user/sven/linux.git/include/linux/jbd2.h, branch v3.0.85

jbd2: Fix oops in jbd2_journal_remove_journal_head()

2011-06-13T19:38:22Z

jbd2_journal_remove_journal_head() can oops when trying to access journal_head returned by bh2jh(). This is caused for example by the following race: TASK1 TASK2 jbd2_journal_commit_transaction() ... processing t_forget list __jbd2_journal_refile_buffer(jh); if (!jh->b_transaction) { jbd_unlock_bh_state(bh); jbd2_journal_try_to_free_buffers() jbd2_journal_grab_journal_head(bh) jbd_lock_bh_state(bh) __journal_try_to_free_buffer() jbd2_journal_put_journal_head(jh) jbd2_journal_remove_journal_head(bh); jbd2_journal_put_journal_head() in TASK2 sees that b_jcount == 0 and buffer is not part of any transaction and thus frees journal_head before TASK1 gets to doing so. Note that even buffer_head can be released by try_to_free_buffers() after jbd2_journal_put_journal_head() which adds even larger opportunity for oops (but I didn't see this happen in reality). Fix the problem by making transactions hold their own journal_head reference (in b_jcount). That way we don't have to remove journal_head explicitely via jbd2_journal_remove_journal_head() and instead just remove journal_head when b_jcount drops to zero. The result of this is that [__]jbd2_journal_refile_buffer(), [__]jbd2_journal_unfile_buffer(), and __jdb2_journal_remove_checkpoint() can free journal_head which needs modification of a few callers. Also we have to be careful because once journal_head is removed, buffer_head might be freed as well. So we have to get our own buffer_head reference where it matters. Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o"

jbd2: Add function jbd2_trans_will_send_data_barrier()

2011-05-24T15:59:18Z

Provide a function which returns whether a transaction with given tid will send a flush to the filesystem device. The function will be used by ext4 to detect whether fsync needs to send a separate flush or not. Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o"

jbd2: fix sending of data flush on journal commit

2011-05-24T15:52:40Z

In data=ordered mode, it's theoretically possible (however rare) that an inode is filed to transaction's t_inode_list and a flusher thread writes all the data and inode is reclaimed before the transaction starts to commit. In such a case, we could erroneously omit sending a flush to file system device when it is different from the journal device (because data can still be in disk cache only). Fix the problem by setting a flag in a transaction when some inode is added to it and then send disk flush in the commit code when the flag is set. Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o"

jbd2: add COW fields to struct jbd2_journal_handle

2011-03-21T01:13:43Z

Add fields needed for the copy-on-write ext4 development work. The h_cowing flag is used by ext4 snapshots code to mark the task in COWING state. The h_XXX_credits fields are used to track buffer credits usage (accounted by COW and non-COW operations). The h_cow_XXX fields are used as per task debugging counters. Merging this commit into mainline will allow users to test ext4 snapshots as a standalone module, without the need to patch and install a development kernel. Signed-off-by: Amir Goldstein Signed-off-by: "Theodore Ts'o"

ext4: dynamically allocate the jbd2_inode in ext4_inode_info as necessary

2011-01-10T17:29:43Z

Replace the jbd2_inode structure (which is 48 bytes) with a pointer and only allocate the jbd2_inode when it is needed --- that is, when the file system has a journal present and the inode has been opened for writing. This allows us to further slim down the ext4_inode_info structure. Signed-off-by: "Theodore Ts'o"

jbd2: Fix I/O hang in jbd2_journal_release_jbd_inode

2010-10-28T01:25:12Z

This fixes a hang seen in jbd2_journal_release_jbd_inode on a lot of Power 6 systems running with ext4. When we get in the hung state, all I/O to the disk in question gets blocked where we stay indefinitely. Looking at the task list, I can see we are stuck in jbd2_journal_release_jbd_inode waiting on a wake up. I added some debug code to detect this scenario and dump additional data if we were stuck in jbd2_journal_release_jbd_inode for longer than 30 minutes. When it hit, I was able to see that i_flags was 0, suggesting we missed the wake up. This patch changes i_flags to be an unsigned long, uses bit operators to access it, and adds barriers around the accesses. Prior to applying this patch, we were regularly hitting this hang on numerous systems in our test environment. After applying the patch, the hangs no longer occur. Signed-off-by: Brian King Signed-off-by: "Theodore Ts'o"

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2010-08-07T20:03:53Z

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (40 commits) ext4: Adding error check after calling ext4_mb_regular_allocator() ext4: Fix dirtying of journalled buffers in data=journal mode ext4: re-inline ext4_rec_len_(to|from)_disk functions jbd2: Remove t_handle_lock from start_this_handle() jbd2: Change j_state_lock to be a rwlock_t jbd2: Use atomic variables to avoid taking t_handle_lock in jbd2_journal_stop ext4: Add mount options in superblock ext4: force block allocation on quota_off ext4: fix freeze deadlock under IO ext4: drop inode from orphan list if ext4_delete_inode() fails ext4: check to make make sure bd_dev is set before dereferencing it jbd2: Make barrier messages less scary ext4: don't print scary messages for allocation failures post-abort ext4: fix EFBIG edge case when writing to large non-extent file ext4: fix ext4_get_blocks references ext4: Always journal quota file modifications ext4: Fix potential memory leak in ext4_fill_super ext4: Don't error out the fs if the user tries to make a file too big ext4: allocate stripe-multiple IOs on stripe boundaries ext4: move aio completion after unwritten extent conversion ... Fix up conflicts in fs/ext4/inode.c as per Ted. Fix up xfs conflicts as per earlier xfs merge.

jbd2: Remove t_handle_lock from start_this_handle()

2010-08-04T01:38:29Z

This should remove the last exclusive lock from start_this_handle(), so that we should now be able to start multiple transactions at the same time on large SMP systems. Signed-off-by: "Theodore Ts'o"

jbd2: Change j_state_lock to be a rwlock_t

2010-08-04T01:35:12Z

Lockstat reports have shown that j_state_lock is a major source of lock contention, especially on systems with more than 4 CPU cores. So change it to be a read/write spinlock. Signed-off-by: "Theodore Ts'o"

jbd2: Use atomic variables to avoid taking t_handle_lock in jbd2_journal_stop

2010-08-02T12:43:25Z

By using an atomic_t for t_updates and t_outstanding credits, this should allow us to not need to take transaction t_handle_lock in jbd2_journal_stop(). Signed-off-by: "Theodore Ts'o"