it did
not handle.

We now are also able to cleanly unmount

typos

Use sysconf(_SC_PAGESIZE) instead of PAGE_SIZE.

Remove code supporting SOCK_STREAM, as SOCK_DGRAM works fine

== file close operations ==
- use PUFFS_KFLAG_WTCACHE to puffs_init so that all writes are
immediatly send to the filesystem, and we do not have anymore write
after inactive. As a consequence, we can close files at inactive
stage, and there is not any concern left with files opened at
create time. We also do not have anymore to open ourselves in readdir and
fsync.

- Fsync on close (inactive stage). That makes sure we will not need to
do these operations once the file is closed (FUSE want an open file).
short sircuit the request that come after the close, bu not fsinc'ing
closed files,

- Use PUFFS_KFLAG_IAONDEMAND to get less inactive calls

== Removed nodes ==
- more ENOENT retunred for operations on removed node (but there
are probably some still missing): getattr, ooen, setattr, fsync

- set PND_REMOVE before sending the UNLINK/RMDIR operations so that we avoid
races during UNLINK completion. Also set PND_REMOVED on node we overwirte
in rename

== Filehandle fixes ==
- queue open operation to avoid getting two fh for one file

- set FH in getattr, if the file is open

- Just requires a read FH for fsyncdir, as we always opendir in read
mode. Ok, this is misleading :-)

== Misc ==
- do not set FUSE_FATTR_ATIME_NOW in setattr, as we provide the time

- short circuit nilpotent operations in setattr

- add a filename diagnostic flag to dump file names

- Use SOCK_DGRAM instead of SOCK_STREAM, as the filesystem seems to
assume datagram semantics: when using SOCK_STREAM, if perfused sends
frames faster than the filesystem consumes them, it will grab multiple
frames at once and discard anything beyond the first one. For now the
code can work both with SOCK_DGRAM and SOCK_STREAM, but SOCK_STREAM
support will probably have to be removed for the sake of readability.

- Remeber to sync parent directories when moving a node

- In debug output, display the requeue type (readdir, write, etc...)

- Do not checkfor peer credentials when perfused is autostarted and
therefore runs with filesystem privileges

- shut up warnings and debug messages when perfused is autostarted

- make perfused patch modifiable with CFLAGS for easier pkgsrc integration

- Fix build warnings

More LP64 fixes

build fixes for LP64

Build fixes for LP64

- if perfused is not already started (cannot connect to /dev/fuse),
FUSE filesystems will attempt to start it on their own, and will
communicate using a socketpair

- do not advertise NULL file handle as being valid when sending themback to the FUSE filesystem.

- unmount if we cannot talk to the FUSE process anymore

- set calling process gid properly

- debug message cleanup

- open the file before doing fsync: glusterfs wants that.

- Automatically call fsync on close for files. If we just close, fsync
will come later and we will have to reopen

- Add a PND_DIRTY flag to keep track of files that really need a sync.
perfuse_node_fsync only calls the FUSE fsync method if there are data
to push.

- Add a PND_OPEN flag to keep track of open files. Checking non NULL
fh is not enough, as some filesystems will always set fh to 0.

- Add a sync diagnostic flag, to watch fsync and dirty flag activity.
Make the fh diagnostic flag more verbose

- Send the fh in setattr (it was hardcoded to 0)

I am now able to build libperfuse in a glusterfs mounted filesystem. Yeah!

libperfuse(3) is a PUFFS relay to FUSE. In order to use it,
FUSE filesystem must be patched to #include <perfuse.h> in the source
files that open /dev/fuse and perform the mount(2) system call. The
FUSE filesystem must be linked with -lperfuse.

libperfuse(3) implements the FUSE kernel interface, on which libfuse or
any FUSE filesystem that opens /dev/fuse directly can be used.

