ext4: store maxbytes for bitmapped files and return EFBIG as appropriate From: Eric Sandeen Calculate & store the max offset for bitmapped files, and catch too-large seeks, truncates, and writes in ext4, shortening or rejecting as appropriate. Signed-off-by: Eric Sandeen --- --- fs/ext4/file.c | 19 ++++++++++++++++++- fs/ext4/inode.c | 15 ++++++++++++++- fs/ext4/super.c | 1 + include/linux/ext4_fs_sb.h | 1 + 4 files changed, 34 insertions(+), 2 deletions(-) Index: linux-2.6.24-rc3/fs/ext4/super.c =================================================================== --- linux-2.6.24-rc3.orig/fs/ext4/super.c 2007-12-05 11:41:21.000000000 -0800 +++ linux-2.6.24-rc3/fs/ext4/super.c 2007-12-05 11:41:41.000000000 -0800 @@ -1922,6 +1922,7 @@ static int ext4_fill_super (struct super } } + sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits); sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits); if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) { Index: linux-2.6.24-rc3/fs/ext4/file.c =================================================================== --- linux-2.6.24-rc3.orig/fs/ext4/file.c 2007-11-16 21:16:36.000000000 -0800 +++ linux-2.6.24-rc3/fs/ext4/file.c 2007-12-05 11:41:41.000000000 -0800 @@ -56,8 +56,25 @@ ext4_file_write(struct kiocb *iocb, cons ssize_t ret; int err; - ret = generic_file_aio_write(iocb, iov, nr_segs, pos); + /* + * If we have encountered a bitmap-format file, the size limit + * is smaller than s_maxbytes, which is for extent-mapped files. + */ + if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) { + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + size_t length = iov_length(iov, nr_segs); + + if (pos > sbi->s_bitmap_maxbytes) + return -EFBIG; + + if (pos + length > sbi->s_bitmap_maxbytes) { + nr_segs = iov_shorten((struct iovec *)iov, nr_segs, + sbi->s_bitmap_maxbytes - pos); + } + } + + ret = generic_file_aio_write(iocb, iov, nr_segs, pos); /* * Skip flushing if there was an error, or if nothing was written. */ Index: linux-2.6.24-rc3/fs/ext4/inode.c =================================================================== --- linux-2.6.24-rc3.orig/fs/ext4/inode.c 2007-12-05 11:33:25.000000000 -0800 +++ linux-2.6.24-rc3/fs/ext4/inode.c 2007-12-05 11:41:41.000000000 -0800 @@ -314,7 +314,9 @@ static int ext4_block_to_path(struct ino offsets[n++] = i_block & (ptrs - 1); final = ptrs; } else { - ext4_warning(inode->i_sb, "ext4_block_to_path", "block > big"); + ext4_warning(inode->i_sb, "ext4_block_to_path", "block %u > max", + i_block + direct_blocks + + indirect_blocks + double_blocks); } if (boundary) *boundary = final - 1 - (i_block & (ptrs - 1)); @@ -3092,6 +3094,17 @@ int ext4_setattr(struct dentry *dentry, ext4_journal_stop(handle); } + if (attr->ia_valid & ATTR_SIZE) { + if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) { + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + + if (attr->ia_size > sbi->s_bitmap_maxbytes) { + error = -EFBIG; + goto err_out; + } + } + } + if (S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) { handle_t *handle; Index: linux-2.6.24-rc3/include/linux/ext4_fs_sb.h =================================================================== --- linux-2.6.24-rc3.orig/include/linux/ext4_fs_sb.h 2007-12-05 11:33:20.000000000 -0800 +++ linux-2.6.24-rc3/include/linux/ext4_fs_sb.h 2007-12-05 11:41:41.000000000 -0800 @@ -38,6 +38,7 @@ struct ext4_sb_info { ext4_group_t s_groups_count; /* Number of groups in the fs */ unsigned long s_overhead_last; /* Last calculated overhead */ unsigned long s_blocks_last; /* Last seen block count */ + loff_t s_bitmap_maxbytes; /* max bytes for bitmap files */ struct buffer_head * s_sbh; /* Buffer containing the super block */ struct ext4_super_block * s_es; /* Pointer to the super block in the buffer */ struct buffer_head ** s_group_desc;