Commit 4fbd1438 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

[PATCH] Fix Raid5/6 above 2 Terabytes

From: Evan Felix <evan.felix@pnl.gov>

Here is a patch that fixes a major issue in the raid5/6 code.  It seems
that the code:

logical_sector = bi->bi_sector & ~(STRIPE_SECTORS-1);
(sector_t)     = (sector_t)    & (constant)

that the right side of the & does not get extended correctly when the
constant is promoted to the sector_t type.  I have CONFIG_LBD turned on so
sector_t should be 64bits wide.  This fails to properly mask the value of
4294967296 (2TB/512) to 4294967296.  in my case it was coming out 0.  this
cause the loop following this code to read from 0 to 4294967296 blocks so
it could write one character.

As you might imagine this makes a format of a 3.5TB filesystem take a very
long time.
parent dfe2c626
...@@ -1358,9 +1358,8 @@ static int make_request (request_queue_t *q, struct bio * bi) ...@@ -1358,9 +1358,8 @@ static int make_request (request_queue_t *q, struct bio * bi)
disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi)); disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi));
} }
logical_sector = bi->bi_sector & ~(STRIPE_SECTORS-1); logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
last_sector = bi->bi_sector + (bi->bi_size>>9); last_sector = bi->bi_sector + (bi->bi_size>>9);
bi->bi_next = NULL; bi->bi_next = NULL;
bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
if ( bio_data_dir(bi) == WRITE ) if ( bio_data_dir(bi) == WRITE )
......
...@@ -1521,7 +1521,7 @@ static int make_request (request_queue_t *q, struct bio * bi) ...@@ -1521,7 +1521,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi)); disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi));
} }
logical_sector = bi->bi_sector & ~(STRIPE_SECTORS-1); logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
last_sector = bi->bi_sector + (bi->bi_size>>9); last_sector = bi->bi_sector + (bi->bi_size>>9);
bi->bi_next = NULL; bi->bi_next = NULL;
......
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