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Message-ID: <d0ec4a04-ab81-7e71-ad56-5b22e1815919@kernel.org>
Date: Sun, 25 Jun 2023 18:27:40 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Cc: stable@...r.kernel.org
Subject: Re: [f2fs-dev] [PATCH] f2fs: remove i_xattr_sem to avoid deadlock and
fix the original issue
On 2023/6/25 15:26, Chao Yu wrote:
> One concern below:
>
> Thread A: Thread B:
> - f2fs_getxattr
> - lookup_all_xattrs
> - read_inline_xattr
> - f2fs_get_node_page(ino)
> - memcpy inline xattr
> - f2fs_put_page
> - f2fs_setxattr
> - __f2fs_setxattr
> - __f2fs_setxattr
> - write_all_xattrs
> - write xnode and inode
> ---> inline xattr may out of update here.
> - read_xattr_block
> - f2fs_get_node_page(xnid)
> - memcpy xnode xattr
> - f2fs_put_page
>
> Do we need to keep xattr_{get,set} being atomical operation?
It seems xfstest starts to complain w/ below message...
[ 3400.856443] F2FS-fs (vdc): inode (2187) has invalid last xattr entry, entry_size: 21468
[ 3400.864042] F2FS-fs (vdc): inode (1595) has invalid last xattr entry, entry_size: 26580
[ 3400.865764] F2FS-fs (vdc): inode (2187) has invalid last xattr entry, entry_size: 21468
[ 3400.880067] F2FS-fs (vdc): inode (9839) has corrupted xattr
[ 3400.880714] F2FS-fs (vdc): inode (10855) has corrupted xattr
Thanks,
>
> Thanks,
>
>>
>> I think we don't need to truncate xattr pages eagerly which introduces lots of
>> data races without big benefits.
>>
>> Cc: <stable@...r.kernel.org>
>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>> ---
>> fs/f2fs/f2fs.h | 1 -
>> fs/f2fs/super.c | 1 -
>> fs/f2fs/xattr.c | 31 ++++++++-----------------------
>> 3 files changed, 8 insertions(+), 25 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 3f5b161dd743..7b9af2d51656 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -838,7 +838,6 @@ struct f2fs_inode_info {
>> /* avoid racing between foreground op and gc */
>> struct f2fs_rwsem i_gc_rwsem[2];
>> - struct f2fs_rwsem i_xattr_sem; /* avoid racing between reading and changing EAs */
>> int i_extra_isize; /* size of extra space located in i_addr */
>> kprojid_t i_projid; /* id for project quota */
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index 1b2c788ed80d..c917fa771f0e 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -1418,7 +1418,6 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
>> INIT_LIST_HEAD(&fi->gdirty_list);
>> init_f2fs_rwsem(&fi->i_gc_rwsem[READ]);
>> init_f2fs_rwsem(&fi->i_gc_rwsem[WRITE]);
>> - init_f2fs_rwsem(&fi->i_xattr_sem);
>> /* Will be used by directory only */
>> fi->i_dir_level = F2FS_SB(sb)->dir_level;
>> diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
>> index 213805d3592c..bdc8a55085a2 100644
>> --- a/fs/f2fs/xattr.c
>> +++ b/fs/f2fs/xattr.c
>> @@ -433,7 +433,7 @@ static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
>> {
>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> size_t inline_size = inline_xattr_size(inode);
>> - struct page *in_page = NULL;
>> + struct page *in_page = ipage;
>> void *xattr_addr;
>> void *inline_addr = NULL;
>> struct page *xpage;
>> @@ -446,29 +446,19 @@ static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
>> /* write to inline xattr */
>> if (inline_size) {
>> - if (ipage) {
>> - inline_addr = inline_xattr_addr(inode, ipage);
>> - } else {
>> + if (!in_page) {
>> in_page = f2fs_get_node_page(sbi, inode->i_ino);
>> if (IS_ERR(in_page)) {
>> f2fs_alloc_nid_failed(sbi, new_nid);
>> return PTR_ERR(in_page);
>> }
>> - inline_addr = inline_xattr_addr(inode, in_page);
>> }
>> + inline_addr = inline_xattr_addr(inode, in_page);
>> - f2fs_wait_on_page_writeback(ipage ? ipage : in_page,
>> - NODE, true, true);
>> - /* no need to use xattr node block */
>> + f2fs_wait_on_page_writeback(in_page, NODE, true, true);
>> if (hsize <= inline_size) {
>> - err = f2fs_truncate_xattr_node(inode);
>> - f2fs_alloc_nid_failed(sbi, new_nid);
>> - if (err) {
>> - f2fs_put_page(in_page, 1);
>> - return err;
>> - }
>> memcpy(inline_addr, txattr_addr, inline_size);
>> - set_page_dirty(ipage ? ipage : in_page);
>> + set_page_dirty(in_page);
>> goto in_page_out;
>> }
>> }
>> @@ -502,12 +492,13 @@ static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
>> memcpy(xattr_addr, txattr_addr + inline_size, VALID_XATTR_BLOCK_SIZE);
>> if (inline_size)
>> - set_page_dirty(ipage ? ipage : in_page);
>> + set_page_dirty(in_page);
>> set_page_dirty(xpage);
>> f2fs_put_page(xpage, 1);
>> in_page_out:
>> - f2fs_put_page(in_page, 1);
>> + if (in_page != ipage)
>> + f2fs_put_page(in_page, 1);
>> return err;
>> }
>> @@ -528,10 +519,8 @@ int f2fs_getxattr(struct inode *inode, int index, const char *name,
>> if (len > F2FS_NAME_LEN)
>> return -ERANGE;
>> - f2fs_down_read(&F2FS_I(inode)->i_xattr_sem);
>> error = lookup_all_xattrs(inode, ipage, index, len, name,
>> &entry, &base_addr, &base_size, &is_inline);
>> - f2fs_up_read(&F2FS_I(inode)->i_xattr_sem);
>> if (error)
>> return error;
>> @@ -565,9 +554,7 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
>> int error;
>> size_t rest = buffer_size;
>> - f2fs_down_read(&F2FS_I(inode)->i_xattr_sem);
>> error = read_all_xattrs(inode, NULL, &base_addr);
>> - f2fs_up_read(&F2FS_I(inode)->i_xattr_sem);
>> if (error)
>> return error;
>> @@ -794,9 +781,7 @@ int f2fs_setxattr(struct inode *inode, int index, const char *name,
>> f2fs_balance_fs(sbi, true);
>> f2fs_lock_op(sbi);
>> - f2fs_down_write(&F2FS_I(inode)->i_xattr_sem);
>> err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
>> - f2fs_up_write(&F2FS_I(inode)->i_xattr_sem);
>> f2fs_unlock_op(sbi);
>> f2fs_update_time(sbi, REQ_TIME);
>
>
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