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ext4: fix FS_IOC_GETFSMAP handling

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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@mit.edu>
Cc: stable@vger.kernel.org
This commit is contained in:
Theodore Ts'o 2024-10-23 00:25:37 -04:00
parent 40eb3104cf
commit 4a622e4d47
3 changed files with 68 additions and 5 deletions
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54
fs/ext4/fsmap.c
View File

@ -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;

18
fs/ext4/mballoc.c
View File

@ -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)

1
fs/ext4/mballoc.h
View File

@ -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);