NTFS: - Use i_size_read() in fs/ntfs/super.c once and then use the cached

[linux-2.6] / fs / ntfs / ChangeLog

ToDo/Notes:
        - Find and fix bugs.
        - Checkpoint or disable the user space journal ($UsnJrnl).
        - In between ntfs_prepare/commit_write, need exclusion between
          simultaneous file extensions.  This is given to us by holding i_sem
          on the inode.  The only places in the kernel when a file is resized
          are prepare/commit write and truncate for both of which i_sem is
          held.  Just have to be careful in readpage/writepage and all other
          helpers not running under i_sem that we play nice...
          Also need to be careful with initialized_size extention in
          ntfs_prepare_write. Basically, just be _very_ careful in this code...
          UPDATE: The only things that need to be checked are read/writepage
          which do not hold i_sem.  Note writepage cannot change i_size but it
          needs to cope with a concurrent i_size change, just like readpage.
          Also both need to cope with concurrent changes to the other sizes,
          i.e. initialized/allocated/compressed size, as well.
        - Implement mft.c::sync_mft_mirror_umount().  We currently will just
          leave the volume dirty on umount if the final iput(vol->mft_ino)
          causes a write of any mirrored mft records due to the mft mirror
          inode having been discarded already.  Whether this can actually ever
          happen is unclear however so it is worth waiting until someone hits
          the problem.
        - Enable the code for setting the NT4 compatibility flag when we start
          making NTFS 1.2 specific modifications.

2.1.23-WIP

        - Add printk rate limiting for ntfs_warning() and ntfs_error() when
          compiled without debug.  This avoids a possible denial of service
          attack.  Thanks to Carl-Daniel Hailfinger from SuSE for pointing this
          out.
        - Use i_size_read() in fs/ntfs/attrib.c::ntfs_attr_set().
        - Use i_size_read() in fs/ntfs/logfile.c::ntfs_{check,empty}_logfile().
        - Use i_size_read() once and then use the cached value in
          fs/ntfs/lcnalloc.c::ntfs_cluster_alloc().
        - Use i_size_read() in fs/ntfs/file.c::ntfs_file_open().
        - Add size_lock to the ntfs_inode structure.  This is an rw spinlock
          and it locks against access to the inode sizes.  Note, ->size_lock
          is also accessed from irq context so you must use the _irqsave and
          _irqrestore lock and unlock functions, respectively.
        - Use i_size_read() in fs/ntfs/compress.c at the start of the read and
          use the cached value afterwards.  Cache the initialized_size in the
          same way and protect access to the two sizes using the size_lock.
        - Use i_size_read() in fs/ntfs/dir.c once and then use the cached
          value afterwards.
        - Use i_size_read() in fs/ntfs/super.c once and then use the cached
          value afterwards.  Cache the initialized_size in the same way and
          protect access to the two sizes using the size_lock.
        - Minor optimization to fs/ntfs/super.c::ntfs_statfs() and its helpers.

2.1.22 - Many bug and race fixes and error handling improvements.

        - Improve error handling in fs/ntfs/inode.c::ntfs_truncate().
        - Change fs/ntfs/inode.c::ntfs_truncate() to return an error code
          instead of void and provide a helper ntfs_truncate_vfs() for the
          vfs ->truncate method.
        - Add a new ntfs inode flag NInoTruncateFailed() and modify
          fs/ntfs/inode.c::ntfs_truncate() to set and clear it appropriately.
        - Fix min_size and max_size definitions in ATTR_DEF structure in
          fs/ntfs/layout.h to be signed.
        - Add attribute definition handling helpers to fs/ntfs/attrib.[hc]:
          ntfs_attr_size_bounds_check(), ntfs_attr_can_be_non_resident(), and
          ntfs_attr_can_be_resident(), which in turn use the new private helper
          ntfs_attr_find_in_attrdef().
        - In fs/ntfs/aops.c::mark_ntfs_record_dirty(), take the
          mapping->private_lock around the dirtying of the buffer heads
          analagous to the way it is done in __set_page_dirty_buffers().
        - Ensure the mft record size does not exceed the PAGE_CACHE_SIZE at
          mount time as this cannot work with the current implementation.
        - Check for location of attribute name and improve error handling in
          general in fs/ntfs/inode.c::ntfs_read_locked_inode() and friends.
        - In fs/ntfs/aops.c::ntfs_writepage(), if the page is fully outside
          i_size, i.e. race with truncate, invalidate the buffers on the page
          so that they become freeable and hence the page does not leak.
        - Remove unused function fs/ntfs/runlist.c::ntfs_rl_merge().  (Adrian
          Bunk)
        - Fix stupid bug in fs/ntfs/attrib.c::ntfs_attr_find() that resulted in
          a NULL pointer dereference in the error code path when a corrupt
          attribute was found.  (Thanks to Domen Puncer for the bug report.)
        - Add MODULE_VERSION() to fs/ntfs/super.c.
        - Make several functions and variables static.  (Adrian Bunk)
        - Modify fs/ntfs/aops.c::mark_ntfs_record_dirty() so it allocates
          buffers for the page if they are not present and then marks the
          buffers belonging to the ntfs record dirty.  This causes the buffers
          to become busy and hence they are safe from removal until the page
          has been written out.
        - Fix stupid bug in fs/ntfs/attrib.c::ntfs_external_attr_find() in the
          error handling code path that resulted in a BUG() due to trying to
          unmap an extent mft record when the mapping of it had failed and it
          thus was not mapped.  (Thanks to Ken MacFerrin for the bug report.)
        - Drop the runlist lock after the vcn has been read in
          fs/ntfs/lcnalloc.c::__ntfs_cluster_free().
        - Rewrite handling of multi sector transfer errors.  We now do not set
          PageError() when such errors are detected in the async i/o handler
          fs/ntfs/aops.c::ntfs_end_buffer_async_read().  All users of mst
          protected attributes now check the magic of each ntfs record as they
          use it and act appropriately.  This has the effect of making errors
          granular per ntfs record rather than per page which solves the case
          where we cannot access any of the ntfs records in a page when a
          single one of them had an mst error.  (Thanks to Ken MacFerrin for
          the bug report.)
        - Fix error handling in fs/ntfs/quota.c::ntfs_mark_quotas_out_of_date()
          where we failed to release i_sem on the $Quota/$Q attribute inode.
        - Fix bug in handling of bad inodes in fs/ntfs/namei.c::ntfs_lookup().
        - Add mapping of unmapped buffers to all remaining code paths, i.e.
          fs/ntfs/aops.c::ntfs_write_mst_block(), mft.c::ntfs_sync_mft_mirror(),
          and write_mft_record_nolock().  From now on we require that the
          complete runlist for the mft mirror is always mapped into memory.
        - Add creation of buffers to fs/ntfs/mft.c::ntfs_sync_mft_mirror().
        - Improve error handling in fs/ntfs/aops.c::ntfs_{read,write}_block().
        - Cleanup fs/ntfs/aops.c::ntfs_{read,write}page() since we know that a
          resident attribute will be smaller than a page which makes the code
          simpler.  Also make the code more tolerant to concurrent ->truncate.

2.1.21 - Fix some races and bugs, rewrite mft write code, add mft allocator.

