@@ -150,6 +150,15 @@ value returned indicates that a preferred extent size was previously
set on the file, a
.B fsx_extsize
of zero indicates that the defaults for that filesystem will be used.
+A
+.B fsx_cowextsize
+value returned indicates that a preferred copy on write extent size was
+previously set on the file, whereas a
+.B fsx_cowextsize
+of zero indicates that the defaults for that filesystem will be used.
+The current default for
+.B fsx_cowextsize
+is 128 blocks.
Currently the meaningful bits for the
.B fsx_xflags
field are:
@@ -240,6 +249,15 @@ and
.BR XFS_XFLAG_DAX
set at the same time, that is to say that DAX files cannot share blocks.
.TP
+.SM "Bit 17 (0x20000) \- XFS_XFLAG_COWEXTSIZE"
+Copy on Write Extent size bit - if a CoW extent size value is set on the file,
+the allocator will allocate extents for staging a copy on write operation
+in multiples of the set size for this file (see
+.B XFS_IOC_FSSETXATTR
+below).
+If the CoW extent size is set on a directory, then new file and directories
+created in the directory will inherit the parent's CoW extent size value.
+.TP
.SM "Bit 31 (0x80000000) \- XFS_XFLAG_HASATTR"
The file has extended attributes associated with it.
.RE
@@ -261,7 +279,8 @@ The final argument points to a variable of type
.BR "struct fsxattr" ,
but only the following fields are used in this call:
.BR fsx_xflags ,
-.B fsx_extsize
+.BR fsx_extsize ,
+.BR fsx_cowextsize ,
and
.BR fsx_projid .
The
@@ -271,6 +290,9 @@ when the file is empty, except in the case of a directory where
the extent size can be set at any time (this value is only used
for regular file allocations, so should only be set on a directory
in conjunction with the XFS_XFLAG_EXTSZINHERIT flag).
+The copy on write extent size,
+.BR fsx_cowextsize ,
+can be set at any time.
.TP
.B XFS_IOC_GETBMAP
Document the new copy-on-write extent size fields and inode flags available in struct fsxattr. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> --- man/man3/xfsctl.3 | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-)