kernel/fs/nilfs2, branch linux-3.2.y

nilfs2: fix race condition that causes file system corruption

2018-02-13T18:32:19Z

commit 31ccb1f7ba3cfe29631587d451cf5bb8ab593550 upstream. There is a race condition between nilfs_dirty_inode() and nilfs_set_file_dirty(). When a file is opened, nilfs_dirty_inode() is called to update the access timestamp in the inode. It calls __nilfs_mark_inode_dirty() in a separate transaction. __nilfs_mark_inode_dirty() caches the ifile buffer_head in the i_bh field of the inode info structure and marks it as dirty. After some data was written to the file in another transaction, the function nilfs_set_file_dirty() is called, which adds the inode to the ns_dirty_files list. Then the segment construction calls nilfs_segctor_collect_dirty_files(), which goes through the ns_dirty_files list and checks the i_bh field. If there is a cached buffer_head in i_bh it is not marked as dirty again. Since nilfs_dirty_inode() and nilfs_set_file_dirty() use separate transactions, it is possible that a segment construction that writes out the ifile occurs in-between the two. If this happens the inode is not on the ns_dirty_files list, but its ifile block is still marked as dirty and written out. In the next segment construction, the data for the file is written out and nilfs_bmap_propagate() updates the b-tree. Eventually the bmap root is written into the i_bh block, which is not dirty, because it was written out in another segment construction. As a result the bmap update can be lost, which leads to file system corruption. Either the virtual block address points to an unallocated DAT block, or the DAT entry will be reused for something different. The error can remain undetected for a long time. A typical error message would be one of the "bad btree" errors or a warning that a DAT entry could not be found. This bug can be reproduced reliably by a simple benchmark that creates and overwrites millions of 4k files. Link: http://lkml.kernel.org/r/1509367935-3086-2-git-send-email-konishi.ryusuke@lab.ntt.co.jp Signed-off-by: Andreas Rohner Signed-off-by: Ryusuke Konishi Tested-by: Andreas Rohner Tested-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

nilfs2: fix gcc uninitialized-variable warnings in powerpc build

2017-11-11T13:34:43Z

commit 4f05028f8d1af782cfd03d09e0a052e9745dc5ad upstream. Some false positive warnings are reported for powerpc build. The following warnings are reported in http://kisskb.ellerman.id.au/kisskb/buildresult/12519703/ CC fs/nilfs2/super.o fs/nilfs2/super.c: In function 'nilfs_resize_fs': fs/nilfs2/super.c:376:2: warning: 'blocknr' may be used uninitialized in this function [-Wuninitialized] fs/nilfs2/super.c:362:11: note: 'blocknr' was declared here CC fs/nilfs2/recovery.o fs/nilfs2/recovery.c: In function 'nilfs_salvage_orphan_logs': fs/nilfs2/recovery.c:631:21: warning: 'sum' may be used uninitialized in this function [-Wuninitialized] fs/nilfs2/recovery.c:585:32: note: 'sum' was declared here fs/nilfs2/recovery.c: In function 'nilfs_search_super_root': fs/nilfs2/recovery.c:873:11: warning: 'sum' may be used uninitialized in this function [-Wuninitialized] Another similar warning is reported in http://kisskb.ellerman.id.au/kisskb/buildresult/12520079/ CC fs/nilfs2/btree.o fs/nilfs2/btree.c: In function 'nilfs_btree_convert_and_insert': include/asm-generic/bitops/non-atomic.h:105:20: warning: 'bh' may be used uninitialized in this function [-Wuninitialized] fs/nilfs2/btree.c:1859:22: note: 'bh' was declared here This cleans out these warnings by forcing the variables to be initialized. Signed-off-by: Ryusuke Konishi Reported-by: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

fs: Give dentry to inode_change_ok() instead of inode

2016-11-20T01:01:43Z

commit 31051c85b5e2aaaf6315f74c72a732673632a905 upstream. inode_change_ok() will be resposible for clearing capabilities and IMA extended attributes and as such will need dentry. Give it as an argument to inode_change_ok() instead of an inode. Also rename inode_change_ok() to setattr_prepare() to better relect that it does also some modifications in addition to checks. Reviewed-by: Christoph Hellwig Signed-off-by: Jan Kara [bwh: Backported to 3.2: - Drop changes to f2fs, lustre, orangefs, overlayfs - Adjust filenames, context - In nfsd, pass dentry to nfsd_sanitize_attrs() - In xfs, pass dentry to xfs_change_file_space(), xfs_set_mode(), xfs_setattr_nonsize(), and xfs_setattr_size() - Update ext3 as well - Mark pohmelfs as BROKEN; it's long dead upstream] Signed-off-by: Ben Hutchings

fs/nilfs2: fix potential underflow in call to crc32_le

2016-08-22T21:37:16Z

commit 63d2f95d63396059200c391ca87161897b99e74a upstream. The value `bytes' comes from the filesystem which is about to be mounted. We cannot trust that the value is always in the range we expect it to be. Check its value before using it to calculate the length for the crc32_le call. It value must be larger (or equal) sumoff + 4. This fixes a kernel bug when accidentially mounting an image file which had the nilfs2 magic value 0x3434 at the right offset 0x406 by chance. The bytes 0x01 0x00 were stored at 0x408 and were interpreted as a s_bytes value of 1. This caused an underflow when substracting sumoff + 4 (20) in the call to crc32_le. BUG: unable to handle kernel paging request at ffff88021e600000 IP: crc32_le+0x36/0x100 ... Call Trace: nilfs_valid_sb.part.5+0x52/0x60 [nilfs2] nilfs_load_super_block+0x142/0x300 [nilfs2] init_nilfs+0x60/0x390 [nilfs2] nilfs_mount+0x302/0x520 [nilfs2] mount_fs+0x38/0x160 vfs_kern_mount+0x67/0x110 do_mount+0x269/0xe00 SyS_mount+0x9f/0x100 entry_SYSCALL_64_fastpath+0x16/0x71 Link: http://lkml.kernel.org/r/1466778587-5184-2-git-send-email-konishi.ryusuke@lab.ntt.co.jp Signed-off-by: Torsten Hilbrich Tested-by: Torsten Hilbrich Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

nilfs2: fix sanity check of btree level in nilfs_btree_root_broken()

2015-08-06T23:32:09Z

commit d8fd150fe3935e1692bf57c66691e17409ebb9c1 upstream. The range check for b-tree level parameter in nilfs_btree_root_broken() is wrong; it accepts the case of "level == NILFS_BTREE_LEVEL_MAX" even though the level is limited to values in the range of 0 to (NILFS_BTREE_LEVEL_MAX - 1). Since the level parameter is read from storage device and used to index nilfs_btree_path array whose element count is NILFS_BTREE_LEVEL_MAX, it can cause memory overrun during btree operations if the boundary value is set to the level parameter on device. This fixes the broken sanity check and adds a comment to clarify that the upper bound NILFS_BTREE_LEVEL_MAX is exclusive. Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

nilfs2: fix deadlock of segment constructor during recovery

2015-05-09T22:16:29Z

commit 283ee1482f349d6c0c09dfb725db5880afc56813 upstream. According to a report from Yuxuan Shui, nilfs2 in kernel 3.19 got stuck during recovery at mount time. The code path that caused the deadlock was as follows: nilfs_fill_super() load_nilfs() nilfs_salvage_orphan_logs() * Do roll-forwarding, attach segment constructor for recovery, and kick it. nilfs_segctor_thread() nilfs_segctor_thread_construct() * A lock is held with nilfs_transaction_lock() nilfs_segctor_do_construct() nilfs_segctor_drop_written_files() iput() iput_final() write_inode_now() writeback_single_inode() __writeback_single_inode() do_writepages() nilfs_writepage() nilfs_construct_dsync_segment() nilfs_transaction_lock() --> deadlock This can happen if commit 7ef3ff2fea8b ("nilfs2: fix deadlock of segment constructor over I_SYNC flag") is applied and roll-forward recovery was performed at mount time. The roll-forward recovery can happen if datasync write is done and the file system crashes immediately after that. For instance, we can reproduce the issue with the following steps: < nilfs2 is mounted on /nilfs (device: /dev/sdb1) > # dd if=/dev/zero of=/nilfs/test bs=4k count=1 && sync # dd if=/dev/zero of=/nilfs/test conv=notrunc oflag=dsync bs=4k count=1 && reboot -nfh < the system will immediately reboot > # mount -t nilfs2 /dev/sdb1 /nilfs The deadlock occurs because iput() can run segment constructor through writeback_single_inode() if MS_ACTIVE flag is not set on sb->s_flags. The above commit changed segment constructor so that it calls iput() asynchronously for inodes with i_nlink == 0, but that change was imperfect. This fixes the another deadlock by deferring iput() in segment constructor even for the case that mount is not finished, that is, for the case that MS_ACTIVE flag is not set. Signed-off-by: Ryusuke Konishi Reported-by: Yuxuan Shui Tested-by: Ryusuke Konishi Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

nilfs2: fix potential memory overrun on inode

2015-05-09T22:16:21Z

commit 957ed60b53b519064a54988c4e31e0087e47d091 upstream. Each inode of nilfs2 stores a root node of a b-tree, and it turned out to have a memory overrun issue: Each b-tree node of nilfs2 stores a set of key-value pairs and the number of them (in "bn_nchildren" member of nilfs_btree_node struct), as well as a few other "bn_*" members. Since the value of "bn_nchildren" is used for operations on the key-values within the b-tree node, it can cause memory access overrun if a large number is incorrectly set to "bn_nchildren". For instance, nilfs_btree_node_lookup() function determines the range of binary search with it, and too large "bn_nchildren" leads nilfs_btree_node_get_key() in that function to overrun. As for intermediate b-tree nodes, this is prevented by a sanity check performed when each node is read from a drive, however, no sanity check has been done for root nodes stored in inodes. This patch fixes the issue by adding missing sanity check against b-tree root nodes so that it's called when on-memory inodes are read from ifile, inode metadata file. Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

nilfs2: fix deadlock of segment constructor over I_SYNC flag

2015-03-06T00:39:19Z

commit 7ef3ff2fea8bf5e4a21cef47ad87710a3d0fdb52 upstream. Nilfs2 eventually hangs in a stress test with fsstress program. This issue was caused by the following deadlock over I_SYNC flag between nilfs_segctor_thread() and writeback_sb_inodes(): nilfs_segctor_thread() nilfs_segctor_thread_construct() nilfs_segctor_unlock() nilfs_dispose_list() iput() iput_final() evict() inode_wait_for_writeback() * wait for I_SYNC flag writeback_sb_inodes() * set I_SYNC flag on inode->i_state __writeback_single_inode() do_writepages() nilfs_writepages() nilfs_construct_dsync_segment() nilfs_segctor_sync() * wait for completion of segment constructor inode_sync_complete() * clear I_SYNC flag after __writeback_single_inode() completed writeback_sb_inodes() calls do_writepages() for dirty inodes after setting I_SYNC flag on inode->i_state. do_writepages() in turn calls nilfs_writepages(), which can run segment constructor and wait for its completion. On the other hand, segment constructor calls iput(), which can call evict() and wait for the I_SYNC flag on inode_wait_for_writeback(). Since segment constructor doesn't know when I_SYNC will be set, it cannot know whether iput() will block or not unless inode->i_nlink has a non-zero count. We can prevent evict() from being called in iput() by implementing sop->drop_inode(), but it's not preferable to leave inodes with i_nlink == 0 for long periods because it even defers file truncation and inode deallocation. So, this instead resolves the deadlock by calling iput() asynchronously with a workqueue for inodes with i_nlink == 0. Signed-off-by: Ryusuke Konishi Cc: Al Viro Tested-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

nilfs2: fix data loss with mmap()

2014-11-05T20:27:46Z

commit 56d7acc792c0d98f38f22058671ee715ff197023 upstream. This bug leads to reproducible silent data loss, despite the use of msync(), sync() and a clean unmount of the file system. It is easily reproducible with the following script: ----------------[BEGIN SCRIPT]-------------------- mkfs.nilfs2 -f /dev/sdb mount /dev/sdb /mnt dd if=/dev/zero bs=1M count=30 of=/mnt/testfile umount /mnt mount /dev/sdb /mnt CHECKSUM_BEFORE="$(md5sum /mnt/testfile)" /root/mmaptest/mmaptest /mnt/testfile 30 10 5 sync CHECKSUM_AFTER="$(md5sum /mnt/testfile)" umount /mnt mount /dev/sdb /mnt CHECKSUM_AFTER_REMOUNT="$(md5sum /mnt/testfile)" umount /mnt echo "BEFORE MMAP:\t$CHECKSUM_BEFORE" echo "AFTER MMAP:\t$CHECKSUM_AFTER" echo "AFTER REMOUNT:\t$CHECKSUM_AFTER_REMOUNT" ----------------[END SCRIPT]-------------------- The mmaptest tool looks something like this (very simplified, with error checking removed): ----------------[BEGIN mmaptest]-------------------- data = mmap(NULL, file_size - file_offset, PROT_READ | PROT_WRITE, MAP_SHARED, fd, file_offset); for (i = 0; i < write_count; ++i) { memcpy(data + i * 4096, buf, sizeof(buf)); msync(data, file_size - file_offset, MS_SYNC)) } ----------------[END mmaptest]-------------------- The output of the script looks something like this: BEFORE MMAP: 281ed1d5ae50e8419f9b978aab16de83 /mnt/testfile AFTER MMAP: 6604a1c31f10780331a6850371b3a313 /mnt/testfile AFTER REMOUNT: 281ed1d5ae50e8419f9b978aab16de83 /mnt/testfile So it is clear, that the changes done using mmap() do not survive a remount. This can be reproduced a 100% of the time. The problem was introduced in commit 136e8770cd5d ("nilfs2: fix issue of nilfs_set_page_dirty() for page at EOF boundary"). If the page was read with mpage_readpage() or mpage_readpages() for example, then it has no buffers attached to it. In that case page_has_buffers(page) in nilfs_set_page_dirty() will be false. Therefore nilfs_set_file_dirty() is never called and the pages are never collected and never written to disk. This patch fixes the problem by also calling nilfs_set_file_dirty() if the page has no buffers attached to it. [akpm@linux-foundation.org: s/PAGE_SHIFT/PAGE_CACHE_SHIFT/] Signed-off-by: Andreas Rohner Tested-by: Andreas Rohner Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

nilfs2: fix segctor bug that causes file system corruption

2014-02-15T19:20:17Z

commit 70f2fe3a26248724d8a5019681a869abdaf3e89a upstream. There is a bug in the function nilfs_segctor_collect, which results in active data being written to a segment, that is marked as clean. It is possible, that this segment is selected for a later segment construction, whereby the old data is overwritten. The problem shows itself with the following kernel log message: nilfs_sufile_do_cancel_free: segment 6533 must be clean Usually a few hours later the file system gets corrupted: NILFS: bad btree node (blocknr=8748107): level = 0, flags = 0x0, nchildren = 0 NILFS error (device sdc1): nilfs_bmap_last_key: broken bmap (inode number=114660) The issue can be reproduced with a file system that is nearly full and with the cleaner running, while some IO intensive task is running. Although it is quite hard to reproduce. This is what happens: 1. The cleaner starts the segment construction 2. nilfs_segctor_collect is called 3. sc_stage is on NILFS_ST_SUFILE and segments are freed 4. sc_stage is on NILFS_ST_DAT current segment is full 5. nilfs_segctor_extend_segments is called, which allocates a new segment 6. The new segment is one of the segments freed in step 3 7. nilfs_sufile_cancel_freev is called and produces an error message 8. Loop around and the collection starts again 9. sc_stage is on NILFS_ST_SUFILE and segments are freed including the newly allocated segment, which will contain active data and can be allocated at a later time 10. A few hours later another segment construction allocates the segment and causes file system corruption This can be prevented by simply reordering the statements. If nilfs_sufile_cancel_freev is called before nilfs_segctor_extend_segments the freed segments are marked as dirty and cannot be allocated any more. Signed-off-by: Andreas Rohner Reviewed-by: Ryusuke Konishi Tested-by: Andreas Rohner Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings