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sort out blockdev_direct_IO variants

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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 <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig
2010-06-04 11:29:53 +02:00
committed by Al Viro
parent 256249584b
commit eafdc7d190
15 changed files with 146 additions and 119 deletions
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74
fs/direct-io.c
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@@ -1136,8 +1136,27 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
return ret;
}
/*
* This is a library function for use by filesystem drivers.
*
* The locking rules are governed by the flags parameter:
* - if the flags value contains DIO_LOCKING we use a fancy locking
* scheme for dumb filesystems.
* For writes this function is called under i_mutex and returns with
* i_mutex held, for reads, i_mutex is not held on entry, but it is
* taken and dropped again before returning.
* For reads and writes i_alloc_sem is taken in shared mode and released
* on I/O completion (which may happen asynchronously after returning to
* the caller).
*
* - if the flags value does NOT contain DIO_LOCKING we don't use any
* internal locking but rather rely on the filesystem to synchronize
* direct I/O reads/writes versus each other and truncate.
* For reads and writes both i_mutex and i_alloc_sem are not held on
* entry and are never taken.
*/
ssize_t
__blockdev_direct_IO_newtrunc(int rw, struct kiocb *iocb, struct inode *inode,
__blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
struct block_device *bdev, const struct iovec *iov, loff_t offset,
unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
dio_submit_t submit_io, int flags)
@@ -1233,57 +1252,4 @@ __blockdev_direct_IO_newtrunc(int rw, struct kiocb *iocb, struct inode *inode,
out:
return retval;
}
EXPORT_SYMBOL(__blockdev_direct_IO_newtrunc);
/*
* This is a library function for use by filesystem drivers.
*
* The locking rules are governed by the flags parameter:
* - if the flags value contains DIO_LOCKING we use a fancy locking
* scheme for dumb filesystems.
* For writes this function is called under i_mutex and returns with
* i_mutex held, for reads, i_mutex is not held on entry, but it is
* taken and dropped again before returning.
* For reads and writes i_alloc_sem is taken in shared mode and released
* on I/O completion (which may happen asynchronously after returning to
* the caller).
*
* - if the flags value does NOT contain DIO_LOCKING we don't use any
* internal locking but rather rely on the filesystem to synchronize
* direct I/O reads/writes versus each other and truncate.
* For reads and writes both i_mutex and i_alloc_sem are not held on
* entry and are never taken.
*/
ssize_t
__blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
struct block_device *bdev, const struct iovec *iov, loff_t offset,
unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
dio_submit_t submit_io, int flags)
{
ssize_t retval;
retval = __blockdev_direct_IO_newtrunc(rw, iocb, inode, bdev, iov,
offset, nr_segs, get_block, end_io, submit_io, flags);
/*
* In case of error extending write may have instantiated a few
* blocks outside i_size. Trim these off again for DIO_LOCKING.
* NOTE: DIO_NO_LOCK/DIO_OWN_LOCK callers have to handle this in
* their own manner. This is a further example of where the old
* truncate sequence is inadequate.
*
* NOTE: filesystems with their own locking have to handle this
* on their own.
*/
if (flags & DIO_LOCKING) {
if (unlikely((rw & WRITE) && retval < 0)) {
loff_t isize = i_size_read(inode);
loff_t end = offset + iov_length(iov, nr_segs);
if (end > isize)
vmtruncate(inode, isize);
}
}
return retval;
}
EXPORT_SYMBOL(__blockdev_direct_IO);