24 Nov, 2013
1 commit
-
Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.Signed-off-by: Kent Overstreet
Cc: Jens Axboe
Cc: Geert Uytterhoeven
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: "Ed L. Cashin"
Cc: Nick Piggin
Cc: Lars Ellenberg
Cc: Jiri Kosina
Cc: Matthew Wilcox
Cc: Geoff Levand
Cc: Yehuda Sadeh
Cc: Sage Weil
Cc: Alex Elder
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris
Cc: Philip Kelleher
Cc: Rusty Russell
Cc: "Michael S. Tsirkin"
Cc: Konrad Rzeszutek Wilk
Cc: Jeremy Fitzhardinge
Cc: Neil Brown
Cc: Alasdair Kergon
Cc: Mike Snitzer
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh
Cc: Benny Halevy
Cc: "James E.J. Bottomley"
Cc: Greg Kroah-Hartman
Cc: "Nicholas A. Bellinger"
Cc: Alexander Viro
Cc: Chris Mason
Cc: "Theodore Ts'o"
Cc: Andreas Dilger
Cc: Jaegeuk Kim
Cc: Steven Whitehouse
Cc: Dave Kleikamp
Cc: Joern Engel
Cc: Prasad Joshi
Cc: Trond Myklebust
Cc: KONISHI Ryusuke
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Ben Myers
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt
Cc: Frederic Weisbecker
Cc: Ingo Molnar
Cc: Len Brown
Cc: Pavel Machek
Cc: "Rafael J. Wysocki"
Cc: Herton Ronaldo Krzesinski
Cc: Ben Hutchings
Cc: Andrew Morton
Cc: Guo Chao
Cc: Tejun Heo
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Wei Yongjun
Cc: "Roger Pau Monné"
Cc: Jan Beulich
Cc: Stefano Stabellini
Cc: Ian Campbell
Cc: Sebastian Ott
Cc: Christian Borntraeger
Cc: Minchan Kim
Cc: Jiang Liu
Cc: Nitin Gupta
Cc: Jerome Marchand
Cc: Joe Perches
Cc: Peng Tao
Cc: Andy Adamson
Cc: fanchaoting
Cc: Jie Liu
Cc: Sunil Mushran
Cc: "Martin K. Petersen"
Cc: Namjae Jeon
Cc: Pankaj Kumar
Cc: Dan Magenheimer
Cc: Mel Gorman 6
10 Sep, 2013
1 commit
-
Not using the return value can in the generic case be racy, so it's
in general good practice to check the return value instead.This also resolved the warning caused on ARM and other architectures:
fs/direct-io.c: In function 'sb_init_dio_done_wq':
fs/direct-io.c:557:2: warning: value computed is not used [-Wunused-value]Signed-off-by: Olof Johansson
Reviewed-by: Jan Kara
Cc: Geert Uytterhoeven
Cc: Stephen Rothwell
Cc: Al Viro
Cc: Christoph Hellwig
Cc: Russell King
Cc: H Peter Anvin
Signed-off-by: Linus Torvalds
04 Sep, 2013
2 commits
-
Call generic_write_sync() from the deferred I/O completion handler if
O_DSYNC is set for a write request. Also make sure various callers
don't call generic_write_sync if the direct I/O code returns
-EIOCBQUEUED.Based on an earlier patch from Jan Kara with updates from
Jeff Moyer and Darrick J. Wong .Signed-off-by: Christoph Hellwig
Signed-off-by: Jan Kara
Signed-off-by: Al Viro -
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
09 May, 2013
1 commit
-
Pull block core updates from Jens Axboe:
- Major bit is Kents prep work for immutable bio vecs.
- Stable candidate fix for a scheduling-while-atomic in the queue
bypass operation.- Fix for the hang on exceeded rq->datalen 32-bit unsigned when merging
discard bios.- Tejuns changes to convert the writeback thread pool to the generic
workqueue mechanism.- Runtime PM framework, SCSI patches exists on top of these in James'
tree.- A few random fixes.
