The problem that has been addressed is that of synchronising updates of
the file size with writes that extend a file. Without the fix the update
of a file's size, as a result of a write beyond eof, is independent of
when the cached data is flushed to disk. Often the file size update would
be written to the filesystem log before the data is flushed to disk. When
a system crashes between these two events and the filesystem log is
replayed on mount the file's size will be set but since the contents never
made it to disk the file is full of holes. If some of the cached data was
flushed to disk then it may just be a section of the file at the end that
has holes.
There are existing fixes to help alleviate this problem, particularly in
the case where a file has been truncated, that force cached data to be
flushed to disk when the file is closed. If the system crashes while the
file(s) are still open then this flushing will never occur.
The fix that we have implemented is to introduce a second file size,
called the in-memory file size, that represents the current file size as
viewed by the user. The existing file size, called the on-disk file size,
is the one that get's written to the filesystem log and we only update it
when it is safe to do so. When we write to a file beyond eof we only
update the in- memory file size in the write operation. Later when the I/O
operation, that flushes the cached data to disk completes, an I/O
completion routine will update the on-disk file size. The on-disk file
size will be updated to the maximum offset of the I/O or to the value of
the in-memory file size if the I/O includes eof.
SGI-PV: 958522
SGI-Modid: xfs-linux-melb:xfs-kern:28322a
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
Don't hide buffer_unwritten behind buffer_delay() and remove the hack that
clears unexpected buffer_unwritten() states now that it can't happen.
Signed-off-by: Dave Chinner <dgc@sgi.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Timothy Shimmin <tes@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When writing less than a filesystem block of data into an unwritten extent
via buffered I/O, __xfs_get_blocks fails to set the buffer new flag. As a
result, the generic code will not zero either edge of the block resulting
in garbage being written to disk either side of the real data. Set the
buffer new state on bufferd writes to unwritten extents to ensure that
zeroing occurs.
SGI-PV: 960328
SGI-Modid: xfs-linux-melb:xfs-kern:28000a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
gcc-4.1 and more recent aggressively inline static functions which
increases XFS stack usage by ~15% in critical paths. Prevent this from
occurring by adding noinline to the STATIC definition.
Also uninline some functions that are too large to be inlined and were
causing problems with CONFIG_FORCED_INLINING=y.
Finally, clean up all the different users of inline, __inline and
__inline__ and put them under one STATIC_INLINE macro. For debug kernels
the STATIC_INLINE macro uninlines those functions.
SGI-PV: 957159
SGI-Modid: xfs-linux-melb:xfs-kern:27585a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: David Chatterton <chatz@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
XFS appears to call clear_page_dirty to get the mapping tree dirty tag
set correctly at the same time the page dirty flag is cleared. I note
that this can be done by set_page_writeback() if we clear the dirty flag
on the page first when we are writing back the entire page.
Hence it seems to me that the XFS call to clear_page_dirty() could
easily be substituted by clear_page_dirty_for_io() followed by a call to
set_page_writeback() to get the mapping tree tags set correctly after
the page has been marked clean.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The only time it is safe to call aio_complete() is when the ->ki_retry
function returns -EIOCBQUEUED to the AIO core. direct_io_worker() has
historically done this by relying on its caller to translate positive return
codes into -EIOCBQUEUED for the aio case. It did this by trying to keep
conditionals in sync. direct_io_worker() knew when finished_one_bio() was
going to call aio_complete(). It would reverse the test and wait and free the
dio in the cases it thought that finished_one_bio() wasn't going to.
Not surprisingly, it ended up getting it wrong. 'ret' could be a negative
errno from the submission path but it failed to communicate this to
finished_one_bio(). direct_io_worker() would return < 0, it's callers
wouldn't raise -EIOCBQUEUED, and aio_complete() would be called. In the
future finished_one_bio()'s tests wouldn't reflect this and aio_complete()
would be called for a second time which can manifest as an oops.
The previous cleanups have whittled the sync and async completion paths down
to the point where we can collapse them and clearly reassert the invariant
that we must only call aio_complete() after returning -EIOCBQUEUED.
direct_io_worker() will only return -EIOCBQUEUED when it is not the last to
drop the dio refcount and the aio bio completion path will only call
aio_complete() when it is the last to drop the dio refcount.
direct_io_worker() can ensure that it is the last to drop the reference count
by waiting for bios to drain. It does this for sync ops, of course, and for
partial dio writes that must fall back to buffered and for aio ops that saw
errors during submission.
This means that operations that end up waiting, even if they were issued as
aio ops, will not call aio_complete() from dio. Instead we return the return
code of the operation and let the aio core call aio_complete(). This is
purposely done to fix a bug where AIO DIO file extensions would call
aio_complete() before their callers have a chance to update i_size.
Now that direct_io_worker() is explicitly returning -EIOCBQUEUED its callers
no longer have to translate for it. XFS needs to be careful not to free
resources that will be used during AIO completion if -EIOCBQUEUED is returned.
We maintain the previous behaviour of trying to write fs metadata for O_SYNC
aio+dio writes.
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Suparna Bhattacharya <suparna@in.ibm.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: <xfs-masters@oss.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
handling.
