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linux/fs/hpfs/anode.c
Gustavo A. R. Silva 68a7449062 fs: hpfs: Avoid multiple -Wflex-array-member-not-at-end warnings 
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

So, in order to avoid ending up with a flexible-array member in the
middle of other structs, we use the `struct_group_tagged()` helper
to create a new tagged `struct bplus_header_fixed`. This structure
groups together all the members of the flexible `struct bplus_header`
except the flexible array.

As a result, the array is effectively separated from the rest of the
members without modifying the memory layout of the flexible structure.
We then change the type of the middle struct member currently causing
trouble from `struct bplus_header` to `struct bplus_header_fixed`.

We also want to ensure that when new members need to be added to the
flexible structure, they are always included within the newly created
tagged struct. For this, we use `static_assert()`. This ensures that the
memory layout for both the flexible structure and the new tagged struct
is the same after any changes.

This approach avoids having to implement `struct bplus_header_fixed`
as a completely separate structure, thus preventing having to maintain
two independent but basically identical structures, closing the door
to potential bugs in the future.

We also use `container_of()` (via a wrapper) whenever we need to retrieve
a pointer to the flexible structure, through which we can access the
flexible-array member, if necessary.

So, with these changes, fix 26 of the following type of warnings:
fs/hpfs/hpfs.h:456:23: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
fs/hpfs/hpfs.h:498:23: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-09-08 16:28:38 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/hpfs/anode.c
*
* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
*
* handling HPFS anode tree that contains file allocation info
*/
#include "hpfs_fn.h"
/* Find a sector in allocation tree */
secno hpfs_bplus_lookup(struct super_block *s, struct inode *inode,
struct bplus_header *btree, unsigned sec,
struct buffer_head *bh)
{
anode_secno a = -1;
struct anode *anode;
int i;
int c1, c2 = 0;
go_down:
if (hpfs_sb(s)->sb_chk) if (hpfs_stop_cycles(s, a, &c1, &c2, "hpfs_bplus_lookup")) return -1;
if (bp_internal(btree)) {
for (i = 0; i < btree->n_used_nodes; i++)
if (le32_to_cpu(btree->u.internal[i].file_secno) > sec) {
a = le32_to_cpu(btree->u.internal[i].down);
brelse(bh);
if (!(anode = hpfs_map_anode(s, a, &bh))) return -1;
btree = GET_BTREE_PTR(&anode->btree);
goto go_down;
}
hpfs_error(s, "sector %08x not found in internal anode %08x", sec, a);
brelse(bh);
return -1;
}
for (i = 0; i < btree->n_used_nodes; i++)
if (le32_to_cpu(btree->u.external[i].file_secno) <= sec &&
le32_to_cpu(btree->u.external[i].file_secno) + le32_to_cpu(btree->u.external[i].length) > sec) {
a = le32_to_cpu(btree->u.external[i].disk_secno) + sec - le32_to_cpu(btree->u.external[i].file_secno);
if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, a, 1, "data")) {
brelse(bh);
return -1;
}
if (inode) {
struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
hpfs_inode->i_file_sec = le32_to_cpu(btree->u.external[i].file_secno);
hpfs_inode->i_disk_sec = le32_to_cpu(btree->u.external[i].disk_secno);
hpfs_inode->i_n_secs = le32_to_cpu(btree->u.external[i].length);