* 'for-3.10/core' of git://git.kernel.dk/linux-block: (40 commits)
relay: move remove_buf_file inside relay_close_buf
partitions/efi.c: replace useless kzalloc's by kmalloc's
fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read()
block: fix max discard sectors limit
blkcg: fix "scheduling while atomic" in blk_queue_bypass_start
Documentation: cfq-iosched: update documentation help for cfq tunables
writeback: expose the bdi_wq workqueue
writeback: replace custom worker pool implementation with unbound workqueue
writeback: remove unused bdi_pending_list
aoe: Fix unitialized var usage
bio-integrity: Add explicit field for owner of bip_buf
block: Add an explicit bio flag for bios that own their bvec
block: Add bio_alloc_pages()
block: Convert some code to bio_for_each_segment_all()
block: Add bio_for_each_segment_all()
bounce: Refactor __blk_queue_bounce to not use bi_io_vec
raid1: use bio_copy_data()
pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage
pktcdvd: use bio_copy_data()
block: Add bio_copy_data()
...
08 May, 2013
1 commit
-
Faster kernel compiles by way of fewer unnecessary includes.
[akpm@linux-foundation.org: fix fallout]
[akpm@linux-foundation.org: fix build]
Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Apr, 2013
2 commits
-
Currently, dio_send_cur_page() submits bio before current page and cached
sdio->cur_page is added to the bio if sdio->boundary is set. This is
actually wrong because sdio->boundary means the current buffer is the last
one before metadata needs to be read. So we should rather submit the bio
after the current page is added to it.Signed-off-by: Jan Kara
Reported-by: Kazuya Mio
Tested-by: Kazuya Mio
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When we read/write a file sequentially, we will read/write not only the
data blocks but also the indirect blocks that may not be physically
adjacent to the data blocks. So filesystems set the BH_Boundary flag to
submit the previous I/O before reading/writing an indirect block.However the generic direct IO code mishandles buffer_boundary(), setting
sdio->boundary before each submit_page_section() call which results in
sending only one page bios as underlying code thinks this page is the last
in the contiguous extent. So fix the problem by setting sdio->boundary
only if the current page is really the last one in the mapped extent.With this patch and "direct-io: submit bio after boundary buffer is added
to it" I've measured about 10% throughput improvement of direct IO reads
on ext3 with SATA harddrive (from 90 MB/s to 100 MB/s). With ramdisk, the
improvement was about 3-fold (from 350 MB/s to 1.2 GB/s). For other
filesystems (such as ext4), the improvements won't be as visible because
the frequency of BH_Boundary flag being set is much smaller.Signed-off-by: Jan Kara
Reported-by: Kazuya Mio
Tested-by: Kazuya Mio
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Mar, 2013
1 commit
-
More prep work for immutable bvecs:
A few places in the code were either open coding or using the wrong
version - fix.After we introduce the bvec iter, it'll no longer be possible to modify
the biovec through bio_for_each_segment_all() - it doesn't increment a
pointer to the current bvec, you pass in a struct bio_vec (not a
pointer) which is updated with what the current biovec would be (taking
into account bi_bvec_done and bi_size).So because of that it's more worthwhile to be consistent about
bio_for_each_segment()/bio_for_each_segment_all() usage.Signed-off-by: Kent Overstreet
CC: Jens Axboe
CC: NeilBrown
CC: Alasdair Kergon
CC: dm-devel@redhat.com
CC: Alexander Viro
23 Feb, 2013
1 commit
-
Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.CC: Christoph Hellwig
CC: Jens Axboe
CC: Jeff Moyer
CC: stable@vger.kernel.org
Acked-by: Jeff Moyer
Signed-off-by: Jan Kara
Signed-off-by: Al Viro
30 Nov, 2012
1 commit
-
Since directio can work on a raw block device, and the block size of the
device can change under it, we need to do the same thing that
fs/buffer.c now does: read the block size a single time, using
ACCESS_ONCE().Reading it multiple times can get different results, which will then
confuse the code because it actually encodes the i_blksize in
relationship to the underlying logical blocksize.Signed-off-by: Linus Torvalds
09 Aug, 2012
1 commit
-
Move unplugging for direct I/O from around ->direct_IO() down to
do_blockdev_direct_IO(). This implicitly adds plugging for direct
writes.CC: Li Shaohua
Acked-by: Jeff Moyer
Signed-off-by: Wu Fengguang
Signed-off-by: Jens Axboe
14 Jul, 2012
1 commit
-
READ is 0, so the result of the bit-and operation is 0. Rewrite with == as
done elsewhere in the same file.This problem was found using Coccinelle (http://coccinelle.lip6.fr/).
