X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=fs%2Fxfs%2Fxfs_super.c;h=2094386af8aca045021964dce6a8295f4ef3ef34;hb=469030d454bd1620c7b2651d9ec8cdcbaa74deb9;hp=d9ae27ddf253bba6763a10fa8fde72425c5d6df1;hpb=715d1285695382b5074e49a0fe475b9ba56a1101;p=linux.git

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index d9ae27ddf253..2094386af8ac 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -62,7 +62,7 @@ enum {
 	Opt_discard, Opt_nodiscard, Opt_dax,
 };
 
-static const struct fs_parameter_spec xfs_param_specs[] = {
+static const struct fs_parameter_spec xfs_fs_parameters[] = {
 	fsparam_u32("logbufs",		Opt_logbufs),
 	fsparam_string("logbsize",	Opt_logbsize),
 	fsparam_string("logdev",	Opt_logdev),
@@ -106,11 +106,6 @@ static const struct fs_parameter_spec xfs_param_specs[] = {
 	{}
 };
 
-static const struct fs_parameter_description xfs_fs_parameters = {
-	.name		= "xfs",
-	.specs		= xfs_param_specs,
-};
-
 struct proc_xfs_info {
 	uint64_t	flag;
 	char		*str;
@@ -193,32 +188,6 @@ xfs_fs_show_options(
 	return 0;
 }
 
-static uint64_t
-xfs_max_file_offset(
-	unsigned int		blockshift)
-{
-	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_write_begin does this in an [unsigned] long long...
-	 *      page->index << (PAGE_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_SIZE << (BITS_PER_LONG-1))-1)
-	 * but for smaller blocksizes it is less (bbits = log2 bsize).
-	 */
-
-#if BITS_PER_LONG == 32
-	ASSERT(sizeof(sector_t) == 8);
-	pagefactor = PAGE_SIZE;
-	bitshift = BITS_PER_LONG;
-#endif
-
-	return (((uint64_t)pagefactor) << bitshift) - 1;
-}
-
 /*
  * Set parameters for inode allocation heuristics, taking into account
  * filesystem size and inode32/inode64 mount options; i.e. specifically
@@ -1146,7 +1115,7 @@ xfs_fc_parse_param(
 	int			size = 0;
 	int			opt;
 
-	opt = fs_parse(fc, &xfs_fs_parameters, param, &result);
+	opt = fs_parse(fc, xfs_fs_parameters, param, &result);
 	if (opt < 0)
 		return opt;
 
@@ -1424,6 +1393,26 @@ xfs_fc_fill_super(
 	if (error)
 		goto out_free_sb;
 
+	/*
+	 * XFS block mappings use 54 bits to store the logical block offset.
+	 * This should suffice to handle the maximum file size that the VFS
+	 * supports (currently 2^63 bytes on 64-bit and ULONG_MAX << PAGE_SHIFT
+	 * bytes on 32-bit), but as XFS and VFS have gotten the s_maxbytes
+	 * calculation wrong on 32-bit kernels in the past, we'll add a WARN_ON
+	 * to check this assertion.
+	 *
+	 * Avoid integer overflow by comparing the maximum bmbt offset to the
+	 * maximum pagecache offset in units of fs blocks.
+	 */
+	if (XFS_B_TO_FSBT(mp, MAX_LFS_FILESIZE) > XFS_MAX_FILEOFF) {
+		xfs_warn(mp,
+"MAX_LFS_FILESIZE block offset (%llu) exceeds extent map maximum (%llu)!",
+			 XFS_B_TO_FSBT(mp, MAX_LFS_FILESIZE),
+			 XFS_MAX_FILEOFF);
+		error = -EINVAL;
+		goto out_free_sb;
+	}
+
 	error = xfs_filestream_mount(mp);
 	if (error)
 		goto out_free_sb;
@@ -1435,7 +1424,7 @@ xfs_fc_fill_super(
 	sb->s_magic = XFS_SUPER_MAGIC;
 	sb->s_blocksize = mp->m_sb.sb_blocksize;
 	sb->s_blocksize_bits = ffs(sb->s_blocksize) - 1;
-	sb->s_maxbytes = xfs_max_file_offset(sb->s_blocksize_bits);
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_max_links = XFS_MAXLINK;
 	sb->s_time_gran = 1;
 	sb->s_time_min = S32_MIN;
@@ -1788,7 +1777,7 @@ static struct file_system_type xfs_fs_type = {
 	.owner			= THIS_MODULE,
 	.name			= "xfs",
 	.init_fs_context	= xfs_init_fs_context,
-	.parameters		= &xfs_fs_parameters,
+	.parameters		= xfs_fs_parameters,
 	.kill_sb		= kill_block_super,
 	.fs_flags		= FS_REQUIRES_DEV,
 };