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ext4: avoid overlapping preallocations due to overflow
[ Upstream commit bedc5d3 ] Let's say we want to allocate 2 blocks starting from 4294966386, after predicting the file size, start is aligned to 4294965248, len is changed to 2048, then end = start + size = 0x100000000. Since end is of type ext4_lblk_t, i.e. uint, end is truncated to 0. This causes (pa->pa_lstart >= end) to always hold when checking if the current extent to be allocated crosses already preallocated blocks, so the resulting ac_g_ex may cross already preallocated blocks. Hence we convert the end type to loff_t and use pa_logical_end() to avoid overflow. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20230724121059.11834-4-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <sashal@kernel.org>
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