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| author | Jaegeuk Kim <jaegeuk@kernel.org> | 2014-11-25 21:59:45 +0300 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2014-11-25 23:08:30 +0300 |
| commit | 5f72739583a29bfaa57448ec2c9b122995d0ae4f (patch) | |
| tree | 0c329857102424b596a22ac0a3335257bb226b2a /fs/f2fs | |
| parent | ce3e6d25f3fbaf48a3e1914d5ac0ddfdc1b38349 (diff) | |
| download | linux-5f72739583a29bfaa57448ec2c9b122995d0ae4f.tar.xz | |
f2fs: fix deadlock during inline_data conversion
A deadlock can be occurred:
Thread 1] Thread 2]
- f2fs_write_data_pages - f2fs_write_begin
- lock_page(page #0)
- grab_cache_page(page #X)
- get_node_page(inode_page)
- grab_cache_page(page #0)
: to convert inline_data
- f2fs_write_data_page
- f2fs_write_inline_data
- get_node_page(inode_page)
In this case, trying to lock inode_page and page #0 causes deadlock.
In order to avoid this, this patch adds a rule for this locking policy,
which is that page #0 should be locked followed by inode_page lock.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs')
| -rw-r--r-- | fs/f2fs/data.c | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 12dd58aa569a..c7bc62641103 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -936,6 +936,17 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping, trace_f2fs_write_begin(inode, pos, len, flags); f2fs_balance_fs(sbi); + + /* + * We should check this at this moment to avoid deadlock on inode page + * and #0 page. The locking rule for inline_data conversion should be: + * lock_page(page #0) -> lock_page(inode_page) + */ + if (index != 0) { + err = f2fs_convert_inline_inode(inode); + if (err) + goto fail; + } repeat: page = grab_cache_page_write_begin(mapping, index, flags); if (!page) { @@ -960,21 +971,10 @@ repeat: set_inode_flag(F2FS_I(inode), FI_DATA_EXIST); sync_inode_page(&dn); goto put_next; - } else if (page->index == 0) { - err = f2fs_convert_inline_page(&dn, page); - if (err) - goto put_fail; - } else { - struct page *p = grab_cache_page(inode->i_mapping, 0); - if (!p) { - err = -ENOMEM; - goto put_fail; - } - err = f2fs_convert_inline_page(&dn, p); - f2fs_put_page(p, 1); - if (err) - goto put_fail; } + err = f2fs_convert_inline_page(&dn, page); + if (err) + goto put_fail; } err = f2fs_reserve_block(&dn, index); if (err) |