From: Arnd Bergmann <a...@arndb.de>
gcc-10 correctly points out a memcpy beyond the end of the structure
it gets copied into:
fs/omfs/file.c: In function 'omfs_grow_extent':
cc1: warning: writing 16 bytes into a region of size 0 [-Wstringop-overflow=]
In file included from fs/omfs/omfs.h:8,
from fs/omfs/file.c:11:
fs/omfs/omfs_fs.h:80:27: note: at offset 0 to object 'e_entry' with size 16
declared here
80 | struct omfs_extent_entry e_entry; /* start of extent entries */
| ^~~~~~~
This is not a bug however, as the file system layout contains an array
of extent entries instead of just a single one that was part of the
structure definition.
Changing the definition to use a c99 flexible array member makes
makes the code match the actual layout, which avoids the warning and
an odd '+1' in the calculation of the number of extent entries.
Fixes: 8f09e98768c1 ("omfs: add file routines")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
fs/omfs/file.c | 12 ++++++------
fs/omfs/omfs_fs.h | 2 +-
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/fs/omfs/file.c b/fs/omfs/file.c
index d1304acf3ff8..4bd9d0c140e1 100644
--- a/fs/omfs/file.c
+++ b/fs/omfs/file.c
@@ -14,7 +14,7 @@ static u32 omfs_max_extents(struct omfs_sb_info *sbi, int
offset)
{
return (sbi->s_sys_blocksize - offset -
sizeof(struct omfs_extent)) /
- sizeof(struct omfs_extent_entry) + 1;
+ sizeof(struct omfs_extent_entry);
}
void omfs_make_empty_table(struct buffer_head *bh, int offset)
@@ -24,8 +24,8 @@ void omfs_make_empty_table(struct buffer_head *bh, int offset)
oe->e_next = ~cpu_to_be64(0ULL);
oe->e_extent_count = cpu_to_be32(1),
oe->e_fill = cpu_to_be32(0x22),
- oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);
- oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);
+ oe->e_entry[0].e_cluster = ~cpu_to_be64(0ULL);
+ oe->e_entry[0].e_blocks = ~cpu_to_be64(0ULL);
}
int omfs_shrink_inode(struct inode *inode)
@@ -68,7 +68,7 @@ int omfs_shrink_inode(struct inode *inode)
last = next;
next = be64_to_cpu(oe->e_next);
- entry = &oe->e_entry;
+ entry = oe->e_entry;
/* ignore last entry as it is the terminator */
for (; extent_count > 1; extent_count--) {
@@ -117,7 +117,7 @@ static int omfs_grow_extent(struct inode *inode, struct
omfs_extent *oe,
u64 *ret_block)
{
struct omfs_extent_entry *terminator;
- struct omfs_extent_entry *entry = &oe->e_entry;
+ struct omfs_extent_entry *entry = oe->e_entry;
struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
u32 extent_count = be32_to_cpu(oe->e_extent_count);
u64 new_block = 0;
@@ -245,7 +245,7 @@ static int omfs_get_block(struct inode *inode, sector_t
block,
extent_count = be32_to_cpu(oe->e_extent_count);
next = be64_to_cpu(oe->e_next);
- entry = &oe->e_entry;
+ entry = oe->e_entry;
if (extent_count > max_extents)
goto out_brelse;
diff --git a/fs/omfs/omfs_fs.h b/fs/omfs/omfs_fs.h
index caecb3d5a344..1ff6b9e41297 100644
--- a/fs/omfs/omfs_fs.h
+++ b/fs/omfs/omfs_fs.h
@@ -77,7 +77,7 @@ struct omfs_extent {
__be64 e_next; /* next extent table location */
__be32 e_extent_count; /* total # extents in this table */
__be32 e_fill;
- struct omfs_extent_entry e_entry; /* start of extent entries */
+ struct omfs_extent_entry e_entry[]; /* start of extent entries */
};
#endif
--
2.29.2
