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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
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@@ -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.
*/