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Message-ID: <20241023135949.3745142-1-tytso@mit.edu>
Date: Wed, 23 Oct 2024 09:59:49 -0400
From: "Theodore Ts'o" <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: "Darrick J. Wong" <djwong@...nel.org>, "Theodore Ts'o" <tytso@....edu>
Subject: [PATCH] ext4: fix FS_IOC_GETFSMAP handling
The original implementation ext4's FS_IOC_GETFSMAP handling only
worked when the range of queried blocks included at least one free
(unallocated) block range. This is because how the metadata blocks
were emitted was as a side effect of ext4_mballoc_query_range()
calling ext4_getfsmap_datadev_helper(), and that function was only
called when a free block range was identified. As a result, this
caused generic/365 to fail.
Fix this by creating a new function ext4_getfsmap_meta_helper() which
gets called so that blocks before the first free block range in a
block group can get properly reported.
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
fs/ext4/fsmap.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++-
fs/ext4/mballoc.c | 18 ++++++++++++----
fs/ext4/mballoc.h | 1 +
3 files changed, 68 insertions(+), 5 deletions(-)
diff --git a/fs/ext4/fsmap.c b/fs/ext4/fsmap.c
index df853c4d3a8c..383c6edea6dd 100644
--- a/fs/ext4/fsmap.c
+++ b/fs/ext4/fsmap.c
@@ -185,6 +185,56 @@ static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr)
return fmr->fmr_physical + fmr->fmr_length;
}
+static int ext4_getfsmap_meta_helper(struct super_block *sb,
+ ext4_group_t agno, ext4_grpblk_t start,
+ ext4_grpblk_t len, void *priv)
+{
+ struct ext4_getfsmap_info *info = priv;
+ struct ext4_fsmap *p;
+ struct ext4_fsmap *tmp;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ ext4_fsblk_t fsb, fs_start, fs_end;
+ int error;
+
+ fs_start = fsb = (EXT4_C2B(sbi, start) +
+ ext4_group_first_block_no(sb, agno));
+ fs_end = fs_start + EXT4_C2B(sbi, len);
+
+ /* Return relevant extents from the meta_list */
+ list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {
+ if (p->fmr_physical < info->gfi_next_fsblk) {
+ list_del(&p->fmr_list);
+ kfree(p);
+ continue;
+ }
+ if (p->fmr_physical <= fs_start ||
+ p->fmr_physical + p->fmr_length <= fs_end) {
+ /* Emit the retained free extent record if present */
+ if (info->gfi_lastfree.fmr_owner) {
+ error = ext4_getfsmap_helper(sb, info,
+ &info->gfi_lastfree);
+ if (error)
+ return error;
+ info->gfi_lastfree.fmr_owner = 0;
+ }
+ error = ext4_getfsmap_helper(sb, info, p);
+ if (error)
+ return error;
+ fsb = p->fmr_physical + p->fmr_length;
+ if (info->gfi_next_fsblk < fsb)
+ info->gfi_next_fsblk = fsb;
+ list_del(&p->fmr_list);
+ kfree(p);
+ continue;
+ }
+ }
+ if (info->gfi_next_fsblk < fsb)
+ info->gfi_next_fsblk = fsb;
+
+ return 0;
+}
+
+
/* Transform a blockgroup's free record into a fsmap */
static int ext4_getfsmap_datadev_helper(struct super_block *sb,
ext4_group_t agno, ext4_grpblk_t start,
@@ -539,6 +589,7 @@ static int ext4_getfsmap_datadev(struct super_block *sb,
error = ext4_mballoc_query_range(sb, info->gfi_agno,
EXT4_B2C(sbi, info->gfi_low.fmr_physical),
EXT4_B2C(sbi, info->gfi_high.fmr_physical),
+ ext4_getfsmap_meta_helper,
ext4_getfsmap_datadev_helper, info);
if (error)
goto err;
@@ -560,7 +611,8 @@ static int ext4_getfsmap_datadev(struct super_block *sb,
/* Report any gaps at the end of the bg */
info->gfi_last = true;
- error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info);
+ error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster + 1,
+ 0, info);
if (error)
goto err;
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index d73e38323879..92f49d7eb3c0 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -6999,13 +6999,14 @@ int
ext4_mballoc_query_range(
struct super_block *sb,
ext4_group_t group,
- ext4_grpblk_t start,
+ ext4_grpblk_t first,
ext4_grpblk_t end,
+ ext4_mballoc_query_range_fn meta_formatter,
ext4_mballoc_query_range_fn formatter,
void *priv)
{
void *bitmap;
- ext4_grpblk_t next;
+ ext4_grpblk_t start, next;
struct ext4_buddy e4b;
int error;
@@ -7016,10 +7017,19 @@ ext4_mballoc_query_range(
ext4_lock_group(sb, group);
- start = max(e4b.bd_info->bb_first_free, start);
+ start = max(e4b.bd_info->bb_first_free, first);
if (end >= EXT4_CLUSTERS_PER_GROUP(sb))
end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
-
+ if (meta_formatter && start != first) {
+ if (start > end)
+ start = end;
+ ext4_unlock_group(sb, group);
+ error = meta_formatter(sb, group, first, start - first,
+ priv);
+ if (error)
+ goto out_unload;
+ ext4_lock_group(sb, group);
+ }
while (start <= end) {
start = mb_find_next_zero_bit(bitmap, end + 1, start);
if (start > end)
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index d8553f1498d3..f8280de3e882 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -259,6 +259,7 @@ ext4_mballoc_query_range(
ext4_group_t agno,
ext4_grpblk_t start,
ext4_grpblk_t end,
+ ext4_mballoc_query_range_fn meta_formatter,
ext4_mballoc_query_range_fn formatter,
void *priv);
--
2.45.2
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