For now, an external daemon called perfused(8) is used. This may change
in the future.

fix typos in word "request(s)".

miscelaneous -> miscellaneous in comment.

branches: 1.22.14;
make the env stuff visible.

make this compile again, and simplify.

branches: 1.20.10; 1.20.14; 1.20.16;
- Fix same vnodes associated with multiple cookies
The scheme used to retreive known nodes on lookup was flawed, as it only
used parent and name. This produced a different cookie for the same file
if it was renamed, when looking up ../ or when dealing with multiple files
associated with the same name through link(2).

We therefore abandon the use of node name and introduce hashed lists of
inodes. This causes a huge rewrite of reclaim code, which do not attempt
to keep parents allocated until all their children are reclaimed

- Fix race conditions in reclaim
There are a few situations where we issue multiple FUSE operations for
a PUFFS operation. On reclaim, we therefore have to wait for all FUSE
operation to complete, not just the current exchanges. We do this by
introducing node reference count with node_ref() and node_rele().

- Detect data loss caused by FAF
VOP_PUTPAGES causes FAF writes where the kernel does not check the
operation result. At least issue a warning on error.

- Enjoy FAF shortcut on setattr
No need to wait for the result if the kernel does not want it. There is
however an exception for setattr that touch the size, we need to wait
for completion because we have other operations queued for after the
resize.

- Fix fchmod() on write-open file
fchmod() on a node open with write privilege will send setattr with both mode and size set. This confuses some FUSE filesystem. Therefore we send two FUSE operations, one for mode, and one for size.

- Remove node TTL handling for netbsd-5 for simplicity sake. The code
still builds on netbsd-5 but does not have the node TTL feature anymore.
It works fine with kernel support on netbsd-6.

Add placeholder so that we can later add allbacks without breaking the ABI

branches: 1.18.2;
Add a FUSE trace facility, with statistics collection. This should help
tracking bugs and performance issues

branches: 1.17.2;
- Fix the confusion between fileno (opaque FUSE reference) and inode
numbers. fileno must be used when exchanging FUSE messages.
- Do not use kernel name cache anymore, as it caused modification from
other machines to be invisible.
- Honour name and attribute cache directive from FUSE filesystem

Serialize access to file size. We already have such a thing in the
kernel, where it fixes race for PUFFS filesystems, but we need it again
in perfused since FUSE filesystems are allowed to reorder requests.

The huge issue is in the asyncrhonous SETATTR sent by fsync. It is
followed by a syncrhnous FSYNC, so if the filesystem does not reorder
requests, once the FSYNC returns, we are confident the SETATTR is done.
But since FUSE can reorder, we need to implement sync in perfused.

simplify and eliminate non literal string formats.

- fix warn/err confusiog
- fix debugging printf
- add func arguments to simple formats

Use SOCK_SEQPACKET in perfuse if available. This fix file operations hangs
where the FUSE filesyste replied to an operation and got an ENOBUFS it did
not handle.

We now are also able to cleanly unmount

typos

Use sysconf(_SC_PAGESIZE) instead of PAGE_SIZE.

Remove code supporting SOCK_STREAM, as SOCK_DGRAM works fine

== file close operations ==
- use PUFFS_KFLAG_WTCACHE to puffs_init so that all writes are
immediatly send to the filesystem, and we do not have anymore write
after inactive. As a consequence, we can close files at inactive
stage, and there is not any concern left with files opened at
create time. We also do not have anymore to open ourselves in readdir and
fsync.

- Fsync on close (inactive stage). That makes sure we will not need to
do these operations once the file is closed (FUSE want an open file).
short sircuit the request that come after the close, bu not fsinc'ing
closed files,

- Use PUFFS_KFLAG_IAONDEMAND to get less inactive calls

== Removed nodes ==
- more ENOENT retunred for operations on removed node (but there
are probably some still missing): getattr, ooen, setattr, fsync

- set PND_REMOVE before sending the UNLINK/RMDIR operations so that we avoid
races during UNLINK completion. Also set PND_REMOVED on node we overwirte
in rename

== Filehandle fixes ==
- queue open operation to avoid getting two fh for one file

