File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/fs/hpfs/alloc.c b/fs/hpfs/alloc.c
new file mode 100644
index 0000000..d6a4b55
--- /dev/null
+++ b/fs/hpfs/alloc.c
@@ -0,0 +1,581 @@
+/*
+ *  linux/fs/hpfs/alloc.c
+ *
+ *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
+ *
+ *  HPFS bitmap operations
+ */
+
+#include "hpfs_fn.h"
+
+static void hpfs_claim_alloc(struct super_block *s, secno sec)
+{
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	if (sbi->sb_n_free != (unsigned)-1) {
+		if (unlikely(!sbi->sb_n_free)) {
+			hpfs_error(s, "free count underflow, allocating sector %08x", sec);
+			sbi->sb_n_free = -1;
+			return;
+		}
+		sbi->sb_n_free--;
+	}
+}
+
+static void hpfs_claim_free(struct super_block *s, secno sec)
+{
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	if (sbi->sb_n_free != (unsigned)-1) {
+		if (unlikely(sbi->sb_n_free >= sbi->sb_fs_size)) {
+			hpfs_error(s, "free count overflow, freeing sector %08x", sec);
+			sbi->sb_n_free = -1;
+			return;
+		}
+		sbi->sb_n_free++;
+	}
+}
+
+static void hpfs_claim_dirband_alloc(struct super_block *s, secno sec)
+{
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	if (sbi->sb_n_free_dnodes != (unsigned)-1) {
+		if (unlikely(!sbi->sb_n_free_dnodes)) {
+			hpfs_error(s, "dirband free count underflow, allocating sector %08x", sec);
+			sbi->sb_n_free_dnodes = -1;
+			return;
+		}
+		sbi->sb_n_free_dnodes--;
+	}
+}
+
+static void hpfs_claim_dirband_free(struct super_block *s, secno sec)
+{
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	if (sbi->sb_n_free_dnodes != (unsigned)-1) {
+		if (unlikely(sbi->sb_n_free_dnodes >= sbi->sb_dirband_size / 4)) {
+			hpfs_error(s, "dirband free count overflow, freeing sector %08x", sec);
+			sbi->sb_n_free_dnodes = -1;
+			return;
+		}
+		sbi->sb_n_free_dnodes++;
+	}
+}
+
+/*
+ * Check if a sector is allocated in bitmap
+ * This is really slow. Turned on only if chk==2
+ */
+
+static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
+{
+	struct quad_buffer_head qbh;
+	__le32 *bmp;
+	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
+	if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f)) & 1) {
+		hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
+		goto fail1;
+	}
+	hpfs_brelse4(&qbh);
+	if (sec >= hpfs_sb(s)->sb_dirband_start && sec < hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
+		unsigned ssec = (sec - hpfs_sb(s)->sb_dirband_start) / 4;
+		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
+		if ((le32_to_cpu(bmp[ssec >> 5]) >> (ssec & 0x1f)) & 1) {
+			hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
+			goto fail1;
+		}
+		hpfs_brelse4(&qbh);
+	}
+	return 0;
+	fail1:
+	hpfs_brelse4(&qbh);
+	fail:
+	return 1;
+}
+
+/*
+ * Check if sector(s) have proper number and additionally check if they're
+ * allocated in bitmap.
+ */
+	
+int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
+{
+	if (start + len < start || start < 0x12 ||
+	    start + len > hpfs_sb(s)->sb_fs_size) {
+	    	hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
+		return 1;
+	}
+	if (hpfs_sb(s)->sb_chk>=2) {
+		int i;
+		for (i = 0; i < len; i++)
+			if (chk_if_allocated(s, start + i, msg)) return 1;
+	}
+	return 0;
+}
+
+static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
+{
+	struct quad_buffer_head qbh;
+	__le32 *bmp;
+	unsigned bs = near & ~0x3fff;
+	unsigned nr = (near & 0x3fff) & ~(n - 1);
+	/*unsigned mnr;*/
+	unsigned i, q;
+	int a, b;
+	secno ret = 0;
+	if (n != 1 && n != 4) {
+		hpfs_error(s, "Bad allocation size: %d", n);
+		return 0;
+	}
+	if (bs != ~0x3fff) {
+		if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
+	} else {
+		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
+	}
+	if (!tstbits(bmp, nr, n + forward)) {
+		ret = bs + nr;
+		goto rt;
+	}
+	q = nr + n; b = 0;
+	while ((a = tstbits(bmp, q, n + forward)) != 0) {
+		q += a;
+		if (n != 1) q = ((q-1)&~(n-1))+n;
+		if (!b) {
+			if (q>>5 != nr>>5) {
+				b = 1;
+				q = nr & 0x1f;
+			}
+		} else if (q > nr) break;
+	}
+	if (!a) {
+		ret = bs + q;
+		goto rt;
+	}
+	nr >>= 5;
+	/*for (i = nr + 1; i != nr; i++, i &= 0x1ff) */
+	i = nr;
+	do {
+		if (!le32_to_cpu(bmp[i])) goto cont;
+		if (n + forward >= 0x3f && le32_to_cpu(bmp[i]) != 0xffffffff) goto cont;
+		q = i<<5;
+		if (i > 0) {
+			unsigned k = le32_to_cpu(bmp[i-1]);
+			while (k & 0x80000000) {
+				q--; k <<= 1;
+			}
+		}
+		if (n != 1) q = ((q-1)&~(n-1))+n;
+		while ((a = tstbits(bmp, q, n + forward)) != 0) {
+			q += a;
+			if (n != 1) q = ((q-1)&~(n-1))+n;
+			if (q>>5 > i) break;
+		}
+		if (!a) {
+			ret = bs + q;
+			goto rt;
+		}
+		cont:
+		i++, i &= 0x1ff;
+	} while (i != nr);
+	rt:
+	if (ret) {
+		if (hpfs_sb(s)->sb_chk && ((ret >> 14) != (bs >> 14) || (le32_to_cpu(bmp[(ret & 0x3fff) >> 5]) | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
+			hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
+			ret = 0;
+			goto b;
+		}
+		bmp[(ret & 0x3fff) >> 5] &= cpu_to_le32(~(((1 << n) - 1) << (ret & 0x1f)));
+		hpfs_mark_4buffers_dirty(&qbh);
+	}
+	b:
+	hpfs_brelse4(&qbh);
+	uls:
+	return ret;
+}
+
+/*
+ * Allocation strategy:	1) search place near the sector specified
+ *			2) search bitmap where free sectors last found
+ *			3) search all bitmaps
+ *			4) search all bitmaps ignoring number of pre-allocated
+ *				sectors
+ */
+
+secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward)
+{
+	secno sec;
+	int i;
+	unsigned n_bmps;
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	int f_p = 0;
+	int near_bmp;
+	if (forward < 0) {
+		forward = -forward;
+		f_p = 1;
+	}
+	n_bmps = (sbi->sb_fs_size + 0x4000 - 1) >> 14;
+	if (near && near < sbi->sb_fs_size) {
+		if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
+		near_bmp = near >> 14;
+	} else near_bmp = n_bmps / 2;
+	/*
+	if (b != -1) {
+		if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
+			b &= 0x0fffffff;
+			goto ret;
+		}
+		if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
+	*/
+	if (!f_p) if (forward > sbi->sb_max_fwd_alloc) forward = sbi->sb_max_fwd_alloc;
+	less_fwd:
+	for (i = 0; i < n_bmps; i++) {
+		if (near_bmp+i < n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i) << 14, n, forward)))) {
+			sbi->sb_c_bitmap = near_bmp+i;
+			goto ret;
+		}	
+		if (!forward) {
+			if (near_bmp-i-1 >= 0 && ((sec = alloc_in_bmp(s, (near_bmp-i-1) << 14, n, forward)))) {
+				sbi->sb_c_bitmap = near_bmp-i-1;
+				goto ret;
+			}
+		} else {
+			if (near_bmp+i >= n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i-n_bmps) << 14, n, forward)))) {
+				sbi->sb_c_bitmap = near_bmp+i-n_bmps;
+				goto ret;
+			}
+		}
+		if (i == 1 && sbi->sb_c_bitmap != -1 && ((sec = alloc_in_bmp(s, (sbi->sb_c_bitmap) << 14, n, forward)))) {
+			goto ret;
+		}
+	}
+	if (!f_p) {
+		if (forward) {
+			sbi->sb_max_fwd_alloc = forward * 3 / 4;
+			forward /= 2;
+			goto less_fwd;
+		}
+	}
+	sec = 0;
+	ret:
+	if (sec) {
+		i = 0;
+		do
+			hpfs_claim_alloc(s, sec + i);
+		while (unlikely(++i < n));
+	}
+	if (sec && f_p) {
+		for (i = 0; i < forward; i++) {
+			if (!hpfs_alloc_if_possible(s, sec + n + i)) {
+				hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
+				sec = 0;
+				break;
+			}
+		}
+	}
+	return sec;
+}
+
+static secno alloc_in_dirband(struct super_block *s, secno near)
+{
+	unsigned nr = near;
+	secno sec;
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	if (nr < sbi->sb_dirband_start)
+		nr = sbi->sb_dirband_start;
+	if (nr >= sbi->sb_dirband_start + sbi->sb_dirband_size)
+		nr = sbi->sb_dirband_start + sbi->sb_dirband_size - 4;
+	nr -= sbi->sb_dirband_start;
+	nr >>= 2;
