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authorSteven Whitehouse <swhiteho@redhat.com>2012-02-08 16:58:32 +0400
committerSteven Whitehouse <swhiteho@redhat.com>2012-02-28 21:10:21 +0400
commit66fc061bda3526650328b73f69985da3518c4256 (patch)
tree350471fda86ebf60fee5436350d36ce9cedbea75 /include/linux/gfs2_ondisk.h
parent47ac5537a794fc71f89d51af492a945bd233f70c (diff)
downloadlinux-66fc061bda3526650328b73f69985da3518c4256.tar.xz
GFS2: FITRIM ioctl support
The FITRIM ioctl provides an alternative way to send discard requests to the underlying device. Using the discard mount option results in every freed block generating a discard request to the block device. This can be slow, since many block devices can only process discard requests of larger sizes, and also such operations can be time consuming. Rather than using the discard mount option, FITRIM allows a sweep of the filesystem on an occasional basis, and also to optionally avoid sending down discard requests for smaller regions. In GFS2 FITRIM will work at resource group granularity. There is a flag for each resource group which keeps track of which resource groups have been trimmed. This flag is reset whenever a deallocation occurs in the resource group, and set whenever a successful FITRIM of that resource group has taken place. This helps to reduce repeated discard requests for the same block ranges, again improving performance. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'include/linux/gfs2_ondisk.h')
-rw-r--r--include/linux/gfs2_ondisk.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/gfs2_ondisk.h b/include/linux/gfs2_ondisk.h
index b148087f49a6..fa98bdb073b9 100644
--- a/include/linux/gfs2_ondisk.h
+++ b/include/linux/gfs2_ondisk.h
@@ -168,6 +168,7 @@ struct gfs2_rindex {
#define GFS2_RGF_METAONLY 0x00000002
#define GFS2_RGF_DATAONLY 0x00000004
#define GFS2_RGF_NOALLOC 0x00000008
+#define GFS2_RGF_TRIMMED 0x00000010
struct gfs2_rgrp {
struct gfs2_meta_header rg_header;