When truncating a file, we unmap pages from userspace first, as that's
usually more efficient than relying, page by page, on the fallback in
truncate_inode_page() - particularly if the file is mapped many times.
Do the same when punching a hole: 3.4 added truncate_pagecache_range()
to do the unmap and trunc, so use it in ext4_ext_punch_hole(), instead
of calling truncate_inode_pages_range() directly.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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 <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Create a new BH_Verified flag to indicate that we've verified all the
data in a buffer_head for correctness. This allows us to bypass
expensive verification steps when they are not necessary without
missing them when they are.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This fixes a scalability problem reported by Andi Kleen and Tim Chen;
they were quite secretive about the precise nature of their workload,
but they later admitted that it only showed up when they were using a
large sparse file, so the amount of data I/O that was needed was close
to zero. I'm not sure how realistic this is and it's only a
regression if you consider changes made since 2.6.39 to be a
"regression" vis-a-vis the policy regarding post-merge window bug
fixes, but Linus agreed it was worth fixing, so I'm including it in
this pull request.
This also fixes the journalled quota mount options, which I
accidentally broke while I was cleaning up the mount option handling.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 regression fixes from Ted Ts'o:
"This fixes a scalability problem reported by Andi Kleen and Tim Chen;
they were quite secretive about the precise nature of their workload,
but they later admitted that it only showed up when they were using a
large sparse file, so the amount of data I/O that was needed was close
to zero.
I'm not sure how realistic this is and it's only a regression if you
consider changes made since 2.6.39 to be a "regression" vis-a-vis the
policy regarding post-merge window bug fixes, but Linus agreed it was
worth fixing, so I'm including it in this pull request.
This also fixes the journalled quota mount options, which I
accidentally broke while I was cleaning up the mount option handling."
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix handling of journalled quota options
ext4: address scalability issue by removing extent cache statistics
Andi Kleen and Tim Chen have reported that under certain circumstances
the extent cache statistics are causing scalability problems due to
cache line bounces.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
->ee_len is __le16, so assigning cpu_to_le32() to it is going to do
Bad Things(tm) on big-endian hosts...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We are going to remove the EOFBLOCKS_FL flag in the future, so this is
the first part of the removal. We can not remove it entirely just now,
since the e2fsck is still checking for it and it might cause headache to
some people. Instead, remove the restrictive checks now and the rest
later, when the new e2fsck code is out and common enough.
This is also needed because punch hole already breaks the EOFBLOCKS_FL
semantics, so it might cause the some troubles. So simply remove it.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The error message produced by the ext4_ext_rm_leaf() when we are
removing blocks which accidentally ends up inside the existing extent,
is not very helpful, because we would like to also know which extent did
we collide with.
This commit changes the error message to get us also the information
about the extent we are colliding with.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Since the commit 'Rewrite punch hole to use ext4_ext_remove_space()'
reworked the punch hole implementation to use ext4_ext_remove_space()
instead of ext4_ext_map_blocks(), we can remove the code which is no
longer needed from the ext4_ext_map_blocks().
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit rewrites ext4 punch hole implementation to use
ext4_ext_remove_space() instead of its home gown way of doing this via
ext4_ext_map_blocks(). There are several reasons for changing this.
Firstly it is quite non obvious that punching hole needs to
ext4_ext_map_blocks() to punch a hole, especially given that this
function should map blocks, not unmap it. It also required a lot of new
code in ext4_ext_map_blocks().
Secondly the design of it is not very effective. The reason is that we
are trying to punch out blocks in ext4_ext_punch_hole() in opposite
direction than in ext4_ext_rm_leaf() which causes the ext4_ext_rm_leaf()
to iterate through the whole tree from the end to the start to find the
requested extent for every extent we are going to punch out.
And finally the current implementation does not use the existing code,
but bring a lot of new code, which is IMO unnecessary since there
already is some infrastructure we can use. Specifically
ext4_ext_remove_space().
