- 10 Oct, 2012 1 commit
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Dmitry Monakhov authored
We assumed that at the time we call ext4_convert_unwritten_extents_endio() extent in question is fully inside [map.m_lblk, map->m_len] because it was already split during submission. But this may not be true due to a race between writeback vs fallocate. If extent in question is larger than requested we will split it again. Special precautions should being done if zeroout required because [map.m_lblk, map->m_len] already contains valid data. Signed-off-by:
Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by:
"Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
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- 05 Oct, 2012 2 commits
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Dmitry Monakhov authored
Fallocate should wait for pended ext4_convert_unwritten_extents() otherwise following race may happen: ftruncate( ,12288); fallocate( ,0, 4096) io_sibmit( ,0, 4096); /* Write to fallocated area, split extent if needed */ fallocate( ,0, 8192); /* Grow extent and broke assumption about extent */ Later kwork completion will do: ->ext4_convert_unwritten_extents (0, 4096) ->ext4_map_blocks(handle, inode, &map, EXT4_GET_BLOCKS_IO_CONVERT_EXT); ->ext4_ext_map_blocks() /* Will find new extent: ex = [0,2] !!!!!! */ ->ext4_ext_handle_uninitialized_extents() ->ext4_convert_unwritten_extents_endio() /* convert [0,2] extent to initialized, but only[0,1] was written */ Signed-off-by: -
Dmitry Monakhov authored
BUG #1) All places where we call ext4_flush_completed_IO are broken because buffered io and DIO/AIO goes through three stages 1) submitted io, 2) completed io (in i_completed_io_list) conversion pended 3) finished io (conversion done) And by calling ext4_flush_completed_IO we will flush only requests which were in (2) stage, which is wrong because: 1) punch_hole and truncate _must_ wait for all outstanding unwritten io regardless to it's state. 2) fsync and nolock_dio_read should also wait because there is a time window between end_page_writeback() and ext4_add_complete_io() As result integrity fsync is broken in case of buffered write to fallocated region: fsync blkdev_completion ->filemap_write_and_wait_range ->ext4_end_bio ->end_page_writeback <-- filemap_write_and_wait_range return ->ext4_flush_completed_IO sees empty i_completed_io_list but pended conversion still exist ->ext4_add_complete_io BUG #2) Race window becomes wider due to the 'ext4: completed_io locking cleanup V4' patch series This patch make following changes: 1) ext4_flush_completed_io() now first try to flush completed io and when wait for any outstanding unwritten io via ext4_unwritten_wait() 2) Rename function to more appropriate name. 3) Assert that all callers of ext4_flush_unwritten_io should hold i_mutex to prevent endless wait Signed-off-by:Jan Kara <jack@suse.cz>
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- 01 Oct, 2012 3 commits
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Theodore Ts'o authored
Commits 5e8830dc and 41c4d25f introduced a regression into v3.6-rc1 for ext4 in nodealloc mode, such that mtime updates would not take place for files modified via mmap if the page was already in the page cache. This would also affect ext3 file systems mounted using the ext4 file system driver. The problem was that ext4_page_mkwrite() had a shortcut which would avoid calling __block_page_mkwrite() under some circumstances, and the above two commit transferred the responsibility of calling file_update_time() to __block_page_mkwrite --- which woudln't get called in some circumstances. Since __block_page_mkwrite() only has three callers, block_page_mkwrite(), ext4_page_mkwrite, and nilfs_page_mkwrite(), the best way to solve this is to move the responsibility for calling file_update_time() to its caller. This problem was found via xfstests #215 with a file system mounted with -o nodelalloc. Signed-off-by:
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Dmitry Monakhov authored
Inode is allowed to have empty leaf only if it this is blockless inode. Signed-off-by:
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Dmitry Monakhov authored
punch_hole is the place where we have to wait for all existing writers (writeback, aio, dio), but currently we simply flush pended end_io request which is not sufficient. Other issue is that punch_hole performed w/o i_mutex held which obviously result in dangerous data corruption due to write-after-free. This patch performs following changes: - Guard punch_hole with i_mutex - Recheck inode flags under i_mutex - Block all new dio readers in order to prevent information leak caused by read-after-free pattern. - punch_hole now wait for all writers in flight NOTE: XXX write-after-free race is still possible because new dirty pages may appear due to mmap(), and currently there is no easy way to stop writeback while punch_hole is in progress. [ Fixed error return from ext4_ext_punch_hole() to make sure that we release i_mutex before returning EPERM or ETXTBUSY -- Ted ] Signed-off-by:
