fat: Fix the race of read/write the FAT12 entry
commit98283bb49c6c8c070ebde9f47489d3e9a83c1323
authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Mon, 16 Jul 2007 00:40:05 +0000 (16 09:40 +0900)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Mon, 16 Jul 2007 17:31:01 +0000 (16 10:31 -0700)
treef124325ac1768bee61b82e7689bc48ea102efe56
parent347e03df1696ab22963f6b8c4f2220c41ec17f82
fat: Fix the race of read/write the FAT12 entry

FAT12 entry is 12bits, so it needs 2 phase to update the value.  And
writer and reader access it without any lock, so reader can get the
half updated value.

This fixes the long standing race condition by adding a global
spinlock to only FAT12 for avoiding any impact against FAT16/32.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/fat/fatent.c