commit 14ccf8c485c8aeda5a28fe60e5122979eeb3b517
Author: Abhijith Das <adas@redhat.com>
Date:   Fri Apr 30 10:49:12 2010 -0500

    gfs2_convert: Does not convert full gfs1 filesystems
    
    We now check to see if the number of blocks we intend
    to allocate while creating GFS2 file system structures
    are less than the available free blocks. If not enough
    blocks are available, we reduce the journal size (1MB
    at a time) until we can fit everything in.
    
    Resolves: rhbz#585081
    Signed-off-by: Abhi Das <adas@redhat.com>

diff --git a/gfs2/convert/gfs2_convert.c b/gfs2/convert/gfs2_convert.c
index f28aac4..8835a5b 100644
--- a/gfs2/convert/gfs2_convert.c
+++ b/gfs2/convert/gfs2_convert.c
@@ -68,6 +68,8 @@
 #define GFS_FORMAT_FS           (1309) /* Filesystem (all-encompassing) */
 #define GFS_FORMAT_MULTI        (1401) /* Multi-Host */
 
+#define DIV_RU(x, y) (((x) + (y) - 1) / (y))
+
 struct gfs1_rgrp {
 	struct gfs2_meta_header rg_header; /* hasn't changed from gfs1 to 2 */
 	uint32_t rg_flags;
@@ -2007,6 +2009,100 @@ static void conv_build_jindex(struct gfs2_sbd *sdp)
 	inode_put(&sdp->md.jiinode);
 }
 
+static unsigned int total_file_blocks(struct gfs2_sbd *sdp, 
+				      uint64_t filesize, int journaled)
+{
+	unsigned int data_blks = 0, meta_blks = 0, total_blks;
+	unsigned int max, height, bsize;
+	uint64_t *arr;
+
+	/* Now find the total meta blocks required for data_blks */
+	if (filesize <= sdp->bsize - sizeof(struct gfs2_dinode)) {
+		total_blks = 1; /* stuffed inode */
+		goto out;
+	}
+
+	if (journaled) {
+		arr = sdp->sd_jheightsize;
+		max = sdp->sd_max_jheight;
+		bsize = sdp->sd_jbsize;
+	} else {
+		arr = sdp->sd_heightsize;
+		max = sdp->sd_max_height;
+		bsize = sdp->bsize;
+	}
+	data_blks = DIV_RU(filesize, bsize); /* total data blocks reqd */
+
+	for (height = 0; height < max; height++)
+		if (arr[height] >= filesize)
+			break;
+	if (height == 1) {
+		total_blks = data_blks + 1; /* dinode has direct ptrs to data blocks */
+		goto out;
+	}
+
+	meta_blks = DIV_RU(data_blks, sdp->sd_inptrs);
+	total_blks = data_blks + meta_blks;
+out:
+	return data_blks + meta_blks;
+}
+
+/* We check if the GFS2 filesystem files/structures created after the call to 
+ * check_fit() in main() will fit in the currently available free blocks
+ */
+static int check_fit(struct gfs2_sbd *sdp)
+{
+	unsigned int blks_need = 0, blks_avail = sdp->blks_total - sdp->blks_alloced;
+
+	/* build_master() */
+	blks_need++; /*creation of master dir inode - 1 block */
+
+	/* conv_build_jindex() */
+	{
+		blks_need++; /* creation of 'jindex' disk inode */
+		/* creation of journals */
+		blks_need += sdp->md.journals *
+			total_file_blocks(sdp, sdp->jsize << 20, 1);
+	}
+	/* build_per_node() */
+	{
+		blks_need++; /* creation of 'per_node' dir inode */
+		/* njourn x (inum_range + statfs_change + quota_change inodes) */
+		blks_need += sdp->md.journals * 3;
+		/* quota change inodes are prealloced */
+		blks_need += sdp->md.journals *
+			total_file_blocks(sdp, sdp->qcsize << 20, 1);
+	}
+	/* build_inum() */
+	blks_need++; /* creation of 'inum' disk inode */
+
+	/* build_statfs() */
+	blks_need++; /* creation of 'statfs' disk inode */
+
+	/* build_rindex() */
+	{
+		osi_list_t *tmp, *head;
+		unsigned int rg_count = 0;
+
+		blks_need++; /* creationg of 'rindex' disk inode */
+		/* find the total # of rindex entries, gives size of rindex inode */
+		for (head = &sdp->rglist, tmp = head->next; tmp != head;
+		     tmp = tmp->next)
+			rg_count++;
+		blks_need += 
+			total_file_blocks(sdp, rg_count * sizeof(struct gfs2_rindex), 1);
+	}
+	/* build_quota() */
+	blks_need++; /* quota inode block and uid=gid=0 quota - total 1 block */
+
+	/* Up until this point we require blks_need blocks. We don't 
+	 * include the blocks freed by the next step (remove_obsolete_gfs1)
+	 * because it's possible for us to exceed the available blocks
+	 * before this step */
+
+	return blks_avail > blks_need;
+}
+
 /* ------------------------------------------------------------------------- */
 /* main - mainline code                                                      */
 /* ------------------------------------------------------------------------- */
@@ -2094,8 +2190,19 @@ int main(int argc, char **argv)
 	/* Create our system files and directories.       */
 	/* ---------------------------------------------- */
 	if (!error) {
+		int jreduce = 0;
 		/* Now we've got to treat it as a gfs2 file system */
 		compute_constants(&sb2);
+
+		/* Check if all the files we're about to create will
+ 		 * fit into the space remaining on the device */
+		while (!check_fit(&sb2)) {
+			sb2.jsize--; /* reduce jsize by 1MB each time */
+			jreduce = 1;
+		}
+		if (jreduce)
+			log_notice("Reduced journal size to %u MB to accommodate "
+				"GFS2 file system structures.\n", sb2.jsize);
 		/* Build the master subdirectory. */
 		build_master(&sb2); /* Does not do inode_put */
 		sb2.sd_sb.sb_master_dir = sb2.master_dir->i_di.di_num;