user/sven/linux.git/fs/ext4/inode.c, branch v4.7.2

ext4: don't call ext4_should_journal_data() on the journal inode

2016-08-16T07:35:00Z

commit 6a7fd522a7c94cdef0a3b08acf8e6702056e635c upstream. If ext4_fill_super() fails early, it's possible for ext4_evict_inode() to call ext4_should_journal_data() before superblock options and flags are fully set up. In that case, the iput() on the journal inode can end up causing a BUG(). Work around this problem by reordering the tests so we only call ext4_should_journal_data() after we know it's not the journal inode. Fixes: 2d859db3e4 ("ext4: fix data corruption in inodes with journalled data") Fixes: 2b405bfa84 ("ext4: fix data=journal fast mount/umount hang") Cc: Jan Kara Signed-off-by: Vegard Nossum Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

ext4: fix deadlock during page writeback

2016-08-16T07:35:00Z

commit 646caa9c8e196880b41cd3e3d33a2ebc752bdb85 upstream. Commit 06bd3c36a733 (ext4: fix data exposure after a crash) uncovered a deadlock in ext4_writepages() which was previously much harder to hit. After this commit xfstest generic/130 reproduces the deadlock on small filesystems. The problem happens when ext4_do_update_inode() sets LARGE_FILE feature and marks current inode handle as synchronous. That subsequently results in ext4_journal_stop() called from ext4_writepages() to block waiting for transaction commit while still holding page locks, reference to io_end, and some prepared bio in mpd structure each of which can possibly block transaction commit from completing and thus results in deadlock. Fix the problem by releasing page locks, io_end reference, and submitting prepared bio before calling ext4_journal_stop(). [ Changed to defer the call to ext4_journal_stop() only if the handle is synchronous. --tytso ] Reported-and-tested-by: Eryu Guan Signed-off-by: Theodore Ts'o Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2016-05-24T19:55:26Z

Pull ext4 updates from Ted Ts'o: "Fix a number of bugs, most notably a potential stale data exposure after a crash and a potential BUG_ON crash if a file has the data journalling flag enabled while it has dirty delayed allocation blocks that haven't been written yet. Also fix a potential crash in the new project quota code and a maliciously corrupted file system. In addition, fix some DAX-specific bugs, including when there is a transient ENOSPC situation and races between writes via direct I/O and an mmap'ed segment that could lead to lost I/O. Finally the usual set of miscellaneous cleanups" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (23 commits) ext4: pre-zero allocated blocks for DAX IO ext4: refactor direct IO code ext4: fix race in transient ENOSPC detection ext4: handle transient ENOSPC properly for DAX dax: call get_blocks() with create == 1 for write faults to unwritten extents ext4: remove unmeetable inconsisteny check from ext4_find_extent() jbd2: remove excess descriptions for handle_s ext4: remove unnecessary bio get/put ext4: silence UBSAN in ext4_mb_init() ext4: address UBSAN warning in mb_find_order_for_block() ext4: fix oops on corrupted filesystem ext4: fix check of dqget() return value in ext4_ioctl_setproject() ext4: clean up error handling when orphan list is corrupted ext4: fix hang when processing corrupted orphaned inode list ext4: remove trailing \n from ext4_warning/ext4_error calls ext4: fix races between changing inode journal mode and ext4_writepages ext4: handle unwritten or delalloc buffers before enabling data journaling ext4: fix jbd2 handle extension in ext4_ext_truncate_extend_restart() ext4: do not ask jbd2 to write data for delalloc buffers jbd2: add support for avoiding data writes during transaction commits ...