This commit changes ext4_ext_remove_space() to accept 'end' parameter so
we can not only truncate to the end of file, but also remove the space
in the middle of the file (punch a hole). Moreover, because the last
block to punch out, might be in the middle of the extent, we have to
split the extent at 'end + 1' so ext4_ext_rm_leaf() can easily either
remove the whole fist part of split extent, or change its size.
ext4_ext_remove_space() is then used to actually remove the space
(extents) from within the hole, instead of ext4_ext_map_blocks().
Note that this also fix the issue with punch hole, where we would forget
to remove empty index blocks from the extent tree, resulting in double
free block error and file system corruption. This is simply because we
now use different code path, where this problem does not exist.
This has been tested with fsx running for several days and xfstests,
plus xfstest #251 with '-o discard' run on the loop image (which
converts discard requestes into punch hole to the backing file). All of
it on 1K and 4K file system block size.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Explicitly test for an extent whose length is zero, and flag that as a
corrupted extent.
This avoids a kernel BUG_ON assertion failure.
Tested: Without this patch, the file system image found in
tests/f_ext_zero_len/image.gz in the latest e2fsprogs sources causes a
kernel panic. With this patch, an ext4 file system error is noted
instead, and the file system is marked as being corrupted.
https://bugzilla.kernel.org/show_bug.cgi?id=42859
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/jack/linux-fs:
ext2/3/4: delete unneeded includes of module.h
ext{3,4}: Fix potential race when setversion ioctl updates inode
udf: Mark LVID buffer as uptodate before marking it dirty
ext3: Don't warn from writepage when readonly inode is spotted after error
jbd: Remove j_barrier mutex
reiserfs: Force inode evictions before umount to avoid crash
reiserfs: Fix quota mount option parsing
udf: Treat symlink component of type 2 as /
udf: Fix deadlock when converting file from in-ICB one to normal one
udf: Cleanup calling convention of inode_getblk()
ext2: Fix error handling on inode bitmap corruption
ext3: Fix error handling on inode bitmap corruption
ext3: replace ll_rw_block with other functions
ext3: NULL dereference in ext3_evict_inode()
jbd: clear revoked flag on buffers before a new transaction started
ext3: call ext3_mark_recovery_complete() when recovery is really needed
Delete any instances of include module.h that were not strictly
required. In the case of ext2, the declaration of MODULE_LICENSE
etc. were in inode.c but the module_init/exit were in super.c, so
relocate the MODULE_LICENCE/AUTHOR block to super.c which makes it
consistent with ext3 and ext4 at the same time.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Fix ext4_debug format in ext4_ext_handle_uninitialized_extents() and
ext4_end_io_dio().
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We found performance regression when using bigalloc with "nodelalloc"
(1MB cluster size):
1. mke2fs -C 1048576 -O ^has_journal,bigalloc /dev/sda
2. mount -o nodelalloc /dev/sda /test/
3. time dd if=/dev/zero of=/test/io bs=1048576 count=1024
The "dd" will cost about 2 seconds to finish, but if we mke2fs without
"bigalloc", "dd" will only cost less than 1 second.
The reason is: when using ext4 with "nodelalloc", it will call
ext4_find_delalloc_cluster() nearly everytime it call
ext4_ext_map_blocks(), and ext4_find_delalloc_range() will also scan
all pages in cluster because no buffer is "delayed". A cluster has
256 pages (1MB cluster), so it will scan 256 * 256k pags when creating
a 1G file. That severely hurts the performance.
Therefore, we return immediately from ext4_find_delalloc_range() in
nodelalloc mode, since by definition there can't be any delalloc
pages.
Signed-off-by: Robin Dong <sanbai@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In get_implied_cluster_alloc(), rr_cluster_end was being
defined and set, but was never used. Removed this.