        - Implement extent mft record deallocation
          fs/ntfs/mft.c::ntfs_extent_mft_record_free().
        - Splitt runlist related functions off from attrib.[hc] to runlist.[hc].
        - Add vol->mft_data_pos and initialize it at mount time.
        - Rename init_runlist() to ntfs_init_runlist(), ntfs_vcn_to_lcn() to
          ntfs_rl_vcn_to_lcn(), decompress_mapping_pairs() to
          ntfs_mapping_pairs_decompress(), ntfs_merge_runlists() to
          ntfs_runlists_merge() and adapt all callers.
        - Add fs/ntfs/runlist.[hc]::ntfs_get_nr_significant_bytes(),
          ntfs_get_size_for_mapping_pairs(), ntfs_write_significant_bytes(),
          and ntfs_mapping_pairs_build(), adapted from libntfs.
        - Make fs/ntfs/lcnalloc.c::ntfs_cluster_free_from_rl_nolock() not
          static and add a declaration for it to lcnalloc.h.
        - Add fs/ntfs/lcnalloc.h::ntfs_cluster_free_from_rl() which is a static
          inline wrapper for ntfs_cluster_free_from_rl_nolock() which takes the
          cluster bitmap lock for the duration of the call.
        - Add fs/ntfs/attrib.[hc]::ntfs_attr_record_resize().
        - Implement the equivalent of memset() for an ntfs attribute in
          fs/ntfs/attrib.[hc]::ntfs_attr_set() and switch
          fs/ntfs/logfile.c::ntfs_empty_logfile() to using it.
        - Remove unnecessary casts from LCN_* constants.
        - Implement fs/ntfs/runlist.c::ntfs_rl_truncate_nolock().
        - Add MFT_RECORD_OLD as a copy of MFT_RECORD in fs/ntfs/layout.h and
          change MFT_RECORD to contain the NTFS 3.1+ specific fields.
        - Add a helper function fs/ntfs/aops.c::mark_ntfs_record_dirty() which
          marks all buffers belonging to an ntfs record dirty, followed by
          marking the page the ntfs record is in dirty and also marking the vfs
          inode containing the ntfs record dirty (I_DIRTY_PAGES).
        - Switch fs/ntfs/index.h::ntfs_index_entry_mark_dirty() to using the
          new helper fs/ntfs/aops.c::mark_ntfs_record_dirty() and remove the no
          longer needed fs/ntfs/index.[hc]::__ntfs_index_entry_mark_dirty().
        - Move ntfs_{un,}map_page() from ntfs.h to aops.h and fix resulting
          include errors.
        - Move the typedefs for runlist_element and runlist from types.h to
          runlist.h and fix resulting include errors.
        - Remove unused {__,}format_mft_record() from fs/ntfs/mft.c.
        - Modify fs/ntfs/mft.c::__mark_mft_record_dirty() to use the helper
          mark_ntfs_record_dirty() which also changes the behaviour in that we
          now set the buffers belonging to the mft record dirty as well as the
          page itself.
        - Update fs/ntfs/mft.c::write_mft_record_nolock() and sync_mft_mirror()
          to cope with the fact that there now are dirty buffers in mft pages.
        - Update fs/ntfs/inode.c::ntfs_write_inode() to also use the helper
          mark_ntfs_record_dirty() and thus to set the buffers belonging to the
          mft record dirty as well as the page itself.
        - Fix compiler warnings on x86-64 in fs/ntfs/dir.c.  (Randy Dunlap,
          slightly modified by me)
        - Add fs/ntfs/mft.c::try_map_mft_record() which fails with -EALREADY if
          the mft record is already locked and otherwise behaves the same way
          as fs/ntfs/mft.c::map_mft_record().
        - Modify fs/ntfs/mft.c::write_mft_record_nolock() so that it only
          writes the mft record if the buffers belonging to it are dirty.
          Otherwise we assume that it was written out by other means already.
        - Attempting to write outside initialized size is _not_ a bug so remove
          the bug check from fs/ntfs/aops.c::ntfs_write_mst_block().  It is in
          fact required to write outside initialized size when preparing to
          extend the initialized size.
        - Map the page instead of using page_address() before writing to it in
          fs/ntfs/aops.c::ntfs_mft_writepage().
        - Provide exclusion between opening an inode / mapping an mft record
          and accessing the mft record in fs/ntfs/mft.c::ntfs_mft_writepage()
          by setting the page not uptodate throughout ntfs_mft_writepage().
        - Clear the page uptodate flag in fs/ntfs/aops.c::ntfs_write_mst_block()
          to ensure noone can see the page whilst the mst fixups are applied.
        - Add the helper fs/ntfs/mft.c::ntfs_may_write_mft_record() which
          checks if an mft record may be written out safely obtaining any
          necessary locks in the process.  This is used by
          fs/ntfs/aops.c::ntfs_write_mst_block().
        - Modify fs/ntfs/aops.c::ntfs_write_mst_block() to also work for
          writing mft records and improve its error handling in the process.
          Now if any of the records in the page fail to be written out, all
          other records will be written out instead of aborting completely.
        - Remove ntfs_mft_aops and update all users to use ntfs_mst_aops.
        - Modify fs/ntfs/inode.c::ntfs_read_locked_inode() to set the
          ntfs_mst_aops for all inodes which are NInoMstProtected() and
          ntfs_aops for all other inodes.
        - Rename fs/ntfs/mft.c::sync_mft_mirror{,_umount}() to
          ntfs_sync_mft_mirror{,_umount}() and change their parameters so they
          no longer require an ntfs inode to be present.  Update all callers.
        - Cleanup the error handling in fs/ntfs/mft.c::ntfs_sync_mft_mirror().
        - Clear the page uptodate flag in fs/ntfs/mft.c::ntfs_sync_mft_mirror()
          to ensure noone can see the page whilst the mst fixups are applied.
        - Remove the no longer needed fs/ntfs/mft.c::ntfs_mft_writepage() and
          fs/ntfs/mft.c::try_map_mft_record().
        - Fix callers of fs/ntfs/aops.c::mark_ntfs_record_dirty() to call it
          with the ntfs inode which contains the page rather than the ntfs
          inode the mft record of which is in the page.
        - Fix race condition in fs/ntfs/inode.c::ntfs_put_inode() by moving the
          index inode bitmap inode release code from there to
          fs/ntfs/inode.c::ntfs_clear_big_inode().  (Thanks to Christoph
          Hellwig for spotting this.)
        - Fix race condition in fs/ntfs/inode.c::ntfs_put_inode() by taking the
          inode semaphore around the code that sets ni->itype.index.bmp_ino to
          NULL and reorganize the code to optimize it a bit.  (Thanks to
          Christoph Hellwig for spotting this.)
        - Modify fs/ntfs/aops.c::mark_ntfs_record_dirty() to no longer take the
          ntfs inode as a parameter as this is confusing and misleading and the
          needed ntfs inode is available via NTFS_I(page->mapping->host).
          Adapt all callers to this change.
        - Modify fs/ntfs/mft.c::write_mft_record_nolock() and
          fs/ntfs/aops.c::ntfs_write_mst_block() to only check the dirty state
          of the first buffer in a record and to take this as the ntfs record
          dirty state.  We cannot look at the dirty state for subsequent
          buffers because we might be racing with
          fs/ntfs/aops.c::mark_ntfs_record_dirty().
        - Move the static inline ntfs_init_big_inode() from fs/ntfs/inode.c to
          inode.h and make fs/ntfs/inode.c::__ntfs_init_inode() non-static and
          add a declaration for it to inode.h.  Fix some compilation issues
          that resulted due to #includes and header file interdependencies.
        - Simplify setup of i_mode in fs/ntfs/inode.c::ntfs_read_locked_inode().
        - Add helpers fs/ntfs/layout.h::MK_MREF() and MK_LE_MREF().
        - Modify fs/ntfs/mft.c::map_extent_mft_record() to only verify the mft
          record sequence number if it is specified (i.e. not zero).
        - Add fs/ntfs/mft.[hc]::ntfs_mft_record_alloc() and various helper
          functions used by it.
        - Update Documentation/filesystems/ntfs.txt with instructions on how to
          use the Device-Mapper driver with NTFS ftdisk/LDM raid.  This removes
          the linear raid problem with the Software RAID / MD driver when one
          or more of the devices has an odd number of sectors.

2.1.20 - Fix two stupid bugs introduced in 2.1.18 release.

        - Fix stupid bug in fs/ntfs/attrib.c::ntfs_attr_reinit_search_ctx()
          where we did not clear ctx->al_entry but it was still set due to
          changes in ntfs_attr_lookup() and ntfs_external_attr_find() in
          particular.
        - Fix another stupid bug in fs/ntfs/attrib.c::ntfs_external_attr_find()
          where we forgot to unmap the extent mft record when we had finished
          enumerating an attribute which caused a bug check to trigger when the
          VFS calls ->clear_inode.

2.1.19 - Many cleanups, improvements, and a minor bug fix.

        - Update ->setattr (fs/ntfs/inode.c::ntfs_setattr()) to refuse to
          change the uid, gid, and mode of an inode as we do not support NTFS
          ACLs yet.
        - Remove BKL use from ntfs_setattr() syncing up with the rest of the
          kernel.
        - Get rid of the ugly transparent union in fs/ntfs/dir.c::ntfs_readdir()
          and ntfs_filldir() as per suggestion from Al Viro.
        - Change '\0' and L'\0' to simply 0 as per advice from Linus Torvalds.
        - Update ->truncate (fs/ntfs/inode.c::ntfs_truncate()) to check if the
          inode size has changed and to only output an error if so.
        - Rename fs/ntfs/attrib.h::attribute_value_length() to ntfs_attr_size().
        - Add le{16,32,64} as well as sle{16,32,64} data types to
          fs/ntfs/types.h.
        - Change ntfschar to be le16 instead of u16 in fs/ntfs/types.h.
        - Add le versions of VCN, LCN, and LSN called leVCN, leLCN, and leLSN,
          respectively, to fs/ntfs/types.h.
        - Update endianness conversion macros in fs/ntfs/endian.h to use the
          new types as appropriate.
        - Do proper type casting when using sle64_to_cpup() in fs/ntfs/dir.c
          and index.c.
        - Add leMFT_REF data type to fs/ntfs/layout.h.
        - Update all NTFS header files with the new little endian data types.
          Affected files are fs/ntfs/layout.h, logfile.h, and time.h.
        - Do proper type casting when using ntfs_is_*_recordp() in
          fs/ntfs/logfile.c, mft.c, and super.c. 
        - Fix all the sparse bitwise warnings.  Had to change all the typedef
          enums storing little endian values to simple enums plus a typedef for
          the datatype to make sparse happy.
        - Fix a bug found by the new sparse bitwise warnings where the default
          upcase table was defined as a pointer to wchar_t rather than ntfschar
          in fs/ntfs/ntfs.h and super.c.
        - Change {const_,}cpu_to_le{16,32}(0) to just 0 as suggested by Al Viro.

2.1.18 - Fix scheduling latencies at mount time as well as an endianness bug.

