linux-toradex.git/fs/ext4/ext4.h, branch v3.0.18

ext4: remove i_mutex lock in ext4_evict_inode to fix lockdep complaining

2011-11-11T17:37:16+00:00

commit 8c0bec2151a47906bf779c6715a10ce04453ab77 upstream.

The i_mutex lock and flush_completed_IO() added by commit 2581fdc810
in ext4_evict_inode() causes lockdep complaining about potential
deadlock in several places.  In most/all of these LOCKDEP complaints
it looks like it's a false positive, since many of the potential
circular locking cases can't take place by the time the
ext4_evict_inode() is called; but since at the very least it may mask
real problems, we need to address this.

This change removes the flush_completed_IO() and i_mutex lock in
ext4_evict_inode().  Instead, we take a different approach to resolve
the software lockup that commit 2581fdc810 intends to fix.  Rather
than having ext4-dio-unwritten thread wait for grabing the i_mutex
lock of an inode, we use mutex_trylock() instead, and simply requeue
the work item if we fail to grab the inode's i_mutex lock.

This should speed up work queue processing in general and also
prevents the following deadlock scenario: During page fault,
shrink_icache_memory is called that in turn evicts another inode B.
Inode B has some pending io_end work so it calls ext4_ioend_wait()
that waits for inode B's i_ioend_count to become zero.  However, inode
B's ioend work was queued behind some of inode A's ioend work on the
same cpu's ext4-dio-unwritten workqueue.  As the ext4-dio-unwritten
thread on that cpu is processing inode A's ioend work, it tries to
grab inode A's i_mutex lock.  Since the i_mutex lock of inode A is
still hold before the page fault happened, we enter a deadlock.

Signed-off-by: Jiaying Zhang 
Signed-off-by: "Theodore Ts'o" 
Cc: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

ext2,ext3,ext4: don't inherit APPEND_FL or IMMUTABLE_FL for new inodes

2011-11-11T17:36:32+00:00

commit 1cd9f0976aa4606db8d6e3dc3edd0aca8019372a upstream.

This doesn't make much sense, and it exposes a bug in the kernel where
attempts to create a new file in an append-only directory using
O_CREAT will fail (but still leave a zero-length file).  This was
discovered when xfstests #79 was generalized so it could run on all
file systems.

Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: fix i_blocks/quota accounting when extent insertion fails

2011-08-05T04:58:39+00:00

commit 7132de744ba76930d13033061018ddd7e3e8cd91 upstream.

The current implementation of ext4_free_blocks() always calls
dquot_free_block This looks quite sensible in the most cases: blocks
to be freed are associated with inode and were accounted in quota and
i_blocks some time ago.

However, there is a case when blocks to free were not accounted by the
time calling ext4_free_blocks() yet:

1. delalloc is on, write_begin pre-allocated some space in quota
2. write-back happens, ext4 allocates some blocks in ext4_ext_map_blocks()
3. then ext4_ext_map_blocks() gets an error (e.g.  ENOSPC) from
   ext4_ext_insert_extent() and calls ext4_free_blocks().

In this scenario, ext4_free_blocks() calls dquot_free_block() who, in
turn, decrements i_blocks for blocks which were not accounted yet (due
to delalloc) After clean umount, e2fsck reports something like:

> Inode 21, i_blocks is 5080, should be 5128.  Fix?
because i_blocks was erroneously decremented as explained above.

The patch fixes the problem by passing the new flag
EXT4_FREE_BLOCKS_NO_QUOT_UPDATE to ext4_free_blocks(), to request
that the dquot_free_block() call be skipped.

Signed-off-by: Maxim Patlasov 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

fs: pass exact type of data dirties to ->dirty_inode

2011-05-27T11:04:40+00:00

Tell the filesystem if we just updated timestamp (I_DIRTY_SYNC) or
anything else, so that the filesystem can track internally if it
needs to push out a transaction for fdatasync or not.

This is just the prototype change with no user for it yet.  I plan
to push large XFS changes for the next merge window, and getting
this trivial infrastructure in this window would help a lot to avoid
tree interdependencies.

Also remove incorrect comments that ->dirty_inode can't block.  That
has been changed a long time ago, and many implementations rely on it.