}
brelse(bh);
return a;
}
hpfs_error(s, "sector %08x not found in external anode %08x", sec, a);
brelse(bh);
return -1;
}
/* Add a sector to tree */
secno hpfs_add_sector_to_btree(struct super_block *s, secno node, int fnod, unsigned fsecno)
{
struct bplus_header *btree;
struct anode *anode = NULL, *ranode = NULL;
struct fnode *fnode;
anode_secno a, na = -1, ra, up = -1;
secno se;
struct buffer_head *bh, *bh1, *bh2;
int n;
unsigned fs;
int c1, c2 = 0;
if (fnod) {
if (!(fnode = hpfs_map_fnode(s, node, &bh))) return -1;
btree = GET_BTREE_PTR(&fnode->btree);
} else {
if (!(anode = hpfs_map_anode(s, node, &bh))) return -1;
btree = GET_BTREE_PTR(&anode->btree);
}
a = node;
go_down:
if ((n = btree->n_used_nodes - 1) < -!!fnod) {
hpfs_error(s, "anode %08x has no entries", a);
brelse(bh);
return -1;
}
if (bp_internal(btree)) {
a = le32_to_cpu(btree->u.internal[n].down);
btree->u.internal[n].file_secno = cpu_to_le32(-1);
mark_buffer_dirty(bh);
brelse(bh);
if (hpfs_sb(s)->sb_chk)
if (hpfs_stop_cycles(s, a, &c1, &c2, "hpfs_add_sector_to_btree #1")) return -1;
if (!(anode = hpfs_map_anode(s, a, &bh))) return -1;
btree = GET_BTREE_PTR(&anode->btree);
goto go_down;
}
if (n >= 0) {
if (le32_to_cpu(btree->u.external[n].file_secno) + le32_to_cpu(btree->u.external[n].length) != fsecno) {
hpfs_error(s, "allocated size %08x, trying to add sector %08x, %cnode %08x",
le32_to_cpu(btree->u.external[n].file_secno) + le32_to_cpu(btree->u.external[n].length), fsecno,
fnod?'f':'a', node);
brelse(bh);
return -1;
}
if (hpfs_alloc_if_possible(s, se = le32_to_cpu(btree->u.external[n].disk_secno) + le32_to_cpu(btree->u.external[n].length))) {
le32_add_cpu(&btree->u.external[n].length, 1);
mark_buffer_dirty(bh);
brelse(bh);
return se;
}
} else {
if (fsecno) {
hpfs_error(s, "empty file %08x, trying to add sector %08x", node, fsecno);
brelse(bh);
return -1;
}
se = !fnod ? node : (node + 16384) & ~16383;
}
if (!(se = hpfs_alloc_sector(s, se, 1, fsecno*ALLOC_M>ALLOC_FWD_MAX ? ALLOC_FWD_MAX : fsecno*ALLOC_M<ALLOC_FWD_MIN ? ALLOC_FWD_MIN : fsecno*ALLOC_M))) {
brelse(bh);
return -1;
}
fs = n < 0 ? 0 : le32_to_cpu(btree->u.external[n].file_secno) + le32_to_cpu(btree->u.external[n].length);
if (!btree->n_free_nodes) {
up = a != node ? le32_to_cpu(anode->up) : -1;
if (!(anode = hpfs_alloc_anode(s, a, &na, &bh1))) {
brelse(bh);
hpfs_free_sectors(s, se, 1);
return -1;
}
if (a == node && fnod) {
anode->up = cpu_to_le32(node);
anode->btree.flags |= BP_fnode_parent;
anode->btree.n_used_nodes = btree->n_used_nodes;
anode->btree.first_free = btree->first_free;
anode->btree.n_free_nodes = 40 - anode->btree.n_used_nodes;
memcpy(&anode->u, &btree->u, btree->n_used_nodes * 12);
btree->flags |= BP_internal;
btree->n_free_nodes = 11;
btree->n_used_nodes = 1;
btree->first_free = cpu_to_le16((char *)&(btree->u.internal[1]) - (char *)btree);
btree->u.internal[0].file_secno = cpu_to_le32(-1);
btree->u.internal[0].down = cpu_to_le32(na);
mark_buffer_dirty(bh);
} else if (!(ranode = hpfs_alloc_anode(s, /*a*/0, &ra, &bh2))) {
brelse(bh);
brelse(bh1);
hpfs_free_sectors(s, se, 1);
hpfs_free_sectors(s, na, 1);
return -1;
}
brelse(bh);
bh = bh1;
btree = GET_BTREE_PTR(&anode->btree);
}
btree->n_free_nodes--; n = btree->n_used_nodes++;
le16_add_cpu(&btree->first_free, 12);
btree->u.external[n].disk_secno = cpu_to_le32(se);
btree->u.external[n].file_secno = cpu_to_le32(fs);
btree->u.external[n].length = cpu_to_le32(1);