- set FH in getattr, if the file is open

- Just requires a read FH for fsyncdir, as we always opendir in read
mode. Ok, this is misleading :-)

== Misc ==
- do not set FUSE_FATTR_ATIME_NOW in setattr, as we provide the time

- short circuit nilpotent operations in setattr

- add a filename diagnostic flag to dump file names

- Use SOCK_DGRAM instead of SOCK_STREAM, as the filesystem seems to
assume datagram semantics: when using SOCK_STREAM, if perfused sends
frames faster than the filesystem consumes them, it will grab multiple
frames at once and discard anything beyond the first one. For now the
code can work both with SOCK_DGRAM and SOCK_STREAM, but SOCK_STREAM
support will probably have to be removed for the sake of readability.

- Remeber to sync parent directories when moving a node

- In debug output, display the requeue type (readdir, write, etc...)

- Do not checkfor peer credentials when perfused is autostarted and
therefore runs with filesystem privileges

- shut up warnings and debug messages when perfused is autostarted

- make perfused patch modifiable with CFLAGS for easier pkgsrc integration

- Fix build warnings

More LP64 fixes

build fixes for LP64

Build fixes for LP64

- if perfused is not already started (cannot connect to /dev/fuse),
FUSE filesystems will attempt to start it on their own, and will
communicate using a socketpair

- do not advertise NULL file handle as being valid when sending themback to the FUSE filesystem.

- unmount if we cannot talk to the FUSE process anymore

- set calling process gid properly

- debug message cleanup

- open the file before doing fsync: glusterfs wants that.

- Automatically call fsync on close for files. If we just close, fsync
will come later and we will have to reopen

- Add a PND_DIRTY flag to keep track of files that really need a sync.
perfuse_node_fsync only calls the FUSE fsync method if there are data
to push.

- Add a PND_OPEN flag to keep track of open files. Checking non NULL
fh is not enough, as some filesystems will always set fh to 0.

- Add a sync diagnostic flag, to watch fsync and dirty flag activity.
Make the fh diagnostic flag more verbose

- Send the fh in setattr (it was hardcoded to 0)

I am now able to build libperfuse in a glusterfs mounted filesystem. Yeah!

libperfuse(3) is a PUFFS relay to FUSE. In order to use it,
FUSE filesystem must be patched to #include <perfuse.h> in the source
files that open /dev/fuse and perform the mount(2) system call. The
FUSE filesystem must be linked with -lperfuse.

libperfuse(3) implements the FUSE kernel interface, on which libfuse or
any FUSE filesystem that opens /dev/fuse directly can be used.

For now, an external daemon called perfused(8) is used. This may change
in the future.

miscelaneous -> miscellaneous in comment.

make the env stuff visible.

make this compile again, and simplify.

branches: 1.20.10; 1.20.14; 1.20.16;
- Fix same vnodes associated with multiple cookies
The scheme used to retreive known nodes on lookup was flawed, as it only
used parent and name. This produced a different cookie for the same file
if it was renamed, when looking up ../ or when dealing with multiple files
associated with the same name through link(2).

We therefore abandon the use of node name and introduce hashed lists of
inodes. This causes a huge rewrite of reclaim code, which do not attempt
to keep parents allocated until all their children are reclaimed

- Fix race conditions in reclaim
There are a few situations where we issue multiple FUSE operations for
a PUFFS operation. On reclaim, we therefore have to wait for all FUSE
operation to complete, not just the current exchanges. We do this by
introducing node reference count with node_ref() and node_rele().

- Detect data loss caused by FAF
VOP_PUTPAGES causes FAF writes where the kernel does not check the
operation result. At least issue a warning on error.

- Enjoy FAF shortcut on setattr
No need to wait for the result if the kernel does not want it. There is
however an exception for setattr that touch the size, we need to wait
for completion because we have other operations queued for after the
resize.

- Fix fchmod() on write-open file
fchmod() on a node open with write privilege will send setattr with both mode and size set. This confuses some FUSE filesystem. Therefore we send two FUSE operations, one for mode, and one for size.

