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| author | Theodore Ts'o <tytso@mit.edu> | 2013-04-23 08:59:35 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-04-23 08:59:35 -0400 |
| commit | 0d606e2c9fccdd4e67febf1e2da500e1bfe9e045 (patch) | |
| tree | 9b908af21c968176149bbbf4016306fa50774055 | |
| parent | 3f8a6411fbada1fa482276591e037f3b1adcf55b (diff) | |
| download | op-kernel-dev-0d606e2c9fccdd4e67febf1e2da500e1bfe9e045.zip op-kernel-dev-0d606e2c9fccdd4e67febf1e2da500e1bfe9e045.tar.gz | |
ext4: fix type-widening bug in inode table readahead code
Due to a missing cast, the high 32-bits of a 64-bit block number used
when calculating the readahead block for inode tables can get lost.
This means we can end up fetching the wrong blocks for readahead for
file systems > 16TB.
Linus found this when experimenting with an enhacement to the sparse
static code checker which checks for missing widening casts before
binary "not" operators.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/inode.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d7518e2..793d44b 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4011,13 +4011,14 @@ make_io: if (EXT4_SB(sb)->s_inode_readahead_blks) { ext4_fsblk_t b, end, table; unsigned num; + __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks; table = ext4_inode_table(sb, gdp); /* s_inode_readahead_blks is always a power of 2 */ - b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1); + b = block & ~((ext4_fsblk_t) ra_blks - 1); if (table > b) b = table; - end = b + EXT4_SB(sb)->s_inode_readahead_blks; + end = b + ra_blks; num = EXT4_INODES_PER_GROUP(sb); if (ext4_has_group_desc_csum(sb)) num -= ext4_itable_unused_count(sb, gdp); |
