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ext4: store maxbytes for bitmapped files and return EFBIG as appropriate

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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 <sandeen@redhat.com>
This commit is contained in:
Eric Sandeen 2008-01-28 23:58:27 -05:00 committed by Theodore Ts'o
parent 19295529db
commit e2b4657453
4 changed files with 35 additions and 2 deletions
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19
fs/ext4/file.c
View File

@ -56,8 +56,25 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
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.
*/

16
fs/ext4/inode.c
View File

@ -314,7 +314,10 @@ static int ext4_block_to_path(struct inode *inode,
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 +3095,17 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
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;

1
fs/ext4/super.c
View File

@ -1922,6 +1922,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
}
}
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) {

1
include/linux/ext4_fs_sb.h
View File

@ -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;