Patchwork [v2,7/7] manpage: update FALLOC_FL_COLLAPSE_RANGE flag in fallocate

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Submitter NamJae Jeon
Date Sept. 2, 2013, 2:30 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/271957/
State Superseded
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NamJae Jeon - Sept. 2, 2013, 2:30 p.m.
From: Namjae Jeon <>

Update FALLOC_FL_COLLAPSE_RANGE flag in fallocate.

Signed-off-by: Namjae Jeon <>
Signed-off-by: Ashish Sangwan <>
 man2/fallocate.2 |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)


diff --git a/man2/fallocate.2 b/man2/fallocate.2
index f5c395d..b042c59 100644
--- a/man2/fallocate.2
+++ b/man2/fallocate.2
@@ -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
 if a filesystem doesn't support the operation, an error is returned.
+.SS Collapsing file space
+Specifiying the
+flag in
+.I mode
+collpse space in the byte range starting at
+.I offset
+and continuing for
+.I len
+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.
 On success,
 .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.