        - Remove vol->nr_mft_records as it was pretty meaningless and optimize
          the calculation of total/free inodes as used by statfs().
        - Fix scheduling latencies in ntfs_fill_super() by dropping the BKL
          because the code itself is using the ntfs_lock semaphore which
          provides safe locking.  (Ingo Molnar)
        - Fix a potential bug in fs/ntfs/mft.c::map_extent_mft_record() that
          could occur in the future for when we start closing/freeing extent
          inodes if we don't set base_ni->ext.extent_ntfs_inos to NULL after
          we free it.
        - Rename {find,lookup}_attr() to ntfs_attr_{find,lookup}() as well as
          find_external_attr() to ntfs_external_attr_find() to cleanup the
          namespace a bit and to be more consistent with libntfs.
        - Rename {{re,}init,get,put}_attr_search_ctx() to
          ntfs_attr_{{re,}init,get,put}_search_ctx() as well as the type
          attr_search_context to ntfs_attr_search_ctx.
        - Force use of ntfs_attr_find() in ntfs_attr_lookup() when searching
          for the attribute list attribute itself.
        - Fix endianness bug in ntfs_external_attr_find().
        - Change ntfs_{external_,}attr_find() to return 0 on success, -ENOENT
          if the attribute is not found, and -EIO on real error.  In the case
          of -ENOENT, the search context is updated to describe the attribute
          before which the attribute being searched for would need to be
          inserted if such an action were to be desired and in the case of
          ntfs_external_attr_find() the search context is also updated to
          indicate the attribute list entry before which the attribute list
          entry of the attribute being searched for would need to be inserted
          if such an action were to be desired.  Also make ntfs_find_attr()
          static and remove its prototype from attrib.h as it is not used
          anywhere other than attrib.c.  Update ntfs_attr_lookup() and all
          callers of ntfs_{external,}attr_{find,lookup}() for the new return
          values.
        - Minor cleanup of fs/ntfs/inode.c::ntfs_init_locked_inode().

2.1.17 - Fix bugs in mount time error code paths and other updates.

        - Implement bitmap modification code (fs/ntfs/bitmap.[hc]).  This
          includes functions to set/clear a single bit or a run of bits.
        - Add fs/ntfs/attrib.[hc]::ntfs_find_vcn() which returns the locked
          runlist element containing a particular vcn.  It also takes care of
          mapping any needed runlist fragments.
        - Implement cluster (de-)allocation code (fs/ntfs/lcnalloc.[hc]).
        - Load attribute definition table from $AttrDef at mount time.
        - Fix bugs in mount time error code paths involving (de)allocation of
          the default and volume upcase tables.
        - Remove ntfs_nr_mounts as it is no longer used.

2.1.16 - Implement access time updates, file sync, async io, and read/writev.

        - Add support for readv/writev and aio_read/aio_write (fs/ntfs/file.c).
          This is done by setting the appropriate file operations pointers to
          the generic helper functions provided by mm/filemap.c.
        - Implement fsync, fdatasync, and msync both for files (fs/ntfs/file.c)
          and directories (fs/ntfs/dir.c).
        - Add support for {a,m,c}time updates to inode.c::ntfs_write_inode().
          Note, except for the root directory and any other system files opened
          by the user, the system files will not have their access times
          updated as they are only accessed at the inode level an hence the
          file level functions which cause the times to be updated are never
          invoked.

2.1.15 - Invalidate quotas when (re)mounting read-write.

        - Add new element itype.index.collation_rule to the ntfs inode
          structure and set it appropriately in ntfs_read_locked_inode().
        - Implement a new inode type "index" to allow efficient access to the
          indices found in various system files and adapt inode handling
          accordingly (fs/ntfs/inode.[hc]).  An index inode is essentially an
          attribute inode (NInoAttr() is true) with an attribute type of
          AT_INDEX_ALLOCATION.  As such, it is no longer allowed to call
          ntfs_attr_iget() with an attribute type of AT_INDEX_ALLOCATION as
          there would be no way to distinguish between normal attribute inodes
          and index inodes.  The function to obtain an index inode is
          ntfs_index_iget() and it uses the helper function
          ntfs_read_locked_index_inode().  Note, we do not overload
          ntfs_attr_iget() as indices consist of multiple attributes so using
          ntfs_attr_iget() to obtain an index inode would be confusing.
        - Ensure that there is no overflow when doing page->index <<
          PAGE_CACHE_SHIFT by casting page->index to s64 in fs/ntfs/aops.c.
        - Use atomic kmap instead of kmap() in fs/ntfs/aops.c::ntfs_read_page()
          and ntfs_read_block().
        - Use case sensitive attribute lookups instead of case insensitive ones.
        - Lock all page cache pages belonging to mst protected attributes while
          accessing them to ensure we never see corrupt data while the page is
          under writeout.
        - Add framework for generic ntfs collation (fs/ntfs/collation.[hc]).
          We have ntfs_is_collation_rule_supported() to check if the collation
          rule you want to use is supported and ntfs_collation() which actually
          collates two data items.  We currently only support COLLATION_BINARY
          and COLLATION_NTOFS_ULONG but support for other collation rules will
          be added as the need arises.
        - Add a new type, ntfs_index_context, to allow retrieval of an index
          entry using the corresponding index key.  To get an index context,
          use ntfs_index_ctx_get() and to release it, use ntfs_index_ctx_put().
          This also adds a new slab cache for the index contexts.  To lookup a
          key in an index inode, use ntfs_index_lookup().  After modifying an
          index entry, call ntfs_index_entry_flush_dcache_page() followed by
          ntfs_index_entry_mark_dirty() to ensure the changes are written out
          to disk.  For details see fs/ntfs/index.[hc].  Note, at present, if
          an index entry is in the index allocation attribute rather than the
          index root attribute it will not be written out (you will get a
          warning message about discarded changes instead).
        - Load the quota file ($Quota) and check if quota tracking is enabled
          and if so, mark the quotas out of date.  This causes windows to
          rescan the volume on boot and update all quota entries.
        - Add a set_page_dirty address space operation for ntfs_m[fs]t_aops.
          It is simply set to __set_page_dirty_nobuffers() to make sure that
          running set_page_dirty() on a page containing mft/ntfs records will
          not affect the dirty state of the page buffers.
        - Add fs/ntfs/index.c::__ntfs_index_entry_mark_dirty() which sets all
          buffers that are inside the ntfs record in the page dirty after which
          it sets the page dirty.  This allows ->writepage to only write the
          dirty index records rather than having to write all the records in
          the page.  Modify fs/ntfs/index.h::ntfs_index_entry_mark_dirty() to
          use this rather than __set_page_dirty_nobuffers().
        - Implement fs/ntfs/aops.c::ntfs_write_mst_block() which enables the
          writing of page cache pages belonging to mst protected attributes
          like the index allocation attribute in directory indices and other
          indices like $Quota/$Q, etc.  This means that the quota is now marked
          out of date on all volumes rather than only on ones where the quota
          defaults entry is in the index root attribute of the $Quota/$Q index.

2.1.14 - Fix an NFSd caused deadlock reported by several users.

        - Modify fs/ntfs/ntfs_readdir() to copy the index root attribute value
          to a buffer so that we can put the search context and unmap the mft
          record before calling the filldir() callback.  We need to do this
          because of NFSd which calls ->lookup() from its filldir callback()
          and this causes NTFS to deadlock as ntfs_lookup() maps the mft record
          of the directory and since ntfs_readdir() has got it mapped already
          ntfs_lookup() deadlocks.

2.1.13 - Enable overwriting of resident files and housekeeping of system files.

        - Implement writing of mft records (fs/ntfs/mft.[hc]), which includes
          keeping the mft mirror in sync with the mft when mirrored mft records
          are written.  The functions are write_mft_record{,_nolock}().  The
          implementation is quite rudimentary for now with lots of things not
          implemented yet but I am not sure any of them can actually occur so
          I will wait for people to hit each one and only then implement it.
        - Commit open system inodes at umount time.  This should make it
          virtually impossible for sync_mft_mirror_umount() to ever be needed.
        - Implement ->write_inode (fs/ntfs/inode.c::ntfs_write_inode()) for the
          ntfs super operations.  This gives us inode writing via the VFS inode
          dirty code paths.  Note:  Access time updates are not implemented yet.
        - Implement fs/ntfs/mft.[hc]::{,__}mark_mft_record_dirty() and make
          fs/ntfs/aops.c::ntfs_writepage() and ntfs_commit_write() use it, thus
          finally enabling resident file overwrite!  (-8  This also includes a
          placeholder for ->writepage (ntfs_mft_writepage()), which for now
          just redirties the page and returns.  Also, at umount time, we for
          now throw away all mft data page cache pages after the last call to
          ntfs_commit_inode() in the hope that all inodes will have been
          written out by then and hence no dirty (meta)data will be lost.  We
          also check for this case and emit an error message telling the user
          to run chkdsk.
        - Use set_page_writeback() and end_page_writeback() in the resident
          attribute code path of fs/ntfs/aops.c::ntfs_writepage() otherwise
          the radix-tree tag PAGECACHE_TAG_DIRTY remains set even though the
          page is clean.
        - Implement ntfs_mft_writepage() so it now checks if any of the mft
          records in the page are dirty and if so redirties the page and
          returns.  Otherwise it just returns (after doing set_page_writeback(),
          unlock_page(), end_page_writeback() or the radix-tree tag
          PAGECACHE_TAG_DIRTY remains set even though the page is clean), thus
          alowing the VM to do with the page as it pleases.  Also, at umount
          time, now only throw away dirty mft (meta)data pages if dirty inodes
          are present and ask the user to email us if they see this happening.
        - Add functions ntfs_{clear,set}_volume_flags(), to modify the volume
          information flags (fs/ntfs/super.c).
        - Mark the volume dirty when (re)mounting read-write and mark it clean
          when unmounting or remounting read-only.  If any volume errors are
          found, the volume is left marked dirty to force chkdsk to run.
        - Add code to set the NT4 compatibility flag when (re)mounting
          read-write for newer NTFS versions but leave it commented out for now
          since we do not make any modifications that are NTFS 1.2 specific yet
          and since setting this flag breaks Captive-NTFS which is not nice.
          This code must be enabled once we start writing NTFS 1.2 specific
          changes otherwise Windows NTFS driver might crash / cause corruption.

