Diff v2 vs v1:
1. Do not use reservation window when allocate block for xattr.
2. Remove BUG() in ext2_try_to_allocate_with_rsv().
Ye Bin (4):
ext2: remove ext2_new_block()
ext2: introduce flag argument for ext2_new_blocks()
ext2: fix race between setxattr and write back
ext2: dump current reservation window info
fs/ext2/balloc.c | 32 +++++++++++++++++---------------
fs/ext2/ext2.h | 8 ++++++--
fs/ext2/inode.c | 2 +-
fs/ext2/xattr.c | 4 +++-
4 files changed, 27 insertions(+), 19 deletions(-)
--
2.31.1
This patch introduce introduce flag argument for ext2_new_blocks(), and also
introduce EXT2_ALLOC_NORESERVE flags.
Signed-off-by: Ye Bin <[email protected]>
---
fs/ext2/balloc.c | 3 ++-
fs/ext2/ext2.h | 7 ++++++-
fs/ext2/inode.c | 2 +-
fs/ext2/xattr.c | 2 +-
4 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index c8515fc501ec..99a19f2ecd6f 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -1193,6 +1193,7 @@ int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
* @goal: given target block(filesystem wide)
* @count: target number of blocks to allocate
* @errp: error code
+ * @flag allocate flags
*
* ext2_new_blocks uses a goal block to assist allocation. If the goal is
* free, or there is a free block within 32 blocks of the goal, that block
@@ -1202,7 +1203,7 @@ int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
* This function also updates quota and i_blocks field.
*/
ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
- unsigned long *count, int *errp)
+ unsigned long *count, int *errp, unsigned int flag)
{
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *gdp_bh;
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 954fb82ab22c..36c8ed5dd0a0 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -398,6 +398,11 @@ struct ext2_inode {
#define EXT2_ERRORS_PANIC 3 /* Panic */
#define EXT2_ERRORS_DEFAULT EXT2_ERRORS_CONTINUE
+/*
+ * Behaviour if use reservation window in ext2_new_blocks()
+ */
+#define EXT2_ALLOC_NORESERVE 0x1
+
/*
* Structure of the super block
*/
@@ -696,7 +701,7 @@ static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
extern int ext2_bg_has_super(struct super_block *sb, int group);
extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
- unsigned long *, int *);
+ unsigned long *, int *, unsigned int);
extern int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
unsigned int count);
extern void ext2_free_blocks (struct inode *, unsigned long,
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index acbab27fe957..462b4e873dc7 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -415,7 +415,7 @@ static int ext2_alloc_blocks(struct inode *inode,
while (1) {
count = target;
/* allocating blocks for indirect blocks and direct blocks */
- current_block = ext2_new_blocks(inode,goal,&count,err);
+ current_block = ext2_new_blocks(inode, goal, &count, err, 0);
if (*err)
goto failed_out;
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index e9546cc65db2..e076386a26f4 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -744,7 +744,7 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
EXT2_I(inode)->i_block_group);
unsigned long count = 1;
int block = ext2_new_blocks(inode, goal, &count,
- &error);
+ &error, 0);
if (error)
goto cleanup;
ea_idebug(inode, "creating block %d", block);
--
2.31.1
There's a issue as follows:
Block Allocation Reservation Windows Map (ext2_try_to_allocate_with_rsv):
reservation window 0x000000006f105382 start: 0, end: 0
reservation window 0x000000008fd1a555 start: 1044, end: 1059
Window map complete.
kernel BUG at fs/ext2/balloc.c:1158!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
RIP: 0010:ext2_try_to_allocate_with_rsv.isra.0+0x15c4/0x1800
Call Trace:
<TASK>
ext2_new_blocks+0x935/0x1690
ext2_new_block+0x73/0xa0
ext2_xattr_set2+0x74f/0x1730
ext2_xattr_set+0x12b6/0x2260
ext2_xattr_user_set+0x9c/0x110
__vfs_setxattr+0x139/0x1d0
__vfs_setxattr_noperm+0xfc/0x370
__vfs_setxattr_locked+0x205/0x2c0
vfs_setxattr+0x19d/0x3b0
do_setxattr+0xff/0x220
setxattr+0x123/0x150
path_setxattr+0x193/0x1e0
__x64_sys_setxattr+0xc8/0x170
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Above issue may happens as follows:
setxattr write back
ext2_xattr_set
ext2_xattr_set2
ext2_new_block
ext2_new_blocks
ext2_try_to_allocate_with_rsv
alloc_new_reservation
--> group=0 [0, 1023] rsv [1016, 1023]
do_writepages
mpage_writepages
write_cache_pages
__mpage_writepage
ext2_get_block
ext2_get_blocks
ext2_alloc_branch
ext2_new_blocks
ext2_try_to_allocate_with_rsv
alloc_new_reservation
-->group=1 [1024, 2047] rsv [1044, 1059]
if ((my_rsv->rsv_start > group_last_block) ||
(my_rsv->rsv_end < group_first_block)
rsv_window_dump
BUG();
Now ext2 mkwrite delay allocate new blocks. So there maybe allocate blocks when
do write back. However, there is no concurrent protection between
ext2_xattr_set() and do_writepages().
To solve about issue don't use reservation window when allocate block for xattr.
Signed-off-by: Ye Bin <[email protected]>
---
fs/ext2/balloc.c | 15 +++++++++------
fs/ext2/xattr.c | 4 ++--
2 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 99a19f2ecd6f..4ff1d831bb80 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -1247,13 +1247,16 @@ ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
* it's a regular file, and
* the desired window size is greater than 0 (One could use ioctl
* command EXT2_IOC_SETRSVSZ to set the window size to 0 to turn off
- * reservation on that particular file)
+ * reservation on that particular file), and unspecified Do not use
+ * reservation window.
*/
- block_i = EXT2_I(inode)->i_block_alloc_info;
- if (block_i) {
- windowsz = block_i->rsv_window_node.rsv_goal_size;
- if (windowsz > 0)
- my_rsv = &block_i->rsv_window_node;
+ if (!(flag & EXT2_ALLOC_NORESERVE)) {
+ block_i = EXT2_I(inode)->i_block_alloc_info;
+ if (block_i) {
+ windowsz = block_i->rsv_window_node.rsv_goal_size;
+ if (windowsz > 0)
+ my_rsv = &block_i->rsv_window_node;
+ }
}
if (!ext2_has_free_blocks(sbi)) {
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index e076386a26f4..21725b8d04c8 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -743,8 +743,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
ext2_fsblk_t goal = ext2_group_first_block_no(sb,
EXT2_I(inode)->i_block_group);
unsigned long count = 1;
- int block = ext2_new_blocks(inode, goal, &count,
- &error, 0);
+ int block = ext2_new_blocks(inode, goal, &count, &error,
+ EXT2_ALLOC_NORESERVE);
if (error)
goto cleanup;
ea_idebug(inode, "creating block %d", block);
--
2.31.1