kernel/linux.git/fs/jbd2/transaction.c, branch linux-5.3.y

jbd2: introduce jbd2_inode dirty range scoping

2019-06-20T21:24:56+00:00

Currently both journal_submit_inode_data_buffers() and journal_finish_inode_data_buffers() operate on the entire address space of each of the inodes associated with a given journal entry. The consequence of this is that if we have an inode where we are constantly appending dirty pages we can end up waiting for an indefinite amount of time in journal_finish_inode_data_buffers() while we wait for all the pages under writeback to be written out. The easiest way to cause this type of workload is do just dd from /dev/zero to a file until it fills the entire filesystem. This can cause journal_finish_inode_data_buffers() to wait for the duration of the entire dd operation. We can improve this situation by scoping each of the inode dirty ranges associated with a given transaction. We do this via the jbd2_inode structure so that the scoping is contained within jbd2 and so that it follows the lifetime and locking rules for that structure. This allows us to limit the writeback & wait in journal_submit_inode_data_buffers() and journal_finish_inode_data_buffers() respectively to the dirty range for a given struct jdb2_inode, keeping us from waiting forever if the inode in question is still being appended to. Signed-off-by: Ross Zwisler Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara Cc: stable@vger.kernel.org

jbd2: fix potential double free

2019-05-11T01:15:47+00:00

When failing from creating cache jbd2_inode_cache, we will destroy the previously created cache jbd2_handle_cache twice. This patch fixes this by moving each cache initialization/destruction to its own separate, individual function. Signed-off-by: Chengguang Xu Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

jbd2: jbd2_get_transaction does not need to return a value

2019-03-01T05:36:57+00:00

In jbd2_get_transaction, a new transaction is initialized, and set to the j_running_transaction. No need for a return value, so remove it. Also, adjust some comments to match the actual operation of this function. Signed-off-by: Liu Song Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara

jbd2: fix compile warning when using JBUFFER_TRACE

2019-02-21T16:24:09+00:00

The jh pointer may be used uninitialized in the two cases below and the compiler complain about it when enabling JBUFFER_TRACE macro, fix them. In file included from fs/jbd2/transaction.c:19:0: fs/jbd2/transaction.c: In function ‘jbd2_journal_get_undo_access’: ./include/linux/jbd2.h:1637:38: warning: ‘jh’ is used uninitialized in this function [-Wuninitialized] #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0) ^ fs/jbd2/transaction.c:1219:23: note: ‘jh’ was declared here struct journal_head *jh; ^ In file included from fs/jbd2/transaction.c:19:0: fs/jbd2/transaction.c: In function ‘jbd2_journal_dirty_metadata’: ./include/linux/jbd2.h:1637:38: warning: ‘jh’ may be used uninitialized in this function [-Wmaybe-uninitialized] #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0) ^ fs/jbd2/transaction.c:1332:23: note: ‘jh’ was declared here struct journal_head *jh; ^ Signed-off-by: zhangyi (F) Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org Reviewed-by: Jan Kara

jbd2: discard dirty data when forgetting an un-journalled buffer

2019-02-11T04:26:06+00:00

We do not unmap and clear dirty flag when forgetting a buffer without journal or does not belongs to any transaction, so the invalid dirty data may still be written to the disk later. It's fine if the corresponding block is never used before the next mount, and it's also fine that we invoke clean_bdev_aliases() related functions to unmap the block device mapping when re-allocating such freed block as data block. But this logic is somewhat fragile and risky that may lead to data corruption if we forget to clean bdev aliases. So, It's better to discard dirty data during forget time. We have been already handled all the cases of forgetting journalled buffer, this patch deal with the remaining two cases. - buffer is not journalled yet, - buffer is journalled but doesn't belongs to any transaction. We invoke __bforget() instead of __brelese() when forgetting an un-journalled buffer in jbd2_journal_forget(). After this patch we can remove all clean_bdev_aliases() related calls in ext4. Suggested-by: Jan Kara Signed-off-by: zhangyi (F) Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara

jbd2: clear dirty flag when revoking a buffer from an older transaction

2019-02-11T04:23:04+00:00

Now, we capture a data corruption problem on ext4 while we're truncating an extent index block. Imaging that if we are revoking a buffer which has been journaled by the committing transaction, the buffer's jbddirty flag will not be cleared in jbd2_journal_forget(), so the commit code will set the buffer dirty flag again after refile the buffer. fsx kjournald2 jbd2_journal_commit_transaction jbd2_journal_revoke commit phase 1~5... jbd2_journal_forget belongs to older transaction commit phase 6 jbddirty not clear __jbd2_journal_refile_buffer __jbd2_journal_unfile_buffer test_clear_buffer_jbddirty mark_buffer_dirty Finally, if the freed extent index block was allocated again as data block by some other files, it may corrupt the file data after writing cached pages later, such as during unmount time. (In general, clean_bdev_aliases() related helpers should be invoked after re-allocation to prevent the above corruption, but unfortunately we missed it when zeroout the head of extra extent blocks in ext4_ext_handle_unwritten_extents()). This patch mark buffer as freed and set j_next_transaction to the new transaction when it already belongs to the committing transaction in jbd2_journal_forget(), so that commit code knows it should clear dirty bits when it is done with the buffer. This problem can be reproduced by xfstests generic/455 easily with seeds (3246 3247 3248 3249). Signed-off-by: zhangyi (F) Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara Cc: stable@vger.kernel.org

jbd2: clean up indentation issue, replace spaces with tab

2018-12-04T05:20:10+00:00

There is a statement that is indented with spaces, replace it with a tab. Reviewed-by: Jan Kara Signed-off-by: Colin Ian King Signed-off-by: Theodore Ts'o

jbd2: avoid long hold times of j_state_lock while committing a transaction

2018-12-04T04:16:07+00:00

We can hold j_state_lock for writing at the beginning of jbd2_journal_commit_transaction() for a rather long time (reportedly for 30 ms) due cleaning revoke bits of all revoked buffers under it. The handling of revoke tables as well as cleaning of t_reserved_list, and checkpoint lists does not need j_state_lock for anything. It is only needed to prevent new handles from joining the transaction. Generally T_LOCKED transaction state prevents new handles from joining the transaction - except for reserved handles which have to allowed to join while we wait for other handles to complete. To prevent reserved handles from joining the transaction while cleaning up lists, add new transaction state T_SWITCH and watch for it when starting reserved handles. With this we can just drop the lock for operations that don't need it. Reported-and-tested-by: Adrian Hunter Suggested-by: "Theodore Y. Ts'o" Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

jbd2: don't mark block as modified if the handle is out of credits

2018-06-17T00:21:45+00:00

Do not set the b_modified flag in block's journal head should not until after we're sure that jbd2_journal_dirty_metadat() will not abort with an error due to there not being enough space reserved in the jbd2 handle. Otherwise, future attempts to modify the buffer may lead a large number of spurious errors and warnings. This addresses CVE-2018-10883. https://bugzilla.kernel.org/show_bug.cgi?id=200071 Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

jbd2: remove NULL check before calling kmem_cache_destroy()

2018-05-21T02:38:26+00:00

The kmem_cache_destroy() function already checks for null pointers, so we can remove the check at the call site. This patch also sets jbd2_handle_cache and jbd2_inode_cache to be NULL after freeing them in jbd2_journal_destroy_handle_cache(). Signed-off-by: Wang Long Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara