Thread A Background GC
- f2fs_setattr isize to 0
- truncate_setsize
- gc_data_segment
- f2fs_get_read_data_page page #0
- set_page_dirty
- set_cold_data
- f2fs_truncate
- f2fs_setattr isize to 4k
- read 4k <--- hit data in cached page #0
Above race condition can cause read out invalid data in a truncated
page, fix it by i_gc_rwsem[WRITE] lock.
Signed-off-by: Chao Yu <yuch...@huawei.com>
---
fs/f2fs/data.c | 4 ++++
fs/f2fs/file.c | 33 +++++++++++++++++++--------------
2 files changed, 23 insertions(+), 14 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 071224ded5f4..a29f3162b887 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2214,10 +2214,14 @@ static void f2fs_write_failed(struct address_space
*mapping, loff_t to)
loff_t i_size = i_size_read(inode);
if (to > i_size) {
+ down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
down_write(&F2FS_I(inode)->i_mmap_sem);
+
truncate_pagecache(inode, i_size);
f2fs_truncate_blocks(inode, i_size, true);
+
up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
}
}
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 7bd2412a8c37..ed5c9b0e0d0c 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -796,22 +796,25 @@ int f2fs_setattr(struct dentry *dentry, struct iattr
*attr)
}
if (attr->ia_valid & ATTR_SIZE) {
- if (attr->ia_size <= i_size_read(inode)) {
- down_write(&F2FS_I(inode)->i_mmap_sem);
- truncate_setsize(inode, attr->ia_size);
+ bool to_smaller = (attr->ia_size <= i_size_read(inode));
+
+ down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(&F2FS_I(inode)->i_mmap_sem);
+
+ truncate_setsize(inode, attr->ia_size);
+
+ if (to_smaller)
err = f2fs_truncate(inode);
- up_write(&F2FS_I(inode)->i_mmap_sem);
- if (err)
- return err;
- } else {
- /*
- * do not trim all blocks after i_size if target size is
- * larger than i_size.
- */
- down_write(&F2FS_I(inode)->i_mmap_sem);
- truncate_setsize(inode, attr->ia_size);
- up_write(&F2FS_I(inode)->i_mmap_sem);
+ /*
+ * do not trim all blocks after i_size if target size is
+ * larger than i_size.
+ */
+ up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ if (err)
+ return err;
+ if (!to_smaller) {
/* should convert inline inode here */
if (!f2fs_may_inline_data(inode)) {
err = f2fs_convert_inline_inode(inode);
@@ -958,6 +961,7 @@ static int punch_hole(struct inode *inode, loff_t offset,
loff_t len)
blk_start = (loff_t)pg_start << PAGE_SHIFT;
blk_end = (loff_t)pg_end << PAGE_SHIFT;
+ down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
down_write(&F2FS_I(inode)->i_mmap_sem);
truncate_inode_pages_range(mapping, blk_start,
blk_end - 1);
@@ -966,6 +970,7 @@ static int punch_hole(struct inode *inode, loff_t offset,
loff_t len)
ret = f2fs_truncate_hole(inode, pg_start, pg_end);
f2fs_unlock_op(sbi);
up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
}
}
--
2.18.0.rc1
------------------------------------------------------------------------------
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