WSL2-Linux-Kernel/fs
Eryu Guan bcff24887d ext4: don't read blocks from disk after extents being swapped
I notice ext4/307 fails occasionally on ppc64 host, reporting md5
checksum mismatch after moving data from original file to donor file.

The reason is that move_extent_per_page() calls __block_write_begin()
and block_commit_write() to write saved data from original inode blocks
to donor inode blocks, but __block_write_begin() not only maps buffer
heads but also reads block content from disk if the size is not block
size aligned.  At this time the physical block number in mapped buffer
head is pointing to the donor file not the original file, and that
results in reading wrong data to page, which get written to disk in
following block_commit_write call.

This also can be reproduced by the following script on 1k block size ext4
on x86_64 host:

    mnt=/mnt/ext4
    donorfile=$mnt/donor
    testfile=$mnt/testfile
    e4compact=~/xfstests/src/e4compact

    rm -f $donorfile $testfile

    # reserve space for donor file, written by 0xaa and sync to disk to
    # avoid EBUSY on EXT4_IOC_MOVE_EXT
    xfs_io -fc "pwrite -S 0xaa 0 1m" -c "fsync" $donorfile

    # create test file written by 0xbb
    xfs_io -fc "pwrite -S 0xbb 0 1023" -c "fsync" $testfile

    # compute initial md5sum
    md5sum $testfile | tee md5sum.txt
    # drop cache, force e4compact to read data from disk
    echo 3 > /proc/sys/vm/drop_caches

    # test defrag
    echo "$testfile" | $e4compact -i -v -f $donorfile
    # check md5sum
    md5sum -c md5sum.txt

Fix it by creating & mapping buffer heads only but not reading blocks
from disk, because all the data in page is guaranteed to be up-to-date
in mext_page_mkuptodate().

Cc: stable@vger.kernel.org
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-02-12 01:20:43 -05:00
..
9p wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
adfs fs/adfs/adfs.h: tidy up comments 2016-01-20 17:09:18 -08:00
affs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
afs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
autofs4
befs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
bfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
btrfs Merge branch 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2016-01-29 15:46:49 -08:00
cachefiles wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2016-01-24 12:34:13 -08:00
cifs Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6 2016-01-24 12:31:12 -08:00
coda Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
configfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
cramfs
debugfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
devpts wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
dlm [regression] fix braino in fs/dlm/user.c 2016-01-21 17:45:15 -05:00
ecryptfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
efivarfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
efs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
exofs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
exportfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ext2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
ext4 ext4: don't read blocks from disk after extents being swapped 2016-02-12 01:20:43 -05:00
f2fs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
fat wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
freevxfs
fscache
fuse wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
gfs2 wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hfsplus wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hostfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hpfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hugetlbfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
isofs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
jbd2
jffs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
jfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
kernfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
lockd
logfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
minix kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
ncpfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
nfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
nfs_common
nfsd wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
nilfs2 wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
nls
notify fsnotify: destroy marks with call_srcu instead of dedicated thread 2016-01-14 16:00:49 -08:00
ntfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ocfs2 wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
omfs
openpromfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
overlayfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
proc wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
pstore wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
qnx4 kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
qnx6 kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
quota wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ramfs
reiserfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
romfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
squashfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
sysfs
sysv kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
tracefs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ubifs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
udf Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
ufs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
xfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
Kconfig dax: re-enable dax pmd mappings 2016-01-15 17:56:32 -08:00
Kconfig.binfmt
Makefile
aio.c
anon_inodes.c
attr.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
bad_inode.c
binfmt_aout.c
binfmt_elf.c ELF: Also pass any interpreter's file header to `arch_check_elf' 2016-01-20 00:39:20 +01:00
binfmt_elf_fdpic.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
binfmt_script.c
block_dev.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
buffer.c
char_dev.c
compat.c
compat_binfmt_elf.c
compat_ioctl.c
coredump.c fs/coredump: prevent "" / "." / ".." core path components 2016-01-20 17:09:18 -08:00
dax.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
dcache.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
dcookies.c
direct-io.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
drop_caches.c
eventfd.c
eventpoll.c epoll: add EPOLLEXCLUSIVE flag 2016-01-20 17:09:18 -08:00
exec.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
fcntl.c
fhandle.c
file.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
file_table.c
filesystems.c find_filesystem(): simplify comparison 2016-01-19 12:02:23 -05:00
fs-writeback.c cgroup, memcg, writeback: drop spurious rcu locking around mem_cgroup_css_from_page() 2016-01-15 17:56:32 -08:00
fs_pin.c
fs_struct.c
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
internal.h
ioctl.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
libfs.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
locks.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
mbcache.c
mount.h
mpage.c
namei.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
namespace.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
no-block.c
nsfs.c
open.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
pipe.c pipe: limit the per-user amount of pages allocated in pipes 2016-01-19 19:25:21 -05:00
pnode.c
pnode.h
posix_acl.c
proc_namespace.c
read_write.c vfs: abort dedupe loop if fatal signals are pending 2016-01-22 20:29:55 -05:00
readdir.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
select.c
seq_file.c
signalfd.c
splice.c
stack.c
stat.c fs/stat.c: drop the last new_valid_dev check 2016-01-16 11:17:23 -08:00
statfs.c
super.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2016-01-14 17:04:19 -08:00
sync.c
timerfd.c timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper 2016-01-17 11:13:55 +01:00
userfaultfd.c
utimes.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
xattr.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00