cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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alloc.c (14698B)


      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 *  linux/fs/hpfs/alloc.c
      4 *
      5 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
      6 *
      7 *  HPFS bitmap operations
      8 */
      9
     10#include "hpfs_fn.h"
     11
     12static void hpfs_claim_alloc(struct super_block *s, secno sec)
     13{
     14	struct hpfs_sb_info *sbi = hpfs_sb(s);
     15	if (sbi->sb_n_free != (unsigned)-1) {
     16		if (unlikely(!sbi->sb_n_free)) {
     17			hpfs_error(s, "free count underflow, allocating sector %08x", sec);
     18			sbi->sb_n_free = -1;
     19			return;
     20		}
     21		sbi->sb_n_free--;
     22	}
     23}
     24
     25static void hpfs_claim_free(struct super_block *s, secno sec)
     26{
     27	struct hpfs_sb_info *sbi = hpfs_sb(s);
     28	if (sbi->sb_n_free != (unsigned)-1) {
     29		if (unlikely(sbi->sb_n_free >= sbi->sb_fs_size)) {
     30			hpfs_error(s, "free count overflow, freeing sector %08x", sec);
     31			sbi->sb_n_free = -1;
     32			return;
     33		}
     34		sbi->sb_n_free++;
     35	}
     36}
     37
     38static void hpfs_claim_dirband_alloc(struct super_block *s, secno sec)
     39{
     40	struct hpfs_sb_info *sbi = hpfs_sb(s);
     41	if (sbi->sb_n_free_dnodes != (unsigned)-1) {
     42		if (unlikely(!sbi->sb_n_free_dnodes)) {
     43			hpfs_error(s, "dirband free count underflow, allocating sector %08x", sec);
     44			sbi->sb_n_free_dnodes = -1;
     45			return;
     46		}
     47		sbi->sb_n_free_dnodes--;
     48	}
     49}
     50
     51static void hpfs_claim_dirband_free(struct super_block *s, secno sec)
     52{
     53	struct hpfs_sb_info *sbi = hpfs_sb(s);
     54	if (sbi->sb_n_free_dnodes != (unsigned)-1) {
     55		if (unlikely(sbi->sb_n_free_dnodes >= sbi->sb_dirband_size / 4)) {
     56			hpfs_error(s, "dirband free count overflow, freeing sector %08x", sec);
     57			sbi->sb_n_free_dnodes = -1;
     58			return;
     59		}
     60		sbi->sb_n_free_dnodes++;
     61	}
     62}
     63
     64/*
     65 * Check if a sector is allocated in bitmap
     66 * This is really slow. Turned on only if chk==2
     67 */
     68
     69static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
     70{
     71	struct quad_buffer_head qbh;
     72	__le32 *bmp;
     73	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
     74	if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f)) & 1) {
     75		hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
     76		goto fail1;
     77	}
     78	hpfs_brelse4(&qbh);
     79	if (sec >= hpfs_sb(s)->sb_dirband_start && sec < hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
     80		unsigned ssec = (sec - hpfs_sb(s)->sb_dirband_start) / 4;
     81		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
     82		if ((le32_to_cpu(bmp[ssec >> 5]) >> (ssec & 0x1f)) & 1) {
     83			hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
     84			goto fail1;
     85		}
     86		hpfs_brelse4(&qbh);
     87	}
     88	return 0;
     89	fail1:
     90	hpfs_brelse4(&qbh);
     91	fail:
     92	return 1;
     93}
     94
     95/*
     96 * Check if sector(s) have proper number and additionally check if they're
     97 * allocated in bitmap.
