The OCFS2 developers have already done all of the hard work to allow volumes larger than 16 TiB. But there is still a "sanity check" in fs/ocfs2/super.c that prevents the mounting of such volumes, even when the cluster size and journal options would allow it. This patch replaces that sanity check with a more sophisticated one to mount a huge volume provided that (a) it is addressable by the raw word/address size of the system (borrowing a test from ext4); (b) the volume is using JBD2; and (c) the JBD2_FEATURE_INCOMPAT_64BIT flag is set on the journal. I factored out the sanity check into its own function. I also moved it from ocfs2_initialize_super() down to ocfs2_check_volume(); any earlier, and the journal will not have been initialized yet. This patch is one of a pair, and it depends on the other ("JBD2: Allow feature checks before journal recovery"). I have tested this patch on small volumes, huge volumes, and huge volumes without 64-bit block support in the journal. All of them appear to work or to fail gracefully, as appropriate. Signed-off-by: Patrick LoPresti <lopresti@xxxxxxxxx> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c index 0eaa929..b809508 100644 --- a/fs/ocfs2/super.c +++ b/fs/ocfs2/super.c @@ -1991,6 +1991,47 @@ static int ocfs2_setup_osb_uuid(struct ocfs2_super *osb, const unsigned char *uu return 0; } +/* Check to make sure entire volume is addressable on this system. + Requires osb_clusters_at_boot to be valid and for the journal to + have been initialized by ocfs2_journal_init(). */ +static int ocfs2_check_addressable(struct ocfs2_super *osb) +{ + int status = 0; + u64 max_block = + ocfs2_clusters_to_blocks(osb->sb, + osb->osb_clusters_at_boot) - 1; + + /* Absolute addressability check (borrowed from ext4/super.c) */ + if ((max_block > + (sector_t)(~0LL) >> (osb->sb->s_blocksize_bits - 9)) || + (max_block > (pgoff_t)(~0LL) >> (PAGE_CACHE_SHIFT - + osb->sb->s_blocksize_bits))) { + mlog(ML_ERROR, "Volume too large " + "to mount safely on this system"); + status = -EFBIG; + goto out; + } + + /* 32-bit block number is always OK. */ + if (max_block <= (u32)~0UL) + goto out; + + /* Volume is "huge", so see if our journal is new enough to + support it. */ + if (!(OCFS2_HAS_COMPAT_FEATURE(osb->sb, + OCFS2_FEATURE_COMPAT_JBD2_SB) && + jbd2_journal_check_used_features(osb->journal->j_journal, 0, 0, + JBD2_FEATURE_INCOMPAT_64BIT))) { + mlog(ML_ERROR, "The journal cannot address the entire volume. " + "Enable the 'block64' journal option with tunefs.ocfs2"); + status = -EFBIG; + goto out; + } + + out: + return status; +} + static int ocfs2_initialize_super(struct super_block *sb, struct buffer_head *bh, int sector_size, @@ -2215,14 +2256,6 @@ static int ocfs2_initialize_super(struct super_block *sb, goto bail; } - if (ocfs2_clusters_to_blocks(osb->sb, le32_to_cpu(di->i_clusters) - 1) - > (u32)~0UL) { - mlog(ML_ERROR, "Volume might try to write to blocks beyond " - "what jbd can address in 32 bits.\n"); - status = -EINVAL; - goto bail; - } - if (ocfs2_setup_osb_uuid(osb, di->id2.i_super.s_uuid, sizeof(di->id2.i_super.s_uuid))) { mlog(ML_ERROR, "Out of memory trying to setup our uuid.\n"); @@ -2381,6 +2414,12 @@ static int ocfs2_check_volume(struct ocfs2_super *osb) goto finally; } + /* Now that journal has been initialized, check to make sure + entire volume is addressable. */ + status = ocfs2_check_addressable(osb); + if (status) + goto finally; + /* If the journal was unmounted cleanly then we don't want to * recover anything. Otherwise, journal_load will do that * dirty work for us :) */ -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html