- Remove node TTL handling for netbsd-5 for simplicity sake. The code
still builds on netbsd-5 but does not have the node TTL feature anymore.
It works fine with kernel support on netbsd-6.

Add placeholder so that we can later add allbacks without breaking the ABI

branches: 1.18.2;
Add a FUSE trace facility, with statistics collection. This should help
tracking bugs and performance issues

branches: 1.17.2;
- Fix the confusion between fileno (opaque FUSE reference) and inode
numbers. fileno must be used when exchanging FUSE messages.
- Do not use kernel name cache anymore, as it caused modification from
other machines to be invisible.
- Honour name and attribute cache directive from FUSE filesystem

Serialize access to file size. We already have such a thing in the
kernel, where it fixes race for PUFFS filesystems, but we need it again
in perfused since FUSE filesystems are allowed to reorder requests.

The huge issue is in the asyncrhonous SETATTR sent by fsync. It is
followed by a syncrhnous FSYNC, so if the filesystem does not reorder
requests, once the FSYNC returns, we are confident the SETATTR is done.
But since FUSE can reorder, we need to implement sync in perfused.

simplify and eliminate non literal string formats.

- fix warn/err confusiog
- fix debugging printf
- add func arguments to simple formats

Use SOCK_SEQPACKET in perfuse if available. This fix file operations hangs
where the FUSE filesyste replied to an operation and got an ENOBUFS it did
not handle.

We now are also able to cleanly unmount

typos

Use sysconf(_SC_PAGESIZE) instead of PAGE_SIZE.

Remove code supporting SOCK_STREAM, as SOCK_DGRAM works fine

== file close operations ==
- use PUFFS_KFLAG_WTCACHE to puffs_init so that all writes are
immediatly send to the filesystem, and we do not have anymore write
after inactive. As a consequence, we can close files at inactive
stage, and there is not any concern left with files opened at
create time. We also do not have anymore to open ourselves in readdir and
fsync.

- Fsync on close (inactive stage). That makes sure we will not need to
do these operations once the file is closed (FUSE want an open file).
short sircuit the request that come after the close, bu not fsinc'ing
closed files,

- Use PUFFS_KFLAG_IAONDEMAND to get less inactive calls

== Removed nodes ==
- more ENOENT retunred for operations on removed node (but there
are probably some still missing): getattr, ooen, setattr, fsync

- set PND_REMOVE before sending the UNLINK/RMDIR operations so that we avoid
races during UNLINK completion. Also set PND_REMOVED on node we overwirte
in rename

== Filehandle fixes ==
- queue open operation to avoid getting two fh for one file

- set FH in getattr, if the file is open

- Just requires a read FH for fsyncdir, as we always opendir in read
mode. Ok, this is misleading :-)

== Misc ==
- do not set FUSE_FATTR_ATIME_NOW in setattr, as we provide the time

- short circuit nilpotent operations in setattr

- add a filename diagnostic flag to dump file names

- Use SOCK_DGRAM instead of SOCK_STREAM, as the filesystem seems to
assume datagram semantics: when using SOCK_STREAM, if perfused sends
frames faster than the filesystem consumes them, it will grab multiple
frames at once and discard anything beyond the first one. For now the
code can work both with SOCK_DGRAM and SOCK_STREAM, but SOCK_STREAM
support will probably have to be removed for the sake of readability.

- Remeber to sync parent directories when moving a node

- In debug output, display the requeue type (readdir, write, etc...)

- Do not checkfor peer credentials when perfused is autostarted and
therefore runs with filesystem privileges

- shut up warnings and debug messages when perfused is autostarted

- make perfused patch modifiable with CFLAGS for easier pkgsrc integration

- Fix build warnings

More LP64 fixes

build fixes for LP64

Build fixes for LP64

- if perfused is not already started (cannot connect to /dev/fuse),
FUSE filesystems will attempt to start it on their own, and will
communicate using a socketpair

- do not advertise NULL file handle as being valid when sending themback to the FUSE filesystem.

