We found a problem with buffer head reference leaks when using an ext4
partition without a journal. In particular, calls to ext4_forget() would
not to a brelse() on the input buffer head, which will cause pages they
belong to to not be reclaimable.
Further investigation showed that all places where ext4_journal_forget() and
ext4_journal_revoke() are called are subject to the same problem. The patch
below changes __ext4_journal_forget/__ext4_journal_revoke to do an explicit
release of the buffer head when the journal handle isn't valid.
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch fixes the mmap/truncate race that was fixed for delayed
allocation by merging ext4_{journalled,normal,da}_writepage() into
ext4_writepage().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
It is possible to see buffer_heads which are not mapped in the
writepage callback in the following scneario (where the fs blocksize
is 1k and the page size is 4k):
1) truncate(f, 1024)
2) mmap(f, 0, 4096)
3) a[0] = 'a'
4) truncate(f, 4096)
5) writepage(...)
Now if we get a writepage callback immediately after (4) and before an
attempt to write at any other offset via mmap address (which implies we
are yet to get a pagefault and do a get_block) what we would have is the
page which is dirty have first block allocated and the other three
buffer_heads unmapped.
In the above case the writepage should go ahead and try to write the
first blocks and clear the page_dirty flag. Further attempts to write
to the page will again create a fault and result in allocating blocks
and marking page dirty. If we don't write any other offset via mmap
address we would still have written the first block to the disk and
rest of the space will be considered as a hole.
So to address this, we change all of the places where we look for
delayed, unmapped, or unwritten buffer heads, and only check for
delayed or unwritten buffer heads instead.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Buffer heads outside i_size will be unmapped. So when we
are doing "walk_page_buffers" limit ourself to i_size.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Josef Bacik <jbacik@redhat.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
----
Contents of long symlinks is written via standard write methods. So
when the write fails, we add inode to orphan list. But symlinks don't
have .truncate method defined so nobody properly removes them from the
on disk orphan list.
Fix this by calling ext4_truncate() directly instead of calling
vmtruncate() (which is saner anyway since we don't need anything
vmtruncate() does except from calling .truncate in these paths). We
also add inode to orphan list only if ext4_can_truncate() is true
(currently, it can be false for symlinks when there are no blocks
allocated) - otherwise orphan list processing will complain and
ext4_truncate() will not remove inode from on-disk orphan list.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The VFS handles updating ctime, so we don't need to update the inode's
ctime in ext4_splace_branch() to update the direct or indirect blocks.
This was harmless when we did this in ext3, but in ext4, thanks to
delayed allocation, updating the ctime in ext4_splice_branch() can
cause the ctime to mysteriously jump when the blocks are finally
allocated.
Thanks to Björn Steinbrink for pointing out this problem on the git
mailing list.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We're running out of space in the mount options word, and
EXT4_MOUNT_ABORT isn't really a mount option, but a run-time flag. So
move it to become EXT4_MF_FS_ABORTED in s_mount_flags.
Also remove bogus ext2_fs.h / ext4.h simultaneous #include protection,
which can never happen.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We can only fit 32 options in s_mount_opt because an unsigned long is
32-bits on a x86 machine. So use an unsigned int to save space on
64-bit platforms.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
If a non-existent file is opened via O_WRONLY|O_CREAT|O_TRUNC, there's
no need to treat this as a true file truncation, so we shouldn't
activate the replace-via-truncate hueristic.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In generic_perform_write if we fail to copy the user data we don't
update the inode->i_size. We should truncate the file in the above
case so that we don't have blocks allocated outside inode->i_size. Add
the inode to orphan list in the same transaction as block allocation
This ensures that if we crash in between the recovery would do the
truncate.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
CC: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We should add inode to the orphan list in the same transaction
as block allocation. This ensures that if we crash after a failed
block allocation and before we do a vmtruncate we don't leak block
(ie block marked as used in bitmap but not claimed by the inode).
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
CC: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Get rid of EXTEND_DISKSIZE flag of ext4_get_blocks_handle(). This
seems to be a relict from some old days and setting disksize in this
function does not make much sense. Currently it was set only by
ext4_getblk(). Since the parameter has some effect only if create ==
1, it is easy to check by grepping through the sources that the three
callers which end up calling ext4_getblk() with create == 1
(ext4_append, ext4_quota_write, ext4_mkdir) do the right thing and set
disksize themselves.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The __ext4_write_dirty_metadata() function was introduced by commit
0390131b, "ext4: Allow ext4 to run without a journal", but nothing
ever used the function, either then or since. So let's remove it and
save a bit of space.
Cc: Frank Mayhar <fmayhar@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
To catch filesystem bugs or corruption which could lead to the
filesystem getting severly damaged, this patch adds a facility for
tracking all of the filesystem metadata blocks by contiguous regions
in a red-black tree. This allows quick searching of the tree to
locate extents which might overlap with filesystem metadata blocks.
This facility is also used by the multi-block allocator to assure that
it is not allocating blocks out of the system zone, as well as by the
routines used when reading indirect blocks and extents information
from disk to make sure their contents are valid.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The ext4_get_blocks() function was depending on the value of
bh_result->b_state as an input parameter to decide whether or not
update the delalloc accounting statistics by calling
ext4_da_update_reserve_space(). We now use a separate flag,
EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE, to requests this update, so that
all callers of ext4_get_blocks() can clear map_bh.b_state before
calling ext4_get_blocks() without worrying about any consistency
issues.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The static function ext4_da_get_block_write() was only used by
mpage_da_map_blocks(). So to simplify the code, merge that function
into mpage_da_map_blocks().
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Enforce that noalloc_get_block_write() is only called to map one block
at a time, and that it always is successful in finding a mapping for
given an inode's logical block block number if it is called with
create == 1.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This adds more documentation to various internal functions in
fs/ext4/inode.c, most notably ext4_ind_get_blocks(),
ext4_da_get_block_write(), ext4_da_get_block_prep(),
ext4_normal_get_block_write().
In addition, the static function ext4_normal_get_block_write() has
been renamed noalloc_get_block_write(), since it is used in many
places far beyond ext4_normal_writepage().
Plenty of warnings have been added to the noalloc_get_block_write()
function, since the way it is used is amazingly fragile.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The functions ext4_get_blocks(), ext4_ext_get_blocks(), and
ext4_ind_get_blocks() used an ad-hoc set of integer variables used as
boolean flags passed in as arguments. Use a single flags parameter
and a setandard set of bitfield flags instead. This saves space on
the call stack, and it also makes the code a bit more understandable.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Another function rename for clarity's sake. The _wrap prefix simply
confuses people, and didn't add much people trying to follow the code
paths.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The static function ext4_get_blocks_handle() is badly named. Of
*course* it takes a handle. Since its counterpart for extent-based
file is ext4_ext_get_blocks(), rename it to be ext4_ind_get_blocks().
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The function ext4_da_get_block_write() is called in exactly one write,
and the last argument, create, is always 1. Remove it to simplify the
code slightly.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Ext4's on-line resizing adds a new block group and then, only at the
last step adjusts s_groups_count. However, it's possible on SMP
systems that another CPU could see the updated the s_group_count and
not see the newly initialized data structures for the just-added block
group. For this reason, it's important to insert a SMP read barrier
after reading s_groups_count and before reading any (for example) the
new block group descriptors allowed by the increased value of
s_groups_count.
Unfortunately, we rather blatently violate this locking protocol
documented in fs/ext4/resize.c. Fortunately, (1) on-line resizes
happen relatively rarely, and (2) it seems rare that the filesystem
code will immediately try to use just-added block group before any
memory ordering issues resolve themselves. So apparently problems
here are relatively hard to hit, since ext3 has been vulnerable to the
same issue for years with no one apparently complaining.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Setting BH_Unwritten buffer_heads as BH_Mapped avoids multiple
(unnecessary) calls to get_block() during the call to the write(2)
system call. Setting BH_Unwritten buffer heads as BH_Mapped requires
that the writepages() functions can handle BH_Unwritten buffer_heads.
After this commit, things work as follows:
ext4_ext_get_block() returns unmapped, unwritten, buffer head when
called with create = 0 for prealloc space. This makes sure we handle
the read path and non-delayed allocation case correctly. Even though
the buffer head is marked unmapped we have valid b_blocknr and b_bdev
values in the buffer_head.
ext4_da_get_block_prep() called for block resrevation will now return
mapped, unwritten, new buffer_head for prealloc space. This avoids
multiple calls to get_block() for write to same offset. By making such
buffers as BH_New, we also assure that sub-block zeroing of buffered
writes happens correctly.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
These struct buffer_heads are allocated on the stack (and hence are
initialized with stack garbage). They are only used to call a
get_blocks() function, so that's mostly OK, but b_state must be
initialized to be 0 so we don't have any unexpected BH_* flags set by
accident, such as BH_Unwritten or BH_Delay.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The BH_Unwritten flag indicates that the buffer is allocated on disk
but has not been written; that is, the disk was part of a persistent
preallocation area. That flag should only be set when a get_blocks()
function is looking up a inode's logical to physical block mapping.
When ext4_get_blocks_wrap() is called with create=1, the uninitialized
extent is converted into an initialized one, so the BH_Unwritten flag
is no longer appropriate. Hence, we need to make sure the
BH_Unwritten is not left set, since the combination of BH_Mapped and
BH_Unwritten is not allowed; among other things, it will result ext4's
get_block() to be called over and over again during the write_begin
phase of write(2).
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Use a very large unsigned number (~0xffff) as as the fake block number
for the delayed new buffer. The VFS should never try to write out this
number, but if it does, this will make it obvious.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We need to mark the buffer_head mapping preallocated space as new
during write_begin. Otherwise we don't zero out the page cache content
properly for a partial write. This will cause file corruption with
preallocation.
Now that we mark the buffer_head new we also need to have a valid
buffer_head blocknr so that unmap_underlying_metadata() unmaps the
correct block.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The EXTENTS_FL flag should never be set on special files, but if it
is, don't bother trying to validate that the extents tree is valid,
since only files, directories, and non-fast symlinks will ever have an
extent data structure. We perhaps should flag the filesystem as being
corrupted if we see a special file (named pipes, device nodes, Unix
domain sockets, etc.) with the EXTENTS_FL flag, but e2fsck doesn't
currently check this case, so we'll just ignore this for now, since
it's harmless.
Without this fix, a special device with the extents flag is flagged as
an error by the kernel, so it is impossible to access or delete the
inode, but e2fsck doesn't see it as a problem, leading to
confused/frustrated users.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Don't try to look at i_file_acl_high unless the INCOMPAT_64BIT feature
bit is set. The field is normally zero, but older versions of e2fsck
didn't automatically check to make sure of this, so in the spirit of
"be liberal in what you accept", don't look at i_file_acl_high unless
we are using a 64-bit filesystem.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
If the block containing external extended attributes (which is stored
in i_file_acl and i_file_acl_high) is larger than the on-disk
filesystem, the process which tried to access the extended attributes
will endlessly issue kernel printks complaining that
"__find_get_block_slow() failed", locking up that CPU until the system
is forcibly rebooted.
So when we read in the inode, make sure the i_file_acl value is legal,
and if not, flag the filesystem as being corrupted.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Commit fe2c8191 introduced a regression on big-endian system, because
the checks to make sure block references in non-extent inodes are
valid failed to use le32_to_cpu().
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Thiemo Nagel <thiemo.nagel@ph.tum.de>
Tested-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (33 commits)
ext4: Regularize mount options
ext4: fix locking typo in mballoc which could cause soft lockup hangs
ext4: fix typo which causes a memory leak on error path
jbd2: Update locking coments
ext4: Rename pa_linear to pa_type
ext4: add checks of block references for non-extent inodes
ext4: Check for an valid i_mode when reading the inode from disk
ext4: Use WRITE_SYNC for commits which are caused by fsync()
ext4: Add auto_da_alloc mount option
ext4: Use struct flex_groups to calculate get_orlov_stats()
ext4: Use atomic_t's in struct flex_groups
ext4: remove /proc tuning knobs
ext4: Add sysfs support
ext4: Track lifetime disk writes
ext4: Fix discard of inode prealloc space with delayed allocation.
ext4: Automatically allocate delay allocated blocks on rename
ext4: Automatically allocate delay allocated blocks on close
ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl
ext4: Simplify delalloc code by removing mpage_da_writepages()
ext4: Save stack space by removing fake buffer heads
...
Change the page_mkwrite prototype to take a struct vm_fault, and return
VM_FAULT_xxx flags. There should be no functional change.
This makes it possible to return much more detailed error information to
the VM (and also can provide more information eg. virtual_address to the
driver, which might be important in some special cases).
This is required for a subsequent fix. And will also make it easier to
merge page_mkwrite() with fault() in future.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Check block references in the inode and indorect blocks for non-extent
inodes to make sure they are valid, and flag an error if they are
invalid.
Signed-off-by: Thiemo Nagel <thiemo.nagel@ph.tum.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Use lowercase names of quota functions instead of old uppercase ones.
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mingming Cao <cmm@us.ibm.com>
CC: linux-ext4@vger.kernel.org
Uses quota reservation/claim/release to handle quota properly for delayed
allocation in the three steps: 1) quotas are reserved when data being copied
to cache when block allocation is defered 2) when new blocks are allocated.
reserved quotas are converted to the real allocated quota, 2) over-booked
quotas for metadata blocks are released back.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Add a mount option which allows the user to disable automatic
allocation of blocks whose allocation by delayed allocation when the
file was originally truncated or when the file is renamed over an
existing file. This feature is intended to save users from the
effects of naive application writers, but it reduces the effectiveness
of the delayed allocation code. This mount option disables this
safety feature, which may be desirable for prodcutions systems where
the risk of unclean shutdowns or unexpected system crashes is low.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Remove tuning knobs in /proc/fs/ext4/<dev/* since they have been
replaced by knobs in sysfs at /sys/fs/ext4/<dev>/*.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
With delayed allocation we should not/cannot discard inode prealloc
space during file close. We would still have dirty pages for which we
haven't allocated blocks yet. With this fix after each get_blocks
request we check whether we have zero reserved blocks and if yes and
we don't have any writers on the file we discard inode prealloc space.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Running without a journal, I oopsed when I ran out of space,
because we called jbd2_journal_force_commit_nested() from
ext4_should_retry_alloc() without a journal.
This should take care of it, I think.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When closing a file that had been previously truncated, force any
delay allocated blocks that to be allocated so that if the filesystem
is mounted with data=ordered, the data blocks will be pushed out to
disk along with the journal commit. Many application programs expect
this, so we do this to avoid zero length files if the system crashes
unexpectedly.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add an ioctl which forces all of the delay allocated blocks to be
allocated. This also provides a function ext4_alloc_da_blocks() which
will be used by the following commits to force files to be fully
allocated to preserve application-expected ext3 behaviour.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The mpage_da_writepages() function is only used in one place, so
inline it to simplify the call stack and make the code easier to
understand.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Curt Wohlgemuth