@@ -7,6 +7,7 @@
.\" 2011-09-19: Added FALLOC_FL_PUNCH_HOLE
.\" 2011-09-19: Substantial restructuring of the page
+.\" 2013-09-01: Added FALLOC_FL_COLLAPSE_RANGE
.TH FALLOCATE 2 2013-06-10 "Linux" "Linux Programmer's Manual"
@@ -109,6 +110,19 @@ does not change.
Not all filesystems support
.BR FALLOC_FL_PUNCH_HOLE ;
if a filesystem doesn't support the operation, an error is returned.
+.SS Collapsing file space
+collpse space in the byte range starting at
+and continuing for
+bytes, where the offset and len are aligned with block size of filesystem.
+Within the specified range, it first de-allocates blocks and eliminates
+the hole created in this process by shifting data blocks into the hole.
.SH RETURN VALUE
.BR fallocate ()
@@ -139,7 +153,8 @@ was less than 0, or
.\" See "Re: [PATCH] fallocate.2: add FALLOC_FL_PUNCH_HOLE flag definition"
.\" 21 Sep 2012
-was less than or equal to 0.
+was less than or equal to 0 or in case of FALLOC_FL_COLLAPSE_RANGE
+offset and len are not aligned with file system's block size.
An I/O error occurred while reading from or writing to a filesystem.