The patch titled Subject: fs/direct-io.c: calculate fs_count correctly in get_more_blocks() has been removed from the -mm tree. Its filename was fs-direct-ioc-calcuate-fs_count-correctly-in-get_more_blocks.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ From: Tao Ma <boyu.mt@xxxxxxxxxx> Subject: fs/direct-io.c: calculate fs_count correctly in get_more_blocks() In get_more_blocks(), we use dio_count to calcuate fs_count and do some tricky things to increase fs_count if dio_count isn't aligned. But actually it still has some corner cases that can't be coverd. See the following example: dio_write foo -s 1024 -w 4096 (direct write 4096 bytes at offset 1024). The same goes if the offset isn't aligned to fs_blocksize. In this case, the old calculation counts fs_count to be 1, but actually we will write into 2 different blocks (if fs_blocksize=4096). The old code just works, since it will call get_block twice (and may have to allocate and create extents twice for filesystems like ext4). So we'd better call get_block just once with the proper fs_count. Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx> Cc: "Theodore Ts'o" <tytso@xxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/direct-io.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff -puN fs/direct-io.c~fs-direct-ioc-calcuate-fs_count-correctly-in-get_more_blocks fs/direct-io.c --- a/fs/direct-io.c~fs-direct-ioc-calcuate-fs_count-correctly-in-get_more_blocks +++ a/fs/direct-io.c @@ -580,9 +580,8 @@ static int get_more_blocks(struct dio *d { int ret; sector_t fs_startblk; /* Into file, in filesystem-sized blocks */ + sector_t fs_endblk; /* Into file, in filesystem-sized blocks */ unsigned long fs_count; /* Number of filesystem-sized blocks */ - unsigned long dio_count;/* Number of dio_block-sized blocks */ - unsigned long blkmask; int create; /* @@ -593,11 +592,9 @@ static int get_more_blocks(struct dio *d if (ret == 0) { BUG_ON(sdio->block_in_file >= sdio->final_block_in_request); fs_startblk = sdio->block_in_file >> sdio->blkfactor; - dio_count = sdio->final_block_in_request - sdio->block_in_file; - fs_count = dio_count >> sdio->blkfactor; - blkmask = (1 << sdio->blkfactor) - 1; - if (dio_count & blkmask) - fs_count++; + fs_endblk = (sdio->final_block_in_request - 1) >> + sdio->blkfactor; + fs_count = fs_endblk - fs_startblk + 1; map_bh->b_state = 0; map_bh->b_size = fs_count << dio->inode->i_blkbits; _ Patches currently in -mm which might be from boyu.mt@xxxxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html