2.1.12 - Fix the second fix to the decompression engine and some cleanups.

        - Add a new address space operations struct, ntfs_mst_aops, for mst
          protected attributes.  This is because the default ntfs_aops do not
          make sense with mst protected data and were they to write anything to
          such an attribute they would cause data corruption so we provide
          ntfs_mst_aops which does not have any write related operations set.
        - Cleanup dirty ntfs inode handling (fs/ntfs/inode.[hc]) which also
          includes an adapted ntfs_commit_inode() and an implementation of
          ntfs_write_inode() which for now just cleans dirty inodes without
          writing them (it does emit a warning that this is happening).
        - Undo the second decompression engine fix (see 2.1.9 release ChangeLog
          entry) as it was only fixing a theoretical bug but at the same time
          it badly broke the handling of sparse and uncompressed compression
          blocks.

2.1.11 - Driver internal cleanups.

        - Only build logfile.o if building the driver with read-write support.
        - Really final white space cleanups.
        - Use generic_ffs() instead of ffs() in logfile.c which allows the
          log_page_size variable to be optimized by gcc into a constant.
        - Rename uchar_t to ntfschar everywhere as uchar_t is unsigned 1-byte
          char as defined by POSIX and as found on some systems.

2.1.10 - Force read-only (re)mounting of volumes with unsupported volume flags.

        - Finish off the white space cleanups (remove trailing spaces, etc).
        - Clean up ntfs_fill_super() and ntfs_read_inode_mount() by removing
          the kludges around the first iget().  Instead of (re)setting ->s_op
          we have the $MFT inode set up by explicit new_inode() / set ->i_ino /
          insert_inode_hash() / call ntfs_read_inode_mount() directly.  This
          kills the need for second super_operations and allows to return error
          from ntfs_read_inode_mount() without resorting to ugly "poisoning"
          tricks.  (Al Viro)
        - Force read-only (re)mounting if any of the following bits are set in
          the volume information flags:
                VOLUME_IS_DIRTY, VOLUME_RESIZE_LOG_FILE,
                VOLUME_UPGRADE_ON_MOUNT, VOLUME_DELETE_USN_UNDERWAY,
                VOLUME_REPAIR_OBJECT_ID, VOLUME_MODIFIED_BY_CHKDSK
          To make this easier we define VOLUME_MUST_MOUNT_RO_MASK with all the
          above bits set so the test is made easy.

2.1.9 - Fix two bugs in decompression engine.

        - Fix a bug where we would not always detect that we have reached the
          end of a compression block because we were ending at minus one byte
          which is effectively the same as being at the end.  The fix is to
          check whether the uncompressed buffer has been fully filled and if so
          we assume we have reached the end of the compression block.  A big
          thank you to Marcin Gibuła for the bug report, the assistance in
          tracking down the bug and testing the fix.
        - Fix a possible bug where when a compressed read is truncated to the
          end of the file, the offset inside the last page was not truncated.

2.1.8 - Handle $MFT mirror and $LogFile, improve time handling, and cleanups.

        - Use get_bh() instead of manual atomic_inc() in fs/ntfs/compress.c.
        - Modify fs/ntfs/time.c::ntfs2utc(), get_current_ntfs_time(), and
          utc2ntfs() to work with struct timespec instead of time_t on the
          Linux UTC time side thus preserving the full precision of the NTFS
          time and only loosing up to 99 nano-seconds in the Linux UTC time.
        - Move fs/ntfs/time.c to fs/ntfs/time.h and make the time functions
          static inline.
        - Remove unused ntfs_dirty_inode().
        - Cleanup super operations declaration in fs/ntfs/super.c.
        - Wrap flush_dcache_mft_record_page() in #ifdef NTFS_RW.
        - Add NInoTestSetFoo() and NInoTestClearFoo() macro magic to
          fs/ntfs/inode.h and use it to declare NInoTest{Set,Clear}Dirty.
        - Move typedefs for ntfs_attr and test_t from fs/ntfs/inode.c to
          fs/ntfs/inode.h so they can be used elsewhere.
        - Determine the mft mirror size as the number of mirrored mft records
          and store it in ntfs_volume->mftmirr_size (fs/ntfs/super.c).
        - Load the mft mirror at mount time and compare the mft records stored
          in it to the ones in the mft.  Force a read-only mount if the two do
          not match (fs/ntfs/super.c).
        - Fix type casting related warnings on 64-bit architectures.  Thanks
          to Meelis Roos for reporting them.
        - Move %L to %ll as %L is floating point and %ll is integer which is
          what we want.
        - Read the journal ($LogFile) and determine if the volume has been
          shutdown cleanly and force a read-only mount if not (fs/ntfs/super.c
          and fs/ntfs/logfile.c).  This is a little bit of a crude check in
          that we only look at the restart areas and not at the actual log
          records so that there will be a very small number of cases where we
          think that a volume is dirty when in fact it is clean.  This should
          only affect volumes that have not been shutdown cleanly and did not
          have any pending, non-check-pointed i/o.
        - If the $LogFile indicates a clean shutdown and a read-write (re)mount
          is requested, empty $LogFile by overwriting it with 0xff bytes to
          ensure that Windows cannot cause data corruption by replaying a stale
          journal after Linux has written to the volume.

2.1.7 - Enable NFS exporting of mounted NTFS volumes.

        - Set i_generation in the VFS inode from the seq_no of the NTFS inode.
        - Make ntfs_lookup() NFS export safe, i.e. use d_splice_alias(), etc.
        - Implement ->get_dentry() in fs/ntfs/namei.c::ntfs_get_dentry() as the
          default doesn't allow inode number 0 which is a valid inode on NTFS
          and even if it did allow that it uses iget() instead of ntfs_iget()
          which makes it useless for us.
        - Implement ->get_parent() in fs/ntfs/namei.c::ntfs_get_parent() as the
          default just returns -EACCES which is not very useful.
        - Define export operations (->s_export_op) for NTFS (ntfs_export_ops)
          and set them up in the super block at mount time (super.c) this
          allows mounted NTFS volumes to be exported via NFS.
        - Add missing return -EOPNOTSUPP; in
          fs/ntfs/aops.c::ntfs_commit_nonresident_write().
        - Enforce no atime and no dir atime updates at mount/remount time as
          they are not implemented yet anyway.
        - Move a few assignments in fs/ntfs/attrib.c::load_attribute_list() to
          after a NULL check.  Thanks to Dave Jones for pointing this out.

2.1.6 - Fix minor bug in handling of compressed directories.

        - Fix bug in handling of compressed directories.  A compressed
          directory is not really compressed so when we set the ->i_blocks
          field of a compressed directory inode we were setting it from the
          non-existing field ni->itype.compressed.size which gave random
          results...  For directories we now always use ni->allocated_size.

2.1.5 - Fix minor bug in attribute list attribute handling.

        - Fix bug in attribute list handling.  Actually it is not as much a bug
          as too much protection in that we were not allowing attribute lists
          which waste space on disk while Windows XP clearly allows it and in
          fact creates such attribute lists so our driver was failing.
        - Update NTFS documentation ready for 2.6 kernel release.

2.1.4 - Reduce compiler requirements.

        - Remove all uses of unnamed structs and unions in the driver to make
          old and newer gcc versions happy. Makes it a bit uglier IMO but at
          least people will stop hassling me about it.

2.1.3 - Important bug fixes in corner cases.

        - super.c::parse_ntfs_boot_sector(): Correct the check for 64-bit
          clusters. (Philipp Thomas)
        - attrib.c::load_attribute_list(): Fix bug when initialized_size is a
          multiple of the block_size but not the cluster size. (Szabolcs
          Szakacsits <szaka@sienet.hu>)

2.1.2 - Important bug fixes aleviating the hangs in statfs.

        - Fix buggy free cluster and free inode determination logic.

2.1.1 - Minor updates.

        - Add handling for initialized_size != data_size in compressed files.
        - Reduce function local stack usage from 0x3d4 bytes to just noise in
          fs/ntfs/upcase.c. (Randy Dunlap <rddunlap@osdl.ord>)
        - Remove compiler warnings for newer gcc.
        - Pages are no longer kmapped by mm/filemap.c::generic_file_write()
          around calls to ->{prepare,commit}_write.  Adapt NTFS appropriately
          in fs/ntfs/aops.c::ntfs_prepare_nonresident_write() by using
          kmap_atomic(KM_USER0).

2.1.0 - First steps towards write support: implement file overwrite.