mark_buffer_dirty(bh);
brelse(bh);
if ((a == node && fnod) || na == -1) return se;
c2 = 0;
while (up != (anode_secno)-1) {
struct anode *new_anode;
if (hpfs_sb(s)->sb_chk)
if (hpfs_stop_cycles(s, up, &c1, &c2, "hpfs_add_sector_to_btree #2")) return -1;
if (up != node || !fnod) {
if (!(anode = hpfs_map_anode(s, up, &bh))) return -1;
btree = GET_BTREE_PTR(&anode->btree);
} else {
if (!(fnode = hpfs_map_fnode(s, up, &bh))) return -1;
btree = GET_BTREE_PTR(&fnode->btree);
}
if (btree->n_free_nodes) {
btree->n_free_nodes--; n = btree->n_used_nodes++;
le16_add_cpu(&btree->first_free, 8);
btree->u.internal[n].file_secno = cpu_to_le32(-1);
btree->u.internal[n].down = cpu_to_le32(na);
btree->u.internal[n-1].file_secno = cpu_to_le32(fs);
mark_buffer_dirty(bh);
brelse(bh);
brelse(bh2);
hpfs_free_sectors(s, ra, 1);
if ((anode = hpfs_map_anode(s, na, &bh))) {
anode->up = cpu_to_le32(up);
if (up == node && fnod)
anode->btree.flags |= BP_fnode_parent;
else
anode->btree.flags &= ~BP_fnode_parent;
mark_buffer_dirty(bh);
brelse(bh);
}
return se;
}
up = up != node ? le32_to_cpu(anode->up) : -1;
btree->u.internal[btree->n_used_nodes - 1].file_secno = cpu_to_le32(/*fs*/-1);
mark_buffer_dirty(bh);
brelse(bh);
a = na;
if ((new_anode = hpfs_alloc_anode(s, a, &na, &bh))) {
anode = new_anode;
/*anode->up = cpu_to_le32(up != -1 ? up : ra);*/
anode->btree.flags |= BP_internal;
anode->btree.n_used_nodes = 1;
anode->btree.n_free_nodes = 59;
anode->btree.first_free = cpu_to_le16(16);
GET_BTREE_PTR(&anode->btree)->u.internal[0].down = cpu_to_le32(a);
GET_BTREE_PTR(&anode->btree)->u.internal[0].file_secno = cpu_to_le32(-1);
mark_buffer_dirty(bh);
brelse(bh);
if ((anode = hpfs_map_anode(s, a, &bh))) {
anode->up = cpu_to_le32(na);
mark_buffer_dirty(bh);
brelse(bh);
}
} else na = a;
}
if ((anode = hpfs_map_anode(s, na, &bh))) {
anode->up = cpu_to_le32(node);
if (fnod)
anode->btree.flags |= BP_fnode_parent;
mark_buffer_dirty(bh);
brelse(bh);
}
if (!fnod) {
if (!(anode = hpfs_map_anode(s, node, &bh))) {
brelse(bh2);
return -1;
}
btree = GET_BTREE_PTR(&anode->btree);
} else {
if (!(fnode = hpfs_map_fnode(s, node, &bh))) {
brelse(bh2);
return -1;
}
btree = GET_BTREE_PTR(&fnode->btree);
}
ranode->up = cpu_to_le32(node);
memcpy(&ranode->btree, btree, le16_to_cpu(btree->first_free));
if (fnod)
ranode->btree.flags |= BP_fnode_parent;
GET_BTREE_PTR(&ranode->btree)->n_free_nodes = (bp_internal(GET_BTREE_PTR(&ranode->btree)) ? 60 : 40) - GET_BTREE_PTR(&ranode->btree)->n_used_nodes;
if (bp_internal(GET_BTREE_PTR(&ranode->btree))) for (n = 0; n < GET_BTREE_PTR(&ranode->btree)->n_used_nodes; n++) {
struct anode *unode;
if ((unode = hpfs_map_anode(s, le32_to_cpu(ranode->u.internal[n].down), &bh1))) {
unode->up = cpu_to_le32(ra);
unode->btree.flags &= ~BP_fnode_parent;
mark_buffer_dirty(bh1);
brelse(bh1);
}
}
btree->flags |= BP_internal;
btree->n_free_nodes = fnod ? 10 : 58;
btree->n_used_nodes = 2;
btree->first_free = cpu_to_le16((char *)&btree->u.internal[2] - (char *)btree);
btree->u.internal[0].file_secno = cpu_to_le32(fs);
btree->u.internal[0].down = cpu_to_le32(ra);
btree->u.internal[1].file_secno = cpu_to_le32(-1);
btree->u.internal[1].down = cpu_to_le32(na);
mark_buffer_dirty(bh);
brelse(bh);
mark_buffer_dirty(bh2);
brelse(bh2);
return se;
}
/*
* Remove allocation tree. Recursion would look much nicer but
* I want to avoid it because it can cause stack overflow.