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

ext4: do not normalize block requests from fallocate()

2011-05-25T11:41:54+00:00

Currently, an fallocate request of size slightly larger than a power of
2 is turned into two block requests, each a power of 2, with the extra
blocks pre-allocated for future use. When an application calls
fallocate, it already has an idea about how large the file may grow so
there is usually little benefit to reserve extra blocks on the
preallocation list. This reduces disk fragmentation.

Tested: fsstress. Also verified manually that fallocat'ed files are
contiguously laid out with this change (whereas without it they begin at
power-of-2 boundaries, leaving blocks in between). CPU usage of
fallocate is not appreciably higher.  In a tight fallocate loop, CPU
usage hovers between 5%-8% with this change, and 5%-7% without it.

Using a simulated file system aging program which the file system to
70%, the percentage of free extents larger than 8MB (as measured by
e2freefrag) increased from 38.8% without this change, to 69.4% with
this change.

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

ext4: enable "punch hole" functionality

2011-05-25T11:41:50+00:00

This patch adds new routines: "ext4_punch_hole" "ext4_ext_punch_hole"
and "ext4_ext_check_cache"

fallocate has been modified to call ext4_punch_hole when the punch hole
flag is passed.  At the moment, we only support punching holes in
extents, so this routine is pretty much a wrapper for the ext4_ext_punch_hole
routine.

The ext4_ext_punch_hole routine first completes all outstanding writes
with the associated pages, and then releases them.  The unblock
aligned data is zeroed, and all blocks in between are punched out.

The ext4_ext_check_cache routine is very similar to ext4_ext_in_cache
except it accepts a ext4_ext_cache parameter instead of a ext4_extent
parameter.  This routine is used by ext4_ext_punch_hole to check and
see if a block in a hole that has been cached.  The ext4_ext_cache
parameter is necessary because the members ext4_extent structure are
not large enough to hold a 32 bit value.  The existing
ext4_ext_in_cache routine has become a wrapper to this new function.

[ext4 punch hole patch series 5/5 v7] 

Signed-off-by: Allison Henderson 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Mingming Cao

ext4: add new function ext4_block_zero_page_range()

2011-05-25T11:41:32+00:00

This patch modifies the existing ext4_block_truncate_page() function
which was used by the truncate code path, and which zeroes out block
unaligned data, by adding a new length parameter, and renames it to
ext4_block_zero_page_rage().  This function can now be used to zero out the
head of a block, the tail of a block, or the middle
of a block.

The ext4_block_truncate_page() function is now a wrapper to
ext4_block_zero_page_range().

[ext4 punch hole patch series 2/5 v7] 

Signed-off-by: Allison Henderson 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Mingming Cao

ext4: add flag to ext4_has_free_blocks

2011-05-25T11:41:26+00:00

This patch adds an allocation request flag to the ext4_has_free_blocks
function which enables the use of reserved blocks.  This will allow a
punch hole to proceed even if the disk is full.  Punching a hole may
require additional blocks to first split the extents.

Because ext4_has_free_blocks is a low level function, the flag needs
to be passed down through several functions listed below:

ext4_ext_insert_extent
ext4_ext_create_new_leaf
ext4_ext_grow_indepth
ext4_ext_split
ext4_ext_new_meta_block
ext4_mb_new_blocks
ext4_claim_free_blocks
ext4_has_free_blocks

[ext4 punch hole patch series 1/5 v7]

Signed-off-by: Allison Henderson 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Mingming Cao

ext4: reserve inodes and feature code for 'quota' feature

2011-05-24T23:00:39+00:00

I am working on patch to add quota as a built-in feature for ext4
filesystem. The implementation is based on the design given at
https://ext4.wiki.kernel.org/index.php/Design_For_1st_Class_Quota_in_Ext4.
This patch reserves the inode numbers 3 and 4 for quota purposes and
also reserves EXT4_FEATURE_RO_COMPAT_QUOTA feature code.

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

ext4: add support for multiple mount protection

2011-05-24T22:31:25+00:00

Prevent an ext4 filesystem from being mounted multiple times.
A sequence number is stored on disk and is periodically updated (every 5
seconds by default) by a mounted filesystem.
At mount time, we now wait for s_mmp_update_interval seconds to make sure
that the MMP sequence does not change.
In case of failure, the nodename, bdevname and the time at which the MMP
block was last updated is displayed.

Signed-off-by: Andreas Dilger 
Signed-off-by: Johann Lombardi 
Signed-off-by: "Theodore Ts'o"