Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 268 insertions, 77 deletions

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index b3361fe2bcb..9c83594d7fb 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -35,9 +35,71 @@
 #define CONFIG_FAT_DEFAULT_IOCHARSET	""
 #endif
 
+#define KB_IN_SECTORS 2
+
+/*
+ * A deserialized copy of the on-disk structure laid out in struct
+ * fat_boot_sector.
+ */
+struct fat_bios_param_block {
+	u16	fat_sector_size;
+	u8	fat_sec_per_clus;
+	u16	fat_reserved;
+	u8	fat_fats;
+	u16	fat_dir_entries;
+	u16	fat_sectors;
+	u16	fat_fat_length;
+	u32	fat_total_sect;
+
+	u8	fat16_state;
+	u32	fat16_vol_id;
+
+	u32	fat32_length;
+	u32	fat32_root_cluster;
+	u16	fat32_info_sector;
+	u8	fat32_state;
+	u32	fat32_vol_id;
+};
+
 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
 
+static struct fat_floppy_defaults {
+	unsigned nr_sectors;
+	unsigned sec_per_clus;
+	unsigned dir_entries;
+	unsigned media;
+	unsigned fat_length;
+} floppy_defaults[] = {
+{
+	.nr_sectors = 160 * KB_IN_SECTORS,
+	.sec_per_clus = 1,
+	.dir_entries = 64,
+	.media = 0xFE,
+	.fat_length = 1,
+},
+{
+	.nr_sectors = 180 * KB_IN_SECTORS,
+	.sec_per_clus = 1,
+	.dir_entries = 64,
+	.media = 0xFC,
+	.fat_length = 2,
+},
+{
+	.nr_sectors = 320 * KB_IN_SECTORS,
+	.sec_per_clus = 2,
+	.dir_entries = 112,
+	.media = 0xFF,
+	.fat_length = 1,
+},
+{
+	.nr_sectors = 360 * KB_IN_SECTORS,
+	.sec_per_clus = 2,
+	.dir_entries = 112,
+	.media = 0xFD,
+	.fat_length = 2,
+},
+};
 
 static int fat_add_cluster(struct inode *inode)
 {
@@ -359,7 +421,7 @@ struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
 
 static int is_exec(unsigned char *extension)
 {
-	unsigned char *exe_extensions = "EXECOMBAT", *walk;
+	unsigned char exe_extensions[] = "EXECOMBAT", *walk;
 
 	for (walk = exe_extensions; *walk; walk += 3)
 		if (!strncmp(extension, walk, 3))
@@ -853,6 +915,8 @@ static int fat_show_options(struct seq_file *m, struct dentry *root)
 		seq_puts(m, ",nfs=stale_rw");
 	if (opts->discard)
 		seq_puts(m, ",discard");
+	if (opts->dos1xfloppy)
+		seq_puts(m, ",dos1xfloppy");
 
 	return 0;
 }
@@ -867,7 +931,7 @@ enum {
 	Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
 	Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
 	Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
-	Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err,
+	Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
 };
 
 static const match_table_t fat_tokens = {
@@ -900,6 +964,7 @@ static const match_table_t fat_tokens = {
 	{Opt_nfs_stale_rw, "nfs"},
 	{Opt_nfs_stale_rw, "nfs=stale_rw"},
 	{Opt_nfs_nostale_ro, "nfs=nostale_ro"},
+	{Opt_dos1xfloppy, "dos1xfloppy"},
 	{Opt_obsolete, "conv=binary"},
 	{Opt_obsolete, "conv=text"},
 	{Opt_obsolete, "conv=auto"},
@@ -1102,6 +1167,9 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
 		case Opt_nfs_nostale_ro:
 			opts->nfs = FAT_NFS_NOSTALE_RO;
 			break;
+		case Opt_dos1xfloppy:
+			opts->dos1xfloppy = 1;
+			break;
 
 		/* msdos specific */
 		case Opt_dots:
@@ -1247,6 +1315,169 @@ static unsigned long calc_fat_clusters(struct super_block *sb)
 	return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
 }
 
+static bool fat_bpb_is_zero(struct fat_boot_sector *b)
+{
+	if (get_unaligned_le16(&b->sector_size))
+		return false;
+	if (b->sec_per_clus)
+		return false;
+	if (b->reserved)
+		return false;
+	if (b->fats)
+		return false;
+	if (get_unaligned_le16(&b->dir_entries))
+		return false;
+	if (get_unaligned_le16(&b->sectors))
+		return false;
+	if (b->media)
+		return false;
+	if (b->fat_length)
+		return false;
+	if (b->secs_track)
+		return false;
+	if (b->heads)
+		return false;
+	return true;
+}
+
+static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
+	int silent, struct fat_bios_param_block *bpb)
+{
+	int error = -EINVAL;
+
+	/* Read in BPB ... */
+	memset(bpb, 0, sizeof(*bpb));
+	bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
+	bpb->fat_sec_per_clus = b->sec_per_clus;
+	bpb->fat_reserved = le16_to_cpu(b->reserved);
+	bpb->fat_fats = b->fats;
+	bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
+	bpb->fat_sectors = get_unaligned_le16(&b->sectors);
+	bpb->fat_fat_length = le16_to_cpu(b->fat_length);
+	bpb->fat_total_sect = le32_to_cpu(b->total_sect);
+
+	bpb->fat16_state = b->fat16.state;
+	bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
+
+	bpb->fat32_length = le32_to_cpu(b->fat32.length);
+	bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
+	bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
+	bpb->fat32_state = b->fat32.state;
+	bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
+
+	/* Validate this looks like a FAT filesystem BPB */
+	if (!bpb->fat_reserved) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR,
+				"bogus number of reserved sectors");
+		goto out;
+	}
+	if (!bpb->fat_fats) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
+		goto out;
+	}
+
+	/*
+	 * Earlier we checked here that b->secs_track and b->head are nonzero,
+	 * but it turns out valid FAT filesystems can have zero there.
+	 */
+
+	if (!fat_valid_media(b->media)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
+				(unsigned)b->media);
+		goto out;
+	}
+
+	if (!is_power_of_2(bpb->fat_sector_size)
+	    || (bpb->fat_sector_size < 512)
+	    || (bpb->fat_sector_size > 4096)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
+			       (unsigned)bpb->fat_sector_size);
+		goto out;
+	}
+
+	if (!is_power_of_2(bpb->fat_sec_per_clus)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
+				(unsigned)bpb->fat_sec_per_clus);
+		goto out;
+	}
+
+	error = 0;
+
+out:
+	return error;
+}
+
+static int fat_read_static_bpb(struct super_block *sb,
+	struct fat_boot_sector *b, int silent,
+	struct fat_bios_param_block *bpb)
+{
+	static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
+
+	struct fat_floppy_defaults *fdefaults = NULL;
+	int error = -EINVAL;
+	sector_t bd_sects;
+	unsigned i;
+
+	bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
+
+	/* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
+	if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR,
+				"%s; no bootstrapping code", notdos1x);
+		goto out;
+	}
+
+	/*
+	 * If any value in this region is non-zero, it isn't archaic
+	 * DOS.
+	 */
+	if (!fat_bpb_is_zero(b)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR,
+				"%s; DOS 2.x BPB is non-zero", notdos1x);
+		goto out;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
+		if (floppy_defaults[i].nr_sectors == bd_sects) {
+			fdefaults = &floppy_defaults[i];
+			break;
+		}
+	}
+
+	if (fdefaults == NULL) {
+		if (!silent)
+			fat_msg(sb, KERN_WARNING,
+				"This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
+				(u64)bd_sects);
+		goto out;
+	}
+
+	if (!silent)
+		fat_msg(sb, KERN_INFO,
+			"This looks like a DOS 1.x volume; assuming default BPB values");
+
+	memset(bpb, 0, sizeof(*bpb));
+	bpb->fat_sector_size = SECTOR_SIZE;
+	bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
+	bpb->fat_reserved = 1;
+	bpb->fat_fats = 2;
+	bpb->fat_dir_entries = fdefaults->dir_entries;
+	bpb->fat_sectors = fdefaults->nr_sectors;
+	bpb->fat_fat_length = fdefaults->fat_length;
+
+	error = 0;
+
+out:
+	return error;
+}
+
 /*
  * Read the super block of an MS-DOS FS.
  */
@@ -1256,12 +1487,11 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 	struct inode *root_inode = NULL, *fat_inode = NULL;
 	struct inode *fsinfo_inode = NULL;
 	struct buffer_head *bh;
-	struct fat_boot_sector *b;
+	struct fat_bios_param_block bpb;
 	struct msdos_sb_info *sbi;
 	u16 logical_sector_size;
 	u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
 	int debug;
-	unsigned int media;
 	long error;
 	char buf[50];
 
@@ -1298,100 +1528,72 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 		goto out_fail;
 	}
 
-	b = (struct fat_boot_sector *) bh->b_data;
-	if (!b->reserved) {
-		if (!silent)
-			fat_msg(sb, KERN_ERR, "bogus number of reserved sectors");
-		brelse(bh);
-		goto out_invalid;
-	}
-	if (!b->fats) {
-		if (!silent)
-			fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
-		brelse(bh);
-		goto out_invalid;
-	}
-
-	/*
-	 * Earlier we checked here that b->secs_track and b->head are nonzero,
-	 * but it turns out valid FAT filesystems can have zero there.
-	 */
+	error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
+		&bpb);
+	if (error == -EINVAL && sbi->options.dos1xfloppy)
+		error = fat_read_static_bpb(sb,
+			(struct fat_boot_sector *)bh->b_data, silent, &bpb);
+	brelse(bh);
 
-	media = b->media;
-	if (!fat_valid_media(media)) {
-		if (!silent)
-			fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
-			       media);
-		brelse(bh);
-		goto out_invalid;
-	}
-	logical_sector_size = get_unaligned_le16(&b->sector_size);
-	if (!is_power_of_2(logical_sector_size)
-	    || (logical_sector_size < 512)
-	    || (logical_sector_size > 4096)) {
-		if (!silent)
-			fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
-			       logical_sector_size);
-		brelse(bh);
-		goto out_invalid;
-	}
-	sbi->sec_per_clus = b->sec_per_clus;
-	if (!is_power_of_2(sbi->sec_per_clus)) {
-		if (!silent)
-			fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
-			       sbi->sec_per_clus);
-		brelse(bh);
+	if (error == -EINVAL)
 		goto out_invalid;
-	}
+	else if (error)
+		goto out_fail;
+
+	logical_sector_size = bpb.fat_sector_size;
+	sbi->sec_per_clus = bpb.fat_sec_per_clus;
 
+	error = -EIO;
 	if (logical_sector_size < sb->s_blocksize) {
 		fat_msg(sb, KERN_ERR, "logical sector size too small for device"
 		       " (logical sector size = %u)", logical_sector_size);
-		brelse(bh);
 		goto out_fail;
 	}
+
 	if (logical_sector_size > sb->s_blocksize) {
-		brelse(bh);
+		struct buffer_head *bh_resize;
 
 		if (!sb_set_blocksize(sb, logical_sector_size)) {
 			fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
 			       logical_sector_size);
 			goto out_fail;
 		}
-		bh = sb_bread(sb, 0);
-		if (bh == NULL) {
+
+		/* Verify that the larger boot sector is fully readable */
+		bh_resize = sb_bread(sb, 0);
+		if (bh_resize == NULL) {
 			fat_msg(sb, KERN_ERR, "unable to read boot sector"
 			       " (logical sector size = %lu)",
 			       sb->s_blocksize);
 			goto out_fail;
 		}
-		b = (struct fat_boot_sector *) bh->b_data;
+		brelse(bh_resize);
 	}
 
 	mutex_init(&sbi->s_lock);
 	sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
 	sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
-	sbi->fats = b->fats;
+	sbi->fats = bpb.fat_fats;
 	sbi->fat_bits = 0;		/* Don't know yet */
-	sbi->fat_start = le16_to_cpu(b->reserved);
-	sbi->fat_length = le16_to_cpu(b->fat_length);
+	sbi->fat_start = bpb.fat_reserved;
+	sbi->fat_length = bpb.fat_fat_length;
 	sbi->root_cluster = 0;
 	sbi->free_clusters = -1;	/* Don't know yet */
 	sbi->free_clus_valid = 0;
 	sbi->prev_free = FAT_START_ENT;
 	sb->s_maxbytes = 0xffffffff;
 
