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| author | Bob Peterson <rpeterso@redhat.com> | 2017-08-30 09:26:09 -0500 |
|---|---|---|
| committer | Bob Peterson <rpeterso@redhat.com> | 2017-08-30 13:29:22 -0500 |
| commit | c4a9d1892f1ce6fe040b717b68bd21e689cc2410 (patch) | |
| tree | 318a7c5a9566218c32e543a28b7e6e3d734f5fcf | |
| parent | d296b15ed58231bd991c0fb0f3592d595539bcd1 (diff) | |
| download | linux-c4a9d1892f1ce6fe040b717b68bd21e689cc2410.tar.bz2 | |
GFS2: Fix non-recursive truncate bug
Before this patch if you truncated a file to a smaller size it
wasn't freeing all the blocks properly. There are two reasons.
First, the metapath comparison was not comparing previous heights.
I added a function, mp_eq_to_hgt, which checks the metapath at
all heights prior to the target height.
Second, in function find_nonnull_ptr, it needed to zero out all
pointers for heights following the target height. Translated into
decimal integer terms, this way a number like 299, when incremented,
becomes 300, not 399. The 2 gets incremented to 3, and the following
digits need to be reset.
These two things allow the truncate state machine to properly find
the blocks it needs to delete.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
| -rw-r--r-- | fs/gfs2/bmap.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index fa3ea29f39cf..3dd0cceefa43 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -1104,8 +1104,15 @@ static bool find_nonnull_ptr(struct gfs2_sbd *sdp, struct metapath *mp, while (true) { ptr = metapointer(h, mp); - if (*ptr) /* if we have a non-null pointer */ + if (*ptr) { /* if we have a non-null pointer */ + /* Now zero the metapath after the current height. */ + h++; + if (h < GFS2_MAX_META_HEIGHT) + memset(&mp->mp_list[h], 0, + (GFS2_MAX_META_HEIGHT - h) * + sizeof(mp->mp_list[0])); return true; + } if (mp->mp_list[h] < ptrs) mp->mp_list[h]++; @@ -1121,6 +1128,13 @@ enum dealloc_states { DEALLOC_DONE = 3, /* process complete */ }; +static bool mp_eq_to_hgt(struct metapath *mp, __u16 *nbof, unsigned int h) +{ + if (memcmp(mp->mp_list, nbof, h * sizeof(mp->mp_list[0]))) + return false; + return true; +} + /** * trunc_dealloc - truncate a file down to a desired size * @ip: inode to truncate @@ -1198,8 +1212,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) /* If we're truncating to a non-zero size and the mp is at the beginning of file for the strip height, we need to preserve the first metadata pointer. */ - preserve1 = (newsize && - (mp.mp_list[mp_h] == nbof[mp_h])); + preserve1 = (newsize && mp_eq_to_hgt(&mp, nbof, mp_h)); bh = mp.mp_bh[mp_h]; gfs2_assert_withdraw(sdp, bh); if (gfs2_assert_withdraw(sdp, |