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authorDaniel McNeil <daniel@osdl.org>2005-04-16 18:25:50 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:25:50 -0400
commit29504ff3be784372c4e2f7e31681a3e0292c4d9a (patch)
tree449f6598e10a1930d113fd7bbe3aa6ca37341d10 /fs
parent1f08ad02379530e1c970d3d104343b9907b4d1b4 (diff)
[PATCH] Direct IO async short read fix
The direct I/O code is mapping the read request to the file system block. If the file size was not on a block boundary, the result would show the the read reading past EOF. This was only happening for the AIO case. The non-AIO case truncates the result to match file size (in direct_io_worker). This patch does the same thing for the AIO case, it truncates the result to match the file size if the read reads past EOF. When I/O completes the result can be truncated to match the file size without using i_size_read(), thus the aio result now matches the number of bytes read to the end of file. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/direct-io.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 5a674a0c7146..1d55e7e67342 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -66,6 +66,7 @@ struct dio {
66 struct bio *bio; /* bio under assembly */ 66 struct bio *bio; /* bio under assembly */
67 struct inode *inode; 67 struct inode *inode;
68 int rw; 68 int rw;
69 loff_t i_size; /* i_size when submitted */
69 int lock_type; /* doesn't change */ 70 int lock_type; /* doesn't change */
70 unsigned blkbits; /* doesn't change */ 71 unsigned blkbits; /* doesn't change */
71 unsigned blkfactor; /* When we're using an alignment which 72 unsigned blkfactor; /* When we're using an alignment which
@@ -230,17 +231,29 @@ static void finished_one_bio(struct dio *dio)
230 spin_lock_irqsave(&dio->bio_lock, flags); 231 spin_lock_irqsave(&dio->bio_lock, flags);
231 if (dio->bio_count == 1) { 232 if (dio->bio_count == 1) {
232 if (dio->is_async) { 233 if (dio->is_async) {
234 ssize_t transferred;
235 loff_t offset;
236
233 /* 237 /*
234 * Last reference to the dio is going away. 238 * Last reference to the dio is going away.
235 * Drop spinlock and complete the DIO. 239 * Drop spinlock and complete the DIO.
236 */ 240 */
237 spin_unlock_irqrestore(&dio->bio_lock, flags); 241 spin_unlock_irqrestore(&dio->bio_lock, flags);
238 dio_complete(dio, dio->block_in_file << dio->blkbits, 242
239 dio->result); 243 /* Check for short read case */
244 transferred = dio->result;
245 offset = dio->iocb->ki_pos;
246
247 if ((dio->rw == READ) &&
248 ((offset + transferred) > dio->i_size))
249 transferred = dio->i_size - offset;
250
251 dio_complete(dio, offset, transferred);
252
240 /* Complete AIO later if falling back to buffered i/o */ 253 /* Complete AIO later if falling back to buffered i/o */
241 if (dio->result == dio->size || 254 if (dio->result == dio->size ||
242 ((dio->rw == READ) && dio->result)) { 255 ((dio->rw == READ) && dio->result)) {
243 aio_complete(dio->iocb, dio->result, 0); 256 aio_complete(dio->iocb, transferred, 0);
244 kfree(dio); 257 kfree(dio);
245 return; 258 return;
246 } else { 259 } else {
@@ -951,6 +964,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
951 dio->page_errors = 0; 964 dio->page_errors = 0;
952 dio->result = 0; 965 dio->result = 0;
953 dio->iocb = iocb; 966 dio->iocb = iocb;
967 dio->i_size = i_size_read(inode);
954 968
955 /* 969 /*
956 * BIO completion state. 970 * BIO completion state.