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- 29 Sep, 2012 8 commits
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Dmitry Monakhov authored
Jan Kara have spotted interesting issue: There are potential data corruption issue with direct IO overwrites racing with truncate: Like: dio write truncate_task ->ext4_ext_direct_IO ->overwrite == 1 ->down_read(&EXT4_I(inode)->i_data_sem); ->mutex_unlock(&inode->i_mutex); ->ext4_setattr() ->inode_dio_wait() ->truncate_setsize() ->ext4_truncate() ->down_write(&EXT4_I(inode)->i_data_sem); ->__blockdev_direct_IO ->ext4_get_block ->submit_io() ->up_read(&EXT4_I(inode)->i_data_sem); # truncate data blocks, allocate them to # other inode - bad stuff happens because # dio is still in flight. In order to serialize with truncate dio worker should grab extra i_dio_count reference before drop i_mutex. Reviewed-by: -
Dmitry Monakhov authored
If we have enough aggressive DIO readers, truncate and other dio waiters will wait forever inside inode_dio_wait(). It is reasonable to disable nonlock DIO read optimization during truncate. Reviewed-by:
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Dmitry Monakhov authored
Current serialization will works only for DIO which holds i_mutex, but nonlocked DIO following race is possible: dio_nolock_read_task truncate_task ->ext4_setattr() ->inode_dio_wait() ->ext4_ext_direct_IO ->ext4_ind_direct_IO ->__blockdev_direct_IO ->ext4_get_block ->truncate_setsize() ->ext4_truncate() #alloc truncated blocks #to other inode ->submit_io() #INFORMATION LEAK In order to serialize with unlocked DIO reads we have to rearrange wait sequence 1) update i_size first 2) if i_size about to be reduced wait for outstanding DIO requests 3) and only after that truncate inode blocks Reviewed-by: -
Dmitry Monakhov authored
Inode's block defrag and ext4_change_inode_journal_flag() may affect nonlocked DIO reads result, so proper synchronization required. - Add missed inode_dio_wait() calls where appropriate - Check inode state under extra i_dio_count reference. Reviewed-by:
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Dmitry Monakhov authored
Current unwritten extent conversion state-machine is very fuzzy. - For unknown reason it performs conversion under i_mutex. What for? My diagnosis: We already protect extent tree with i_data_sem, truncate and punch_hole should wait for DIO, so the only data we have to protect is end_io->flags modification, but only flush_completed_IO and end_io_work modified this flags and we can serialize them via i_completed_io_lock. Currently all these games with mutex_trylock result in the following deadlock truncate: kworker: ext4_setattr ext4_end_io_work mutex_lock(i_mutex) inode_dio_wait(inode) ->BLOCK DEADLOCK<- mutex_trylock() inode_dio_done() #TEST_CASE1_BEGIN MNT=/mnt_scrach unlink $MNT/file fallocate -l $((1024*1024*1024)) $MNT/file aio-stress -I 100000 -O -s 100m -n -t 1 -c 10 -o 2 -o 3 $MNT/file sleep 2 truncate -s 0 $MNT/file #TEST_CASE1_END Or use 286's xfstests https://github.com/dmonakhov/xfstests/blob/devel/286 This patch makes state machine simple and clean: (1) xxx_end_io schedule final extent conversion simply by calling ext4_add_complete_io(), which append it to ei->i_completed_io_list NOTE1: because of (2A) work should be queued only if ->i_completed_io_list was empty, otherwise the work is scheduled already. (2) ext4_flush_completed_IO is responsible for handling all pending end_io from ei->i_completed_io_list Flushing sequence consists of following stages: A) LOCKED: Atomically drain completed_io_list to local_list B) Perform extents conversion C) LOCKED: move converted io's to to_free list for final deletion This logic depends on context which we was called from. D) Final end_io context destruction NOTE1: i_mutex is no longer required because end_io->flags modification is protected by ei->ext4_complete_io_lock Full list of changes: - Move all completion end_io related routines to page-io.c in order to improve logic locality - Move open coded logic from various xx_end_xx routines to ext4_add_complete_io() - remove EXT4_IO_END_FSYNC - Improve SMP scalability by removing useless i_mutex which does not protect io->flags anymore. - Reduce lock contention on i_completed_io_lock by optimizing list walk. - Rename ext4_end_io_nolock to end4_end_io and make it static - Check flush completion status to ext4_ext_punch_hole(). Because it is not good idea to punch blocks from corrupted inode. Changes since V3 (in request to Jan's comments): Fall back to active flush_completed_IO() approach in order to prevent performance issues with nolocked DIO reads. Changes since V2: Fix use-after-free caused by race truncate vs end_io_work Signed-off-by: -
Dmitry Monakhov authored
ext4_set_io_unwritten_flag() will increment i_unwritten counter, so once we mark end_io with EXT4_END_IO_UNWRITTEN we have to revert it back on error path. - add missed error checks to prevent counter leakage - ext4_end_io_nolock() will clear EXT4_END_IO_UNWRITTEN flag to signal that conversion finished. - add BUG_ON to ext4_free_end_io() to prevent similar leakage in future. Visible effect of this bug is that unaligned aio_stress may deadlock Reviewed-by:
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Dmitry Monakhov authored
AIO/DIO prefix is wrong because it account unwritten extents which also may be scheduled from buffered write endio Reviewed-by:
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Dmitry Monakhov authored
Generic inode has unused i_private pointer which may be used as cur_aio_dio storage. TODO: If cur_aio_dio will be passed as an argument to get_block_t this allow to have concurent AIO_DIO requests. Reviewed-by:Zheng Liu <wenqing.lz@taobao.com> Reviewed-by:
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- 27 Sep, 2012 12 commits
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Wei Yongjun authored
Convert cpu_to_leXX(leXX_to_cpu(E1) + E2) to use leXX_add_cpu(). dpatch engine is used to auto generate this patch. (https://github.com/weiyj/dpatch) Signed-off-by:
Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by:
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Carlos Maiolino authored
When ext4_bread() returns NULL and err is set to zero, this means there is no phyical block mapped to the specified logical block number. (Previous to commit 90b0a973, err was uninitialized in this case, which caused other problems.) The directory handling routines use ext4_bread() in many places, the fact that ext4_bread() now returns NULL with err set to zero could cause problems since a number of these functions will simply return the value of err if the result of ext4_bread() was the NULL pointer, causing the caller of the function to think that the function was successful. Since directories should never contain holes, this case can only happen if the file system is corrupted. This commit audits all of the callers of ext4_bread(), and makes sure they do the right thing if a hole in a directory is found by ext4_bread(). Some ext4_bread() callers did not need any changes either because they already had its own hole detector paths. Signed-off-by:
Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by:
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Theodore Ts'o authored
As discussed at the Plumber's Conference, reserve the bit 0x04 in fallocate() to prevent collisions with a commonly used out-of-tree patch which implements the no-hide-stale feature. Signed-off-by: -
Wang Sheng-Hui authored
In the check code above, if orig_start != donor_start, we would return -EINVAL. So here, orig_start should be equal with donor_start. Remove the redundant check here. Signed-off-by:
Wang Sheng-Hui <shhuiw@gmail.com> Signed-off-by:
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Eric Sandeen authored
If the file system contains errors and it is being mounted read-only, don't clear the orphan list. We should minimize changes to the file system if it is mounted read-only. Signed-off-by:
Eric Sandeen <sandeen@redhat.com> Signed-off-by:
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Jan Kara authored
ext4 users of data=journal mode with blocksize < pagesize were occasionally hitting assertion failure in jbd2_journal_commit_transaction() checking whether the transaction has at least as many credits reserved as buffers attached. The core of the problem is that when a file gets truncated, buffers that still need checkpointing or that are attached to the committing transaction are left with buffer_mapped set. When this happens to buffers beyond i_size attached to a page stradding i_size, subsequent write extending the file will see these buffers and as they are mapped (but underlying blocks were freed) things go awry from here. The assertion failure just coincidentally (and in this case luckily as we would start corrupting filesystem) triggers due to journal_head not being properly cleaned up as well. We fix the problem by unmapping buffers if possible (in lots of cases we just need a buffer attached to a transaction as a place holder but it must not be written out anyway). And in one case, we just have to bite the bullet and wait for transaction commit to finish. CC: Josef Bacik <jbacik@fusionio.com> Signed-off-by: -
Djalal Harouni authored
When the EXT4_IOC_MOVE_EXT ioctl() fails on bigalloc file systems, we should jump to the 'mext_out' label to release the donor file reference. Signed-off-by:
Djalal Harouni <tixxdz@opendz.org> Signed-off-by:
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Lukas Czerner authored
With a minor tweaks regarding minimum extent size to discard and discarded bytes reporting the FITRIM can be enabled on bigalloc file system and it works without any problem. This patch fixes minlen handling and discarded bytes reporting to take into consideration bigalloc enabled file systems and finally removes the restriction and allow FITRIM to be used on file system with bigalloc feature enabled. Reviewed-by:
Lukas Czerner <lczerner@redhat.com> Signed-off-by:
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Jan Kara authored