     98 */
     99	
    100int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
    101{
    102	if (start + len < start || start < 0x12 ||
    103	    start + len > hpfs_sb(s)->sb_fs_size) {
    104	    	hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
    105		return 1;
    106	}
    107	if (hpfs_sb(s)->sb_chk>=2) {
    108		int i;
    109		for (i = 0; i < len; i++)
    110			if (chk_if_allocated(s, start + i, msg)) return 1;
    111	}
    112	return 0;
    113}
    114
    115static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
    116{
    117	struct quad_buffer_head qbh;
    118	__le32 *bmp;
    119	unsigned bs = near & ~0x3fff;
    120	unsigned nr = (near & 0x3fff) & ~(n - 1);
    121	/*unsigned mnr;*/
    122	unsigned i, q;
    123	int a, b;
    124	secno ret = 0;
    125	if (n != 1 && n != 4) {
    126		hpfs_error(s, "Bad allocation size: %d", n);
    127		return 0;
    128	}
    129	if (bs != ~0x3fff) {
    130		if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
    131	} else {
    132		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
    133	}
    134	if (!tstbits(bmp, nr, n + forward)) {
    135		ret = bs + nr;
    136		goto rt;
    137	}
    138	q = nr + n; b = 0;
    139	while ((a = tstbits(bmp, q, n + forward)) != 0) {
    140		q += a;
    141		if (n != 1) q = ((q-1)&~(n-1))+n;
    142		if (!b) {
    143			if (q>>5 != nr>>5) {
    144				b = 1;
    145				q = nr & 0x1f;
    146			}
    147		} else if (q > nr) break;
    148	}
    149	if (!a) {
    150		ret = bs + q;
    151		goto rt;
    152	}
    153	nr >>= 5;
    154	/*for (i = nr + 1; i != nr; i++, i &= 0x1ff) */
    155	i = nr;
    156	do {
    157		if (!le32_to_cpu(bmp[i])) goto cont;
    158		if (n + forward >= 0x3f && le32_to_cpu(bmp[i]) != 0xffffffff) goto cont;
    159		q = i<<5;
    160		if (i > 0) {
    161			unsigned k = le32_to_cpu(bmp[i-1]);
    162			while (k & 0x80000000) {
    163				q--; k <<= 1;
    164			}
    165		}
    166		if (n != 1) q = ((q-1)&~(n-1))+n;
    167		while ((a = tstbits(bmp, q, n + forward)) != 0) {
    168			q += a;
    169			if (n != 1) q = ((q-1)&~(n-1))+n;
    170			if (q>>5 > i) break;
    171		}
    172		if (!a) {
    173			ret = bs + q;
    174			goto rt;
    175		}
    176		cont:
    177		i++, i &= 0x1ff;
    178	} while (i != nr);
    179	rt:
    180	if (ret) {
    181		if (hpfs_sb(s)->sb_chk && ((ret >> 14) != (bs >> 14) || (le32_to_cpu(bmp[(ret & 0x3fff) >> 5]) | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
    182			hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
    183			ret = 0;
    184			goto b;
    185		}
    186		bmp[(ret & 0x3fff) >> 5] &= cpu_to_le32(~(((1 << n) - 1) << (ret & 0x1f)));
    187		hpfs_mark_4buffers_dirty(&qbh);
    188	}
    189	b:
    190	hpfs_brelse4(&qbh);
    191	uls:
    192	return ret;
    193}
    194
    195/*
    196 * Allocation strategy:	1) search place near the sector specified
    197 *			2) search bitmap where free sectors last found
    198 *			3) search all bitmaps
    199 *			4) search all bitmaps ignoring number of pre-allocated
    200 *				sectors
    201 */
    202
    203secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward)
    204{
    205	secno sec;
    206	int i;
    207	unsigned n_bmps;
    208	struct hpfs_sb_info *sbi = hpfs_sb(s);
    209	int f_p = 0;
    210	int near_bmp;
    211	if (forward < 0) {
    212		forward = -forward;
    213		f_p = 1;
    214	}
    215	n_bmps = (sbi->sb_fs_size + 0x4000 - 1) >> 14;
    216	if (near && near < sbi->sb_fs_size) {
    217		if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
    218		near_bmp = near >> 14;
    219	} else near_bmp = n_bmps / 2;
    220	/*
    221	if (b != -1) {
    222		if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
    223			b &= 0x0fffffff;
    224			goto ret;
    225		}
    226		if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
    227	*/
    228	if (!f_p) if (forward > sbi->sb_max_fwd_alloc) forward = sbi->sb_max_fwd_alloc;
    229	less_fwd:
    230	for (i = 0; i < n_bmps; i++) {
    231		if (near_bmp+i < n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i) << 14, n, forward)))) {
    232			sbi->sb_c_bitmap = near_bmp+i;
    233			goto ret;
    234		}	
    235		if (!forward) {
    236			if (near_bmp-i-1 >= 0 && ((sec = alloc_in_bmp(s, (near_bmp-i-1) << 14, n, forward)))) {
    237				sbi->sb_c_bitmap = near_bmp-i-1;
    238				goto ret;
    239			}
    240		} else {
    241			if (near_bmp+i >= n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i-n_bmps) << 14, n, forward)))) {
    242				sbi->sb_c_bitmap = near_bmp+i-n_bmps;
    243				goto ret;
    244			}
    245		}
    246		if (i == 1 && sbi->sb_c_bitmap != -1 && ((sec = alloc_in_bmp(s, (sbi->sb_c_bitmap) << 14, n, forward)))) {
    247			goto ret;
    248		}
    249	}
    250	if (!f_p) {
    251		if (forward) {
    252			sbi->sb_max_fwd_alloc = forward * 3 / 4;
    253			forward /= 2;
    254			goto less_fwd;
    255		}
    256	}
    257	sec = 0;
    258	ret:
    259	if (sec) {
    260		i = 0;
    261		do
    262			hpfs_claim_alloc(s, sec + i);
    263		while (unlikely(++i < n));
    264	}
    265	if (sec && f_p) {
    266		for (i = 0; i < forward; i++) {
    267			if (!hpfs_alloc_if_possible(s, sec + n + i)) {
    268				hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
    269				sec = 0;
    270				break;
    271			}
    272		}
    273	}
    274	return sec;
    275}
    276
    277static secno alloc_in_dirband(struct super_block *s, secno near)
    278{
    279	unsigned nr = near;
    280	secno sec;
    281	struct hpfs_sb_info *sbi = hpfs_sb(s);
    282	if (nr < sbi->sb_dirband_start)
    283		nr = sbi->sb_dirband_start;
    284	if (nr >= sbi->sb_dirband_start + sbi->sb_dirband_size)
    285		nr = sbi->sb_dirband_start + sbi->sb_dirband_size - 4;
    286	nr -= sbi->sb_dirband_start;
    287	nr >>= 2;
    288	sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
    289	if (!sec) return 0;
    290	hpfs_claim_dirband_alloc(s, sec);
    291	return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
    292}
    293
    294/* Alloc sector if it's free */
    295
    296int hpfs_alloc_if_possible(struct super_block *s, secno sec)
    297{
    298	struct quad_buffer_head qbh;
    299	__le32 *bmp;
    300	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
    301	if (le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) & (1 << (sec & 0x1f))) {
    302		bmp[(sec & 0x3fff) >> 5] &= cpu_to_le32(~(1 << (sec & 0x1f)));
    303		hpfs_mark_4buffers_dirty(&qbh);
    304		hpfs_brelse4(&qbh);
    305		hpfs_claim_alloc(s, sec);
    306		return 1;
    307	}
    308	hpfs_brelse4(&qbh);
    309	end:
    310	return 0;
    311}
    312
    313/* Free sectors in bitmaps */
    314
    315void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
    316{
    317	struct quad_buffer_head qbh;
    318	__le32 *bmp;
    319	struct hpfs_sb_info *sbi = hpfs_sb(s);
    320	/*pr_info("2 - ");*/
    321	if (!n) return;
    322	if (sec < 0x12) {
    323		hpfs_error(s, "Trying to free reserved sector %08x", sec);
    324		return;
    325	}
    326	sbi->sb_max_fwd_alloc += n > 0xffff ? 0xffff : n;
    327	if (sbi->sb_max_fwd_alloc > 0xffffff) sbi->sb_max_fwd_alloc = 0xffffff;
    328	new_map:
    329	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
    330		return;
    331	}	
    332	new_tst:
    333	if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f) & 1)) {
    334		hpfs_error(s, "sector %08x not allocated", sec);
    335		hpfs_brelse4(&qbh);
    336		return;
    337	}
    338	bmp[(sec & 0x3fff) >> 5] |= cpu_to_le32(1 << (sec & 0x1f));
    339	hpfs_claim_free(s, sec);
    340	if (!--n) {
    341		hpfs_mark_4buffers_dirty(&qbh);
    342		hpfs_brelse4(&qbh);
    343		return;
    344	}	
    345	if (!(++sec & 0x3fff)) {
    346		hpfs_mark_4buffers_dirty(&qbh);
    347		hpfs_brelse4(&qbh);
    348		goto new_map;
    349	}
    350	goto new_tst;
    351}
    352
    353/*
    354 * Check if there are at least n free dnodes on the filesystem.
