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hfs: fix error code when writing beyond volume capacity

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Likewise HFS+, HFS has the same issue of returning
the -ENOSPC error code instead of -EFBIG in the case
if there is the effort to write beyond 8TiB.

The root cause is that hfs_fill_super() sets s_maxbytes
as MAX_LFS_FILESIZE. VFS therefore considers the write
position valid and calls into the filesystem. Because HFS
does not support holes, cont_write_begin() zero-fills
the entire intermediate range from the current end-of-file
to the target offset. On a small test volume this exhausts
free space long before any block-number overflow is detected,
producing -ENOSPC instead of -EFBIG.

This patch fixes the issue by adding a bounds check
at the top of hfs_write_begin(). If the requested write
position is at or beyond the actual capacity of the volume
in bytes, return -EFBIG immediately before cont_write_begin()
is entered and before any zero-fill I/O is attempted.

cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Link: https://lore.kernel.org/r/20260706221804.140295-2-slava@dubeyko.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
This commit is contained in:
Viacheslav Dubeyko
2026-07-06 15:18:05 -07:00
parent e2ea5cac61
commit c6decf13bf
1 changed files with 9 additions and 1 deletions
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10
fs/hfs/inode.c
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@@ -49,11 +49,19 @@ int hfs_write_begin(const struct kiocb *iocb, struct address_space *mapping,
loff_t pos, unsigned int len, struct folio **foliop,
void **fsdata)
{
struct inode *inode = mapping->host;
struct hfs_sb_info *sbi = HFS_SB(inode->i_sb);
loff_t total_capacity;
int ret;
total_capacity = (loff_t)sbi->fs_ablocks * sbi->alloc_blksz;
if (pos >= total_capacity)
return -EFBIG;
ret = cont_write_begin(iocb, mapping, pos, len, foliop, fsdata,
hfs_get_block,
&HFS_I(mapping->host)->phys_size);
&HFS_I(inode)->phys_size);
if (unlikely(ret))
hfs_write_failed(mapping, pos + len);