-	if (!sbi->fat_length && b->fat32.length) {
+	if (!sbi->fat_length && bpb.fat32_length) {
 		struct fat_boot_fsinfo *fsinfo;
 		struct buffer_head *fsinfo_bh;
 
 		/* Must be FAT32 */
 		sbi->fat_bits = 32;
-		sbi->fat_length = le32_to_cpu(b->fat32.length);
-		sbi->root_cluster = le32_to_cpu(b->fat32.root_cluster);
+		sbi->fat_length = bpb.fat32_length;
+		sbi->root_cluster = bpb.fat32_root_cluster;
 
 		/* MC - if info_sector is 0, don't multiply by 0 */
-		sbi->fsinfo_sector = le16_to_cpu(b->fat32.info_sector);
+		sbi->fsinfo_sector = bpb.fat32_info_sector;
 		if (sbi->fsinfo_sector == 0)
 			sbi->fsinfo_sector = 1;
 
@@ -1399,7 +1601,6 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 		if (fsinfo_bh == NULL) {
 			fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
 			       " (sector = %lu)", sbi->fsinfo_sector);
-			brelse(bh);
 			goto out_fail;
 		}
 
@@ -1422,35 +1623,28 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 
 	/* interpret volume ID as a little endian 32 bit integer */
 	if (sbi->fat_bits == 32)
-		sbi->vol_id = (((u32)b->fat32.vol_id[0]) |
-					((u32)b->fat32.vol_id[1] << 8) |
-					((u32)b->fat32.vol_id[2] << 16) |
-					((u32)b->fat32.vol_id[3] << 24));
+		sbi->vol_id = bpb.fat32_vol_id;
 	else /* fat 16 or 12 */
-		sbi->vol_id = (((u32)b->fat16.vol_id[0]) |
-					((u32)b->fat16.vol_id[1] << 8) |
-					((u32)b->fat16.vol_id[2] << 16) |
-					((u32)b->fat16.vol_id[3] << 24));
+		sbi->vol_id = bpb.fat16_vol_id;
 
 	sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
 	sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
 
 	sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
-	sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
+	sbi->dir_entries = bpb.fat_dir_entries;
 	if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
 		if (!silent)
 			fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
 			       " (%u)", sbi->dir_entries);
-		brelse(bh);
 		goto out_invalid;
 	}
 
 	rootdir_sectors = sbi->dir_entries
 		* sizeof(struct msdos_dir_entry) / sb->s_blocksize;
 	sbi->data_start = sbi->dir_start + rootdir_sectors;
-	total_sectors = get_unaligned_le16(&b->sectors);
+	total_sectors = bpb.fat_sectors;
 	if (total_sectors == 0)
-		total_sectors = le32_to_cpu(b->total_sect);
+		total_sectors = bpb.fat_total_sect;
 
 	total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
 
@@ -1459,9 +1653,9 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 
 	/* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
 	if (sbi->fat_bits == 32)
-		sbi->dirty = b->fat32.state & FAT_STATE_DIRTY;
+		sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
 	else /* fat 16 or 12 */
-		sbi->dirty = b->fat16.state & FAT_STATE_DIRTY;
+		sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
 
 	/* check that FAT table does not overflow */
 	fat_clusters = calc_fat_clusters(sb);
@@ -1470,7 +1664,6 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 		if (!silent)
 			fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
 			       total_clusters);
-		brelse(bh);
 		goto out_invalid;
 	}
 
@@ -1483,8 +1676,6 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 	if (sbi->prev_free < FAT_START_ENT)
 		sbi->prev_free = FAT_START_ENT;
 
-	brelse(bh);
-
 	/* set up enough so that it can read an inode */
 	fat_hash_init(sb);
 	dir_hash_init(sb);