        - Add configuration option for developmental write support with an
          appropriately scary configuration help text.
        - Initial implementation of fs/ntfs/aops.c::ntfs_writepage() and its
          helper fs/ntfs/aops.c::ntfs_write_block(). This enables mmap(2) based
          overwriting of existing files on ntfs. Note: Resident files are
          only written into memory, and not written out to disk at present, so
          avoid writing to files smaller than about 1kiB.
        - Initial implementation of fs/ntfs/aops.c::ntfs_prepare_write(), its
          helper fs/ntfs/aops.c::ntfs_prepare_nonresident_write() and their
          counterparts, fs/ntfs/aops.c::ntfs_commit_write(), and
          fs/ntfs/aops.c::ntfs_commit_nonresident_write(), respectively. Also,
          add generic_file_write() to the ntfs file operations (fs/ntfs/file.c).
          This enables write(2) based overwriting of existing files on ntfs.
          Note: As with mmap(2) based overwriting, resident files are only
          written into memory, and not written out to disk at present, so avoid
          writing to files smaller than about 1kiB.
        - Implement ->truncate (fs/ntfs/inode.c::ntfs_truncate()) and
          ->setattr() (fs/ntfs/inode.c::ntfs_setattr()) inode operations for
          files with the purpose of intercepting and aborting all i_size
          changes which we do not support yet. ntfs_truncate() actually only
          emits a warning message but AFAICS our interception of i_size changes
          elsewhere means ntfs_truncate() never gets called for i_size changes.
          It is only called from generic_file_write() when we fail in
          ntfs_prepare_{,nonresident_}write() in order to discard any
          instantiated buffers beyond i_size. Thus i_size is not actually
          changed so our warning message is enough. Unfortunately it is not
          possible to easily determine if i_size is being changed or not hence
          we just emit an appropriately worded error message.

2.0.25 - Small bug fixes and cleanups.

        - Unlock the page in an out of memory error code path in
          fs/ntfs/aops.c::ntfs_read_block().
        - If fs/ntfs/aops.c::ntfs_read_page() is called on an uptodate page,
          just unlock the page and return. (This can happen due to ->writepage
          clearing PageUptodate() during write out of MstProtected()
          attributes.
        - Remove leaked write code again.

2.0.24 - Cleanups.

        - Treat BUG_ON() as ASSERT() not VERIFY(), i.e. do not use side effects
          inside BUG_ON(). (Adam J. Richter)
        - Split logical OR expressions inside BUG_ON() into individual BUG_ON()
          calls for improved debugging. (Adam J. Richter)
        - Add errors flag to the ntfs volume state, accessed via
          NVol{,Set,Clear}Errors(vol).
        - Do not allow read-write remounts of read-only volumes with errors.
        - Clarify comment for ntfs file operation sendfile which was added by
          Christoph Hellwig a while ago (just using generic_file_sendfile())
          to say that ntfs ->sendfile is only used for the case where the
          source data is on the ntfs partition and the destination is
          somewhere else, i.e. nothing we need to concern ourselves with.
        - Add generic_file_write() as our ntfs file write operation.

2.0.23 - Major bug fixes (races, deadlocks, non-i386 architectures).

        - Massive internal locking changes to mft record locking. Fixes lock
          recursion and replaces the mrec_lock read/write semaphore with a
          mutex. Also removes the now superfluous mft_count. This fixes several
          race conditions and deadlocks, especially in the future write code.
        - Fix ntfs over loopback for compressed files by adding an
          optimization barrier. (gcc was screwing up otherwise ?)
        - Miscellaneous cleanups all over the code and a fix or two in error
          handling code paths.
        Thanks go to Christoph Hellwig for pointing out the following two:
        - Remove now unused function fs/ntfs/malloc.h::vmalloc_nofs().
        - Fix ntfs_free() for ia64 and parisc by checking for VMALLOC_END, too.

2.0.22 - Cleanups, mainly to ntfs_readdir(), and use C99 initializers.

        - Change fs/ntfs/dir.c::ntfs_reddir() to only read/write ->f_pos once
          at entry/exit respectively.
        - Use C99 initializers for structures.
        - Remove unused variable blocks from fs/ntfs/aops.c::ntfs_read_block().

2.0.21 - Check for, and refuse to work with too large files/directories/volumes.

        - Limit volume size at mount time to 2TiB on architectures where
          unsigned long is 32-bits (fs/ntfs/super.c::parse_ntfs_boot_sector()).
          This is the most we can do without overflowing the 32-bit limit of
          the block device size imposed on us by sb_bread() and sb_getblk()
          for the time being.
        - Limit file/directory size at open() time to 16TiB on architectures
          where unsigned long is 32-bits (fs/ntfs/file.c::ntfs_file_open() and
          fs/ntfs/dir.c::ntfs_dir_open()). This is the most we can do without
          overflowing the page cache page index.

2.0.20 - Support non-resident directory index bitmaps, fix page leak in readdir.

        - Move the directory index bitmap to use an attribute inode instead of
          having special fields for it inside the ntfs inode structure. This
          means that the index bitmaps now use the page cache for i/o, too,
          and also as a side effect we get support for non-resident index
          bitmaps for free.
        - Simplify/cleanup error handling in fs/ntfs/dir.c::ntfs_readdir() and
          fix a page leak that manifested itself in some cases.
        - Add fs/ntfs/inode.c::ntfs_put_inode(), which we need to release the
          index bitmap inode on the final iput().

2.0.19 - Fix race condition, improvements, and optimizations in i/o interface.

        - Apply block optimization added to fs/ntfs/aops.c::ntfs_read_block()
          to fs/ntfs/compress.c::ntfs_file_read_compressed_block() as well.
        - Drop the "file" from ntfs_file_read_compressed_block().
        - Rename fs/ntfs/aops.c::ntfs_enb_buffer_read_async() to
          ntfs_end_buffer_async_read() (more like the fs/buffer.c counterpart).
        - Update ntfs_end_buffer_async_read() with the improved logic from
          its updated counterpart fs/buffer.c::end_buffer_async_read(). Apply
          further logic improvements to better determine when we set PageError.
        - Update submission of buffers in fs/ntfs/aops.c::ntfs_read_block() to
          check for the buffers being uptodate first in line with the updated
          fs/buffer.c::block_read_full_page(). This plugs a small race
          condition.

2.0.18 - Fix race condition in reading of compressed files.

        - There was a narrow window between checking a buffer head for being
          uptodate and locking it in ntfs_file_read_compressed_block(). We now
          lock the buffer and then check whether it is uptodate or not.

2.0.17 - Cleanups and optimizations - shrinking the ToDo list.

        - Modify fs/ntfs/inode.c::ntfs_read_locked_inode() to return an error
          code and update callers, i.e. ntfs_iget(), to pass that error code
          up instead of just using -EIO.
        - Modifications to super.c to ensure that both mount and remount
          cannot set any write related options when the driver is compiled
          read-only.
        - Optimize block resolution in fs/ntfs/aops.c::ntfs_read_block() to
          cache the current runlist element. This should improve performance
          when reading very large and/or very fragmented data.

2.0.16 - Convert access to $MFT/$BITMAP to attribute inode API.

        - Fix a stupid bug introduced in 2.0.15 where we were unmapping the
          wrong inode in fs/ntfs/inode.c::ntfs_attr_iget().
        - Fix debugging check in fs/ntfs/aops.c::ntfs_read_block().
        - Convert $MFT/$BITMAP access to attribute inode API and remove all
          remnants of the ugly mftbmp address space and operations hack. This
          means we finally have only one readpage function as well as only one
          async io completion handler. Yey! The mft bitmap is now just an
          attribute inode and is accessed from vol->mftbmp_ino just as if it
          were a normal file. Fake inodes rule. (-:

2.0.15 - Fake inodes based attribute i/o via the pagecache, fixes and cleanups.

        - Fix silly bug in fs/ntfs/super.c::parse_options() which was causing
          remounts to fail when the partition had an entry in /etc/fstab and
          the entry specified the nls= option.
        - Apply same macro magic used in fs/ntfs/inode.h to fs/ntfs/volume.h to
          expand all the helper functions NVolFoo(), NVolSetFoo(), and
          NVolClearFoo().
        - Move copyright statement from driver initialisation message to
          module description (fs/super.c). This makes the initialisation
          message fit on one line and fits in better with rest of kernel.
        - Update fs/ntfs/attrib.c::map_run_list() to work on both real and
          attribute inodes, and both for files and directories.
        - Implement fake attribute inodes allowing all attribute i/o to go via
          the page cache and to use all the normal vfs/mm functionality:
          - Add ntfs_attr_iget() and its helper ntfs_read_locked_attr_inode()
            to fs/ntfs/inode.c.
          - Add needed cleanup code to ntfs_clear_big_inode().
        - Merge address space operations for files and directories (aops.c),
          now just have ntfs_aops:
          - Rename:
                end_buffer_read_attr_async() -> ntfs_end_buffer_read_async(),
                ntfs_attr_read_block()       -> ntfs_read_block(),
                ntfs_file_read_page()        -> ntfs_readpage().
          - Rewrite fs/ntfs/aops.c::ntfs_readpage() to work on both real and
            attribute inodes, and both for files and directories.
          - Remove obsolete fs/ntfs/aops.c::ntfs_mst_readpage().

2.0.14 - Run list merging code cleanup, minor locking changes, typo fixes.

        - Change fs/ntfs/super.c::ntfs_statfs() to not rely on BKL by moving
          the locking out of super.c::get_nr_free_mft_records() and taking and
          dropping the mftbmp_lock rw_semaphore in ntfs_statfs() itself.
        - Bring attribute runlist merging code (fs/ntfs/attrib.c) in sync with
          current userspace ntfs library code. This means that if a merge
          fails the original runlists are always left unmodified instead of
          being silently corrupted.
        - Misc typo fixes.

2.0.13 - Use iget5_locked() in preparation for fake inodes and small cleanups.

        - Remove nr_mft_bits and the now superfluous union with nr_mft_records
          from ntfs_volume structure.
        - Remove nr_lcn_bits and the now superfluous union with nr_clusters
          from ntfs_volume structure.
        - Use iget5_locked() and friends instead of conventional iget(). Wrap
          the call in fs/ntfs/inode.c::ntfs_iget() and update callers of iget()
          to use ntfs_iget(). Leave only one iget() call at mount time so we
          don't need an ntfs_iget_mount().
        - Change fs/ntfs/inode.c::ntfs_new_extent_inode() to take mft_no as an
          additional argument.

