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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2008-07-11 19:27:31 -0400
committerTheodore Ts'o <tytso@mit.edu>2008-07-11 19:27:31 -0400
commite7dfb2463e3c1b10c38372023e0186d25dec1fa6 (patch)
tree48e05520ccaf7e0c8a2f5bdfc9851069277a6a79
parentf3b35f063e9a795495fe2f7a2fe55fab11f8ab12 (diff)
ext4: Fix mb_find_next_bit not to return larger than max
Some architectures implement ext4_find_next_bit and ext4_find_next_zero_bit in such a way that they return greater than max for some input values. Make sure mb_find_next_bit and mb_find_next_zero_bit return the right values. On 2.6.25 we have include/asm-x86/bitops_32.h static inline unsigned find_first_bit(const unsigned long *addr, unsigned size) { unsigned x = 0; while (x < size) { unsigned long val = *addr++; if (val) return __ffs(val) + x; x += (sizeof(*addr)<<3); } return x; } This can return value greater than size. Reported and fixed here for lustre https://bugzilla.lustre.org/show_bug.cgi?id=15932 https://bugzilla.lustre.org/attachment.cgi?id=17205 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/mballoc.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index c9900aade150..ba3aad27f442 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -381,22 +381,28 @@ static inline void mb_clear_bit_atomic(spinlock_t *lock, int bit, void *addr)
static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
- int fix = 0;
+ int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
- max += fix;
+ tmpmax = max + fix;
start += fix;
- return ext4_find_next_zero_bit(addr, max, start) - fix;
+ ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
+ if (ret > max)
+ return max;
+ return ret;
}
static inline int mb_find_next_bit(void *addr, int max, int start)
{
- int fix = 0;
+ int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
- max += fix;
+ tmpmax = max + fix;
start += fix;
- return ext4_find_next_bit(addr, max, start) - fix;
+ ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
+ if (ret > max)
+ return max;
+ return ret;
}
static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
@@ -3473,8 +3479,6 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
if (bit >= end)
break;
next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
- if (next > end)
- next = end;
start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +
le32_to_cpu(sbi->s_es->s_first_data_block);
mb_debug(" free preallocated %u/%u in group %u\n",