GFS2: fallocate support

This patch adds support for fallocate to gfs2.  Since the gfs2 does not support
uninitialized data blocks, it must write out zeros to all the blocks.  However,
since it does not need to lock any pages to read from, gfs2 can write out the
zero blocks much more efficiently.  On a moderately full filesystem, fallocate
works around 5 times faster on average.  The fallocate call also allows gfs2 to
add blocks to the file without changing the filesize, which will make it
possible for gfs2 to preallocate space for the rindex file, so that gfs2 can
grow a completely full filesystem.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 66b6d4d8b1d2..f9ddcf401753 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -589,6 +589,8 @@ static int gfs2_ri_update(struct gfs2_inode *ip)
         struct inode *inode = &ip->i_inode;
         struct file_ra_state ra_state;
         u64 rgrp_count = i_size_read(inode);
+        struct gfs2_rgrpd *rgd;
+        unsigned int max_data = 0;
         int error;
 
         do_div(rgrp_count, sizeof(struct gfs2_rindex));
@@ -603,6 +605,10 @@ static int gfs2_ri_update(struct gfs2_inode *ip)
                 }
         }
 
+        list_for_each_entry(rgd, &sdp->sd_rindex_list, rd_list)
+                if (rgd->rd_data > max_data)
+                        max_data = rgd->rd_data;
+        sdp->sd_max_rg_data = max_data;
         sdp->sd_rindex_uptodate = 1;
         return 0;
 }
@@ -622,6 +628,8 @@ static int gfs2_ri_update_special(struct gfs2_inode *ip)
         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
         struct inode *inode = &ip->i_inode;
         struct file_ra_state ra_state;
+        struct gfs2_rgrpd *rgd;
+        unsigned int max_data = 0;
         int error;
 
         file_ra_state_init(&ra_state, inode->i_mapping);
@@ -636,6 +644,10 @@ static int gfs2_ri_update_special(struct gfs2_inode *ip)
                         return error;
                 }
         }
+        list_for_each_entry(rgd, &sdp->sd_rindex_list, rd_list)
+                if (rgd->rd_data > max_data)
+                        max_data = rgd->rd_data;
+        sdp->sd_max_rg_data = max_data;
 
         sdp->sd_rindex_uptodate = 1;
         return 0;