linux-toradex.git/fs/ext4/ext4_extents.h, branch v3.9.3

ext4: remove single extent cache

2013-02-18T05:31:07+00:00

Single extent cache could be removed because we have extent status tree
as a extent cache, and it would be better.

Signed-off-by: Zheng Liu 
Signed-off-by: "Theodore Ts'o" 
Cc: Jan kara

ext4: rationalize ext4_extents.h inclusion

2012-11-28T18:03:30+00:00

Previously, ext4_extents.h was being included at the end of ext4.h,
which was bad for a number of reasons: (a) it was not being included
in the expected place, and (b) it caused the header to be included
multiple times.  There were #ifdef's to prevent this from causing any
problems, but it still was unnecessary.

By moving the function declarations that were in ext4_extents.h to
ext4.h, which is standard practice for where the function declarations
for the rest of ext4.h can be found, we can remove ext4_extents.h from
being included in ext4.h at all, and then we can only include
ext4_extents.h where it is needed in ext4's source files.

It should be possible to move a few more things into ext4.h, and
further reduce the number of source files that need to #include
ext4_extents.h, but that's a cleanup for another day.

Reported-by: Sachin Kamat 
Reported-by: Wei Yongjun 
Signed-off-by: "Theodore Ts'o"

ext4: prevent race while walking extent tree for fiemap

2012-11-28T17:32:26+00:00

Currently ext4_ext_walk_space() only takes i_data_sem for read when
searching for the extent at given block with ext4_ext_find_extent().
Then it drops the lock and the extent tree can be changed at will.
However later on we're searching for the 'next' extent, but the extent
tree might already have changed, so the information might not be
accurate.

In fact we can hit BUG_ON(end <= start) if the extent got inserted into
the tree after the one we found and before the block we were searching
for. This has been reproduced by running xfstests 225 in loop on s390x
architecture, but theoretically we could hit this on any other
architecture as well, but probably not as often.

Moreover the extent currently in delayed allocation might be allocated
after we search the extent tree and before we search extent status tree
delayed buffers resulting in those delayed buffers being completely
missed, even though completely written and allocated.

We fix all those problems in several steps:

 1. remove unnecessary callback indirection
 2. rename functions
        ext4_ext_walk_space -> ext4_fill_fiemap_extents
        ext4_ext_fiemap_cb -> ext4_find_delayed_extent
 3. move fiemap_fill_next_extent() into ext4_fill_fiemap_extents()
 4. hold the i_data_sem for:
        ext4_ext_find_extent()
        ext4_ext_next_allocated_block()
        ext4_find_delayed_extent()
 5. call fiemap_fill_next_extent after releasing the i_data_sem
 6. move path reinitialization into the critical section.

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

ext4: reimplement ext4_find_delay_alloc_range on extent status tree

2012-11-09T02:57:35+00:00

Signed-off-by: Yongqiang Yang 
Signed-off-by: Allison Henderson 
Signed-off-by: Zheng Liu 
Signed-off-by: "Theodore Ts'o"

ext4: verify and calculate checksums for extent tree blocks

2012-04-29T22:37:10+00:00

Calculate and verify the checksum for each extent tree block.  The
checksum is located in the space immediately after the last possible
ext4_extent in the block.  The space is is typically the last 4-8
bytes in the block.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"

ext4: change on-disk layout to support extended metadata checksumming

2012-04-29T22:23:10+00:00

Define flags and change structure definitions to allow checksumming of
ext4 metadata.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"

ext4: add no_printk argument validation, fix fallout

2012-03-20T03:11:43+00:00

Add argument validation to debug functions.
Use ##__VA_ARGS__.

Fix format and argument mismatches.

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

ext4: Fix bigalloc quota accounting and i_blocks value

2011-09-09T23:04:51+00:00

With bigalloc changes, the i_blocks value was not correctly set (it was still
set to number of blocks being used, but in case of bigalloc, we want i_blocks
to represent the number of clusters being used). Since the quota subsystem sets
the i_blocks value, this patch fixes the quota accounting and makes sure that
the i_blocks value is set correctly.

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

ext4: use FIEMAP_EXTENT_LAST flag for last extent in fiemap

2011-06-06T04:06:52+00:00

Currently we are not marking the extent as the last one
(FIEMAP_EXTENT_LAST) if there is a hole at the end of the file. This is
because we just do not check for it right now and continue searching for
next extent. But at the point we hit the hole at the end of the file, it
is too late.

This commit adds check for the allocated block in subsequent extent and
if there is no more extents (block = EXT_MAX_BLOCKS) just flag the
current one as the last one.

This behaviour has been spotted unintentionally by 252 xfstest, when the
test hangs out, because of wrong loop condition. However on other
filesystems (like xfs) it will exit anyway, because we notice the last
extent flag and exit.

With this patch xfstest 252 does not hang anymore, ext4 fiemap
implementation still reports bad extent type in some cases, however
this seems to be different issue.

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

ext4: Fix max file size and logical block counting of extent format file

2011-06-06T04:05:17+00:00

Kazuya Mio reported that he was able to hit BUG_ON(next == lblock)
in ext4_ext_put_gap_in_cache() while creating a sparse file in extent
format and fill the tail of file up to its end. We will hit the BUG_ON
when we write the last block (2^32-1) into the sparse file.

The root cause of the problem lies in the fact that we specifically set
s_maxbytes so that block at s_maxbytes fit into on-disk extent format,
which is 32 bit long. However, we are not storing start and end block
number, but rather start block number and length in blocks. It means
that in order to cover extent from 0 to EXT_MAX_BLOCK we need
EXT_MAX_BLOCK+1 to fit into len (because we counting block 0 as well) -
and it does not.

The only way to fix it without changing the meaning of the struct
ext4_extent members is, as Kazuya Mio suggested, to lower s_maxbytes
by one fs block so we can cover the whole extent we can get by the
on-disk extent format.

Also in many places EXT_MAX_BLOCK is used as length instead of maximum
logical block number as the name suggests, it is all a bit messy. So
this commit renames it to EXT_MAX_BLOCKS and change its usage in some
places to actually be maximum number of blocks in the extent.

The bug which this commit fixes can be reproduced as follows:

 dd if=/dev/zero of=/mnt/mp1/file bs= count=1 seek=$((2**32-2))
 sync
 dd if=/dev/zero of=/mnt/mp1/file bs= count=1 seek=$((2**32-1))

Reported-by: Kazuya Mio 
Signed-off-by: Lukas Czerner 
Signed-off-by: "Theodore Ts'o"