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ntfs: take invalidate_lock in ntfs_setattr_size()

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ntfs_setattr_size() updates i_size and resizes the on-disk attribute
without holding mapping->invalidate_lock.  Page faults take the lock
shared, so a fault racing the resize can resolve a VCN against the
transient runlist state of ntfs_non_resident_attr_expand() and fail
with a spurious SIGBUS, and can interleave with the size-change
epilogue (truncate_pagecache(), i_size_write(),
pagecache_isize_extended()).

Take invalidate_lock exclusively around the whole resize after
inode_dio_wait(), matching the fallocate path and other filesystems
such as xfs, which wraps truncate in its mmaplock (= invalidate_lock).

Fixes: 9c87959601 ("ntfs: update file operations")
Cc: stable@vger.kernel.org
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Reviewed-by: Baolin Liu <liubaolin@kylinos.cn>
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This commit is contained in:
Hongling Zeng 2026-08-31 16:30:14 +08:00 committed by Namjae Jeon
parent 4dc8f4ee2d
commit 9cc5761b8f
1 changed files with 11 additions and 4 deletions
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15
fs/ntfs/file.c
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@ -270,18 +270,25 @@ static int ntfs_setattr_size(struct inode *vi, struct iattr *attr)
return err;
inode_dio_wait(vi);
/*
* Serialize with page faults and pagecache instantiation so that
* readers cannot observe the size change until the attribute
* updates below have completed.
*/
filemap_invalidate_lock(vi->i_mapping);
if (attr->ia_size > old_size) {
truncate_pagecache(vi, old_size);
i_size_write(vi, attr->ia_size);
pagecache_isize_extended(vi, old_size, attr->ia_size);
} else
} else {
truncate_setsize(vi, attr->ia_size);
}
err = ntfs_truncate_vfs(vi, attr->ia_size, old_size);
if (err) {
if (err)
i_size_write(vi, old_size);
return err;
}
filemap_invalidate_unlock(vi->i_mapping);
return err;
}