[Devel] [PATCH RH8] ext4: protect superblock modifications with a buffer lock
Kirill Tkhai
ktkhai at virtuozzo.com
Wed Jul 28 18:56:37 MSK 2021
From: Jan Kara <jack at suse.cz>
ms commit 05c2c00f3769
Protect all superblock modifications (including checksum computation)
with a superblock buffer lock. That way we are sure computed checksum
matches current superblock contents (a mismatch could cause checksum
failures in nojournal mode or if an unjournalled superblock update races
with a journalled one). Also we avoid modifying superblock contents
while it is being written out (which can cause DIF/DIX failures if we
are running in nojournal mode).
Signed-off-by: Jan Kara <jack at suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-4-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso at mit.edu>
https://jira.sw.ru/browse/PSBM-132364
Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
fs/ext4/ext4_jbd2.c | 1 -
fs/ext4/file.c | 3 +++
fs/ext4/inode.c | 3 +++
fs/ext4/namei.c | 6 ++++++
fs/ext4/resize.c | 12 ++++++++++++
fs/ext4/super.c | 4 ++--
fs/ext4/xattr.c | 3 +++
7 files changed, 29 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index 5c154c23c225..e60c91dd69fa 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -332,7 +332,6 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line,
struct buffer_head *bh = EXT4_SB(sb)->s_sbh;
int err = 0;
- ext4_superblock_csum_set(sb);
if (ext4_handle_valid(handle)) {
err = jbd2_journal_dirty_metadata(handle, bh);
if (err)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index ca7480039fd3..316f41881b2e 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -432,8 +432,11 @@ static int ext4_sample_last_mounted(struct super_block *sb,
err = ext4_journal_get_write_access(handle, sbi->s_sbh);
if (err)
goto out_journal;
+ lock_buffer(sbi->s_sbh);
strlcpy(sbi->s_es->s_last_mounted, cp,
sizeof(sbi->s_es->s_last_mounted));
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(sbi->s_sbh);
ext4_handle_dirty_super(handle, sb);
out_journal:
ext4_journal_stop(handle);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 34893ab118dc..26772856e7da 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5388,7 +5388,10 @@ static int ext4_do_update_inode(handle_t *handle,
err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
if (err)
goto out_brelse;
+ lock_buffer(EXT4_SB(sb)->s_sbh);
ext4_set_feature_large_file(sb);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(EXT4_SB(sb)->s_sbh);
ext4_handle_sync(handle);
err = ext4_handle_dirty_super(handle, sb);
}
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 46391fb93317..48a796150b09 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2829,7 +2829,10 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode)
(le32_to_cpu(sbi->s_es->s_inodes_count))) {
/* Insert this inode at the head of the on-disk orphan list */
NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
+ lock_buffer(sbi->s_sbh);
sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(sbi->s_sbh);
dirty = true;
}
list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
@@ -2912,7 +2915,10 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode)
mutex_unlock(&sbi->s_orphan_lock);
goto out_brelse;
}
+ lock_buffer(sbi->s_sbh);
sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
+ ext4_superblock_csum_set(inode->i_sb);
+ unlock_buffer(sbi->s_sbh);
mutex_unlock(&sbi->s_orphan_lock);
err = ext4_handle_dirty_super(handle, inode->i_sb);
} else {
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 4819b4769aad..8f10b725539d 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -880,7 +880,10 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
rcu_assign_pointer(EXT4_SB(sb)->s_group_desc[gdb_num], gdb_bh);
EXT4_SB(sb)->s_gdb_count++;
+ lock_buffer(EXT4_SB(sb)->s_sbh);
le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(EXT4_SB(sb)->s_sbh);
err = ext4_handle_dirty_super(handle, sb);
if (err)
ext4_std_error(sb, err);
@@ -1345,6 +1348,7 @@ static void ext4_update_super(struct super_block *sb,
reserved_blocks *= blocks_count;
do_div(reserved_blocks, 100);
+ lock_buffer(sbi->s_sbh);
ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
@@ -1382,6 +1386,8 @@ static void ext4_update_super(struct super_block *sb,
* active. */
ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
reserved_blocks);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(sbi->s_sbh);
/* Update the free space counts */
percpu_counter_add(&sbi->s_freeclusters_counter,
@@ -1682,8 +1688,11 @@ static int ext4_group_extend_no_check(struct super_block *sb,
goto errout;
}
+ lock_buffer(EXT4_SB(sb)->s_sbh);
ext4_blocks_count_set(es, o_blocks_count + add);
ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(EXT4_SB(sb)->s_sbh);
ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
o_blocks_count + add);
/* We add the blocks to the bitmap and set the group need init bit */
@@ -1839,10 +1848,13 @@ static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
if (err)
goto errout;
+ lock_buffer(sbi->s_sbh);
ext4_clear_feature_resize_inode(sb);
ext4_set_feature_meta_bg(sb);
sbi->s_es->s_first_meta_bg =
cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(sbi->s_sbh);
err = ext4_handle_dirty_super(handle, sb);
if (err) {
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 50d6f574419b..bd0cb9dcae2c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5202,6 +5202,8 @@ static int ext4_commit_super(struct super_block *sb, int sync)
if (!buffer_mapped(sbh))
return error;
+ if (sync)
+ lock_buffer(sbh);
/*
* If the file system is mounted read-only, don't update the
* superblock write time. This avoids updating the superblock
@@ -5233,8 +5235,6 @@ static int ext4_commit_super(struct super_block *sb, int sync)
&EXT4_SB(sb)->s_freeinodes_counter));
BUFFER_TRACE(sbh, "marking dirty");
ext4_superblock_csum_set(sb);
- if (sync)
- lock_buffer(sbh);
if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {
/*
* Oh, dear. A previous attempt to write the
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 9b29a40738ac..f793576fd548 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -790,7 +790,10 @@ static void ext4_xattr_update_super_block(handle_t *handle,
BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
+ lock_buffer(EXT4_SB(sb)->s_sbh);
ext4_set_feature_xattr(sb);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(EXT4_SB(sb)->s_sbh);
ext4_handle_dirty_super(handle, sb);
}
}
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