- biosize=size
- Sets the preferred buffered I/O size (default size is 64K).
- "size" must be expressed as the logarithm (base2) of the
- desired I/O size.
- Valid values for this option are 14 through 16, inclusive
- (i.e. 16K, 32K, and 64K bytes). On machines with a 4K
- pagesize, 13 (8K bytes) is also a valid size.
- The preferred buffered I/O size can also be altered on an
- individual file basis using the ioctl(2) system call.
+ allocsize=size
+ Sets the buffered I/O end-of-file preallocation size when
+ doing delayed allocation writeout (default size is 64KiB).
+ Valid values for this option are page size (typically 4KiB)
+ through to 1GiB, inclusive, in power-of-2 increments.
+
+ attr2/noattr2
+ The options enable/disable (default is disabled for backward
+ compatibility on-disk) an "opportunistic" improvement to be
+ made in the way inline extended attributes are stored on-disk.
+ When the new form is used for the first time (by setting or
+ removing extended attributes) the on-disk superblock feature
+ bit field will be updated to reflect this format being in use.
+
+ barrier
+ Enables the use of block layer write barriers for writes into
+ the journal and unwritten extent conversion. This allows for
+ drive level write caching to be enabled, for devices that
+ support write barriers.
+
+ dmapi
+ Enable the DMAPI (Data Management API) event callouts.
+ Use with the "mtpt" option.
+
+ grpid/bsdgroups and nogrpid/sysvgroups
+ These options define what group ID a newly created file gets.
+ When grpid is set, it takes the group ID of the directory in
+ which it is created; otherwise (the default) it takes the fsgid
+ of the current process, unless the directory has the setgid bit
+ set, in which case it takes the gid from the parent directory,
+ and also gets the setgid bit set if it is a directory itself.
+
+ ihashsize=value
+ Sets the number of hash buckets available for hashing the
+ in-memory inodes of the specified mount point. If a value
+ of zero is used, the value selected by the default algorithm
+ will be displayed in /proc/mounts.