nfs4: Don't flush cache when closing read only share reservation

NFS4 specification requires that modified data has to be flushed before
sending CLOSE request. Our original implementation was stricter than that
by flushing all modified data at each file close. That caused problems
with e.g. Tracker, which likes to periodically open files for read only,
in a situation when there were still asynchronous writes pending
(e.g. large file copied).

nfs4: Fix CID #991617: Set cookie file system at its creation

nfs4: fixed two warnings.

* warnings about comparison between signed and unsigned integer expressions.
* the use of max_c() was superflous anyway as the result is only used for a comparison
with the left value.

nfs4: fix few issues related with file caches
* update metadata cache when writing to cache
* do not limit size of a io request
* minor checks in Inode::Write

nfs4: support hard links properly

The main purpose of this patch is to prevent VFS from removing a vnode to early
what might have happened if the NFS client knew it had more than one name but
then one of them was deleted. Moreover, all discovered and still valid names
are stored what may be useful in proper file handle recovery when they are
volatile.

This patch fixes both #9558 and #9561.

nfs4: Fix error handling issues in Inode::Open() and Inode::Create()

This fixes CID 991498.

nfs4: Fix write commit race condition

nfs4: Fix few Inode::fOpenState related race conditions

nfs4: Save open mode in case of open reclaimation

nfs4: Fix problems with reading directory entries
* Inode::ReadDir missed an entry when given buffer was too small
* Each OpenDirCookie now has its own copy of directory snapshot what
would prevent Inode::ReadDir from accessing freed memory when removing
files and reading directory entries simultaneously
* Several minor issues fixed

nfs4: Add numerous assertion checks

nfs4, dns_resolver: fix numerous style violations

nfs4: Fix some cache revalidator problems

nfs4: Update FileInfo at rename

nfs4: Fix several problems with emulated attributes

nfs4: Fix amount of data written when using AIO

nfs4: Add basic emulation of named attributes

nfs4: Fix server reboot recovery

nfs4: Add basic support for extended attributes

nfs4: Implement node monitoring

nfs4: Check if user is allowed to use open state

nfs4: Add support for CB_GETATTR

nfs4: Repair O_TRUNC support

nfs4: Return delegation before open upgrade

nfs4: Support delegations of created files

nfs4: Do not sync too often if delegation is held

nfs4: Reclaim delegations after server reboot

nfs4: Return delegations when asked to

nfs4: Move cache management inside Inode class

nfs4: Use one open state per inode

nfs4: Do not open too much files on server

nfs4: Add ACCESS cache

nfs4: Move low level NFS4 code to Inode's base class

nfs4: Use existing write cookie, do not send COMMIT if not necessary

nfs4: Use unstable writes and commit before close

nfs4: Change write policy from write through to write back

nfs4: Basic data cache implementation

nfs4: Fix several issues introduced in previous commits

nfs4: Cache file attributes and filesystem info

nfs4: Rename Filehandle to FileHandle and Filesystem to FileSystem

nfs4: Remove several superfluous 'else'

nfs4: Abandon owner and owner_group when id mapping causes problems

nfs4: Do not attempt to set owner, owner_group when not supported

nfs4: Add id mapper

nfs4: Use FileInfo instead of filehandle to identify a file

nfs4: OpenConfirm used wrong filehandle

nfs4: Put file and dir specific code in separate files

nfs4: Don't flush cache when closing read only share reservation

NFS4 specification requires that modified data has to be flushed before
sending CLOSE request. Our original implementation was stricter than that
by flushing all modified data at each file close. That caused problems
with e.g. Tracker, which likes to periodically open files for read only,
in a situation when there were still asynchronous writes pending
(e.g. large file copied).

nfs4: Fix CID #991617: Set cookie file system at its creation

nfs4: fixed two warnings.

* warnings about comparison between signed and unsigned integer expressions.
* the use of max_c() was superflous anyway as the result is only used for a comparison
with the left value.

nfs4: fix few issues related with file caches
* update metadata cache when writing to cache
* do not limit size of a io request
* minor checks in Inode::Write

nfs4: support hard links properly

The main purpose of this patch is to prevent VFS from removing a vnode to early
what might have happened if the NFS client knew it had more than one name but
then one of them was deleted. Moreover, all discovered and still valid names
are stored what may be useful in proper file handle recovery when they are
volatile.

This patch fixes both #9558 and #9561.

nfs4: Fix error handling issues in Inode::Open() and Inode::Create()

This fixes CID 991498.

nfs4: Fix write commit race condition

nfs4: Fix few Inode::fOpenState related race conditions

nfs4: Save open mode in case of open reclaimation

nfs4: Fix problems with reading directory entries
* Inode::ReadDir missed an entry when given buffer was too small
* Each OpenDirCookie now has its own copy of directory snapshot what
would prevent Inode::ReadDir from accessing freed memory when removing
files and reading directory entries simultaneously
* Several minor issues fixed

nfs4: Add numerous assertion checks

nfs4, dns_resolver: fix numerous style violations

nfs4: Fix some cache revalidator problems

nfs4: Update FileInfo at rename

nfs4: Fix several problems with emulated attributes

nfs4: Fix amount of data written when using AIO

nfs4: Add basic emulation of named attributes

nfs4: Fix server reboot recovery

nfs4: Add basic support for extended attributes

nfs4: Implement node monitoring

nfs4: Check if user is allowed to use open state

nfs4: Add support for CB_GETATTR

nfs4: Repair O_TRUNC support

nfs4: Return delegation before open upgrade

nfs4: Support delegations of created files

nfs4: Do not sync too often if delegation is held

nfs4: Reclaim delegations after server reboot

nfs4: Return delegations when asked to

nfs4: Move cache management inside Inode class

nfs4: Use one open state per inode

nfs4: Do not open too much files on server

nfs4: Add ACCESS cache

nfs4: Move low level NFS4 code to Inode's base class

nfs4: Use existing write cookie, do not send COMMIT if not necessary

nfs4: Use unstable writes and commit before close

nfs4: Change write policy from write through to write back

nfs4: Basic data cache implementation

nfs4: Fix several issues introduced in previous commits

nfs4: Cache file attributes and filesystem info

nfs4: Rename Filehandle to FileHandle and Filesystem to FileSystem

nfs4: Remove several superfluous 'else'

nfs4: Abandon owner and owner_group when id mapping causes problems

nfs4: Do not attempt to set owner, owner_group when not supported

nfs4: Add id mapper

nfs4: Use FileInfo instead of filehandle to identify a file

nfs4: OpenConfirm used wrong filehandle

nfs4: Put file and dir specific code in separate files