linux/fs
Brian Foster cb52ee334a xfs: prevent multi-fsb dir readahead from reading random blocks
Directory block readahead uses a complex iteration mechanism to map
between high-level directory blocks and underlying physical extents.
This mechanism attempts to traverse the higher-level dir blocks in a
manner that handles multi-fsb directory blocks and simultaneously
maintains a reference to the corresponding physical blocks.

This logic doesn't handle certain (discontiguous) physical extent
layouts correctly with multi-fsb directory blocks. For example,
consider the case of a 4k FSB filesystem with a 2 FSB (8k) directory
block size and a directory with the following extent layout:

 EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL
   0: [0..7]:          88..95            0 (88..95)             8
   1: [8..15]:         80..87            0 (80..87)             8
   2: [16..39]:        168..191          0 (168..191)          24
   3: [40..63]:        5242952..5242975  1 (72..95)            24

Directory block 0 spans physical extents 0 and 1, dirblk 1 lies
entirely within extent 2 and dirblk 2 spans extents 2 and 3. Because
extent 2 is larger than the directory block size, the readahead code
erroneously assumes the block is contiguous and issues a readahead
based on the physical mapping of the first fsb of the dirblk. This
results in read verifier failure and a spurious corruption or crc
failure, depending on the filesystem format.

Further, the subsequent readahead code responsible for walking
through the physical table doesn't correctly advance the physical
block reference for dirblk 2. Instead of advancing two physical
filesystem blocks, the first iteration of the loop advances 1 block
(correctly), but the subsequent iteration advances 2 more physical
blocks because the next physical extent (extent 3, above) happens to
cover more than dirblk 2. At this point, the higher-level directory
block walking is completely off the rails of the actual physical
layout of the directory for the respective mapping table.

Update the contiguous dirblock logic to consider the current offset
in the physical extent to avoid issuing directory readahead to
unrelated blocks. Also, update the mapping table advancing code to
consider the current offset within the current dirblock to avoid
advancing the mapping reference too far beyond the dirblock.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-04-25 09:40:40 -07:00
..
9p Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 21:44:35 -08:00
adfs
affs sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
afs afs: Don't wait for page writeback with the page lock held 2017-03-16 16:29:30 +00:00
autofs4 sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
befs sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
bfs
btrfs Merge branch 'for-linus-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2017-03-23 11:39:33 -07:00
cachefiles sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
ceph Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
cifs Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6 2017-03-03 16:00:59 -08:00
coda Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
configfs
cramfs
crypto A code cleanup and bugfix for fs/crypto. 2017-03-25 15:36:56 -07:00
debugfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2017-02-23 20:33:51 -08:00
devpts
dlm net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
ecryptfs Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
efivarfs
efs
exofs locking/atomic, kref: Add kref_read() 2017-01-14 11:37:18 +01:00
exportfs Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
ext2 sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
ext4 Fix a memory leak on an error path, and two races when modifying 2017-03-26 10:29:21 -07:00
f2fs f2fs: combine nat_bits and free_nid_bitmap cache 2017-03-20 10:00:18 -04:00
fat fat: fix using uninitialized fields of fat_inode/fsinfo_inode 2017-03-09 17:01:10 -08:00
freevxfs
fscache KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload() 2017-03-02 10:09:00 +11:00
fuse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse 2017-03-03 12:14:13 -08:00
gfs2 gfs2: Avoid alignment hole in struct lm_lockname 2017-03-15 10:06:07 -04:00
hfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 21:44:35 -08:00
hfsplus sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
hostfs
hpfs sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
hugetlbfs sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
isofs sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
jbd2 jbd2: don't leak memory if setting up journal fails 2017-03-15 15:08:48 -04:00
jffs2 sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
jfs fs: add i_blocksize() 2017-02-27 18:43:46 -08:00
kernfs kernfs: Check KERNFS_HAS_RELEASE before calling kernfs_release_file() 2017-03-17 10:25:59 +09:00
lockd sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
minix statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00
ncpfs Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
nfs NFS client fixes for 4.11 2017-03-17 14:16:22 -07:00
nfs_common
nfsd Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
nilfs2 sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
nls
notify sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
ntfs sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
ocfs2 net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
omfs sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
openpromfs
orangefs Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
overlayfs overlayfs: remove now unnecessary header file include 2017-03-08 10:42:13 -08:00
proc Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
pstore fs/pstore: fs/squashfs: change usage of LZ4 to work with new LZ4 version 2017-02-24 17:46:57 -08:00
qnx4
qnx6
quota sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
ramfs
reiserfs fs: add i_blocksize() 2017-02-27 18:43:46 -08:00
romfs romfs: use different way to generate fsid for BLOCK or MTD 2017-01-24 16:26:14 -08:00
squashfs fs/pstore: fs/squashfs: change usage of LZ4 to work with new LZ4 version 2017-02-24 17:46:57 -08:00
sysfs
sysv statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00
tracefs
ubifs statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00
udf statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00
ufs
xfs xfs: prevent multi-fsb dir readahead from reading random blocks 2017-04-25 09:40:40 -07:00
aio.c Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
anon_inodes.c
attr.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
bad_inode.c statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00
binfmt_aout.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
binfmt_elf_fdpic.c sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h> 2017-03-02 08:42:39 +01:00
binfmt_elf.c sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h> 2017-03-02 08:42:39 +01:00
binfmt_em86.c
binfmt_flat.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
binfmt_misc.c sched/headers: Prepare to remove the <linux/mm_types.h> dependency from <linux/sched.h> 2017-03-02 08:42:37 +01:00
binfmt_script.c
block_dev.c block: Initialize bd_bdi on inode initialization 2017-03-02 08:56:59 -07:00
buffer.c sched/headers: Prepare for the reduction of <linux/sched.h>'s signal API dependency 2017-03-02 08:42:37 +01:00
char_dev.c
compat_binfmt_elf.c fs/binfmt: Convert obsolete cputime type to nsecs 2017-02-01 09:13:51 +01:00
compat_ioctl.c
compat.c sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
coredump.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
dax.c sched/headers: Prepare for the reduction of <linux/sched.h>'s signal API dependency 2017-03-02 08:42:37 +01:00
dcache.c
dcookies.c
direct-io.c fs: add i_blocksize() 2017-02-27 18:43:46 -08:00
drop_caches.c
eventfd.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
eventpoll.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
exec.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h> 2017-03-02 08:42:35 +01:00
fcntl.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h> 2017-03-02 08:42:35 +01:00
fhandle.c
file_table.c sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
file.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
filesystems.c
fs_pin.c
fs_struct.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h> 2017-03-02 08:42:35 +01:00
fs-writeback.c writeback: fix memory leak in wb_queue_work() 2017-03-13 08:27:34 -06:00
inode.c
internal.h iomap: constify struct iomap_ops 2017-01-30 16:32:25 -08:00
ioctl.c sched/headers: Prepare for the reduction of <linux/sched.h>'s signal API dependency 2017-03-02 08:42:37 +01:00
iomap.c iomap_dio_rw: Prevent reading file data beyond iomap_dio->i_size 2017-04-25 09:40:40 -07:00
Kconfig dax: fix build warnings with FS_DAX and !FS_IOMAP 2017-01-24 16:26:14 -08:00
Kconfig.binfmt
libfs.c Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
locks.c
Makefile
mbcache.c
mount.h mnt: Tuck mounts under others instead of creating shadow/side mounts. 2017-02-04 00:01:06 +13:00
mpage.c fs: add i_blocksize() 2017-02-27 18:43:46 -08:00
namei.c Merge remote-tracking branch 'ovl/for-viro' into for-linus 2017-03-02 06:41:22 -05:00
namespace.c sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
no-block.c
nsfs.c nsfs: Add an ioctl() to return owner UID of a userns 2017-02-03 14:35:43 +13:00
open.c vfs: wrap write f_ops with file_{start,end}_write() 2017-02-07 15:05:04 +01:00
pipe.c
pnode.c mnt: Tuck mounts under others instead of creating shadow/side mounts. 2017-02-04 00:01:06 +13:00
pnode.h mnt: Tuck mounts under others instead of creating shadow/side mounts. 2017-02-04 00:01:06 +13:00
posix_acl.c sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
proc_namespace.c sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
read_write.c Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
readdir.c
select.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
seq_file.c
signalfd.c
splice.c Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
stack.c
stat.c Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
statfs.c
super.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2017-02-23 20:33:51 -08:00
sync.c vfs: use helper for calling f_op->fsync() 2017-02-20 16:51:23 +01:00
timerfd.c timerfd: Only check CAP_WAKE_ALARM when it is needed 2017-03-01 12:53:44 +01:00
userfaultfd.c Merge branch 'prep-for-5level' 2017-03-10 08:59:07 -08:00
utimes.c
xattr.c