diff options
| author | Jan Kara <jack@suse.cz> | 2019-11-05 17:44:07 +0100 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-11-05 18:13:25 +0100 |
| commit | add3efdd78b8a0478ce423bb9d4df6bd95e8b335 (patch) | |
| tree | 0555cd095901cba4a4a91e86d58eaf459e9f2c51 /include | |
| parent | Linux 5.4-rc3 (diff) | |
| download | linux-add3efdd78b8a0478ce423bb9d4df6bd95e8b335.tar.xz linux-add3efdd78b8a0478ce423bb9d4df6bd95e8b335.zip | |
jbd2: Fix possible overflow in jbd2_log_space_left()
When number of free space in the journal is very low, the arithmetic in
jbd2_log_space_left() could underflow resulting in very high number of
free blocks and thus triggering assertion failure in transaction commit
code complaining there's not enough space in the journal:
J_ASSERT(journal->j_free > 1);
Properly check for the low number of free blocks.
CC: stable@vger.kernel.org
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/jbd2.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 603fbc4e2f70..10e6049c0ba9 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1582,7 +1582,7 @@ static inline int jbd2_space_needed(journal_t *journal) static inline unsigned long jbd2_log_space_left(journal_t *journal) { /* Allow for rounding errors */ - unsigned long free = journal->j_free - 32; + long free = journal->j_free - 32; if (journal->j_committing_transaction) { unsigned long committing = atomic_read(&journal-> @@ -1591,7 +1591,7 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal) /* Transaction + control blocks */ free -= committing + (committing >> JBD2_CONTROL_BLOCKS_SHIFT); } - return free; + return max_t(long, free, 0); } /* |