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
If a file is fallocated on a hole, map->m_lblk + map->m_len may be greater
than ee_block + ee_len.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
Commit 1939dd84b3 ("ext4: cleanup ext4_ext_grow_indepth code") added a
reference to ext4_extent_header.eh_depth, but forget to pass the value
read through le16_to_cpu. The result is a crash on big-endian
machines, such as this crash on a POWER7 server:
attempt to access beyond end of device
sda8: rw=0, want=776392648163376, limit=168558560
Unable to handle kernel paging request for data at address 0x6b6b6b6b6b6b6bcb
Faulting instruction address: 0xc0000000001f5f38
cpu 0x14: Vector: 300 (Data Access) at [c000001bd1aaecf0]
pc: c0000000001f5f38: .__brelse+0x18/0x60
lr: c0000000002e07a4: .ext4_ext_drop_refs+0x44/0x80
sp: c000001bd1aaef70
msr: 9000000000009032
dar: 6b6b6b6b6b6b6bcb
dsisr: 40000000
current = 0xc000001bd15b8010
paca = 0xc00000000ffe4600
pid = 19911, comm = flush-8:0
enter ? for help
[c000001bd1aaeff0] c0000000002e07a4 .ext4_ext_drop_refs+0x44/0x80
[c000001bd1aaf090] c0000000002e0c58 .ext4_ext_find_extent+0x408/0x4c0
[c000001bd1aaf180] c0000000002e145c .ext4_ext_insert_extent+0x2bc/0x14c0
[c000001bd1aaf2c0] c0000000002e3fb8 .ext4_ext_map_blocks+0x628/0x1710
[c000001bd1aaf420] c0000000002b2974 .ext4_map_blocks+0x224/0x310
[c000001bd1aaf4d0] c0000000002b7f2c .mpage_da_map_and_submit+0xbc/0x490
[c000001bd1aaf5a0] c0000000002b8688 .write_cache_pages_da+0x2c8/0x430
[c000001bd1aaf720] c0000000002b8b28 .ext4_da_writepages+0x338/0x670
[c000001bd1aaf8d0] c000000000157280 .do_writepages+0x40/0x90
[c000001bd1aaf940] c0000000001ea830 .writeback_single_inode+0xe0/0x530
[c000001bd1aafa00] c0000000001eb680 .writeback_sb_inodes+0x210/0x300
[c000001bd1aafb20] c0000000001ebc84 .__writeback_inodes_wb+0xd4/0x140
[c000001bd1aafbe0] c0000000001ebfec .wb_writeback+0x2fc/0x3e0
[c000001bd1aafce0] c0000000001ed770 .wb_do_writeback+0x2f0/0x300
[c000001bd1aafdf0] c0000000001ed848 .bdi_writeback_thread+0xc8/0x340
[c000001bd1aafed0] c0000000000c5494 .kthread+0xb4/0xc0
[c000001bd1aaff90] c000000000021f48 .kernel_thread+0x54/0x70
This is due to getting ext_depth(inode) == 0x101 and therefore running
off the end of the path array in ext4_ext_drop_refs into following
unallocated structures.
This fixes it by adding the necessary le16_to_cpu.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The variable 'block' is removed by commit 750c9c47, so use the
replacement ex_ee_block instead.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch fixes a syntax error which omits a comma. Besides this,
logical block number is unsigend 32 bits, so printk should use %u
instead %d.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
If an fallocate request fits in EXT_UNINIT_MAX_LEN, then set the
EXT4_GET_BLOCKS_NO_NORMALIZE flag. For larger fallocate requests,
let mballoc.c normalize the request.
This fixes a problem where large requests were being split into
non-contiguous extents due to commit 556b27abf7: ext4: do not
normalize block requests from fallocate.
Testing:
*) Checked that 8.x MB falloc'ed files are still laid down next to
each other (contiguously).
*) Checked that the maximum size extent (127.9MB) is allocated as 1
extent.
*) Checked that a 1GB file is somewhat contiguous (often 5-6
non-contiguous extents now).
*) Checked that a 120MB file can still be falloc'ed even if there are
no single extents large enough to hold it.