SGI-PV: 955302
SGI-Modid: xfs-linux-melb:xfs-kern:26804a
Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
__blockdev_direct_IO for the DIO_OWN_LOCKING case for direct I/O reads
since it drops and reacquires the i_mutex while holding the iolock and
this violates the locking order.
SGI-PV: 955696
SGI-Modid: xfs-linux-melb:xfs-kern:26898a
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: David Chatterton <chatz@sgi.com>
Same as with already do with the file operations: keep them in .rodata and
prevents people from doing runtime patching.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
truncate down followed by delayed allocation (buffered writes) - worst
case scenario for the notorious NULL files problem. This reduces the
window where we are exposed to that problem significantly.
SGI-PV: 917976
SGI-Modid: xfs-linux-melb:xfs-kern:26100a
Signed-off-by: Nathan Scott <nathans@sgi.com>
nonblock mode with the new IO path code (since 2.6.16).
SGI-PV: 951662
SGI-Modid: xfs-linux-melb:xfs-kern:25676a
Signed-off-by: Nathan Scott <nathans@sgi.com>
Now that get_block() can handle mapping multiple disk blocks, no need to have
->get_blocks(). This patch removes fs specific ->get_blocks() added for DIO
and makes it users use get_block() instead.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch changes mpage_readpages() and get_block() to get the disk mapping
information for multiple blocks at the same time.
b_size represents the amount of disk mapping that needs to mapped. On the
successful get_block() b_size indicates the amount of disk mapping thats
actually mapped. Only the filesystems who care to use this information and
provide multiple disk blocks at a time can choose to do so.
No changes are needed for the filesystems who wants to ignore this.
[akpm@osdl.org: cleanups]
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The return value of this function is never used, so let's be honest and
declare it as void.
Some places where invalidatepage returned 0, I have inserted comments
suggesting a BUG_ON.
[akpm@osdl.org: JBD BUG fix]
[akpm@osdl.org: rework for git-nfs]
[akpm@osdl.org: don't go BUG in block_invalidate_page()]
Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
rewrite clustering. This prevents writing excessive amounts of clean data
when doing random rewrites of a cached file.
SGI-PV: 951193
SGI-Modid: xfs-linux-melb:xfs-kern:25531a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
the trace.
SGI-PV: 948300
SGI-Modid: xfs-linux-melb:xfs-kern:208069a
Signed-off-by: Yingping Lu <yingping@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
obscure corruption case
SGI-PV: 942658
SGI-Modid: xfs-linux-melb:xfs-kern:207119a
Signed-off-by: Eric Sandeen <sandeen@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
the clustering of extra pages in a buffered write.
SGI-PV: 949210
SGI-Modid: xfs-linux-melb:xfs-kern:25130a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
Migrate a page with buffers without requiring writeback
This introduces a new address space operation migratepage() that may be used
by a filesystem to implement its own version of page migration.
A version is provided that migrates buffers attached to pages. Some
filesystems (ext2, ext3, xfs) are modified to utilize this feature.
The swapper address space operation are modified so that a regular
migrate_page() will occur for anonymous pages without writeback (migrate_pages
forces every anonymous page to have a swap entry).
Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
a page while we are still submitting other buffers on the same page for
I/O.
SGI-PV: 948197
SGI-Modid: xfs-linux-melb:xfs-kern:25004a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
trylock and deal with block layer congestion properly. Patch from David
Chinner and Christoph Hellwig.
SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203830a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
performances on rewrites since we can reduce the number of allocator
calls.
SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203829a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
case is very similar to delayed and unwritten extends. Reorganize the code
to share some code for these cases.
SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203827a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
handling offets From David Chinner and Christoph Hellwig
SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203826a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
page and a relative offset into that page around, and returns the current
xfs_iomap_t if the block at the specified offset fits into it, or a NULL
pointer otherwise. This patch passed the full 64bit offset into the inode
that all callers have anyway, and changes the return value to a simple
boolean. Also the function gets a more descriptive name: xfs_iomap_valid.
SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203825a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
allows us to submit much larger I/Os instead of sending down lots of small
buffer_heads. To do this we need to have a rather complicated I/O
submission and completion tracking infrastructure. Part of the latter has
been merged already a long time ago for direct I/O support. Part of the
problem is that we need to track sub-pagesize regions and for that we
still need buffer_heads for the time beeing. Long-term I hope we can move
to better data strucutures and/or maybe move this to fs/mpage.c instead of
having it in XFS. Original patch from Nathan Scott with various updates
from David Chinner and Christoph Hellwig.
SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203822a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
- ->releasepage() annotated (s/int/gfp_t), instances updated
- missing gfp_t in fs/* added
- fixed misannotation from the original sweep caught by bitwise checks:
XFS used __nocast both for gfp_t and for flags used by XFS allocator.
The latter left with unsigned int __nocast; we might want to add a
different type for those but for now let's leave them alone. That,
BTW, is a case when __nocast use had been actively confusing - it had
been used in the same code for two different and similar types, with
no way to catch misuses. Switch of gfp_t to bitwise had caught that
immediately...
One tricky bit is left alone to be dealt with later - mapping->flags is
a mix of gfp_t and error indications. Left alone for now.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