Signed-off-by: Julia Lawall
Reviewed-by: Jeff Moyer
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro
01 Jun, 2012
1 commit
-
Use the same mechanism as the block devices are using, but move the
helper functions from fs/direct-io.c into fs/inode.c to remove the
dependency on CONFIG_BLOCK.Signed-off-by: Trond Myklebust
Cc: Christoph Hellwig
Cc: Al Viro
Cc: Fred Isaman
Signed-off-by: Linus Torvalds
24 Feb, 2012
1 commit
-
With kernel 3.1, Christoph removed i_alloc_sem and replaced it with
calls (namely inode_dio_wait() and inode_dio_done()) which are
EXPORT_SYMBOL_GPL() thus they cannot be used by non-GPL file systems and
further inode_dio_wait() was pushed from notify_change() into the file
system ->setattr() method but no non-GPL file system can make this call.That means non-GPL file systems cannot exist any more unless they do not
use any VFS functionality related to reading/writing as far as I can
tell or at least as long as they want to implement direct i/o.Both Linus and Al (and others) have said on LKML that this breakage of
the VFS API should not have happened and that the change was simply
missed as it was not documented in the change logs of the patches that
did those changes.This patch changes the two function exports in question to be
EXPORT_SYMBOL() thus restoring the VFS API as it used to be - accessible
for all modules.Christoph, who introduced the two functions and exported them GPL-only
is CC-ed on this patch to give him the opportunity to object to the
symbols being changed in this manner if he did indeed intend them to be
GPL-only and does not want them to become available to all modules.Signed-off-by: Anton Altaparmakov
CC: Christoph Hellwig
Signed-off-by: Linus Torvalds
13 Jan, 2012
2 commits
-
Some investigation of a transaction processing workload showed that a
major consumer of cycles in __blockdev_direct_IO is the cache miss while
accessing the block size. This is because it has to walk the chain from
block_dev to gendisk to queue.The block size is needed early on to check alignment and sizes. It's only
done if the check for the inode block size fails. But the costly block
device state is unconditionally fetched.- Reorganize the code to only fetch block dev state when actually
needed.Then do a prefetch on the block dev early on in the direct IO path. This
is worth it, because there is substantial code run before we actually
touch the block dev now.- I also added some unlikelies to make it clear the compiler that block
device fetch code is not normally executed.This gave a small, but measurable improvement on a large database
benchmark (about 0.3%)[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: using prefetch requires including prefetch.h]
Signed-off-by: Andi Kleen
Cc: Jeff Moyer
Cc: Jens Axboe
Cc: Christoph Hellwig
Signed-off-by: Stephen Rothwell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In get_more_blocks(), we use dio_count to calcuate fs_count and do some
tricky things to increase fs_count if dio_count isn't aligned. But
actually it still has some corner cases that can't be coverd. See the
following example:dio_write foo -s 1024 -w 4096
(direct write 4096 bytes at offset 1024). The same goes if the offset
isn't aligned to fs_blocksize.In this case, the old calculation counts fs_count to be 1, but actually we
will write into 2 different blocks (if fs_blocksize=4096). The old code
just works, since it will call get_block twice (and may have to allocate
and create extents twice for filesystems like ext4). So we'd better call
get_block just once with the proper fs_count.Signed-off-by: Tao Ma
Cc: "Theodore Ts'o"
Cc: Christoph Hellwig
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Oct, 2011
7 commits
-
This doesn't change anything for the compiler, but hch thought it would
make the code clearer.I moved the reference counting into its own little inline.
Signed-off-by: Andi Kleen
Acked-by: Jeff Moyer
Signed-off-by: Christoph Hellwig -
Add inlines to all the submission path functions. While this increases
code size it also gives gcc a lot of optimization opportunities
in this critical hotpath.In particular -- together with some other changes -- this
allows gcc to get rid of the unnecessary clearing of
sdio at the beginning and optimize the messy parameter passing.
Any non inlining of a function which takes a sdio parameter
would break this optimization because they cannot be done if the
address of a structure is taken.Note that benefits are only seen with CONFIG_OPTIMIZE_INLINING
and CONFIG_CC_OPTIMIZE_FOR_SIZE both set to off.This gives about 2.2% improvement on a large database benchmark
with a high IOPS rate.Signed-off-by: Andi Kleen
Signed-off-by: Christoph Hellwig -
Only a single b_private field in the map_bh buffer head is needed after
the submission path. Move map_bh separately to avoid storing
this information in the long term slab.This avoids the weird 104 byte hole in struct dio_submit which also needed
to be memseted early.Signed-off-by: Andi Kleen
Signed-off-by: Christoph Hellwig -
A direct slab call is slightly faster than kmalloc and can be better cached
per CPU. It also avoids rounding to the next kmalloc slab.In addition this enforces cache line alignment for struct dio to avoid
any false sharing.Signed-off-by: Andi Kleen
Acked-by: Jeff Moyer
Signed-off-by: Christoph Hellwig -
Fix most problems reported by pahole.
