[Devel] [PATCH RHEL8 COMMIT] ms/ext4: protect superblock modifications with a buffer lock
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Aug 13 15:41:25 MSK 2021
The commit is pushed to "branch-rh8-4.18.0-305.3.1.vz8.7.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-305.3.1.vz8.7.6
------>
commit 2cdfba2aef43d21be420d41a7ad14966dc0e27ca
Author: Jan Kara <jack at suse.cz>
Date: Fri Aug 13 15:41:24 2021 +0300
ms/ext4: protect superblock modifications with a buffer lock
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 eb7375e38241..c1f85ea79e1a 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -434,8 +434,11 @@ 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 564784aface9..9f0f7881c308 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5405,7 +5405,10 @@ 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 1ac50f780413..340bb604721a 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2839,7 +2839,10 @@ 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);
@@ -2922,7 +2925,10 @@ 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 6f8a90f4cb77..1f2cd671a430 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -882,7 +882,10 @@ 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);
@@ -1347,6 +1350,7 @@ 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) *
@@ -1384,6 +1388,8 @@ 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,
@@ -1684,8 +1690,11 @@ 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 */
@@ -1841,10 +1850,13 @@ 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 9584642937c3..b2d74281f3bc 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5271,6 +5271,8 @@ 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
@@ -5302,8 +5304,6 @@ 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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