2.0.12 - Initial cleanup of address space operations following 2.0.11 changes.

        - Merge fs/ntfs/aops.c::end_buffer_read_mst_async() and
          fs/ntfs/aops.c::end_buffer_read_file_async() into one function
          fs/ntfs/aops.c::end_buffer_read_attr_async() using NInoMstProtected()
          to determine whether to apply mst fixups or not.
        - Above change allows merging fs/ntfs/aops.c::ntfs_file_read_block()
          and fs/ntfs/aops.c::ntfs_mst_readpage() into one function
          fs/ntfs/aops.c::ntfs_attr_read_block(). Also, create a tiny wrapper
          fs/ntfs/aops.c::ntfs_mst_readpage() to transform the parameters from
          the VFS readpage function prototype to the ntfs_attr_read_block()
          function prototype.

2.0.11 - Initial preparations for fake inode based attribute i/o.

        - Move definition of ntfs_inode_state_bits to fs/ntfs/inode.h and
          do some macro magic (adapted from include/linux/buffer_head.h) to
          expand all the helper functions NInoFoo(), NInoSetFoo(), and
          NInoClearFoo().
        - Add new flag to ntfs_inode_state_bits: NI_Sparse.
        - Add new fields to ntfs_inode structure to allow use of fake inodes
          for attribute i/o: type, name, name_len. Also add new state bits:
          NI_Attr, which, if set, indicates the inode is a fake inode, and
          NI_MstProtected, which, if set, indicates the attribute uses multi
          sector transfer protection, i.e. fixups need to be applied after
          reads and before/after writes.
        - Rename fs/ntfs/inode.c::ntfs_{new,clear,destroy}_inode() to
          ntfs_{new,clear,destroy}_extent_inode() and update callers.
        - Use ntfs_clear_extent_inode() in fs/ntfs/inode.c::__ntfs_clear_inode()
          instead of ntfs_destroy_extent_inode().
        - Cleanup memory deallocations in {__,}ntfs_clear_{,big_}inode().
        - Make all operations on ntfs inode state bits use the NIno* functions.
        - Set up the new ntfs inode fields and state bits in
          fs/ntfs/inode.c::ntfs_read_inode() and add appropriate cleanup of
          allocated memory to __ntfs_clear_inode().
        - Cleanup ntfs_inode structure a bit for better ordering of elements
          w.r.t. their size to allow better packing of the structure in memory.

2.0.10 - There can only be 2^32 - 1 inodes on an NTFS volume.

        - Add check at mount time to verify that the number of inodes on the
          volume does not exceed 2^32 - 1, which is the maximum allowed for
          NTFS according to Microsoft.
        - Change mft_no member of ntfs_inode structure to be unsigned long.
          Update all users. This makes ntfs_inode->mft_no just a copy of struct
          inode->i_ino. But we can't just always use struct inode->i_ino and
          remove mft_no because extent inodes do not have an attached struct
          inode.

2.0.9 - Decompression engine now uses a single buffer and other cleanups.

        - Change decompression engine to use a single buffer protected by a
          spin lock instead of per-CPU buffers. (Rusty Russell)
        - Do not update cb_pos when handling a partial final page during
          decompression of a sparse compression block, as the value is later
          reset without being read/used. (Rusty Russell)
        - Switch to using the new KM_BIO_SRC_IRQ for atomic kmap()s. (Andrew
          Morton)
        - Change buffer size in ntfs_readdir()/ntfs_filldir() to use
          NLS_MAX_CHARSET_SIZE which makes the buffers almost 1kiB each but
          it also makes everything safer so it is a good thing.
        - Miscellaneous minor cleanups to comments.

2.0.8 - Major updates for handling of case sensitivity and dcache aliasing.

        Big thanks go to Al Viro and other inhabitants of #kernel for investing
        their time to discuss the case sensitivity and dcache aliasing issues.

        - Remove unused source file fs/ntfs/attraops.c.
        - Remove show_inodes mount option(s), thus dropping support for
          displaying of short file names.
        - Remove deprecated mount option posix.
        - Restore show_sys_files mount option.
        - Add new mount option case_sensitive, to determine if the driver
          treats file names as case sensitive or not. If case sensitive, create
          file names in the POSIX namespace. Otherwise create file names in the
          LONG/WIN32 namespace. Note, files remain accessible via their short
          file name, if it exists.
        - Remove really dumb logic bug in boot sector recovery code.
        - Fix dcache aliasing issues wrt short/long file names via changes
          to fs/ntfs/dir.c::ntfs_lookup_inode_by_name() and
          fs/ntfs/namei.c::ntfs_lookup():
          - Add additional argument to ntfs_lookup_inode_by_name() in which we
            return information about the matching file name if the case is not
            matching or the match is a short file name. See comments above the
            function definition for details.
          - Change ntfs_lookup() to only create dcache entries for the correctly
            cased file name and only for the WIN32 namespace counterpart of DOS
            namespace file names. This ensures we have only one dentry per
            directory and also removes all dcache aliasing issues between short
            and long file names once we add write support. See comments above
            function for details.
        - Fix potential 1 byte overflow in fs/ntfs/unistr.c::ntfs_ucstonls().

2.0.7 - Minor cleanups and updates for changes in core kernel code.

        - Remove much of the NULL struct element initializers.
        - Various updates to make compatible with recent kernels.
        - Remove defines of MAX_BUF_PER_PAGE and include linux/buffer_head.h
          in fs/ntfs/ntfs.h instead.
        - Remove no longer needed KERNEL_VERSION checks. We are now in the
          kernel proper so they are no longer needed.

2.0.6 - Major bugfix to make compatible with other kernel changes.

        - Initialize the mftbmp address space properly now that there are more
          fields in the struct address_space. This was leading to hangs and
          oopses on umount since 2.5.12 because of changes to other parts of
          the kernel. We probably want a kernel generic init_address_space()
          function...
        - Drop BKL from ntfs_readdir() after consultation with Al Viro. The
          only caller of ->readdir() is vfs_readdir() which holds i_sem during
          the call, and i_sem is sufficient protection against changes in the
          directory inode (including ->i_size).
        - Use generic_file_llseek() for directories (as opposed to
          default_llseek()) as this downs i_sem instead of the BKL which is
          what we now need for exclusion against ->f_pos changes considering we
          no longer take the BKL in ntfs_readdir().

2.0.5 - Major bugfix. Buffer overflow in extent inode handling.

        - No need to set old blocksize in super.c::ntfs_fill_super() as the
          VFS does so via invocation of deactivate_super() calling
          fs->fill_super() calling block_kill_super() which does it.
        - BKL moved from VFS into dir.c::ntfs_readdir(). (Linus Torvalds)
          -> Do we really need it? I don't think so as we have exclusion on
          the directory ntfs_inode rw_semaphore mrec_lock. We mmight have to
          move the ->f_pos accesses under the mrec_lock though. Check this...
        - Fix really, really, really stupid buffer overflow in extent inode
          handling in mft.c::map_extent_mft_record().

2.0.4 - Cleanups and updates for kernel 2.5.11.

        - Add documentation on how to use the MD driver to be able to use NTFS
          stripe and volume sets in Linux and generally cleanup documentation
          a bit.
        Remove all uses of kdev_t in favour of struct block_device *:
        - Change compress.c::ntfs_file_read_compressed_block() to use
          sb_getblk() instead of getblk().
        - Change super.c::ntfs_fill_super() to use bdev_hardsect_size() instead
          of get_hardsect_size().
        - No need to get old blocksize in super.c::ntfs_fill_super() as
          fs/super.c::get_sb_bdev() already does this.
        - Set bh->b_bdev instead of bh->b_dev throughout aops.c.

2.0.3 - Small bug fixes, cleanups, and performance improvements.

        - Remove some dead code from mft.c.
        - Optimize readpage and read_block functions throughout aops.c so that
          only initialized blocks are read. Non-initialized ones have their
          buffer head mapped, zeroed, and set up to date, without scheduling
          any i/o. Thanks to Al Viro for advice on how to avoid the device i/o.
        Thanks go to Andrew Morton for spotting the below:
        - Fix buglet in allocate_compression_buffers() error code path.
        - Call flush_dcache_page() after modifying page cache page contents in
          ntfs_file_readpage().
        - Check for existence of page buffers throughout aops.c before calling
          create_empty_buffers(). This happens when an I/O error occurs and the
          read is retried. (It also happens once writing is implemented so that
          needed doing anyway but I had left it for later...)
        - Don't BUG_ON() uptodate and/or mapped buffers throughout aops.c in
          readpage and read_block functions. Reasoning same as above (i.e. I/O
          error retries and future write code paths.)

2.0.2 - Minor updates and cleanups.

        - Cleanup: rename mst.c::__post_read_mst_fixup to post_write_mst_fixup
          and cleanup the code a bit, removing the unused size parameter.
        - Change default fmask to 0177 and update documentation.
        - Change attrib.c::get_attr_search_ctx() to return the search context
          directly instead of taking the address of a pointer. A return value
          of NULL means the allocation failed. Updated all callers
          appropriately.
        - Update to 2.5.9 kernel (preserving backwards compatibility) by
          replacing all occurences of page->buffers with page_buffers(page).
        - Fix minor bugs in runlist merging, also minor cleanup.
        - Updates to bootsector layout and mft mirror contents descriptions.
        - Small bug fix in error detection in unistr.c and some cleanups.
        - Grow name buffer allocations in unistr.c in aligned mutlipled of 64
          bytes.

