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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2008-07-12 01:27:31 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2008-07-12 01:27:31 +0200 |
| commit | e7dfb2463e3c1b10c38372023e0186d25dec1fa6 (patch) | |
| tree | 48e05520ccaf7e0c8a2f5bdfc9851069277a6a79 /fs/ext4 | |
| parent | ext4: validate directory entry data before use (diff) | |
| download | linux-e7dfb2463e3c1b10c38372023e0186d25dec1fa6.tar.xz linux-e7dfb2463e3c1b10c38372023e0186d25dec1fa6.zip | |
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>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/mballoc.c | 20 |
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", |