kernel.git/fs/direct-io.c, branch linux-2.6.37.y

fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio

2011-02-17T23:14:51Z

commit 20d9600cb407b0b55fef6ee814b60345c6f58264 upstream. 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

fs/direct-io.c: fix truncation error in dio_complete() return

2010-10-26T23:52:13Z

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

O_DIRECT: fix the splitting up of contiguous I/O

2010-09-10T01:57:22Z

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

sort out blockdev_direct_IO variants

2010-08-09T20:47:29Z

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

direct-io: move aio_complete into ->end_io

2010-07-26T21:09:02Z

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

fs: introduce new truncate sequence

2010-05-28T02:15:33Z

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

direct-io: do not merge logically non-contiguous requests

2010-05-25T14:34:56Z

Btrfs cannot handle having logically non-contiguous requests submitted. For example if you have Logical: [0-4095][HOLE][8192-12287] Physical: [0-4095] [4096-8191] Normally the DIO code would put these into the same BIO's. The problem is we need to know exactly what offset is associated with what BIO so we can do our checksumming and unlocking properly, so putting them in the same BIO doesn't work. So add another check where we submit the current BIO if the physical blocks are not contigous OR the logical blocks are not contiguous. Signed-off-by: Josef Bacik Signed-off-by: Chris Mason

direct-io: add a hook for the fs to provide its own submit_bio function

2010-05-25T14:34:55Z

Because BTRFS can do RAID and such, we need our own submit hook so we can setup the bio's in the correct fashion, and handle checksum errors properly. So there are a few changes here 1) The submit_io hook. This is straightforward, just call this instead of submit_bio. 2) Allow the fs to return -ENOTBLK for reads. Usually this has only worked for writes, since writes can fallback onto buffered IO. But BTRFS needs the option of falling back on buffered IO if it encounters a compressed extent, since we need to read the entire extent in and decompress it. So if we get -ENOTBLK back from get_block we'll return back and fallback on buffered just like the write case. I've tested these changes with fsx and everything seems to work. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason

dio: fix use-after-free

2009-12-17T09:52:13Z

Signed-off-by: Al Viro

direct-io: cleanup blockdev_direct_IO locking

2009-12-16T15:20:13Z

Currently the locking in blockdev_direct_IO is a mess, we have three different locking types and very confusing checks for some of them. The most complicated one is DIO_OWN_LOCKING for reads, which happens to not actually be used. This patch gets rid of the DIO_OWN_LOCKING - as mentioned above the read case is unused anyway, and the write side is almost identical to DIO_NO_LOCKING. The difference is that DIO_NO_LOCKING always sets the create argument for the get_blocks callback to zero, but we can easily move that to the actual get_blocks callbacks. There are four users of the DIO_NO_LOCKING mode: gfs already ignores the create argument and thus is fine with the new version, ocfs2 only errors out if create were ever set, and we can remove this dead code now, the block device code only ever uses create for an error message if we are fully beyond the device which can never happen, and last but not least XFS will need the new behavour for writes. Now we can replace the lock_type variable with a flags one, where no flag means the DIO_NO_LOCKING behaviour and DIO_LOCKING is kept as the first flag. Separate out the check for not allowing to fill holes into a separate flag, although for now both flags always get set at the same time. Also revamp the documentation of the locking scheme to actually make sense. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Christoph Hellwig Cc: Dave Chinner Cc: Badari Pulavarty Cc: Jeff Moyer Cc: Jens Axboe Cc: Zach Brown Cc: Al Viro Cc: Alex Elder Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds