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Jan Kara authored
Akira-san has been reporting rare deadlocks of his machine when running xfstests test 269 on ext4 filesystem. The problem turned out to be in ext4_da_reserve_metadata() and ext4_da_reserve_space() which called ext4_should_retry_alloc() while holding i_data_sem. Since ext4_should_retry_alloc() can force a transaction commit, this is a lock ordering violation and leads to deadlocks. Fix the problem by just removing the retry loops. These functions should just report ENOSPC to the caller (e.g. ext4_da_write_begin()) and that function must take care of retrying after dropping all necessary locks. Reported-and-tested-by:
Akira Fujita <a-fujita@rs.jp.nec.com> Reviewed-by:
Zheng Liu <wenqing.lz@taobao.com> Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
"Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
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