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Commit 455e3a58 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: don't allow any writes on aborted atomic writes 



In order to prevent abusing atomic writes by abnormal users, we've added a
threshold, 20% over memory footprint, which disallows further atomic writes.
Previously, however, SQLite doesn't know the files became normal, so that
it could write stale data and commit on revoked normal database file.

Once f2fs detects such the abnormal behavior, this patch tries to avoid further
writes in write_begin().

Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 797c1cb5

fs/f2fs/data.c

+3 −2
Original line number Diff line number Diff line
@@ -2291,8 +2291,9 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping, 


	trace_f2fs_write_begin(inode, pos, len, flags);



	if (f2fs_is_atomic_file(inode) &&

			!f2fs_available_free_memory(sbi, INMEM_PAGES)) {

	if ((f2fs_is_atomic_file(inode) &&

			!f2fs_available_free_memory(sbi, INMEM_PAGES)) ||

			is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST)) {

		err = -ENOMEM;

		drop_atomic = true;

		goto fail;

fs/f2fs/file.c

+6 −1
Original line number Diff line number Diff line
@@ -1708,8 +1708,11 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) 


	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	if (f2fs_is_atomic_file(inode))

	if (f2fs_is_atomic_file(inode)) {

		if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST))

			ret = -EINVAL;

		goto out;

	}



	ret = f2fs_convert_inline_inode(inode);

	if (ret)
@@ -1871,6 +1874,8 @@ static int f2fs_ioc_abort_volatile_write(struct file *filp) 
		ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 0, true);

	}



	clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);



	inode_unlock(inode);



	mnt_drop_write_file(filp);