Code tracking when transaction needs to be committed on fdatasync(2) forgets to handle a situation when only inode's i_size is changed. Thus in such situations fdatasync(2) doesn't force transaction with new i_size to disk and that can result in wrong i_size after a crash. Fix the issue by updating inode's i_datasync_tid whenever its size is updated. CC: <stable@vger.kernel.org> # >= 2.6.32 Reported-by:
Kristian Nielsen <knielsen@knielsen-hq.org> Signed-off-by:
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Bernd Schubert authored
ext4_special_inode_operations have their own ifdef CONFIG_EXT4_FS_XATTR to mask those methods. And ext4_iget also always sets it, so there is an inconsistency. Signed-off-by:
Bernd Schubert <bernd.schubert@itwm.fraunhofer.de> Signed-off-by:
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Lukas Czerner authored
Remove unused function ext4_ext_check_cache() and merge the code back to the ext4_ext_in_cache(). Reviewed-by:
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Wei Yongjun authored
Using kmem_cache_zalloc() instead of kmem_cache_alloc() and memset(). spatch with a semantic match is used to found this problem. (http://coccinelle.lip6.fr/) Signed-off-by:
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- 26 Sep, 2012 6 commits
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Dmitry Monakhov authored
Uninitialized extent may became initialized(parallel writeback task) at any moment after we drop i_data_sem, so we have to recheck extent's state after we hold page's lock and i_data_sem. If we about to change page's mapping we must hold page's lock in order to serialize other users. Signed-off-by:
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Dmitry Monakhov authored
Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: -
Dmitry Monakhov authored
Proper block swap for inodes with full journaling enabled is truly non obvious task. In order to be on a safe side let's explicitly disable it for now. Signed-off-by:
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Dmitry Monakhov authored
- Remove usless checks, because it is too late to check that inode != NULL at the moment it was referenced several times. - Double lock routines looks very ugly and locking ordering relays on order of i_ino, but other kernel code rely on order of pointers. Let's make them simple and clean. - check that inodes belongs to the same SB as soon as possible. Signed-off-by:
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Tao Ma authored
When performing an online resize, we add a bunch of groups at one time in ext4_flex_group_add, so in most cases a lot of group descriptors will be in the same group block. But in the end of this function, update_backups will be called for every group descriptor and the same block will be copied and journalled again and again. It is really a waste. Fix things so we only update a particular bg descriptor block once and skip subsequent updates of the same block. Signed-off-by:
Tao Ma <boyu.mt@taobao.com> Signed-off-by:
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Dmitry Monakhov authored
bh_submit_read() is responsible for unlock bh on endio. In addition, we need to use bh_uptodate_or_lock() to avoid races. Signed-off-by:
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- 24 Sep, 2012 3 commits
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Yongqiang Yang authored
Recently, I ecountered some corrupted filesystems in which some groups' free inode counts were 65535, it seemed that free inode count was overflow. This patch teaches ext4 to check free inode count before allocaing an inode. Signed-off-by:
Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by:
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Yongqiang Yang authored
Free block counters should be checked before doing allocation. Signed-off-by:
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Herton Ronaldo Krzesinski authored
The crash was caused by a variable being erronously declared static in token2str(). In addition to /proc/mounts, the problem can also be easily replicated by accessing /proc/fs/ext4/<partition>/options in parallel: $ cat /proc/fs/ext4/<partition>/options > options.txt ... and then running the following command in two different terminals: $ while diff /proc/fs/ext4/<partition>/options options.txt; do true; done This is also the cause of the following a crash while running xfstests #234, as reported in the following bug reports: https://bugs.launchpad.net/bugs/1053019 https://bugzilla.kernel.org/show_bug.cgi?id=47731Signed-off-by:
Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Signed-off-by:
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- 20 Sep, 2012 2 commits
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Tao Ma authored
The update_backups() function is used to backup all the metadata blocks, so we should not take it for granted that 'data' is pointed to a super block and use ext4_superblock_csum_set to calculate the checksum there. In case where the data is a group descriptor block, it will corrupt the last group descriptor, and then e2fsck will complain about it it. As all the metadata checksums should already be OK when we do the backup, remove the wrong ext4_superblock_csum_set and it should be just fine. Reported-by:
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Theodore Ts'o authored
In ext4_nonda_switch(), if the file system is getting full we used to call writeback_inodes_sb_if_idle(). The problem is that we can be holding i_mutex already, and this causes a potential deadlock when writeback_inodes_sb_if_idle() when it tries to take s_umount. (See lockdep output below). As it turns out we don't need need to hold s_umount; the fact that we are in the middle of the write(2) system call will keep the superblock pinned. Unfortunately writeback_inodes_sb() checks to make sure s_umount is taken, and the VFS uses a different mechanism for making sure the file system doesn't get unmounted out from under us. The simplest way of dealing with this is to just simply grab s_umount using a trylock, and skip kicking the writeback flusher thread in the very unlikely case that we can't take a read lock on s_umount without blocking. Also, we now check the cirteria for kicking the writeback thread before we decide to whether to fall back to non-delayed writeback, so if there are any outstanding delayed allocation writes, we try to get them resolved as soon as possible. [ INFO: possible circular locking dependency detected ] 3.6.0-rc1-00042-gce894ca #367 Not tainted ------------------------------------------------------- dd/8298 is trying to acquire lock: (&type->s_umount_key#18){++++..}, at: [<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46 but task is already holding lock: (&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3 which lock already depends on the new lock. 2 locks held by dd/8298: #0: (sb_writers#2){.+.+.+}, at: [<c01ddcc5>] generic_file_aio_write+0x56/0xd3 #1: (&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3 stack backtrace: Pid: 8298, comm: dd Not tainted 3.6.0-rc1-00042-gce894ca #367 Call Trace: [<c015b79c>] ? console_unlock+0x345/0x372 [<c06d62a1>] print_circular_bug+0x190/0x19d [<c019906c>] __lock_acquire+0x86d/0xb6c [<c01999db>] ? mark_held_locks+0x5c/0x7b [<c0199724>] lock_acquire+0x66/0xb9 [<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46 [<c06db935>] down_read+0x28/0x58 [<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46 [<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46 [<c026f3b2>] ext4_nonda_switch+0xe1/0xf4 [<c0271ece>] ext4_da_write_begin+0x27/0x193 [<c01dcdb0>] generic_file_buffered_write+0xc8/0x1bb [<c01ddc47>] __generic_file_aio_write+0x1dd/0x205 [<c01ddce7>] generic_file_aio_write+0x78/0xd3 [<c026d336>] ext4_file_write+0x480/0x4a6 [<c0198c1d>] ? __lock_acquire+0x41e/0xb6c [<c0180944>] ? sched_clock_cpu+0x11a/0x13e [<c01967e9>] ? trace_hardirqs_off+0xb/0xd [<c018099f>] ? local_clock+0x37/0x4e [<c0209f2c>] do_sync_write+0x67/0x9d [<c0209ec5>] ? wait_on_retry_sync_kiocb+0x44/0x44 [<c020a7b9>] vfs_write+0x7b/0xe6 [<c020a9a6>] sys_write+0x3b/0x64 [<c06dd4bd>] syscall_call+0x7/0xb Signed-off-by:
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- 19 Sep, 2012 2 commits
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Andrey Sidorov authored
Do not iterate over data blocks scanning for bh's to forget as they're never exist. This improves time taken by unlink / truncate syscall. Tested by continuously truncating file that is being written by dd. Another test is rm -rf of linux tree while tar unpacks it. With ordered data mode condition unlikely(!tbh) was always met in ext4_free_blocks. With journal data mode tbh was found only few times, so optimisation is also possible. Unlinking fallocated 60G file after doing sync && echo 3 > /proc/sys/vm/drop_caches && time rm --help X86 before (linux 3.6-rc4): # time rm -f test1 real 0m2.710s user 0m0.000s sys 0m1.530s X86 after: # time rm -f test1 real 0m0.644s user 0m0.003s sys 0m0.060s MIPS before (linux 2.6.37): # time rm -f test1 real 0m 4.93s user 0m 0.00s sys 0m 4.61s MIPS after: # time rm -f test1 real 0m 0.16s user 0m 0.00s sys 0m 0.06s Signed-off-by:
Andrey Sidorov <qrxd43@motorola.com>
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Theodore Ts'o authored
Commit 1c6bd717 introduced a regression where an online resize operation which did not change the number of block groups would fail, i.e: mke2fs -t /dev/vdc 60000 mount /dev/vdc resize2fs /dev/vdc 60001 This was due to a bug in the logic regarding when to try converting the filesystem to use meta_bg. Also fix up a number of other minor issues with the online resizing code: (a) Fix a sparse warning; (b) only check to make sure the device is large enough once, instead of multiple times through the resize loop. Signed-off-by:
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- 18 Sep, 2012 1 commit
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Anatol Pomozov authored
Instead of checking whether the handle is valid, we check if journal is enabled. This avoids taking the s_orphan_lock mutex in all cases when there is no journal in use, including the error paths where ext4_orphan_del() is called with a handle set to NULL. Signed-off-by:
Anatol Pomozov <anatol.pomozov@gmail.com> Signed-off-by:
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