There is still a weird 104 byte hole after map_bh. I'm not sure what
causes this.Signed-off-by: Andi Kleen
Acked-by: Jeff Moyer
Signed-off-by: Christoph Hellwig -
There's nothing on the stack, even before my changes.
Signed-off-by: Andi Kleen
Acked-by: Jeff Moyer
Signed-off-by: Christoph Hellwig -
This large, but largely mechanic, patch moves all fields in struct dio
that are only used in the submission path into a separate on stack
data structure. This has the advantage that the memory is very likely
cache hot, which is not guaranteed for memory fresh out of kmalloc.This also gives gcc more optimization potential because it can easier
determine that there are no external aliases for these variables.The sdio initialization is a initialization now instead of memset.
This allows gcc to break sdio into individual fields and optimize
away unnecessary zeroing (after all the functions are inlined)Signed-off-by: Andi Kleen
Acked-by: Jeff Moyer
Signed-off-by: Christoph Hellwig
27 Jul, 2011
1 commit
-
This allows us to move duplicated code in
(atomic_inc_not_zero() for now) toSigned-off-by: Arun Sharma
Reviewed-by: Eric Dumazet
Cc: Ingo Molnar
Cc: David Miller
Cc: Eric Dumazet
Acked-by: Mike Frysinger
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 Jul, 2011
4 commits
-
For filesystems that delay their end_io processing we should keep our
i_dio_count until the the processing is done. Enable this by moving
the inode_dio_done call to the end_io handler if one exist. Note that
the actual move to the workqueue for ext4 and XFS is not done in
this patch yet, but left to the filesystem maintainers. At least
for XFS it's not needed yet either as XFS has an internal equivalent
to i_dio_count.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
Maintain i_dio_count for all filesystems, not just those using DIO_LOCKING.
This these filesystems to also protect truncate against direct I/O requests
by using common code. Right now the only non-DIO_LOCKING filesystem that
appears to do so is XFS, which uses an opencoded variant of the i_dio_count
scheme.Behaviour doesn't change for filesystems never calling inode_dio_wait.
For ext4 behaviour changes when using the dioread_nonlock option, which
previously was missing any protection between truncate and direct I/O reads.
For ocfs2 that handcrafted i_dio_count manipulations are replaced with
the common code now enable.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
i_alloc_sem is a rather special rw_semaphore. It's the last one that may
be released by a non-owner, and it's write side is always mirrored by
real exclusion. It's intended use it to wait for all pending direct I/O
requests to finish before starting a truncate.Replace it with a hand-grown construct:
- exclusion for truncates is already guaranteed by i_mutex, so it can
simply fall way
- the reader side is replaced by an i_dio_count member in struct inode
that counts the number of pending direct I/O requests. Truncate can't
proceed as long as it's non-zero
- when i_dio_count reaches non-zero we wake up a pending truncate using
wake_up_bit on a new bit in i_flags
- new references to i_dio_count can't appear while we are waiting for
it to read zero because the direct I/O count always needs i_mutex
(or an equivalent like XFS's i_iolock) for starting a new operation.This scheme is much simpler, and saves the space of a spinlock_t and a
struct list_head in struct inode (typically 160 bits on a non-debug 64-bit
system).Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
Reject zero sized reads as soon as we know our I/O length, and don't
borther with locks or allocations that might have to be cleaned up
otherwise.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
25 Mar, 2011
1 commit
-
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...Fix up conflicts in fs/{aio.c,super.c}
10 Mar, 2011
2 commits
-
With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.Signed-off-by: Jens Axboe
-
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().Signed-off-by: Jens Axboe
15 Feb, 2011
1 commit
21 Jan, 2011
1 commit
-
When using devices that support max_segments > BIO_MAX_PAGES (256), direct
IO tries to allocate a bio with more pages than allowed, which leads to an
oops in dio_bio_alloc(). Clamp the request to the supported maximum, and
change dio_bio_alloc() to reflect that bio_alloc() will always return a
bio when called with __GFP_WAIT and a valid number of vectors.[akpm@linux-foundation.org: remove redundant BUG_ON()]
Signed-off-by: David Dillow
Reviewed-by: Jeff Moyer
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Jan, 2011
1 commit
-
Signed-off-by: Namhyung Kim
Cc: Jiri Kosina
Signed-off-by: Jiri Kosina
27 Oct, 2010
1 commit
-
Fix up truncation (ssize_t->int). This only matters with >2G
reads/writes, which the kernel doesn't permit.Signed-off-by: Edward Shishkin
Reviewed-by: Christoph Hellwig
Acked-by: Jeff Moyer
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Sep, 2010
1 commit
-
commit c2c6ca4 (direct-io: do not merge logically non-contiguous requests)
introduced a bug whereby all O_DIRECT I/Os were submitted a page at a time
to the block layer. The problem is that the code expected
dio->block_in_file to correspond to the current page in the dio. In fact,
it corresponds to the previous page submitted via submit_page_section.