*/
void hpfs_remove_btree(struct super_block *s, struct bplus_header *btree)
{
struct bplus_header *btree1 = btree;
struct anode *anode = NULL;
anode_secno ano = 0, oano;
struct buffer_head *bh;
int level = 0;
int pos = 0;
int i;
int c1, c2 = 0;
int d1, d2;
go_down:
d2 = 0;
while (bp_internal(btree1)) {
ano = le32_to_cpu(btree1->u.internal[pos].down);
if (level) brelse(bh);
if (hpfs_sb(s)->sb_chk)
if (hpfs_stop_cycles(s, ano, &d1, &d2, "hpfs_remove_btree #1"))
return;
if (!(anode = hpfs_map_anode(s, ano, &bh))) return;
btree1 = GET_BTREE_PTR(&anode->btree);
level++;
pos = 0;
}
for (i = 0; i < btree1->n_used_nodes; i++)
hpfs_free_sectors(s, le32_to_cpu(btree1->u.external[i].disk_secno), le32_to_cpu(btree1->u.external[i].length));
go_up:
if (!level) return;
brelse(bh);
if (hpfs_sb(s)->sb_chk)
if (hpfs_stop_cycles(s, ano, &c1, &c2, "hpfs_remove_btree #2")) return;
hpfs_free_sectors(s, ano, 1);
oano = ano;
ano = le32_to_cpu(anode->up);
if (--level) {
if (!(anode = hpfs_map_anode(s, ano, &bh))) return;
btree1 = GET_BTREE_PTR(&anode->btree);
} else btree1 = btree;
for (i = 0; i < btree1->n_used_nodes; i++) {
if (le32_to_cpu(btree1->u.internal[i].down) == oano) {
if ((pos = i + 1) < btree1->n_used_nodes)
goto go_down;
else
goto go_up;
}
}
hpfs_error(s,
"reference to anode %08x not found in anode %08x "
"(probably bad up pointer)",
oano, level ? ano : -1);
if (level)
brelse(bh);
}
/* Just a wrapper around hpfs_bplus_lookup .. used for reading eas */
static secno anode_lookup(struct super_block *s, anode_secno a, unsigned sec)
{
struct anode *anode;
struct buffer_head *bh;
if (!(anode = hpfs_map_anode(s, a, &bh))) return -1;
return hpfs_bplus_lookup(s, NULL, GET_BTREE_PTR(&anode->btree), sec, bh);
}
int hpfs_ea_read(struct super_block *s, secno a, int ano, unsigned pos,
unsigned len, char *buf)
{
struct buffer_head *bh;
char *data;
secno sec;
unsigned l;
while (len) {
if (ano) {
if ((sec = anode_lookup(s, a, pos >> 9)) == -1)
return -1;
} else sec = a + (pos >> 9);
if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, sec, 1, "ea #1")) return -1;
if (!(data = hpfs_map_sector(s, sec, &bh, (len - 1) >> 9)))
return -1;
l = 0x200 - (pos & 0x1ff); if (l > len) l = len;
memcpy(buf, data + (pos & 0x1ff), l);
brelse(bh);
buf += l; pos += l; len -= l;
}
return 0;
}
int hpfs_ea_write(struct super_block *s, secno a, int ano, unsigned pos,
unsigned len, const char *buf)
{
struct buffer_head *bh;
char *data;
secno sec;
unsigned l;
while (len) {
if (ano) {
if ((sec = anode_lookup(s, a, pos >> 9)) == -1)
return -1;
} else sec = a + (pos >> 9);
if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, sec, 1, "ea #2")) return -1;
if (!(data = hpfs_map_sector(s, sec, &bh, (len - 1) >> 9)))
return -1;
l = 0x200 - (pos & 0x1ff); if (l > len) l = len;
memcpy(data + (pos & 0x1ff), buf, l);
mark_buffer_dirty(bh);
brelse(bh);
buf += l; pos += l; len -= l;
}
return 0;
}
void hpfs_ea_remove(struct super_block *s, secno a, int ano, unsigned len)
{
struct anode *anode;
struct buffer_head *bh;
if (ano) {
if (!(anode = hpfs_map_anode(s, a, &bh))) return;
hpfs_remove_btree(s, GET_BTREE_PTR(&anode->btree));
brelse(bh);
hpfs_free_sectors(s, a, 1);
} else hpfs_free_sectors(s, a, (len + 511) >> 9);
}
/* Truncate allocation tree. Doesn't join anodes - I hope it doesn't matter */
void hpfs_truncate_btree(struct super_block *s, secno f, int fno, unsigned secs)
{
struct fnode *fnode;
struct anode *anode;
struct buffer_head *bh;