    355 * Called before adding to dnode. If we run out of space while
    356 * splitting dnodes, it would corrupt dnode tree.
    357 */
    358
    359int hpfs_check_free_dnodes(struct super_block *s, int n)
    360{
    361	int n_bmps = (hpfs_sb(s)->sb_fs_size + 0x4000 - 1) >> 14;
    362	int b = hpfs_sb(s)->sb_c_bitmap & 0x0fffffff;
    363	int i, j;
    364	__le32 *bmp;
    365	struct quad_buffer_head qbh;
    366	if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
    367		for (j = 0; j < 512; j++) {
    368			unsigned k;
    369			if (!le32_to_cpu(bmp[j])) continue;
    370			for (k = le32_to_cpu(bmp[j]); k; k >>= 1) if (k & 1) if (!--n) {
    371				hpfs_brelse4(&qbh);
    372				return 0;
    373			}
    374		}
    375	}
    376	hpfs_brelse4(&qbh);
    377	i = 0;
    378	if (hpfs_sb(s)->sb_c_bitmap != -1) {
    379		bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
    380		goto chk_bmp;
    381	}
    382	chk_next:
    383	if (i == b) i++;
    384	if (i >= n_bmps) return 1;
    385	bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
    386	chk_bmp:
    387	if (bmp) {
    388		for (j = 0; j < 512; j++) {
    389			u32 k;
    390			if (!le32_to_cpu(bmp[j])) continue;
    391			for (k = 0xf; k; k <<= 4)
    392				if ((le32_to_cpu(bmp[j]) & k) == k) {
    393					if (!--n) {
    394						hpfs_brelse4(&qbh);
    395						return 0;
    396					}
    397				}
    398		}
    399		hpfs_brelse4(&qbh);
    400	}
    401	i++;
    402	goto chk_next;
    403}
    404
    405void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
    406{
    407	if (hpfs_sb(s)->sb_chk) if (dno & 3) {
    408		hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
    409		return;
    410	}
    411	if (dno < hpfs_sb(s)->sb_dirband_start ||
    412	    dno >= hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
    413		hpfs_free_sectors(s, dno, 4);
    414	} else {
    415		struct quad_buffer_head qbh;
    416		__le32 *bmp;
    417		unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
    418		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
    419			return;
    420		}
    421		bmp[ssec >> 5] |= cpu_to_le32(1 << (ssec & 0x1f));
    422		hpfs_mark_4buffers_dirty(&qbh);
    423		hpfs_brelse4(&qbh);
    424		hpfs_claim_dirband_free(s, dno);
    425	}
    426}
    427
    428struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
    429			 dnode_secno *dno, struct quad_buffer_head *qbh)
    430{
    431	struct dnode *d;
    432	if (hpfs_get_free_dnodes(s) > FREE_DNODES_ADD) {
    433		if (!(*dno = alloc_in_dirband(s, near)))
    434			if (!(*dno = hpfs_alloc_sector(s, near, 4, 0))) return NULL;
    435	} else {
    436		if (!(*dno = hpfs_alloc_sector(s, near, 4, 0)))
    437			if (!(*dno = alloc_in_dirband(s, near))) return NULL;
    438	}
    439	if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
    440		hpfs_free_dnode(s, *dno);
    441		return NULL;
    442	}
    443	memset(d, 0, 2048);
    444	d->magic = cpu_to_le32(DNODE_MAGIC);
    445	d->first_free = cpu_to_le32(52);
    446	d->dirent[0] = 32;
    447	d->dirent[2] = 8;
    448	d->dirent[30] = 1;
    449	d->dirent[31] = 255;
    450	d->self = cpu_to_le32(*dno);
    451	return d;
    452}
    453
    454struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
    455			  struct buffer_head **bh)
    456{
    457	struct fnode *f;
    458	if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD))) return NULL;
    459	if (!(f = hpfs_get_sector(s, *fno, bh))) {
    460		hpfs_free_sectors(s, *fno, 1);
    461		return NULL;
    462	}	
    463	memset(f, 0, 512);