This was purely an oversight, as the dio->cur_page_fs_offset field was
introduced for just this purpose. This patch simply uses the correct
variable when calculating whether there is a mismatch between contiguous
logical blocks and contiguous physical blocks (as described in the
comments).I also switched the if conditional following this check to an else if, to
ensure that we never call dio_bio_submit twice for the same dio (in
theory, this should not happen, anyway).I've tested this by running blktrace and verifying that a 64KB I/O was
submitted as a single I/O. I also ran the patched kernel through
xfstests' aio tests using xfs, ext4 (with 1k and 4k block sizes) and btrfs
and verified that there were no regressions as compared to an unpatched
kernel.Signed-off-by: Jeff Moyer
Acked-by: Josef Bacik
Cc: Christoph Hellwig
Cc: Chris Mason
Cc: [2.6.35.x]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Aug, 2010
1 commit
-
Move the call to vmtruncate to get rid of accessive blocks to the callers
in prepearation of the new truncate calling sequence. This was only done
for DIO_LOCKING filesystems, so the __blockdev_direct_IO_newtrunc variant
was not needed anyway. Get rid of blockdev_direct_IO_no_locking and
its _newtrunc variant while at it as just opencoding the two additional
paramters is shorted than the name suffix.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
27 Jul, 2010
1 commit
-
Filesystems with unwritten extent support must not complete an AIO request
until the transaction to convert the extent has been commited. That means
the aio_complete calls needs to be moved into the ->end_io callback so
that the filesystem can control when to call it exactly.This makes a bit of a mess out of dio_complete and the ->end_io callback
prototype even more complicated.Signed-off-by: Christoph Hellwig
Reviewed-by: Jan Kara
Signed-off-by: Alex Elder
28 May, 2010
1 commit
-
Introduce a new truncate calling sequence into fs/mm subsystems. Rather than
setattr > vmtruncate > truncate, have filesystems call their truncate sequence
from ->setattr if filesystem specific operations are required. vmtruncate is
deprecated, and truncate_pagecache and inode_newsize_ok helpers introduced
previously should be used.simple_setattr is introduced for simple in-ram filesystems to implement
the new truncate sequence. Eventually all filesystems should be converted
to implement a setattr, and the default code in notify_change should go
away.simple_setsize is also introduced to perform just the ATTR_SIZE portion
of simple_setattr (ie. changing i_size and trimming pagecache).To implement the new truncate sequence:
- filesystem specific manipulations (eg freeing blocks) must be done in
the setattr method rather than ->truncate.
- vmtruncate can not be used by core code to trim blocks past i_size in
the event of write failure after allocation, so this must be performed
in the fs code.
- convert usage of helpers block_write_begin, nobh_write_begin,
cont_write_begin, and *blockdev_direct_IO* to use _newtrunc postfixed
variants. These avoid calling vmtruncate to trim blocks (see previous).
- inode_setattr should not be used. generic_setattr is a new function
to be used to copy simple attributes into the generic inode.
- make use of the better opportunity to handle errors with the new sequence.Big problem with the previous calling sequence: the filesystem is not called
until i_size has already changed. This means it is not allowed to fail the
call, and also it does not know what the previous i_size was. Also, generic
code calling vmtruncate to truncate allocated blocks in case of error had
no good way to return a meaningful error (or, for example, atomically handle
block deallocation).Cc: Christoph Hellwig
Acked-by: Jan Kara
Signed-off-by: Nick Piggin
Signed-off-by: Al Viro
