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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: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim 2018-07-27 18:15:11 +09:00
parent 797c1cb56b
commit 455e3a5887
2 changed files with 9 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/f2fs/data.c
View File

@ -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;

7
fs/f2fs/file.c
View File

@ -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);