diff options
Diffstat (limited to 'fs/direct-io.c')
| -rw-r--r-- | fs/direct-io.c | 123 |
1 files changed, 95 insertions, 28 deletions
diff --git a/fs/direct-io.c b/fs/direct-io.c index e82adc2..7600aac 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -82,6 +82,8 @@ struct dio { int reap_counter; /* rate limit reaping */ get_block_t *get_block; /* block mapping function */ dio_iodone_t *end_io; /* IO completion function */ + dio_submit_t *submit_io; /* IO submition function */ + loff_t logical_offset_in_bio; /* current first logical block in bio */ sector_t final_block_in_bio; /* current final block in bio + 1 */ sector_t next_block_for_io; /* next block to be put under IO, in dio_blocks units */ @@ -96,6 +98,7 @@ struct dio { unsigned cur_page_offset; /* Offset into it, in bytes */ unsigned cur_page_len; /* Nr of bytes at cur_page_offset */ sector_t cur_page_block; /* Where it starts */ + loff_t cur_page_fs_offset; /* Offset in file */ /* BIO completion state */ spinlock_t bio_lock; /* protects BIO fields below */ @@ -300,6 +303,26 @@ static void dio_bio_end_io(struct bio *bio, int error) spin_unlock_irqrestore(&dio->bio_lock, flags); } +/** + * dio_end_io - handle the end io action for the given bio + * @bio: The direct io bio thats being completed + * @error: Error if there was one + * + * This is meant to be called by any filesystem that uses their own dio_submit_t + * so that the DIO specific endio actions are dealt with after the filesystem + * has done it's completion work. + */ +void dio_end_io(struct bio *bio, int error) +{ + struct dio *dio = bio->bi_private; + + if (dio->is_async) + dio_bio_end_aio(bio, error); + else + dio_bio_end_io(bio, error); +} +EXPORT_SYMBOL_GPL(dio_end_io); + static int dio_bio_alloc(struct dio *dio, struct block_device *bdev, sector_t first_sector, int nr_vecs) @@ -316,6 +339,7 @@ dio_bio_alloc(struct dio *dio, struct block_device *bdev, bio->bi_end_io = dio_bio_end_io; dio->bio = bio; + dio->logical_offset_in_bio = dio->cur_page_fs_offset; return 0; } @@ -340,10 +364,15 @@ static void dio_bio_submit(struct dio *dio) if (dio->is_async && dio->rw == READ) bio_set_pages_dirty(bio); - submit_bio(dio->rw, bio); + if (dio->submit_io) + dio->submit_io(dio->rw, bio, dio->inode, + dio->logical_offset_in_bio); + else + submit_bio(dio->rw, bio); dio->bio = NULL; dio->boundary = 0; + dio->logical_offset_in_bio = 0; } /* @@ -603,10 +632,26 @@ static int dio_send_cur_page(struct dio *dio) int ret = 0; if (dio->bio) { + loff_t cur_offset = dio->block_in_file << dio->blkbits; + loff_t bio_next_offset = dio->logical_offset_in_bio + + dio->bio->bi_size; + /* - * See whether this new request is contiguous with the old + * See whether this new request is contiguous with the old. + * + * Btrfs cannot handl having logically non-contiguous requests + * submitted. For exmple if you have + * + * Logical: [0-4095][HOLE][8192-12287] + * Phyiscal: [0-4095] [4096-8181] + * + * We cannot submit those pages together as one BIO. So if our + * current logical offset in the file does not equal what would + * be the next logical offset in the bio, submit the bio we + * have. */ - if (dio->final_block_in_bio != dio->cur_page_block) + if (dio->final_block_in_bio != dio->cur_page_block || + cur_offset != bio_next_offset) dio_bio_submit(dio); /* * Submit now if the underlying fs is about to perform a @@ -701,6 +746,7 @@ submit_page_section(struct dio *dio, struct page *page, dio->cur_page_offset = offset; dio->cur_page_len = len; dio->cur_page_block = blocknr; + dio->cur_page_fs_offset = dio->block_in_file << dio->blkbits; out: return ret; } @@ -935,7 +981,7 @@ static ssize_t direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, const struct iovec *iov, loff_t offset, unsigned long nr_segs, unsigned blkbits, get_block_t get_block, dio_iodone_t end_io, - struct dio *dio) + dio_submit_t submit_io, struct dio *dio) { unsigned long user_addr; unsigned long flags; @@ -952,6 +998,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, dio->get_block = get_block; dio->end_io = end_io; + dio->submit_io = submit_io; dio->final_block_in_bio = -1; dio->next_block_for_io = -1; @@ -1008,7 +1055,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, } } /* end iovec loop */ - if (ret == -ENOTBLK && (rw & WRITE)) { + if (ret == -ENOTBLK) { /* * The remaining part of the request will be * be handled by buffered I/O when we return @@ -1087,30 +1134,11 @@ 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(int rw, struct kiocb *iocb, struct inode *inode, +__blockdev_direct_IO_newtrunc(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, - int flags) + dio_submit_t submit_io, int flags) { int seg; size_t size; @@ -1197,11 +1225,49 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, (end > i_size_read(inode))); retval = direct_io_worker(rw, iocb, inode, iov, offset, - nr_segs, blkbits, get_block, end_io, dio); + nr_segs, blkbits, get_block, end_io, + submit_io, dio); + +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. @@ -1209,12 +1275,13 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, 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); } } -out: return retval; } EXPORT_SYMBOL(__blockdev_direct_IO); |