    464	f->magic = cpu_to_le32(FNODE_MAGIC);
    465	f->ea_offs = cpu_to_le16(0xc4);
    466	f->btree.n_free_nodes = 8;
    467	f->btree.first_free = cpu_to_le16(8);
    468	return f;
    469}
    470
    471struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
    472			  struct buffer_head **bh)
    473{
    474	struct anode *a;
    475	if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD))) return NULL;
    476	if (!(a = hpfs_get_sector(s, *ano, bh))) {
    477		hpfs_free_sectors(s, *ano, 1);
    478		return NULL;
    479	}
    480	memset(a, 0, 512);
    481	a->magic = cpu_to_le32(ANODE_MAGIC);
    482	a->self = cpu_to_le32(*ano);
    483	a->btree.n_free_nodes = 40;
    484	a->btree.n_used_nodes = 0;
    485	a->btree.first_free = cpu_to_le16(8);
    486	return a;
    487}
    488
    489static unsigned find_run(__le32 *bmp, unsigned *idx)
    490{
    491	unsigned len;
    492	while (tstbits(bmp, *idx, 1)) {
    493		(*idx)++;
    494		if (unlikely(*idx >= 0x4000))
    495			return 0;
    496	}
    497	len = 1;
    498	while (!tstbits(bmp, *idx + len, 1))
    499		len++;
    500	return len;
    501}
    502
    503static int do_trim(struct super_block *s, secno start, unsigned len, secno limit_start, secno limit_end, unsigned minlen, unsigned *result)
    504{
    505	int err;
    506	secno end;
    507	if (fatal_signal_pending(current))
    508		return -EINTR;
    509	end = start + len;
    510	if (start < limit_start)
    511		start = limit_start;
    512	if (end > limit_end)
    513		end = limit_end;
    514	if (start >= end)
    515		return 0;
    516	if (end - start < minlen)
    517		return 0;
    518	err = sb_issue_discard(s, start, end - start, GFP_NOFS, 0);
    519	if (err)
    520		return err;
    521	*result += end - start;
    522	return 0;
    523}
    524
    525int hpfs_trim_fs(struct super_block *s, u64 start, u64 end, u64 minlen, unsigned *result)
    526{
    527	int err = 0;
    528	struct hpfs_sb_info *sbi = hpfs_sb(s);
    529	unsigned idx, len, start_bmp, end_bmp;
    530	__le32 *bmp;
    531	struct quad_buffer_head qbh;
    532
    533	*result = 0;
    534	if (!end || end > sbi->sb_fs_size)
    535		end = sbi->sb_fs_size;
    536	if (start >= sbi->sb_fs_size)
    537		return 0;
    538	if (minlen > 0x4000)
    539		return 0;
    540	if (start < sbi->sb_dirband_start + sbi->sb_dirband_size && end > sbi->sb_dirband_start) {
    541		hpfs_lock(s);
    542		if (sb_rdonly(s)) {
    543			err = -EROFS;
    544			goto unlock_1;
    545		}
    546		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
    547			err = -EIO;
    548			goto unlock_1;
    549		}
    550		idx = 0;
    551		while ((len = find_run(bmp, &idx)) && !err) {
    552			err = do_trim(s, sbi->sb_dirband_start + idx * 4, len * 4, start, end, minlen, result);
    553			idx += len;
    554		}
    555		hpfs_brelse4(&qbh);
    556unlock_1:
    557		hpfs_unlock(s);
    558	}
    559	start_bmp = start >> 14;
    560	end_bmp = (end + 0x3fff) >> 14;
    561	while (start_bmp < end_bmp && !err) {
    562		hpfs_lock(s);
    563		if (sb_rdonly(s)) {
    564			err = -EROFS;
    565			goto unlock_2;
    566		}
    567		if (!(bmp = hpfs_map_bitmap(s, start_bmp, &qbh, "trim"))) {
    568			err = -EIO;
    569			goto unlock_2;
    570		}
    571		idx = 0;
    572		while ((len = find_run(bmp, &idx)) && !err) {
    573			err = do_trim(s, (start_bmp << 14) + idx, len, start, end, minlen, result);
    574			idx += len;
    575		}
    576		hpfs_brelse4(&qbh);
    577unlock_2:
    578		hpfs_unlock(s);
    579		start_bmp++;
    580	}
    581	return err;
    582}