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Commit 5a254031 authored by Mark Fasheh's avatar Mark Fasheh
Browse files

ocfs2: Fix max offset calculations 



ocfs2_max_file_offset() was over-estimating the largest file size for
several cases. This wasn't really a problem before, but now that we support
sparse files, it needs to be more accurate.

Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent ce76fd30

fs/ocfs2/super.c

+40 −28
Original line number Diff line number Diff line
@@ -316,39 +316,51 @@ static void ocfs2_destroy_inode(struct inode *inode) 
	kmem_cache_free(ocfs2_inode_cachep, OCFS2_I(inode));

}



/* From xfs_super.c:xfs_max_file_offset

 * Copyright (c) 2000-2004 Silicon Graphics, Inc.

 */

static unsigned long long ocfs2_max_file_offset(unsigned int blockshift)

static unsigned long long ocfs2_max_file_offset(unsigned int bbits,

						unsigned int cbits)

{

	unsigned int pagefactor = 1;

	unsigned int bitshift = BITS_PER_LONG - 1;



	/* Figure out maximum filesize, on Linux this can depend on

	 * the filesystem blocksize (on 32 bit platforms).

	 * __block_prepare_write does this in an [unsigned] long...

	 *      page->index << (PAGE_CACHE_SHIFT - bbits)

	 * So, for page sized blocks (4K on 32 bit platforms),

	 * this wraps at around 8Tb (hence MAX_LFS_FILESIZE which is

	 *      (((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1)

	 * but for smaller blocksizes it is less (bbits = log2 bsize).

	 * Note1: get_block_t takes a long (implicit cast from above)

	 * Note2: The Large Block Device (LBD and HAVE_SECTOR_T) patch

	 * can optionally convert the [unsigned] long from above into

	 * an [unsigned] long long.

	unsigned int bytes = 1 << cbits;

	unsigned int trim = bytes;

	unsigned int bitshift = 32;



	/*

	 * i_size and all block offsets in ocfs2 are always 64 bits

	 * wide. i_clusters is 32 bits, in cluster-sized units. So on

	 * 64 bit platforms, cluster size will be the limiting factor.

	 */



#if BITS_PER_LONG == 32

# if defined(CONFIG_LBD)

	BUILD_BUG_ON(sizeof(sector_t) != 8);

	pagefactor = PAGE_CACHE_SIZE;

	bitshift = BITS_PER_LONG;

	/*

	 * We might be limited by page cache size.

	 */

	if (bytes > PAGE_CACHE_SIZE) {

		bytes = PAGE_CACHE_SIZE;

		trim = 1;

		/*

		 * Shift by 31 here so that we don't get larger than

		 * MAX_LFS_FILESIZE

		 */

		bitshift = 31;

	}

# else

	pagefactor = PAGE_CACHE_SIZE >> (PAGE_CACHE_SHIFT - blockshift);

	/*

	 * We are limited by the size of sector_t. Use block size, as

	 * that's what we expose to the VFS.

	 */

	bytes = 1 << bbits;

	trim = 1;

	bitshift = 31;

# endif

#endif



	return (((unsigned long long)pagefactor) << bitshift) - 1;

	/*

	 * Trim by a whole cluster when we can actually approach the

	 * on-disk limits. Otherwise we can overflow i_clusters when

	 * an extent start is at the max offset.

	 */

	return (((unsigned long long)bytes) << bitshift) - trim;

}



static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
@@ -1259,8 +1271,8 @@ static int ocfs2_initialize_super(struct super_block *sb, 
				  int sector_size)

{

	int status = 0;

	int i;

	struct ocfs2_dinode *di = NULL;

	int i, cbits, bbits;

	struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;

	struct inode *inode = NULL;

	struct buffer_head *bitmap_bh = NULL;

	struct ocfs2_journal *journal;
@@ -1281,7 +1293,9 @@ static int ocfs2_initialize_super(struct super_block *sb, 
	sb->s_export_op = &ocfs2_export_ops;

	sb->s_flags |= MS_NOATIME;

	/* this is needed to support O_LARGEFILE */

	sb->s_maxbytes = ocfs2_max_file_offset(sb->s_blocksize_bits);

	cbits = le32_to_cpu(di->id2.i_super.s_clustersize_bits);

	bbits = le32_to_cpu(di->id2.i_super.s_blocksize_bits);

	sb->s_maxbytes = ocfs2_max_file_offset(bbits, cbits);



	osb->sb = sb;

	/* Save off for ocfs2_rw_direct */
@@ -1341,8 +1355,6 @@ static int ocfs2_initialize_super(struct super_block *sb, 
		goto bail;

	}



	di = (struct ocfs2_dinode *)bh->b_data;



	osb->max_slots = le16_to_cpu(di->id2.i_super.s_max_slots);

	if (osb->max_slots > OCFS2_MAX_SLOTS || osb->max_slots == 0) {

		mlog(ML_ERROR, "Invalid number of node slots (%u)\n",