- unmount if we cannot talk to the FUSE process anymore

- set calling process gid properly

- debug message cleanup

- open the file before doing fsync: glusterfs wants that.

- Automatically call fsync on close for files. If we just close, fsync
will come later and we will have to reopen

- Add a PND_DIRTY flag to keep track of files that really need a sync.
perfuse_node_fsync only calls the FUSE fsync method if there are data
to push.

- Add a PND_OPEN flag to keep track of open files. Checking non NULL
fh is not enough, as some filesystems will always set fh to 0.

- Add a sync diagnostic flag, to watch fsync and dirty flag activity.
Make the fh diagnostic flag more verbose

- Send the fh in setattr (it was hardcoded to 0)

I am now able to build libperfuse in a glusterfs mounted filesystem. Yeah!

libperfuse(3) is a PUFFS relay to FUSE. In order to use it,
FUSE filesystem must be patched to #include <perfuse.h> in the source
files that open /dev/fuse and perform the mount(2) system call. The
FUSE filesystem must be linked with -lperfuse.

libperfuse(3) implements the FUSE kernel interface, on which libfuse or
any FUSE filesystem that opens /dev/fuse directly can be used.

For now, an external daemon called perfused(8) is used. This may change
in the future.

make the env stuff visible.

make this compile again, and simplify.

branches: 1.20.10; 1.20.14;
- Fix same vnodes associated with multiple cookies
The scheme used to retreive known nodes on lookup was flawed, as it only
used parent and name. This produced a different cookie for the same file
if it was renamed, when looking up ../ or when dealing with multiple files
associated with the same name through link(2).

We therefore abandon the use of node name and introduce hashed lists of
inodes. This causes a huge rewrite of reclaim code, which do not attempt
to keep parents allocated until all their children are reclaimed

- Fix race conditions in reclaim
There are a few situations where we issue multiple FUSE operations for
a PUFFS operation. On reclaim, we therefore have to wait for all FUSE
operation to complete, not just the current exchanges. We do this by
introducing node reference count with node_ref() and node_rele().

- Detect data loss caused by FAF
VOP_PUTPAGES causes FAF writes where the kernel does not check the
operation result. At least issue a warning on error.

- Enjoy FAF shortcut on setattr
No need to wait for the result if the kernel does not want it. There is
however an exception for setattr that touch the size, we need to wait
for completion because we have other operations queued for after the
resize.

- Fix fchmod() on write-open file
fchmod() on a node open with write privilege will send setattr with both mode and size set. This confuses some FUSE filesystem. Therefore we send two FUSE operations, one for mode, and one for size.

- Remove node TTL handling for netbsd-5 for simplicity sake. The code
still builds on netbsd-5 but does not have the node TTL feature anymore.
It works fine with kernel support on netbsd-6.

Add placeholder so that we can later add allbacks without breaking the ABI

branches: 1.18.2;
Add a FUSE trace facility, with statistics collection. This should help
tracking bugs and performance issues

branches: 1.17.2;
- Fix the confusion between fileno (opaque FUSE reference) and inode
numbers. fileno must be used when exchanging FUSE messages.
- Do not use kernel name cache anymore, as it caused modification from
other machines to be invisible.
- Honour name and attribute cache directive from FUSE filesystem

Serialize access to file size. We already have such a thing in the
kernel, where it fixes race for PUFFS filesystems, but we need it again
in perfused since FUSE filesystems are allowed to reorder requests.

The huge issue is in the asyncrhonous SETATTR sent by fsync. It is
followed by a syncrhnous FSYNC, so if the filesystem does not reorder
requests, once the FSYNC returns, we are confident the SETATTR is done.
But since FUSE can reorder, we need to implement sync in perfused.

simplify and eliminate non literal string formats.

