linux.git/fs/ext4/super.c, branch v3.14

ext4: don't try to modify s_flags if the the file system is read-only

2014-02-12T17:16:04+00:00

If an ext4 file system is created by some tool other than mke2fs
(perhaps by someone who has a pathalogical fear of the GPL) that
doesn't set one or the other of the EXT2_FLAGS_{UN}SIGNED_HASH flags,
and that file system is then mounted read-only, don't try to modify
the s_flags field.  Otherwise, if dm_verity is in use, the superblock
will change, causing an dm_verity failure.

Signed-off-by: "Theodore Ts'o" 
Cc: stable@vger.kernel.org

ext4: Do not reserve clusters when fs doesn't support extents

2013-12-09T02:11:59+00:00

When the filesystem doesn't support extents (like in ext2/3
compatibility modes), there is no need to reserve any clusters. Space
estimates for writing are exact, hole punching doesn't need new
metadata, and there are no unwritten extents to convert.

This fixes a problem when filesystem still having some free space when
accessed with a native ext2/3 driver suddently reports ENOSPC when
accessed with ext4 driver.

Reported-by: Geert Uytterhoeven 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Lukas Czerner 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@vger.kernel.org

ext4: fix del_timer() misuse for ->s_err_report

2013-12-09T01:52:31+00:00

That thing should be del_timer_sync(); consider what happens
if ext4_put_super() call of del_timer() happens to come just as it's
getting run on another CPU.  Since that timer reschedules itself
to run next day, you are pretty much guaranteed that you'll end up
with kfree'd scheduled timer, with usual fun consequences.  AFAICS,
that's -stable fodder all way back to 2010... [the second del_timer_sync()
is almost certainly not needed, but it doesn't hurt either]

Signed-off-by: Al Viro 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@vger.kernel.org

ext4: use prandom_u32() instead of get_random_bytes()

2013-11-08T05:14:53+00:00

Many of the uses of get_random_bytes() do not actually need
cryptographically secure random numbers.  Replace those uses with a
call to prandom_u32(), which is faster and which doesn't consume
entropy from the /dev/random driver.

Signed-off-by: "Theodore Ts'o"

ext4: add ratelimiting to ext4 messages

2013-10-18T01:11:01+00:00

In the case of a storage device that suddenly disappears, or in the
case of significant file system corruption, this can result in a huge
flood of messages being sent to the console.  This can overflow the
file system containing /var/log/messages, or if a serial console is
configured, this can slow down the system so much that a hardware
watchdog can end up triggering forcing a system reboot.

Google-Bug-Id: 7258357

Signed-off-by: "Theodore Ts'o"

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2013-09-06T16:36:28+00:00

Pull trivial tree from Jiri Kosina:
 "The usual trivial updates all over the tree -- mostly typo fixes and
  documentation updates"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (52 commits)
  doc: Documentation/cputopology.txt fix typo
  treewide: Convert retrun typos to return
  Fix comment typo for init_cma_reserved_pageblock
  Documentation/trace: Correcting and extending tracepoint documentation
  mm/hotplug: fix a typo in Documentation/memory-hotplug.txt
  power: Documentation: Update s2ram link
  doc: fix a typo in Documentation/00-INDEX
  Documentation/printk-formats.txt: No casts needed for u64/s64
  doc: Fix typo "is is" in Documentations
  treewide: Fix printks with 0x%#
  zram: doc fixes
  Documentation/kmemcheck: update kmemcheck documentation
  doc: documentation/hwspinlock.txt fix typo
  PM / Hibernate: add section for resume options
  doc: filesystems : Fix typo in Documentations/filesystems
  scsi/megaraid fixed several typos in comments
  ppc: init_32: Fix error typo "CONFIG_START_KERNEL"
  treewide: Add __GFP_NOWARN to k.alloc calls with v.alloc fallbacks
  page_isolation: Fix a comment typo in test_pages_isolated()
  doc: fix a typo about irq affinity
  ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-09-05T15:50:26+00:00

Pull vfs pile 1 from Al Viro:
 "Unfortunately, this merge window it'll have a be a lot of small piles -
  my fault, actually, for not keeping #for-next in anything that would
  resemble a sane shape ;-/

  This pile: assorted fixes (the first 3 are -stable fodder, IMO) and
  cleanups + %pd/%pD formats (dentry/file pathname, up to 4 last
  components) + several long-standing patches from various folks.

  There definitely will be a lot more (starting with Miklos'
  check_submount_and_drop() series)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  direct-io: Handle O_(D)SYNC AIO
  direct-io: Implement generic deferred AIO completions
  add formats for dentry/file pathnames
  kvm eventfd: switch to fdget
  powerpc kvm: use fdget
  switch fchmod() to fdget
  switch epoll_ctl() to fdget
  switch copy_module_from_fd() to fdget
  git simplify nilfs check for busy subtree
  ibmasmfs: don't bother passing superblock when not needed
  don't pass superblock to hypfs_{mkdir,create*}
  don't pass superblock to hypfs_diag_create_files
  don't pass superblock to hypfs_vm_create_files()
  oprofile: get rid of pointless forward declarations of struct super_block
  oprofilefs_create_...() do not need superblock argument
  oprofilefs_mkdir() doesn't need superblock argument
  don't bother with passing superblock to oprofile_create_stats_files()
  oprofile: don't bother with passing superblock to ->create_files()
  don't bother passing sb to oprofile_create_files()
  coh901318: don't open-code simple_read_from_buffer()
  ...

direct-io: Implement generic deferred AIO completions

2013-09-04T13:23:46+00:00

Add support to the core direct-io code to defer AIO completions to user
context using a workqueue.  This replaces opencoded and less efficient
code in XFS and ext4 (we save a memory allocation for each direct IO)
and will be needed to properly support O_(D)SYNC for AIO.

The communication between the filesystem and the direct I/O code requires
a new buffer head flag, which is a bit ugly but not avoidable until the
direct I/O code stops abusing the buffer_head structure for communicating
with the filesystems.

Currently this creates a per-superblock unbound workqueue for these
completions, which is taken from an earlier patch by Jan Kara.  I'm
not really convinced about this use and would prefer a "normal" global
workqueue with a high concurrency limit, but this needs further discussion.

JK: Fixed ext4 part, dynamic allocation of the workqueue.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jan Kara 
Signed-off-by: Al Viro

ext4: allow specifying external journal by pathname mount option

2013-08-28T23:05:07+00:00

It's always been a hassle that if an external journal's
device number changes, the filesystem won't mount.
And since boot-time enumeration can change, device number
changes aren't unusual.

The current mechanism to update the journal location is by
passing in a mount option w/ a new devnum, but that's a hassle;
it's a manual approach, fixing things after the fact.

Adding a mount option, "-o journal_path=/dev/$DEVICE" would
help, since then we can do i.e.

# mount -o journal_path=/dev/disk/by-label/$JOURNAL_LABEL ...

and it'll mount even if the devnum has changed, as shown here:

# losetup /dev/loop0 journalfile
# mke2fs -L mylabel-journal -O journal_dev /dev/loop0 
# mkfs.ext4 -L mylabel -J device=/dev/loop0 /dev/sdb1

Change the journal device number:

# losetup -d /dev/loop0
# losetup /dev/loop1 journalfile 

And today it will fail:

# mount /dev/sdb1 /mnt/test
mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

# dmesg | tail -n 1
[17343.240702] EXT4-fs (sdb1): error: couldn't read superblock of external journal

But with this new mount option, we can specify the new path:

# mount -o journal_path=/dev/loop1 /dev/sdb1 /mnt/test
#

(which does update the encoded device number, incidentally):

# umount /dev/sdb1
# dumpe2fs -h /dev/sdb1 | grep "Journal device"
dumpe2fs 1.41.12 (17-May-2010)
Journal device:	          0x0701

But best of all we can just always mount by journal-path, and
it'll always work:

# mount -o journal_path=/dev/disk/by-label/mylabel-journal /dev/sdb1 /mnt/test
#

So the journal_path option can be specified in fstab, and as long as
the disk is available somewhere, and findable by label (or by UUID),
we can mount.

Signed-off-by: Eric Sandeen 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Jan Kara 
Reviewed-by: Carlos Maiolino

treewide: Add __GFP_NOWARN to k.alloc calls with v.alloc fallbacks

2013-08-20T11:06:40+00:00

Don't emit OOM warnings when k.alloc calls fail when
there there is a v.alloc immediately afterwards.

Converted a kmalloc/vmalloc with memset to kzalloc/vzalloc.

Signed-off-by: Joe Perches 
Acked-by: "Theodore Ts'o" 
Signed-off-by: Jiri Kosina