+	sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
+	if (!sec) return 0;
+	hpfs_claim_dirband_alloc(s, sec);
+	return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
+}
+
+/* Alloc sector if it's free */
+
+int hpfs_alloc_if_possible(struct super_block *s, secno sec)
+{
+	struct quad_buffer_head qbh;
+	__le32 *bmp;
+	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
+	if (le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) & (1 << (sec & 0x1f))) {
+		bmp[(sec & 0x3fff) >> 5] &= cpu_to_le32(~(1 << (sec & 0x1f)));
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		hpfs_claim_alloc(s, sec);
+		return 1;
+	}
+	hpfs_brelse4(&qbh);
+	end:
+	return 0;
+}
+
+/* Free sectors in bitmaps */
+
+void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
+{
+	struct quad_buffer_head qbh;
+	__le32 *bmp;
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	/*pr_info("2 - ");*/
+	if (!n) return;
+	if (sec < 0x12) {
+		hpfs_error(s, "Trying to free reserved sector %08x", sec);
+		return;
+	}
+	sbi->sb_max_fwd_alloc += n > 0xffff ? 0xffff : n;
+	if (sbi->sb_max_fwd_alloc > 0xffffff) sbi->sb_max_fwd_alloc = 0xffffff;
+	new_map:
+	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
+		return;
+	}	
+	new_tst:
+	if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f) & 1)) {
+		hpfs_error(s, "sector %08x not allocated", sec);
+		hpfs_brelse4(&qbh);
+		return;
+	}
+	bmp[(sec & 0x3fff) >> 5] |= cpu_to_le32(1 << (sec & 0x1f));
+	hpfs_claim_free(s, sec);
+	if (!--n) {
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		return;
+	}	
+	if (!(++sec & 0x3fff)) {
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		goto new_map;
+	}
+	goto new_tst;
+}
+
+/*
+ * Check if there are at least n free dnodes on the filesystem.
+ * Called before adding to dnode. If we run out of space while
+ * splitting dnodes, it would corrupt dnode tree.
+ */
+
+int hpfs_check_free_dnodes(struct super_block *s, int n)
+{
+	int n_bmps = (hpfs_sb(s)->sb_fs_size + 0x4000 - 1) >> 14;
+	int b = hpfs_sb(s)->sb_c_bitmap & 0x0fffffff;
+	int i, j;
+	__le32 *bmp;
+	struct quad_buffer_head qbh;
+	if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
+		for (j = 0; j < 512; j++) {
+			unsigned k;
+			if (!le32_to_cpu(bmp[j])) continue;
+			for (k = le32_to_cpu(bmp[j]); k; k >>= 1) if (k & 1) if (!--n) {
+				hpfs_brelse4(&qbh);
+				return 0;
+			}
+		}
+	}
+	hpfs_brelse4(&qbh);
+	i = 0;
+	if (hpfs_sb(s)->sb_c_bitmap != -1) {
+		bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
+		goto chk_bmp;
+	}
+	chk_next:
+	if (i == b) i++;
+	if (i >= n_bmps) return 1;
+	bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
+	chk_bmp:
+	if (bmp) {
+		for (j = 0; j < 512; j++) {
+			u32 k;
+			if (!le32_to_cpu(bmp[j])) continue;
+			for (k = 0xf; k; k <<= 4)
+				if ((le32_to_cpu(bmp[j]) & k) == k) {
+					if (!--n) {
+						hpfs_brelse4(&qbh);
+						return 0;
+					}
+				}
+		}
+		hpfs_brelse4(&qbh);
+	}
+	i++;
+	goto chk_next;
+}
+
+void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
+{
+	if (hpfs_sb(s)->sb_chk) if (dno & 3) {
+		hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
+		return;
+	}
+	if (dno < hpfs_sb(s)->sb_dirband_start ||
+	    dno >= hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
+		hpfs_free_sectors(s, dno, 4);
+	} else {
+		struct quad_buffer_head qbh;
+		__le32 *bmp;
+		unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
+		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
+			return;
+		}
+		bmp[ssec >> 5] |= cpu_to_le32(1 << (ssec & 0x1f));
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		hpfs_claim_dirband_free(s, dno);
+	}
+}
+
+struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
+			 dnode_secno *dno, struct quad_buffer_head *qbh)
+{
+	struct dnode *d;
+	if (hpfs_get_free_dnodes(s) > FREE_DNODES_ADD) {
+		if (!(*dno = alloc_in_dirband(s, near)))
+			if (!(*dno = hpfs_alloc_sector(s, near, 4, 0))) return NULL;
+	} else {
+		if (!(*dno = hpfs_alloc_sector(s, near, 4, 0)))
+			if (!(*dno = alloc_in_dirband(s, near))) return NULL;
+	}
+	if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
+		hpfs_free_dnode(s, *dno);
+		return NULL;
+	}
+	memset(d, 0, 2048);
+	d->magic = cpu_to_le32(DNODE_MAGIC);
+	d->first_free = cpu_to_le32(52);
+	d->dirent[0] = 32;
+	d->dirent[2] = 8;
+	d->dirent[30] = 1;
+	d->dirent[31] = 255;
+	d->self = cpu_to_le32(*dno);
+	return d;
+}
+
+struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
+			  struct buffer_head **bh)
+{
+	struct fnode *f;
+	if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD))) return NULL;
+	if (!(f = hpfs_get_sector(s, *fno, bh))) {
+		hpfs_free_sectors(s, *fno, 1);
+		return NULL;
+	}	
+	memset(f, 0, 512);
+	f->magic = cpu_to_le32(FNODE_MAGIC);
+	f->ea_offs = cpu_to_le16(0xc4);
+	f->btree.n_free_nodes = 8;
+	f->btree.first_free = cpu_to_le16(8);
+	return f;
+}
+
+struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
+			  struct buffer_head **bh)
+{
+	struct anode *a;
+	if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD))) return NULL;
+	if (!(a = hpfs_get_sector(s, *ano, bh))) {
+		hpfs_free_sectors(s, *ano, 1);
+		return NULL;
+	}
+	memset(a, 0, 512);
+	a->magic = cpu_to_le32(ANODE_MAGIC);
+	a->self = cpu_to_le32(*ano);
+	a->btree.n_free_nodes = 40;
+	a->btree.n_used_nodes = 0;
+	a->btree.first_free = cpu_to_le16(8);
+	return a;
+}
+
+static unsigned find_run(__le32 *bmp, unsigned *idx)
+{
+	unsigned len;
+	while (tstbits(bmp, *idx, 1)) {
+		(*idx)++;
+		if (unlikely(*idx >= 0x4000))
+			return 0;
+	}
+	len = 1;
+	while (!tstbits(bmp, *idx + len, 1))
+		len++;
+	return len;
+}
+
+static int do_trim(struct super_block *s, secno start, unsigned len, secno limit_start, secno limit_end, unsigned minlen, unsigned *result)
+{
+	int err;
+	secno end;
+	if (fatal_signal_pending(current))
+		return -EINTR;
+	end = start + len;
+	if (start < limit_start)
+		start = limit_start;
+	if (end > limit_end)
+		end = limit_end;
+	if (start >= end)
+		return 0;
+	if (end - start < minlen)
+		return 0;
+	err = sb_issue_discard(s, start, end - start, GFP_NOFS, 0);
+	if (err)
+		return err;
+	*result += end - start;
+	return 0;
+}
+
+int hpfs_trim_fs(struct super_block *s, u64 start, u64 end, u64 minlen, unsigned *result)
+{
+	int err = 0;
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	unsigned idx, len, start_bmp, end_bmp;
+	__le32 *bmp;
+	struct quad_buffer_head qbh;
+
+	*result = 0;
+	if (!end || end > sbi->sb_fs_size)
+		end = sbi->sb_fs_size;
+	if (start >= sbi->sb_fs_size)
+		return 0;
+	if (minlen > 0x4000)
+		return 0;
+	if (start < sbi->sb_dirband_start + sbi->sb_dirband_size && end > sbi->sb_dirband_start) {
+		hpfs_lock(s);
+		if (s->s_flags & MS_RDONLY) {
+			err = -EROFS;
+			goto unlock_1;
+		}
+		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
+			err = -EIO;
+			goto unlock_1;
+		}
+		idx = 0;
+		while ((len = find_run(bmp, &idx)) && !err) {
+			err = do_trim(s, sbi->sb_dirband_start + idx * 4, len * 4, start, end, minlen, result);
+			idx += len;
+		}
+		hpfs_brelse4(&qbh);
+unlock_1:
+		hpfs_unlock(s);
+	}
+	start_bmp = start >> 14;
+	end_bmp = (end + 0x3fff) >> 14;
+	while (start_bmp < end_bmp && !err) {
+		hpfs_lock(s);
+		if (s->s_flags & MS_RDONLY) {
+			err = -EROFS;
+			goto unlock_2;
+		}
+		if (!(bmp = hpfs_map_bitmap(s, start_bmp, &qbh, "trim"))) {
+			err = -EIO;
+			goto unlock_2;
+		}
+		idx = 0;
+		while ((len = find_run(bmp, &idx)) && !err) {
+			err = do_trim(s, (start_bmp << 14) + idx, len, start, end, minlen, result);
+			idx += len;
+		}
+		hpfs_brelse4(&qbh);
+unlock_2:
+		hpfs_unlock(s);
+		start_bmp++;
+	}
+	return err;
+}