- fix warn/err confusiog
- fix debugging printf
- add func arguments to simple formats

Use SOCK_SEQPACKET in perfuse if available. This fix file operations hangs
where the FUSE filesyste replied to an operation and got an ENOBUFS it did
not handle.

We now are also able to cleanly unmount

typos

Use sysconf(_SC_PAGESIZE) instead of PAGE_SIZE.

Remove code supporting SOCK_STREAM, as SOCK_DGRAM works fine

== file close operations ==
- use PUFFS_KFLAG_WTCACHE to puffs_init so that all writes are
immediatly send to the filesystem, and we do not have anymore write
after inactive. As a consequence, we can close files at inactive
stage, and there is not any concern left with files opened at
create time. We also do not have anymore to open ourselves in readdir and
fsync.

- Fsync on close (inactive stage). That makes sure we will not need to
do these operations once the file is closed (FUSE want an open file).
short sircuit the request that come after the close, bu not fsinc'ing
closed files,

- Use PUFFS_KFLAG_IAONDEMAND to get less inactive calls

== Removed nodes ==
- more ENOENT retunred for operations on removed node (but there
are probably some still missing): getattr, ooen, setattr, fsync

- set PND_REMOVE before sending the UNLINK/RMDIR operations so that we avoid
races during UNLINK completion. Also set PND_REMOVED on node we overwirte
in rename

== Filehandle fixes ==
- queue open operation to avoid getting two fh for one file

- set FH in getattr, if the file is open

- Just requires a read FH for fsyncdir, as we always opendir in read
mode. Ok, this is misleading :-)

== Misc ==
- do not set FUSE_FATTR_ATIME_NOW in setattr, as we provide the time

- short circuit nilpotent operations in setattr

- add a filename diagnostic flag to dump file names

- Use SOCK_DGRAM instead of SOCK_STREAM, as the filesystem seems to
assume datagram semantics: when using SOCK_STREAM, if perfused sends
frames faster than the filesystem consumes them, it will grab multiple
frames at once and discard anything beyond the first one. For now the
code can work both with SOCK_DGRAM and SOCK_STREAM, but SOCK_STREAM
support will probably have to be removed for the sake of readability.

- Remeber to sync parent directories when moving a node

- In debug output, display the requeue type (readdir, write, etc...)

- Do not checkfor peer credentials when perfused is autostarted and
therefore runs with filesystem privileges

- shut up warnings and debug messages when perfused is autostarted

- make perfused patch modifiable with CFLAGS for easier pkgsrc integration

- Fix build warnings

More LP64 fixes

build fixes for LP64

Build fixes for LP64

- if perfused is not already started (cannot connect to /dev/fuse),
FUSE filesystems will attempt to start it on their own, and will
communicate using a socketpair

- do not advertise NULL file handle as being valid when sending themback to the FUSE filesystem.

- unmount if we cannot talk to the FUSE process anymore

- set calling process gid properly

- debug message cleanup

- open the file before doing fsync: glusterfs wants that.

- Automatically call fsync on close for files. If we just close, fsync
will come later and we will have to reopen

- Add a PND_DIRTY flag to keep track of files that really need a sync.
perfuse_node_fsync only calls the FUSE fsync method if there are data
to push.

- Add a PND_OPEN flag to keep track of open files. Checking non NULL
fh is not enough, as some filesystems will always set fh to 0.

- Add a sync diagnostic flag, to watch fsync and dirty flag activity.
Make the fh diagnostic flag more verbose

- Send the fh in setattr (it was hardcoded to 0)

I am now able to build libperfuse in a glusterfs mounted filesystem. Yeah!

libperfuse(3) is a PUFFS relay to FUSE. In order to use it,
FUSE filesystem must be patched to #include <perfuse.h> in the source
files that open /dev/fuse and perform the mount(2) system call. The
FUSE filesystem must be linked with -lperfuse.

libperfuse(3) implements the FUSE kernel interface, on which libfuse or
any FUSE filesystem that opens /dev/fuse directly can be used.

For now, an external daemon called perfused(8) is used. This may change
in the future.