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| author | Theodore Ts'o <tytso@mit.edu> | 2022-08-09 10:52:57 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2022-08-09 10:52:57 -0400 |
| commit | 7464397a0c5df0416a7ef3436747045b36fb7882 (patch) | |
| tree | 7d81729fea2b00e05c6877936addf6b90054dec2 | |
| parent | b770b0fe7e2564afd95f2008533c6db435e74456 (diff) | |
| download | e2fsprogs-7464397a0c5df0416a7ef3436747045b36fb7882.tar.gz | |
e2fsck: fix potential fencepost error in e2fsck_should_rebuild_extents()
The ext2_extent_info.max_depth is zero-based (e.g., it is zero when
the entire extent tree fits in the inode). Hence, if it is equal to
MAX_EXTENT_DEPTH_COUNT we should always rebuild the extent tree to
shorten it.
Also, for 1k block file systems, it's possible for the worst-case
extent tree in its most compact form to have a maximum depth of 6, not
5. So set MAX_EXTENT_DEPTH_COUNT to 8 just to be sure we have plenty
of headroom. (The kernel supports an extent depth up to 2**16, but
e2fsck only keeps statistics up to MAX_EXTENT_DEPTH_COUNT, and if it's
deeper than that, we know that it will be profitable to rebuild the
extent tree in any case.)
Addresses-Coverity-Bug: 1507761
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | e2fsck/e2fsck.h | 2 | ||||
| -rw-r--r-- | e2fsck/extents.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h index 00b20919a..75baf2cda 100644 --- a/e2fsck/e2fsck.h +++ b/e2fsck/e2fsck.h @@ -233,7 +233,7 @@ typedef struct ea_refcount *ext2_refcount_t; */ typedef struct e2fsck_struct *e2fsck_t; -#define MAX_EXTENT_DEPTH_COUNT 5 +#define MAX_EXTENT_DEPTH_COUNT 8 /* * This strucutre is used to manage the list of extents in a file. Placing diff --git a/e2fsck/extents.c b/e2fsck/extents.c index 86fe00e79..70798f346 100644 --- a/e2fsck/extents.c +++ b/e2fsck/extents.c @@ -583,7 +583,7 @@ errcode_t e2fsck_should_rebuild_extents(e2fsck_t ctx, sizeof(struct ext3_extent); /* If the extent tree is too deep, then rebuild it. */ - if (info->max_depth > MAX_EXTENT_DEPTH_COUNT) { + if (info->max_depth > MAX_EXTENT_DEPTH_COUNT-1) { pctx->blk = info->max_depth; op = PR_1E_CAN_COLLAPSE_EXTENT_TREE; goto rebuild; |