Signed-off-by: Greg Harm <gharm@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
EXT4_IO_END_UNWRITTEN flag set and the increase of i_aiodio_unwritten
should be done simultaneously since ext4_end_io_nolock always clear
the flag and decrease the counter in the same time.
We have found some bugs that the flag is set while leaving
i_aiodio_unwritten unchanged(commit 32c80b32c0). So this patch just tries
to create a helper function to wrap them to avoid any future bug.
The idea is inspired by Eric.
Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When ext4_ext_map_blocks() is called by punch_hole, trace should
trace blocks punched out.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4_ext_insert_extent() (respectively ext4_ext_insert_index())
was using EXT_MAX_EXTENT() (resp. EXT_MAX_INDEX()) to determine
how many entries needed to be moved beyond the insertion point.
In practice this means that (320 - I) * 24 bytes were memmove()'d
when I is the insertion point, rather than (#entries - I) * 24 bytes.
This patch uses EXT_LAST_EXTENT() (resp. EXT_LAST_INDEX()) instead
to only move existing entries. The code flow is also simplified
slightly to highlight similarities and reduce code duplication in
the insertion logic.
This patch reduces system CPU consumption by over 25% on a 4kB
synchronous append DIO write workload when used with the
pre-2.6.39 x86_64 memmove() implementation. With the much faster
2.6.39 memmove() implementation we still see a decrease in
system CPU usage between 2% and 7%.
Note that the ext_debug() output changes with this patch, splitting
some log information between entries. Users of the ext_debug() output
should note that the "move %d" units changed from reporting the number
of bytes moved to reporting the number of entries moved.
Signed-off-by: Eric Gouriou <egouriou@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch introduces a fast path in ext4_ext_convert_to_initialized()
for the case when the conversion can be performed by transferring
the newly initialized blocks from the uninitialized extent into
an adjacent initialized extent. Doing so removes the expensive
invocations of memmove() which occur during extent insertion and
the subsequent merge.
In practice this should be the common case for clients performing
append writes into files pre-allocated via
fallocate(FALLOC_FL_KEEP_SIZE). In such a workload performed via
direct IO and when using a suboptimal implementation of memmove()
(x86_64 prior to the 2.6.39 rewrite), this patch reduces kernel CPU
consumption by 32%.
Two new trace points are added to ext4_ext_convert_to_initialized()
to offer visibility into its operations. No exit trace point has
been added due to the multiplicity of return points. This can be
revisited once the upstream cleanup is backported.
Signed-off-by: Eric Gouriou <egouriou@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When we want to convert the unitialized extent in direct write, we can
either do it in ext4_end_io_nolock(AIO case) or in
ext4_ext_direct_IO(non AIO case) and EXT4_I(inode)->cur_aio_dio is a
guard for ext4_ext_map_blocks to find the right case. In e9e3bcecf,
we mistakenly change it by:
- if (io)
+ if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
io->flag = EXT4_IO_END_UNWRITTEN;
- else
+ atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
+ } else
ext4_set_inode_state(inode,
EXT4_STATE_DIO_UNWRITTEN);
So now if we map 2 blocks, and the first one set the
EXT_IO_END_UNWRITTEN, the 2nd mapping will set inode state because of
the check for the flag. This is wrong.
Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In ext4_ext_next_allocated_block(), the path[depth] might
have a p_ext that is NULL -- see ext4_ext_binsearch(). In
such a case, dereferencing it will crash the machine.
This patch checks for p_ext == NULL in
ext4_ext_next_allocated_block() before dereferencinging it.
Tested using a hand-crafted an inode with eh_entries == 0 in
an extent block, verified that running FIEMAP on it crashes
without this patch, works fine with it.
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When allocated is unsigned it breaks the error handling at the end
of the function when we call:
allocated = ext4_split_extent(...);
if (allocated < 0)
err = allocated;
I've made it a signed int instead of unsigned.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
EOFBLOCK_FL should be updated if called w/o FALLOCATE_FL_KEEP_SIZE
Currently it happens only if new extent was allocated.