struct bplus_header *btree;
anode_secno node = f;
int i, j, nodes;
int c1, c2 = 0;
if (fno) {
if (!(fnode = hpfs_map_fnode(s, f, &bh))) return;
btree = GET_BTREE_PTR(&fnode->btree);
} else {
if (!(anode = hpfs_map_anode(s, f, &bh))) return;
btree = GET_BTREE_PTR(&anode->btree);
}
if (!secs) {
hpfs_remove_btree(s, btree);
if (fno) {
btree->n_free_nodes = 8;
btree->n_used_nodes = 0;
btree->first_free = cpu_to_le16(8);
btree->flags &= ~BP_internal;
mark_buffer_dirty(bh);
} else hpfs_free_sectors(s, f, 1);
brelse(bh);
return;
}
while (bp_internal(btree)) {
nodes = btree->n_used_nodes + btree->n_free_nodes;
for (i = 0; i < btree->n_used_nodes; i++)
if (le32_to_cpu(btree->u.internal[i].file_secno) >= secs) goto f;
brelse(bh);
hpfs_error(s, "internal btree %08x doesn't end with -1", node);
return;
f:
for (j = i + 1; j < btree->n_used_nodes; j++)
hpfs_ea_remove(s, le32_to_cpu(btree->u.internal[j].down), 1, 0);
btree->n_used_nodes = i + 1;
btree->n_free_nodes = nodes - btree->n_used_nodes;
btree->first_free = cpu_to_le16(8 + 8 * btree->n_used_nodes);
mark_buffer_dirty(bh);
if (btree->u.internal[i].file_secno == cpu_to_le32(secs)) {
brelse(bh);
return;
}
node = le32_to_cpu(btree->u.internal[i].down);
brelse(bh);
if (hpfs_sb(s)->sb_chk)
if (hpfs_stop_cycles(s, node, &c1, &c2, "hpfs_truncate_btree"))
return;
if (!(anode = hpfs_map_anode(s, node, &bh))) return;
btree = GET_BTREE_PTR(&anode->btree);
}
nodes = btree->n_used_nodes + btree->n_free_nodes;
for (i = 0; i < btree->n_used_nodes; i++)
if (le32_to_cpu(btree->u.external[i].file_secno) + le32_to_cpu(btree->u.external[i].length) >= secs) goto ff;
brelse(bh);
return;
ff:
if (secs <= le32_to_cpu(btree->u.external[i].file_secno)) {
hpfs_error(s, "there is an allocation error in file %08x, sector %08x", f, secs);
if (i) i--;
}
else if (le32_to_cpu(btree->u.external[i].file_secno) + le32_to_cpu(btree->u.external[i].length) > secs) {
hpfs_free_sectors(s, le32_to_cpu(btree->u.external[i].disk_secno) + secs -
le32_to_cpu(btree->u.external[i].file_secno), le32_to_cpu(btree->u.external[i].length)
- secs + le32_to_cpu(btree->u.external[i].file_secno)); /* I hope gcc optimizes this :-) */
btree->u.external[i].length = cpu_to_le32(secs - le32_to_cpu(btree->u.external[i].file_secno));
}
for (j = i + 1; j < btree->n_used_nodes; j++)
hpfs_free_sectors(s, le32_to_cpu(btree->u.external[j].disk_secno), le32_to_cpu(btree->u.external[j].length));
btree->n_used_nodes = i + 1;
btree->n_free_nodes = nodes - btree->n_used_nodes;
btree->first_free = cpu_to_le16(8 + 12 * btree->n_used_nodes);
mark_buffer_dirty(bh);
brelse(bh);
}
/* Remove file or directory and it's eas - note that directory must
be empty when this is called. */
void hpfs_remove_fnode(struct super_block *s, fnode_secno fno)
{
struct buffer_head *bh;
struct fnode *fnode;
struct extended_attribute *ea;
struct extended_attribute *ea_end;
if (!(fnode = hpfs_map_fnode(s, fno, &bh))) return;
if (!fnode_is_dir(fnode)) hpfs_remove_btree(s, GET_BTREE_PTR(&fnode->btree));
else hpfs_remove_dtree(s, le32_to_cpu(fnode->u.external[0].disk_secno));
ea_end = fnode_end_ea(fnode);
for (ea = fnode_ea(fnode); ea < ea_end; ea = next_ea(ea))
if (ea_indirect(ea))
hpfs_ea_remove(s, ea_sec(ea), ea_in_anode(ea), ea_len(ea));
hpfs_ea_ext_remove(s, le32_to_cpu(fnode->ea_secno), fnode_in_anode(fnode), le32_to_cpu(fnode->ea_size_l));
brelse(bh);
hpfs_free_sectors(s, fno, 1);
}
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