ext4: pre-zero allocated blocks for DAX IO

2016-05-13T04:51:15Z

Currently ext4 treats DAX IO the same way as direct IO. I.e., it allocates unwritten extents before IO is done and converts unwritten extents afterwards. However this way DAX IO can race with page fault to the same area: ext4_ext_direct_IO() dax_fault() dax_io() get_block() - allocates unwritten extent copy_from_iter_pmem() get_block() - converts unwritten block to written and zeroes it out ext4_convert_unwritten_extents() So data written with DAX IO gets lost. Similarly dax_new_buf() called from dax_io() can overwrite data that has been already written to the block via mmap. Fix the problem by using pre-zeroed blocks for DAX IO the same way as we use them for DAX mmap. The downside of this solution is that every allocating write writes each block twice (once zeros, once data). Fixing the race with locking is possible as well however we would need to lock-out faults for the whole range written to by DAX IO. And that is not easy to do without locking-out faults for the whole file which seems too aggressive. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

ext4: refactor direct IO code

2016-05-13T04:44:16Z

Currently ext4 direct IO handling is split between ext4_ext_direct_IO() and ext4_ind_direct_IO(). However the extent based function calls into the indirect based one for some cases and for example it is not able to handle file extending. Previously it was not also properly handling retries in case of ENOSPC errors. With DAX things would get even more contrieved so just refactor the direct IO code and instead of indirect / extent split do the split to read vs writes. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

ext4: handle transient ENOSPC properly for DAX

2016-05-13T04:38:16Z

ext4_dax_get_blocks() was accidentally omitted fixing get blocks handlers to properly handle transient ENOSPC errors. Fix it now to use ext4_get_blocks_trans() helper which takes care of these errors. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

direct-io: eliminate the offset argument to ->direct_IO

2016-05-01T23:58:39Z

Including blkdev_direct_IO and dax_do_io. It has to be ki_pos to actually work, so eliminate the superflous argument. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

ext4: fix races between changing inode journal mode and ext4_writepages

2016-04-26T03:22:35Z

In ext4, there is a race condition between changing inode journal mode and ext4_writepages(). While ext4_writepages() is executed on a non-journalled mode inode, the inode's journal mode could be enabled by ioctl() and then, some pages dirtied after switching the journal mode will be still exposed to ext4_writepages() in non-journaled mode. To resolve this problem, we use fs-wide per-cpu rw semaphore by Jan Kara's suggestion because we don't want to waste ext4_inode_info's space for this extra rare case. Signed-off-by: Daeho Jeong Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara

ext4: handle unwritten or delalloc buffers before enabling data journaling

2016-04-26T03:21:00Z

We already allocate delalloc blocks before changing the inode mode into "per-file data journal" mode to prevent delalloc blocks from remaining not allocated, but another issue concerned with "BH_Unwritten" status still exists. For example, by fallocate(), several buffers' status change into "BH_Unwritten", but these buffers cannot be processed by ext4_alloc_da_blocks(). So, they still remain in unwritten status after per-file data journaling is enabled and they cannot be changed into written status any more and, if they are journaled and eventually checkpointed, these unwritten buffer will cause a kernel panic by the below BUG_ON() function of submit_bh_wbc() when they are submitted during checkpointing. static int submit_bh_wbc(int rw, struct buffer_head *bh,... { ... BUG_ON(buffer_unwritten(bh)); Moreover, when "dioread_nolock" option is enabled, the status of a buffer is changed into "BH_Unwritten" after write_begin() completes and the "BH_Unwritten" status will be cleared after I/O is done. Therefore, if a buffer's status is changed into unwrutten but the buffer's I/O is not submitted and completed, it can cause the same problem after enabling per-file data journaling. You can easily generate this bug by executing the following command. ./kvm-xfstests -C 10000 -m nodelalloc,dioread_nolock generic/269 To resolve these problems and define a boundary between the previous mode and per-file data journaling mode, we need to flush and wait all the I/O of buffers of a file before enabling per-file data journaling of the file. Signed-off-by: Daeho Jeong Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara

ext4: do not ask jbd2 to write data for delalloc buffers

2016-04-24T04:56:08Z

Currently we ask jbd2 to write all dirty allocated buffers before committing a transaction when doing writeback of delay allocated blocks. However this is unnecessary since we move all pages to writeback state before dropping a transaction handle and then submit all the necessary IO. We still need the transaction commit to wait for all the outstanding writeback before flushing disk caches during transaction commit to avoid data exposure issues though. Use the new jbd2 capability and ask it to only wait for outstanding writeback during transaction commit when writing back data in ext4_writepages(). Tested-by: "HUANG Weller (CM/ESW12-CN)" Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o