TESTCASE:
fallocate test_file -n -l4096
fallocate test_file -l4096
Last fallocate cmd has updated size, but keept EOFBLOCK_FL set. And
fsck will complain about that.
Also remove ping pong in ext4_fallocate() in case of new extents,
where ext4_ext_map_blocks() clear EOFBLOCKS bit, and later
ext4_falloc_update_inode() restore it again.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
- Both callers(truncate and punch_hole) already aligned left end point
so we no longer need split logic here.
- Remove dead duplicated code.
- Call ext4_ext_dirty only after we have updated eh_entries, otherwise
we'll loose entries update. Regression caused by d583fb87a3
266'th testcase in xfstests (http://patchwork.ozlabs.org/patch/120872)
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Currently code make an impression what grow procedure is very complicated
and some mythical paths, blocks are involved. But in fact grow in depth
it relatively simple procedure:
1) Just create new meta block and copy root data to that block.
2) Convert root from extent to index if old depth == 0
3) Update root block pointer
This patch does:
- Reorganize code to make it more self explanatory
- Do not pass path parameter to new_meta_block() in order to
provoke allocation from inode's group because top-level block
should site closer to it's inode, but not to leaf data block.
[ This happens anyway, due to logic in mballoc; we should drop
the path parameter from new_meta_block() entirely. -- tytso ]
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The third parameter to ext4_free_blocks is a struct buffer_head *. This
parameter should be NULL not 0.
This quiets the sparse noise:
warning: Using plain integer as NULL pointer
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add a sanity check to make sure ix hasn't gone beyond the valid bounds
of the extent block.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4_extent_idx.e_block is __le32, so use le32_to_cpu() in
ext4_ext_search_left().
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The comment describing what ext4_ext_search_right() does is incorrect.
We return 0 in *phys when *logical is the 'largest' allocated block,
not smallest.
Fix a few other typos while we're at it.
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Currently, there exists a race between delayed allocated writes and
the writeback when bigalloc feature is in use. The race was because we
wanted to determine what blocks in a cluster are under delayed
allocation and we were using buffer_delayed(bh) check for it. But, the
writeback codepath clears this bit without any synchronization which
resulted in a race and an ext4 warning similar to:
EXT4-fs (ram1): ext4_da_update_reserve_space: ino 13, used 1 with only 0
reserved data blocks
The race existed in two places.
(1) between ext4_find_delalloc_range() and ext4_map_blocks() when called from
writeback code path.
(2) between ext4_find_delalloc_range() and ext4_da_get_block_prep() (where
buffer_delayed(bh) is set.
To fix (1), this patch introduces a new buffer_head state bit -
BH_Da_Mapped. This bit is set under the protection of
EXT4_I(inode)->i_data_sem when we have actually mapped the delayed
allocated blocks during the writeout time. We can now reliably check
for this bit inside ext4_find_delalloc_range() to determine whether
the reservation for the blocks have already been claimed or not.
To fix (2), it was necessary to set buffer_delay(bh) under the
protection of i_data_sem. So, I extracted the very beginning of
ext4_map_blocks into a new function - ext4_da_map_blocks() - and
performed the required setting of bh_delay bit and the quota
reservation under the protection of i_data_sem. These two fixes makes
the checking of buffer_delay(bh) and buffer_da_mapped(bh) consistent,
thus removing the race.
Tested: I was able to reproduce the problem by running 'dd' and
'fsync' in parallel. Also, xfstests sometimes used to reproduce this
race. After the fix both my test and xfstests were successful and no
race (warning message) was observed.
Google-Bug-Id: 4997027
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch adds some tracepoints in ext4/extents.c and updates a tracepoint in
ext4/inode.c.
Tested: Built and ran the kernel and verified that these tracepoints work.