2.0.1 - Minor updates.

        - Make default umask correspond to documentation.
        - Improve documentation.
        - Set default mode to include execute bit. The {u,f,d}mask can be used
          to take it away if desired. This allows binaries to be executed from
          a mounted ntfs partition.

2.0.0 - New version number. Remove TNG from the name. Now in the kernel.

        - Add kill_super, just keeping up with the vfs changes in the kernel.
        - Repeat some changes from tng-0.0.8 that somehow got lost on the way
          from the CVS import into BitKeeper.
        - Begin to implement proper handling of allocated_size vs
          initialized_size vs data_size (i.e. i_size). Done are
          mft.c::ntfs_mft_readpage(), aops.c::end_buffer_read_index_async(),
          and attrib.c::load_attribute_list().
        - Lock the runlist in attrib.c::load_attribute_list() while using it.
        - Fix memory leak in ntfs_file_read_compressed_block() and generally
          clean up compress.c a little, removing some uncommented/unused debug
          code.
        - Tidy up dir.c a little bit.
        - Don't bother getting the runlist in inode.c::ntfs_read_inode().
        - Merge mft.c::ntfs_mft_readpage() and aops.c::ntfs_index_readpage()
          creating aops.c::ntfs_mst_readpage(), improving the handling of
          holes and overflow in the process and implementing the correct
          equivalent of ntfs_file_get_block() in ntfs_mst_readpage() itself.
          I am aiming for correctness at the moment. Modularisation can come
          later.
        - Rename aops.c::end_buffer_read_index_async() to
          end_buffer_read_mst_async() and optimize the overflow checking and
          handling.
        - Use the host of the mftbmp address space mapping to hold the ntfs
          volume. This is needed so the async i/o completion handler can
          retrieve a pointer to the volume. Hopefully this will not cause
          problems elsewhere in the kernel... Otherwise will need to use a
          fake inode.
        - Complete implementation of proper handling of allocated_size vs
          initialized_size vs data_size (i.e. i_size) in whole driver.
          Basically aops.c is now completely rewritten.
        - Change NTFS driver name to just NTFS and set version number to 2.0.0
          to make a clear distinction from the old driver which is still on
          version 1.1.22.

tng-0.0.8 - 08/03/2002 - Now using BitKeeper, http://linux-ntfs.bkbits.net/

        - Replace bdevname(sb->s_dev) with sb->s_id.
        - Remove now superfluous new-line characters in all callers of
          ntfs_debug().
        - Apply kludge in ntfs_read_inode(), setting i_nlink to 1 for
          directories. Without this the "find" utility gets very upset which is
          fair enough as Linux/Unix do not support directory hard links.
        - Further runlist merging work. (Richard Russon)
        - Backwards compatibility for gcc-2.95. (Richard Russon)
        - Update to kernel 2.5.5-pre1 and rediff the now tiny patch.
        - Convert to new file system declaration using ->ntfs_get_sb() and
          replacing ntfs_read_super() with ntfs_fill_super().
        - Set s_maxbytes to MAX_LFS_FILESIZE to avoid page cache page index
          overflow on 32-bit architectures.
        - Cleanup upcase loading code to use ntfs_(un)map_page().
        - Disable/reenable preemtion in critical sections of compession engine.
        - Replace device size determination in ntfs_fill_super() with
          sb->s_bdev->bd_inode->i_size (in bytes) and remove now superfluous
          function super.c::get_nr_blocks().
        - Implement a mount time option (show_inodes) allowing choice of which
          types of inode names readdir() returns and modify ntfs_filldir()
          accordingly. There are several parameters to show_inodes:
                system: system files
                win32:  long file names (including POSIX file names) [DEFAULT]
                long:   same as win32
                dos:    short file names only (excluding POSIX file names)
                short:  same as dos
                posix:  same as both win32 and dos
                all:    all file names
          Note that the options are additive, i.e. specifying:
                -o show_inodes=system,show_inodes=win32,show_inodes=dos
          is the same as specifying:
                -o show_inodes=all
          Note that the "posix" and "all" options will show all directory
          names, BUT the link count on each directory inode entry is set to 1,
          due to Linux not supporting directory hard links. This may well
          confuse some userspace applications, since the directory names will
          have the same inode numbers. Thus it is NOT advisable to use the
          "posix" or "all" options. We provide them only for completeness sake.
        - Add copies of allocated_size, initialized_size, and compressed_size to
          the ntfs inode structure and set them up in
          inode.c::ntfs_read_inode(). These reflect the unnamed data attribute
          for files and the index allocation attribute for directories.
        - Add copies of allocated_size and initialized_size to ntfs inode for
          $BITMAP attribute of large directories and set them up in
          inode.c::ntfs_read_inode().
        - Add copies of allocated_size and initialized_size to ntfs volume for
          $BITMAP attribute of $MFT and set them up in
          super.c::load_system_files().
        - Parse deprecated ntfs driver options (iocharset, show_sys_files,
          posix, and utf8) and tell user what the new options to use are. Note
          we still do support them but they will be removed with kernel 2.7.x.
        - Change all occurences of integer long long printf formatting to hex
          as printk() will not support long long integer format if/when the
          div64 patch goes into the kernel.
        - Make slab caches have stable names and change the names to what they
          were intended to be. These changes are required/made possible by the
          new slab cache name handling which removes the length limitation by
          requiring the caller of kmem_cache_create() to supply a stable name
          which is then referenced but not copied.
        - Rename run_list structure to run_list_element and create a new
          run_list structure containing a pointer to a run_list_element
          structure and a read/write semaphore. Adapt all users of runlists
          to new scheme and take and release the lock as needed. This fixes a
          nasty race as the run_list changes even when inodes are locked for
          reading and even when the inode isn't locked at all, so we really
          needed the serialization. We use a semaphore rather than a spinlock
          as memory allocations can sleep and doing everything GFP_ATOMIC
          would be silly.
        - Cleanup read_inode() removing all code checking for lowest_vcn != 0.
          This can never happen due to the nature of lookup_attr() and how we
          support attribute lists. If it did happen it would imply the inode
          being corrupt.
        - Check for lowest_vcn != 0 in ntfs_read_inode() and mark the inode as
          bad if found.
        - Update to 2.5.6-pre2 changes in struct address_space.
        - Use parent_ino() when accessing d_parent inode number in dir.c.
        - Import Sourceforge CVS repository into BitKeeper repository:
                http://linux-ntfs.bkbits.net/ntfs-tng-2.5
        - Update fs/Makefile, fs/Config.help, fs/Config.in, and
          Documentation/filesystems/ntfs.txt for NTFS TNG.
        - Create kernel configuration option controlling whether debugging
          is enabled or not.
        - Add the required export of end_buffer_io_sync() from the patches
          directory to the kernel code.
        - Update inode.c::ntfs_show_options() with show_inodes mount option.
        - Update errors mount option.

tng-0.0.7 - 13/02/2002 - The driver is now feature complete for read-only!

        - Cleanup mft.c and it's debug/error output in particular. Fix a minor
          bug in mapping of extent inodes. Update all the comments to fit all
          the recent code changes.
        - Modify vcn_to_lcn() to cope with entirely unmapped runlists.
        - Cleanups in compress.c, mostly comments and folding help.
        - Implement attrib.c::map_run_list() as a generic helper.
        - Make compress.c::ntfs_file_read_compressed_block() use map_run_list()
          thus making code shorter and enabling attribute list support.
        - Cleanup incorrect use of [su]64 with %L printf format specifier in
          all source files. Type casts to [unsigned] long long added to correct
          the mismatches (important for architectures which have long long not
          being 64 bits).
        - Merge async io completion handlers for directory indexes and $MFT
          data into one by setting the index_block_size{_bits} of the ntfs
          inode for $MFT to the mft_record_size{_bits} of the ntfs_volume.
        - Cleanup aops.c, update comments.
        - Make ntfs_file_get_block() use map_run_list() so all files now
          support attribute lists.
        - Make ntfs_dir_readpage() almost verbatim copy of
          block_read_full_page() by using ntfs_file_get_block() with only real
          difference being the use of our own async io completion handler
          rather than the default one, thus reducing the amount of code and
          automatically enabling attribute list support for directory indices.
        - Fix bug in load_attribute_list() - forgot to call brelse in error
          code path.
        - Change parameters to find_attr() and lookup_attr(). We no longer
          pass in the upcase table and its length. These can be gotten from
          ctx->ntfs_ino->vol->upcase{_len}. Update all callers.
        - Cleanups in attrib.c.
        - Implement merging of runlists, attrib.c::merge_run_lists() and its
          helpers. (Richard Russon)
        - Attribute lists part 2, attribute extents and multi part runlists:
          enable proper support for LCN_RL_NOT_MAPPED and automatic mapping of
          further runlist parts via attrib.c::map_run_list().
        - Tiny endianness bug fix in decompress_mapping_pairs().

tng-0.0.6 - Encrypted directories, bug fixes, cleanups, debugging enhancements.

        - Enable encrypted directories. (Their index root is marked encrypted
          to indicate that new files in that directory should be created
          encrypted.)
        - Fix bug in NInoBmpNonResident() macro. (Cut and paste error.)
        - Enable $Extend system directory. Most (if not all) extended system
          files do not have unnamed data attributes so ntfs_read_inode() had to
          special case them but that is ok, as the special casing recovery
          happens inside an error code path so there is zero slow down in the
          normal fast path. The special casing is done by introducing a new
          function inode.c::ntfs_is_extended_system_file() which checks if any
          of the hard links in the inode point to $Extend as being their parent
          directory and if they do we assume this is an extended system file.
        - Create a sysctl/proc interface to allow {dis,en}abling of debug output
          when compiled with -DDEBUG. Default is debug messages to be disabled.
          To enable them, one writes a non-zero value to /proc/sys/fs/ntfs-debug
          (if /proc is enabled) or uses sysctl(2) to effect the same (if sysctl
          interface is enabled). Inspired by old ntfs driver.
        - Add debug_msgs insmod/kernel boot parameter to set whether debug
          messages are {dis,en}abled. This is useful to enable debug messages
          during ntfs initialization and is the only way to activate debugging
          when the sysctl interface is not enabled.
        - Cleanup debug output in various places.
        - Remove all dollar signs ($) from the source (except comments) to
          enable compilation on architectures whose gcc compiler does not
          support dollar signs in the names of variables/constants. Attribute
          types now start with AT_ instead of $ and $I30 is now just I30.
        - Cleanup ntfs_lookup() and add consistency check of sequence numbers.
        - Load complete runlist for $MFT/$BITMAP during mount and cleanup
          access functions. This means we now cope with $MFT/$BITMAP being
          spread accross several mft records.
        - Disable modification of mft_zone_multiplier on remount. We can always
          reenable this later on if we really want to, but we will need to make
          sure we readjust the mft_zone size / layout accordingly.

tng-0.0.5 - Modernize for 2.5.x and further in line-ing with Al Viro's comments.

        - Use sb_set_blocksize() instead of set_blocksize() and verify the
          return value.
        - Use sb_bread() instead of bread() throughout.
        - Add index_vcn_size{_bits} to ntfs_inode structure to store the size
          of a directory index block vcn. Apply resulting simplifications in
          dir.c everywhere.
        - Fix a small bug somewhere (but forgot what it was).
        - Change ntfs_{debug,error,warning} to enable gcc to do type checking
          on the printf-format parameter list and fix bugs reported by gcc
          as a result. (Richard Russon)
        - Move inode allocation strategy to Al's new stuff but maintain the
          divorce of ntfs_inode from struct inode. To achieve this we have two
          separate slab caches, one for big ntfs inodes containing a struct
          inode and pure ntfs inodes and at the same time fix some faulty
          error code paths in ntfs_read_inode().
        - Show mount options in proc (inode.c::ntfs_show_options()).

tng-0.0.4 - Big changes, getting in line with Al Viro's comments.

        - Modified (un)map_mft_record functions to be common for read and write
          case. To specify which is which, added extra parameter at front of
          parameter list. Pass either READ or WRITE to this, each has the
          obvious meaning.
        - General cleanups to allow for easier folding in vi.
        - attrib.c::decompress_mapping_pairs() now accepts the old runlist
          argument, and invokes attrib.c::merge_run_lists() to merge the old
          and the new runlists.
        - Removed attrib.c::find_first_attr().
        - Implemented loading of attribute list and complete runlist for $MFT.
          This means we now cope with $MFT being spread across several mft
          records.
        - Adapt to 2.5.2-pre9 and the changed create_empty_buffers() syntax.
        - Adapt major/minor/kdev_t/[bk]devname stuff to new 2.5.x kernels.
        - Make ntfs_volume be allocated via kmalloc() instead of using a slab
          cache. There are too little ntfs_volume structures at any one time
          to justify a private slab cache.
        - Fix bogus kmap() use in async io completion. Now use kmap_atomic().
          Use KM_BIO_IRQ on advice from IRC/kernel...
        - Use ntfs_map_page() in map_mft_record() and create ->readpage method
          for reading $MFT (ntfs_mft_readpage). In the process create dedicated
          address space operations (ntfs_mft_aops) for $MFT inode mapping. Also
          removed the now superfluous exports from the kernel core patch.
        - Fix a bug where kfree() was used insted of ntfs_free().
        - Change map_mft_record() to take ntfs_inode as argument instead of
          vfs inode. Dito for unmap_mft_record(). Adapt all callers.
        - Add pointer to ntfs_volume to ntfs_inode.
        - Add mft record number and sequence number to ntfs_inode. Stop using
          i_ino and i_generation for in-driver purposes.
        - Implement attrib.c::merge_run_lists(). (Richard Russon)
        - Remove use of proper inodes by extent inodes. Move i_ino and
          i_generation to ntfs_inode to do this. Apply simplifications that
          result and remove iget_no_wait(), etc.
        - Pass ntfs_inode everywhere in the driver (used to be struct inode).
        - Add reference counting in ntfs_inode for the ntfs inode itself and
          for the mapped mft record.
        - Extend mft record mapping so we can (un)map extent mft records (new
          functions (un)map_extent_mft_record), and so mappings are reference
          counted and don't have to happen twice if already mapped - just ref
          count increases.
        - Add -o iocharset as alias to -o nls for backwards compatibility.
        - The latest core patch is now tiny. In fact just a single additional
          export is necessary over the base kernel.

tng-0.0.3 - Cleanups, enhancements, bug fixes.

        - Work on attrib.c::decompress_mapping_pairs() to detect base extents
          and setup the runlist appropriately using knowledge provided by the
          sizes in the base attribute record.
        - Balance the get_/put_attr_search_ctx() calls so we don't leak memory
          any more.
        - Introduce ntfs_malloc_nofs() and ntfs_free() to allocate/free a single
          page or use vmalloc depending on the amount of memory requested.
        - Cleanup error output. The __FUNCTION__ "(): " is now added
          automatically. Introduced a new header file debug.h to support this
          and also moved ntfs_debug() function into it.
        - Make reading of compressed files more intelligent and especially get
          rid of the vmalloc_nofs() from readpage(). This now uses per CPU
          buffers (allocated at first mount with cluster size <= 4kiB and
          deallocated on last umount with cluster size <= 4kiB), and
          asynchronous io for the compressed data using a list of buffer heads.
          Er, we use synchronous io as async io only works on whole pages
          covered by buffers and not on individual buffer heads...
        - Bug fix for reading compressed files with sparse compression blocks.

tng-0.0.2 - Now handles larger/fragmented/compressed volumes/files/dirs.

        - Fixed handling of directories when cluster size exceeds index block
          size.
        - Hide DOS only name space directory entries from readdir() but allow
          them in lookup(). This should fix the problem that Linux doesn't
          support directory hard links, while still allowing access to entries
          via their short file name. This also has the benefit of mimicking
          what Windows users are used to, so it is the ideal solution.
        - Implemented sync_page everywhere so no more hangs in D state when
          waiting for a page.
        - Stop using bforget() in favour of brelse().
        - Stop locking buffers unnecessarily.
        - Implemented compressed files (inode->mapping contains uncompressed
          data, raw compressed data is currently bread() into a vmalloc()ed
          memory buffer).
        - Enable compressed directories. (Their index root is marked compressed
          to indicate that new files in that directory should be created
          compressed.)
        - Use vsnprintf rather than vsprintf in the ntfs_error and ntfs_warning
          functions. (Thanks to Will Dyson for pointing this out.)
        - Moved the ntfs_inode and ntfs_volume (the former ntfs_inode_info and
          ntfs_sb_info) out of the common inode and super_block structures and
          started using the generic_ip and generic_sbp pointers instead. This
          makes ntfs entirely private with respect to the kernel tree.
        - Detect compiler version and abort with error message if gcc less than
          2.96 is used.
        - Fix bug in name comparison function in unistr.c.
        - Implement attribute lists part 1, the infrastructure: search contexts
          and operations, find_external_attr(), lookup_attr()) and make the
          code use the infrastructure.
        - Fix stupid buffer overflow bug that became apparent on larger run
          list containing attributes.
        - Fix bugs in readdir() that became apparent on larger directories.

        The driver is now really useful and survives the test
                find . -type f -exec md5sum "{}" \;
        without any error messages on a over 1GiB sized partition with >16k
        files on it, including compressed files and directories and many files
        and directories with attribute lists.

tng-0.0.1 - The first useful version.

        - Added ntfs_lookup().
        - Added default upcase generation and handling.
        - Added compile options to be shown on module init.
        - Many bug fixes that were "hidden" before.
        - Update to latest kernel.
        - Added ntfs_readdir().
        - Added file operations for mmap(), read(), open() and llseek(). We just
          use the generic ones. The whole point of going through implementing
          readpage() methods and where possible get_block() call backs is that
          this allows us to make use of the generic high level methods provided
          by the kernel.

        The driver is now actually useful! Yey. (-: It undoubtedly has got bugs
        though and it doesn't implement accesssing compressed files yet. Also,
        accessing files with attribute list attributes is not implemented yet
        either. But for small or simple file systems it should work and allow
        you to list directories, use stat on directory entries and the file
        system, open, read, mmap and llseek around in files. A big mile stone
        has been reached!

tng-0.0.0 - Initial version tag.

        Initial driver implementation. The driver can mount and umount simple
        NTFS file systems (i.e. ones without attribute lists in the system
        files). If the mount fails there might be problems in the error handling
        code paths, so be warned. Otherwise it seems to be loading the system
        files nicely and the mft record read mapping/unmapping seems to be
        working nicely, too. Proof of inode metadata in the page cache and non-
        resident file unnamed stream data in the page cache concepts is thus
        complete.