Also ran xfstests.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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 <adityakali@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When we are truncating (as opposed unlinking) a file, we need to worry
about partial truncates of a file, especially in the light of sparse
files. The changes here make sure that arbitrary truncates of sparse
files works correctly. Yeah, it's messy.
Note that these functions will need to be revisted when the punch
ioctl is integrated --- in fact this commit will probably have merge
conflicts with the punch changes which Allison Henders and the IBM LTC
have been working on. I will need to fix this up when either patch
hits mainline.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
If we need to allocate a new block in ext4_ext_map_blocks(), the
function needs to see if the cluster has already been allocated.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
While running extended fsx tests to verify the first
two patches, a similar bug was also found in the
truncate operation.
This bug happens because the truncate routine only zeros
the unblock aligned portion of the last page. This means
that the block aligned portions of the page appearing after
i_size are left unzeroed, and the buffer heads still mapped.
This bug is corrected by using ext4_discard_partial_page_buffers
in the truncate routine to zero the partial page and unmap
the buffer headers.
Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add debugging information in case jbd2_journal_dirty_metadata() is
called with a buffer_head which didn't have
jbd2_journal_get_write_access() called on it, or if the journal_head
has the wrong transaction in it. In addition, return an error code.
This won't change anything for ocfs2, which will BUG_ON() the non-zero
exit code.
For ext4, the caller of this function is ext4_handle_dirty_metadata(),
and on seeing a non-zero return code, will call __ext4_journal_stop(),
which will print the function and line number of the (buggy) calling
function and abort the journal. This will allow us to recover instead
of bug halting, which is better from a robustness and reliability
point of view.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch fixes a second punch hole bug found by xfstests 127.
This bug happens because punch hole needs to flush the pages
of the hole to avoid race conditions. But if the end of the
hole is in the same page as i_size, the buffer heads beyond
i_size need to be unmapped and the page needs to be zeroed
after it is flushed.
To correct this, the new ext4_discard_partial_page_buffers
routine is used to zero and unmap the partial page
beyond i_size if the end of the hole appears in the same
page as i_size.
The code has also been optimized to set the end of the hole
to the page after i_size if the specified hole exceeds i_size,
and the code that flushes the pages has been simplified.
Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com>
This patch addresses a bug found by xfstests 75, 112, 127
when blocksize = 1k
This bug happens because the punch hole code only zeros
out non block aligned regions of the page. This means that if the
blocks are smaller than a page, then the block aligned regions of
the page inside the hole are left un-zeroed, and their buffer heads
are still mapped. This bug is corrected by using
ext4_discard_partial_page_buffers to properly zero the partial page
at the head and tail of the hole, and unmap the corresponding buffer
heads
This patch also addresses a bug reported by Lukas while working on a
new patch to add discard support for loop devices using punch hole.
The bug happened because of the first and last block number
needed to be cast to a larger data type before calculating the
byte offset, but since now we only need the byte offsets of the
pages, we no longer even need to be calculating the byte offsets
of the blocks. The code to do the block offset calculations is
removed in this patch.
Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com>
The logical block number in map.l_blk is a __u32, and so before we
shift it left, by the block size, we neeed cast it to a 64-bit size.
Otherwise i_size can be corrupted on an ENOSPC.
# df -T /mnt/mp1
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda6 ext4 9843276 153056 9190200 2% /mnt/mp1
# fallocate -o 0 -l 2199023251456 /mnt/mp1/testfile
fallocate: /mnt/mp1/testfile: fallocate failed: No space left on device
# stat /mnt/mp1/testfile
File: `/mnt/mp1/testfile'
Size: 4293656576 Blocks: 19380440 IO Block: 4096 regular file
Device: 806h/2054d Inode: 12 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2011-07-25 13:01:31.414490496 +0900
Modify: 2011-07-25 13:01:31.414490496 +0900
Change: 2011-07-25 13:01:31.454490495 +0900
Signed-off-by: Utako Kusaka <u-kusaka@wm.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
--
fs/ext4/extents.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
